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Category Archives: Photography 101

photography lessons designed to help those who want to learn to use a camera and/or take better pictures

digital’s frustrating weakness (a.k.a. sensor dust)

You know you have sensor dust when:

annoying little gray spots show up on your digital files.  They are especially troublesome/noticeable when they overlay on skin tones, or in places that make them more tedious to Photoshop:

Sensor dust is nothing new (Google it.) When I bought my first digital SLR in 2005, I also bought a brush from Visible Dust to clean the sensor. Back then, I used it all the time. Last year, when I moved to the D700, I set my menu options to “clean sensor at shutdown.” I’m careful with my gear. I take proper precautions when changing lenses. All of those things combined bought me some time, and I got out of the habit of paying attention to dust.

Even still, sensor dust is inevitable, and when it starts to regularly cost me time spent Photoshopping, I get annoyed, and I want it fixed — quickly. So I dug out my old Visible Dust brush.

If I had read more than I did before I started, I would have learned that sensor cleaning has changed in the last few years. What happened to xrdbear is exactly what happened to me:

And I got very, very scared. So scared, in fact, that I set everything down and walked away for a full day rather than face what I imagined to be a nearly catastrophic error resulting in a very costly repair bill.

The next morning, I went back to reading. I started with bythom, and then moved on to this photo.net thread. I looked at Ken Rockwell, but I quickly clicked away because he was telling me what I already knew, that I shouldn’t be messing with my sensor.

I used a brush cleaning solution to clean my sensor brushes, and then I swept them over the trouble spots (in some cases, several passes, in others, probably a dozen or so) to rid my sensor of the oil streaks.

WHEW! I got my images zeroed back to a no-visible-dust default:

I’ve since returned to Ken Rockwell’s page advising me to never do as I did, probably to avoid the exact dilemma I found myself in (or worse); he cleans his cameras with a vacuum and sends them back to Nikon when they get really bad.

[return to the PHOTO 101 Table of Contents]

August 15, 2010 - 8:45 pm

Paul Metzgar - I HATE sensor dust… It seems like no matter what you do it just won’t stay out of there! I have only tried cleaning my sensor once, on my old D80. The dust had gotten very bad, so after much reading around, I decided to very gently use canned air. I shot a few full blasts off first (away from the camera, to clear out any gunk) then very gently blew off the sensor. It worked great for me, hopefully wont have to try it anytime soon on the D700!

August 15, 2010 - 9:19 pm

christine - I’ve tried canned air, but I’m always worried it’s going to shoot liquid onto my sensor.

A lot of people in forums have recommended Giottos bulbs, around $10 from B&H. I haven’t tried it yet.

http://www.bhphotovideo.com/c/product/423072-REG/Giottos_CL2810.html

August 16, 2010 - 10:41 am

kate gardiner photography - i actually only recently discovered that setting in the menu about it’s self-cleaning mode. which is funny since the mirror lock up option is right above it. i use canned air all the time. i shoot a couple shots of air away from the camera to avoid the liquid problem. so far so good. i do have the advantage that since i don’t do a lot of studio work i normally shoot with wide apertures so the dirt may be there i just don’t see it. :mrgreen:

September 22, 2010 - 1:38 pm

Mike - Love the little girl you are using as a demo for sensor dust. :)
I am going to send a family to you who needs some newborn pics.

Lesson 2.1: Histogram

The instant feedback of digital photography has made the process of learning to take great pictures infinitely easier. Did I get everybody in the frame?  Check the LCD.  Did anybody blink?  Check the LCD.

Is my picture too bright/dark?  This is where checking the back of the camera can get beginners into trouble.

It’s important to understand how to read a histogram. Looking at the LCD screen on the back of the camera might not render an accurate picture (your camera’s LCD screen might be set to maximum brightness, for example, which can give you the impression that your pictures are washed out or overexposed) and the LCD screen is also a very small representation of the big picture (pardon all puns.)

A histogram is a graph that displays brightness values. It’s divided into five equal sections moving from left to right: very dark | dark | 30 percent gray | light | very light. The center of the histogram, 30 percent gray, is the value most camera manufacturers use as the default tone for metering and calculating exposure.

Let’s say the building blocks of a histogram begin with a rectangle drawn on a piece of paper. Only instead of looking at it straight-on, you’re going to view it eye-level to the table so that the graph becomes a vertical axis (and shows nothing at this point.) Then you’re going to use a box of tiny little square tiles from Home Depot. Each individual tile represents one value of brightness in your image. You start placing tiles representing pixels into the graph, stacking them according to lightness or darkness. As you get more than one of the same value, you begin stacking them.  You will find that images have a LOT of one value, less of others, so some of those little tile stacks will rise pretty high, maybe even to the top of your graph, others will be short. After all the tiles are stacked from the image, you’re looking at a histogram (vertical axis graphic representation of light and dark values.)

Generally speaking, the goal in a properly exposed image is to find most of your tiles stacked heavily in the middle and tapering off into very dark (left) or very light (right) edges. (Of course, this rule was made to be broken; first learn the rules, then learn to break them.)

Take for example this image of David and Shelley’s thank-you cards.  I’ll consider this image “properly exposed” because it’s a straightforward exposure using the exact settings my camera’s light meter told me to use (I had it set to use center-weighted metering; more on that later.):

Nikon D700, 135mm lens, f4 @ 1/250 second, ISO 200

Nikon D700, 135mm lens, f4 @ 1/250 second, ISO 200

Here’s how all of the individual tiles stack up to represent this image in my histogram:

Notice that there’s a good representation of tiles stacked across the histogram, heaviest in the center and stretching out to either side? This particular image is slightly heavier toward the right as there are a lot of lighter tones in it. (I also blew out the front of the cream colored table the cards were resting on. I did this intentionally, I was metering for the cards, my main subject, not so much the table or wall behind them.)

Here’s an example of this same scene, image intentionally underexposed:

Nikon D700, 135mm lens, f4 @ 1/3200 second, ISO 200

Nikon D700, 135mm lens, f4 @ 1/3200 second, ISO 200

Look at the histogram now and how all my little tiles are stacked heavily to the left; there’s no mistaking that no matter how the image appears on my LCD, it’s in fact very dark; also look at the cream table, which is closer to properly exposed then it was above (the !!! warning sign is still there, just disregard it for now. If you are working in Photoshop and come across it, it’s warning you that the histogram you’re seeing is cached from memory and you’ve since made adjustments to the image that might change its appearance. Just click it and Photoshop will generate a new histogram and the warning will go away.):

histogram of underexposed image

And the same scene intentionally overexposed:

Nikon D700, 135mm lens, f4 @ 1/30 second, ISO 200

Nikon D700, 135mm lens, f4 @ 1/30 second, ISO 200

And its resulting histogram:

overexposed histogram

overexposed histogram

Something interesting that I didn’t intend to find when shooting this example: I avoided most of these exposure issues in post processing by shooting in RAW. As I imported the underexposed and overexposed images into Lightroom, they appeared pretty similar to the correctly exposed image. I had to go back and manually un-do all of my regular workflow develop settings to get them to look like they did on my LCD as I was shooting.:)

[return to the PHOTO 101 Table of Contents]

Katz Eye™ split prism focusing screen

J&A2009-2

Katz Eye is one of the leading brands of replacement focussing screen for digital single lens reflex cameras (dSLR). Today’s dSLRs ship with a stock focus screen that is optimized for auto-focus; Katz Eye lets camera owners replace this stock screen with one more suitable for manual focus. This is very helpful for photographers who are looking to move to manual focus Zeiss lenses, or photographers who work in low-light situations where their dSLR has a hard time keeping up on auto-focus.

The Katz Eye website is geared toward photographers who already know why they want one; the company is starting to realize, however, that there are a lot of photographers out there who don’t know about this split-prism focusing option, and they have plans to update their website with more information in the future.

I was nervous about installing the product myself, so before I ordered, I sent an email to customer service. I got a very detailed response almost immediately:

“The installation process isn’t too bad if you have a steady hand, good light, reasonable (or corrected) vision, and the patience to absorb all the available information in the installation guide,” emailed Rachael Katz.  “It’s a bit tricky, as the screen is easily scratched and the handling tab is quite small (about 1.5mm x 3mm), and keeping things clean during the process is always a concern.”

Rachael said many of her customers also choose to send the camera to Katz Eye or a local installer for professional assistance, and that ultimately, only I could know what is best for my unique situation. “Hopefully you will find your questions answered, but if not, please let me know and I will do my best to clarify for you,” she said. Totally comfortable that these people stand behind their product and are available to help customers, I placed my order.

Not to be outdone by the Katz Eye users on Flickr who complete the process themselves without difficulty, I set aside a quiet morning and mustered the nerve to operate on my camera. The only change I made from the installation instructions was to use a pair of flat-nose pliers with smooth jaws rather than tweezers to grip the tiny tab — but then again, if I hadn’t been drinking a grande Americano, maybe the tweezers would have worked just fine.

The whole operation took about 5 minutes start to finish; my first test shot with my new split prism screen, focus aimed at the star over the Starbucks siren’s head:

Nikon D700, Zeiss 35mm lens, f2 @ 1/400 second, ISO 400

Nikon D700, Zeiss 35mm lens, f2 @ 1/400 second, ISO 400

Since I’m first and foremost a portrait photographer, I should practice on people. And speaking of those I practice on most, they need to be picked up from school right about now, so I’m off.

Bottom line: I’d absolutely recommend this company and product. Here’s a link to another user who gave it [an artful] whirl.

UPDATE: Kate, here’s a very low-tech look through the viewfinder via my iPhone (onOne software app works, but it doesn’t capture the viewfinder details.) The split prism is a tiny circle in the center of the viewfinder between the “S” and “T” rendered in both focus and texture. If my iPhone phone quality were better, you could see the texture.

very low-tech look through the viewfinder via iPhone

very low-tech look through the viewfinder via iPhone

September 4, 2009 - 2:56 pm

kate gardiner photography - hmm… looks pretty good. wish i could see what it looks like through the viewfinder. was tough to translate the photos on that link.

September 4, 2009 - 6:02 pm

christine - just added the very low-tech photo to give you a rough idea; anybody out there know how to capture a Nikon viewfinder??? I think all of the ones I’ve seen online were shot with Canon, I’m not sure Nikon lets us?

September 4, 2009 - 10:26 pm

kate gardiner photography - that is sooooo bitchin! nice low tech solution. impressed the iphone cam pulled it off. thanks for giving a bird’s eye view!

August 26, 2010 - 11:11 am

jsvfoto - :smile:
Christine,
How do you find the non-prism area of the screen? Is it as bright as the original stock screen or is there a noticeable difference in brightness between the two. I look forward to your reply.

Sincerely,
jsv

August 26, 2010 - 11:54 am

christine - hi JSV! that’s a great question. I didn’t see any noticeable difference in brightness when I swapped my original stock screen for the Katz Eye. I’ve been so happy with it. if I wanted to, I could always put the stock screen back into my camera body, but I don’t know why I would. I’ve gotten quite attached to it.

this week, I’ve been using a Zeiss 18mm that I rented from from lensrentals.com (another company I’ve been very happy with) and using my Katz Eye with every frame.

SOOC Nikon 28-70mm AF vs. Zeiss 35mm manual focus lens

crop-0093-3

Wasn’t it brilliant of Christopher to show up in his favorite T-shirt? Total surprise, he had no idea I went to college at Oregon. I seized the opportunity to use the bright colors of a fun shirt to do a side-by-side comparison.

The test shots surprised me.

Nikon D700, 35mm Zeiss lens, f4 @ 1/250, ISO 200

Nikon D700, 35mm Zeiss lens, f4 @ 1/250, ISO 200

 

Nikon D700, 28-70mm lens at 35mm, f4 @ 1/250, ISO 200

Nikon D700, 28-70mm lens at 35mm, f4 @ 1/250, ISO 200

Both images straight-out-of-the-camera (SOOC), no color correction or sharpening or enhancements. (The first image of Christopher holding up his running shoes was color corrected and run through my general filters.) Both acceptable, workable images, pulled back. The surprise? I totally expected the Zeiss prime to yield sharper results than the Nikon zoom, but a close-up crop of the eyes (where I was aiming my focus) clearly points to Nikon.

side-by-side

It’s harder to see side-by-side when the images get smaller on screen, so look again at Christopher’s eyebrows, the reflection of me in his sunglasses, and the line where his sunglasses meets the bright studio strobe, first in the Zeiss (where you can see my left hand turning the focus ring) and then in the Nikon (where my left hand is mostly needed to support the behemoth 28-70mm):

Zeiss 35mm

Zeiss 35mm

 

Nikon 28-70mm at 35mm

Nikon 28-70mm at 35mm

Aside from the chromatic aberrations, which Zeiss wins hands-down, I’m pretty sure hopeful? pointing out the possibility that what we’re seeing is operator error. For the last four years, the auto-focus Nikon has been my go-to lens, especially since I work so much with small children. When I picked up the Nikon to test on Christopher, I shot it using auto-focus. Perhaps I should have switched it over to manual focus for a more fair comparison; but then, I still think there’s something to say about results getting skewed based on the total number of hours I’ve spent working with each lens.

And there’s one more point that bothers me: 20+ years ago when I was shooting with manual focus lenses on film SLRs, the camera body had a split focusing screen. Remember those? My D700 has only a plain screen. I’m interested in a 35mm f/2 manual focus Zeiss precisely for those times when a D700 starts tripping all over itself to autofocus in low light.

Hmmm. A split focusing screen test might be next up in this summer Zeiss experiment.

P.S. I didn’t have the heart to tell him that sunglasses are counterproductive in Eugene!:)

August 27, 2009 - 10:28 am

kate gardiner photography - I definitely think you should give the experiment another go. It looks like your focal points were actually in two different places. Look at the “o” on the temple piece of the glasses. On the Zeiss that was your main point of focus while on the nikon it was slightly behind that on his eyebrow.

August 28, 2009 - 4:43 am

Ray - I like you there in those counterproductive sunglasses. You’re the God of the machine.

August 28, 2009 - 9:59 am

christine - it’s definitely operator error, Kate; I was aiming to focus on his eyes with the Zeiss, but I missed. I’m leaning toward getting a split-screen, thinking that would help equal the playing field for another experiment. but what are the chances I might find another young man who happens to whip out a Pac-10 shirt from one of my three schools??? :)

Ray, if I were a reader who didn’t know any better, I might wonder if you aren’t smitten with me, you of all people placing me in a category like that. :)

Lesson 6: ISO

We’ve learned that aperture controls the amount of light coming in through the lens, shutter speed controls the amount of time in which light is allowed to reach the sensor. ISO lets you control how sensitive your sensor is in reacting to that light.

50   100   200   400  800   1600   3200  6400

50 100 200 400 800 1600 3200 6400

Just like the aperture and shutter speed scales, ISO moves from left to right, 32 being the lowest and 3200 being quite high, each stop along the way doubling or halving (depending on which direction you’re going) the amount of light sensitivity the sensor needs to properly record an image.

ISO is always the first setting I choose when trying to determine exposure. When I pick up my camera, I verify the ISO setting and, if necessary, change it. I do this first, religiously and without fail.

Q: First, religiously and without fail? Why?

A: Okay, okay. Since you asked, I’ll tell you. But it’s a painful story and not one of my brightest moments.

Once, many years ago while I was still shooting film, I took my camera to an LSU game at Tiger Stadium. I shot the entire night game on ISO 3200.

LSU won and life was good.

And then I returned to my newborn photo business (officially about a month old) and shot a maternity session (Monica had the baby the very next day), a family Christmas card (Miette’s husband left the very next day for a four-month deployment) another family for Christmas cards (Jenny has three young boys and a husband — a family dynamic that tends to scream “We’re only here because Mommy is making us, hurry up and get this over with!”) And then my parents flew out from Oregon for a visit and I was very excited to get a portrait of the two of them. I can still see that image of them, standing together backlit in evening light, cooperating with my instructions with the courtesy amused parents afford children learning.

Fast forward one week. 12 rolls of film return from the lab with not one — NOT ONE — usable image among them. I shot four sessions with my shutter speed and aperture set as if I were shooting on ISO 100, when in fact my ISO was still dialed to 3200 from the game.

…Wherever you go, you will top all the rest.

Except when you don’t.
Because, sometimes, you won’t.

I’m sorry to say so
but, sadly, it’s true
that Bang-ups
and Hang-ups
can happen to you.

You can get all hung up
in a prickle-ly perch.
And your gang will fly on.
you’ll be left in a Lurch.

You’ll come down from the Lurch
with an unpleasant bump.
And the chances are, then,
that you’ll be in a Slump.

And when you’re in a Slump,
you’re not in for much fun.
Un-slumping yourself
is not easily done.

— Dr. Seuss, Oh, the Places You’ll Go!

Not easily done no kidding. Especially after the kind of complete and utter failure that produces honest quitters, made infinitely more painful by such an elementary mistake and the involvement of people I genuinely care about. I spent that day making the most humbling and difficult phone calls of my photographic career, three of the four sessions impossible to re-shoot.

I will never forget Jenny’s response to me I sat in the pit of my Slump and waited for her anguish to crush what little spirit I had left:

“Christine, if that’s the worst thing to happen to me today, then I’m in pretty good shape!”

And while she went on to talk of other things, I sat thinking of the very powerful and generous lesson in forgiveness she had just given me, a gift I’ve never forgotten.

Along with some other lessons I won’t soon forget, not the least of which: Check, double check and triple check your settings before you start shooting. Now that the world has pretty much gone digital, this step is infinitely more reassuring. Even after checking my settings, I always take a test shot to verify my camera is seeing the settings I envision it to see. And then I can put the technical details aside and just shoot.

For me, ISO is the easiest place to begin; then I choose my aperture (because I tend to shoot wide open or in the critical aperture range) and then I choose whatever shutter speed I need to make all of that happen. (And then I double check image quality, white balance, metering and exposure compensation, because I consider it painful to spend time correcting in Lightroom or Photoshop what it takes .02 seconds to fix in-camera. But that’s a post title all its own!)

Here is my very simple formula for choosing ISO: choose the lesser of all evils. Back in the film days, I could buy film with ISO 32. Today, the digital SLR I’m shooting has a lowest ISO setting of 200. So I always start out hopeful that ISO 200 will do the job and I bump that up only as and if necessary because I still need more light after my aperture settings are in place and I can’t make any more adjustments to shutter speed (for reasons we’ve already learned, such as the relationship between focal length and shutter speed or showing the intended effects of freezing/blurring action, etc.)

If, after I’ve set my aperture and shutter speed, I find I still don’t have enough light, then I have to stop and think about the photo. Is it a portrait that the client might want a 20-inch-by-30-inch printed for over the mantle? If so, then I’m probably going to whip out my strobes and dial them to produce enough light to keep me at ISO 200 which in turn will keep me in business.:)

But generally speaking for the rest of the time, if there is no client involved and I still don’t have enough light, then I simply bump up my ISO and have fun shooting rather than drag out more gear and spend more time fiddling with photography (which tends to frustrate my family very quickly these days).

Q: Why wouldn’t you just use ISO 3200 all the time?

A: You could.

I don’t, because the image quality isn’t creamy and crisp; but sometimes, if the difference is ISO 3200 or no picture at all, I’ll dial 3200 and keep shooting. Which is what I did on this evening when MeDannyP came to visit (original post here):

Nikon D300, 18-200mm f/3.5-5.6 lens at 18mm, f3.5 @ 1/125 second, ISO 800

Nikon D300, 18-200mm f/3.5-5.6 lens at 18mm, f3.5 @ 1/125 second, ISO 800

Nikon D300, 18-200mm f/3.5-5.6 lens at 18mm, f3.5 @ 1/15 second, ISO 3200

Nikon D300, 18-200mm f/3.5-5.6 lens at 18mm, f3.5 @ 1/15 second, ISO 3200

Granted, grown men at the end of the evening under harsh sodium vapor lights are going to photograph grittier than young children under properly balanced studio strobes firing from behind a large softbox, but compare anyhow the ISO 800 and ISO 3200 above with this next photo, taken with the same camera body set at ISO 200 (original post here):

Nikon D300, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/125 second, ISO 200, strobes

Nikon D300, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/125 second, ISO 200, strobes

Homeschool Moms who bring me their children don’t want sodium vapor 5-o’clock shadows in a quick snapshot to tack up on the fridge; they want creamy enlargements fit for frames. They want ISO 200.

Technology is moving ever closer to the photographer’s side, first with digital and now, more recently, by making great strides in digital ISO. Nikon and Canon (and perhaps others, but Nikon and Canon are the two companies I’m familiar with) are producing camera bodies that yield extremely usable images on high ISO settings. Next time MeDannyP is in town visiting, I’ll reshoot inside Union Station with the D700 at ISO 3200 and post the two images side by side; but I can already tell you the visible result is that with the D700, Nikon took shooting at higher ISOs two steps forward. If you’re looking to buy a camera, compare images shot at high ISOs to take advantage of the newest technology you can afford to get your hands on. The higher usable ISO, the more light you have to work with (the key word being “usable.”)

Exposure = ISO + Aperture + Shutter Speed

Q: If the answer to the equation begins with ISO, and even you admit it’s the first setting you choose, why did you teach me aperture and shutter speed first?

A: Because ISO is so easy. It’s either smooth and creamy at one extreme or harsh and gritty on the other, and everything else in the middle.

Nuances of shutter speed and aperture are more difficult to wrap your brain around, so I figured let’s get those out of the way. Congratulations! Not only have you already made it through the hardest part, you’ve just finished exposure!

[return to the PHOTO 101 Table of Contents]

July 9, 2009 - 6:10 pm

kate gardiner - i shot a wedding not so long ago where i forgot to change my iso after shooting in a very dark church. the outdoor portraits were VERY grainy and ick. So i ran a few photoshop noise plugins, made them b/w and called it “arty grain”. :O) still kick myself over that.

July 15, 2009 - 10:50 am

Susan Richey - Christine – WoW! Thank you so much for taking the time to share your knowledge. Your work is amazing and your willingness to help others is commendable. I will be sure to come back to your blog often!

July 20, 2009 - 1:13 pm

Katie Artz - Hi You! I just wanted to tell you how amazing your website is! I wish I would have had your lessons earlier! I thought I had it down to memory but reading thru your blog I definately learned more! You explain everything simply and perfectly! I am still working on my photography, taking a class on lighting right now and needed some inspiration, so naturally I looked at your website. Hope all is well with you and your family!

Lesson 5: using shutter speed

Exposure = ISO + Aperture + Shutter Speed.

We’ve learned that aperture controls the amount of light coming in through the lens. Shutter speed controls the amount of time in which light is allowed to reach the sensor. (Coming tomorrow: ISO lets you control how sensitive your sensor is in reacting to that light.)

We’ve also learned that shutter speeds should generally be equal to or faster than the focal length of your lens if you are handholding your camera. So keeping that in mind, take a look at your lens, make note of your focal length, and then look at this shutter speed chart, paying particular attention to the sweet spot setting that corresponds with your focal length.

shutterspeed

Whereas aperture is determined by the lens, shutter speed (and ISO) is determined by the camera body. Shutter speed is literally the speed in which your camera body’s shutter opens and closes during exposure.

Shutter speeds are measured in fractions of seconds. 1/2 is one-half second, which is pretty fast in general terms but actually pretty slow for a shutter speed. 1/8000 of a second is pretty fast in general terms and in photography.

Shutter speeds are important when you’re trying to show action, either by using blur to show movement or by freezing action.

For example, look at the difference I made in these two photographs of my son simply by paying attention to my shutter speed (and then adjusting my aperture accordingly until my meter said I had enough light):

Nikon D700, 28-70mm lens at 28mm, f2.8 @ 1/1000 second, ISO 200

Nikon D700, 28-70mm lens at 28mm, f2.8 @ 1/1000 second, ISO 200

Nikon D700, 28-70mm lens at 28mm, f16 @ 1/15 second, ISO 200

Nikon D700, 28-70mm lens at 28mm, f16 @ 1/15 second, ISO 200

In the top photo, I froze the action with a 1/1000 of a second shutter speed; it sort of looks like we were just sitting around on some playground equipment because the shutter was much faster than the action. Technically, it’s correct — any camera on program (or auto) mode could have taken this shot.

But a camera on program mode doesn’t always capture the truth or the flavor of an image. That’s the photographer’s job. In this case, changing the shutter speed to 1/15 of a second made the image unmistakably, dizzyingly merry-go-round.

Then for sport I shot two frames at the exact same settings, simply to illustrate the relationship between shutter speed and action. If there’s action you wish to freeze, a fast shutter speed is a requirement. But if there’s no action, the fast shutter speed is hardly noticeable.

Nikon D700, 28-70mm lens at 56mm, f2.8 @ 1/2000 second, ISO 200

Nikon D700, 28-70mm lens at 56mm, f2.8 @ 1/2000 second, ISO 200

 

Nikon D700, 28-70mm lens at 56mm, f2.8 @ 1/2000 second, ISO 200

Nikon D700, 28-70mm lens at 56mm, f2.8 @ 1/2000 second, ISO 200

In the first image, it’s the frozen action that the image is all about. A fast shutter speed is required for this. The second image, shot with the exact same settings as the first, is all about depth of field, and depth of field is controlled by…

Bueller? Bueller? Anyone? Anyone?

Aperture!

[return to the PHOTO 101 Table of Contents]

July 8, 2009 - 6:19 pm

Lindy - I love the second photo- you can really feel the motion (I”m getting dizzy just looking at it! :o

Lesson 4: exposure review

This image, my friends, is an example of first learn the rules, then learn to break them.:)

Nikon D700, 28-70mm f/2.8 lens at 62mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 62mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Relax. Today is a fun day, lesson is a review, assignment is relevant to a festive American holiday.

Going back to last lesson’s extra credit question: Originally, our goal wasn’t to change the exposure ratio by lightening or darkening the image; the goal was to change the aperture in order to change the amount of detail in the background behind our subject so that I could show you examples of why you might choose to shoot wide open and why you might choose to shoot stopped down. In other words, exercise some control over the image we’re shooting to render us photographers rather than people holding glorified point-and-shoots. Remember when I talked in aperture about learning the whole stops so that you can effortlessly jump from stop to stop in your head? That’s what I was challenging you to do with this question. The problem I ran into, that you can see clearly in the close-up crop of each image, is that I used a shutter speed that was too slow for a handheld shot; it caused the image to blur. And for our purposes, correct exposure is not too bright, not too dark, in focus and generally, technically correct. Image blur due to camera shake is operator error.

Notice I called it extra credit and not an assignment — that’s because you’re going to have to jump into ISO and/or shutter speed, and we haven’t fully covered those yet! (Never hurts to get your mind thinking in the direction you want to go, though.)

So back to the question: if we increase our shutter speed, the inherent effect is that we’ve decreased the amount of light coming in by one-half. The way to make up for that loss of light, keeping all things equal, is to increase the amount of light by one stop with ISO or aperture. So if we’re at f/16 and 1/30 and ISO 400, and we want to move our shutter speed to a minimum of 1/60 because our focal length is roughly a normal lens (remember, 50mm lens needs 1/50 shutter speed or faster), we have two options: open our aperture (or lens opening, think circles) one stop or bump up our ISO one stop higher; both would let in twice the amount of light to compensate for the shutter speed’s loss.

In this example, f/16 at 1/30 ISO 400 is the same as f/11 at 1/60 ISO 400 is the same as f/16 at 1/60 ISO 800.

Q: Whoa! I have no idea what you just said. Come again?

A: That’s okay. Hardly anybody gets that the first time.

What I need for you to walk away with from this post is the crux of another huge point that has nothing to do with fractions: there is no one single exposure possibility to make a particular image. Think about that. I’m going to say it again, differently, to hammer my point home: there are lots of different exposure combinations possible for every single image you take. Aperture showed you two extremes of possibility, shooting wide open and shooting stopped down; shutter speed (tomorrow? Depends on how fun tonight is, I suppose.) will show you two more extremes of possibility, freezing and blurring motion.

If I handed a beginner my camera in manual mode and asked the beginner to pick the settings to shoot a portrait of me, a beginner would search his or her brain for the “correct” exposure. That kind of thinking gets beginners into trouble. If you’ve been a beginner for a long time, you need to do an about-face; turn yourself around and slowly start backing out of the dark, optionless void of glorified Xerox machine photography. There is no “correct” exposure. There’s only the exposure the photographer chooses to make the image he or she wants.

Remember this:

Q: What kind of camera should I buy?

A: What kind of pictures are you looking to take?

I understand where it comes from: we’ve all taken photos that were technically incorrect. Perhaps we missed an important shot that can never be re-created — a baby’s first steps or a graduate accepting a degree, and that makes us fear photographic mistakes. We have a natural desire to learn how NOT to mess up a photo like that again.

Technology is improving and we want to buy a camera that will save us from ourselves, take the picture without making mistakes. See “there is no magic pill…” in the introduction to this crash course. You can’t buy the camera that will take the pictures you want. You have to learn how to take those pictures with your camera.

Q: You’re wrong! I CAN buy a camera that will take pictures on program mode better than I can take them in manual! Technology IS there! I know for a fact, because my brother has one and he does it all the time! His pictures of my nephew are WAY better than my pictures of my son. I just want what he has, so I thought I’d ask you, too, and get a second opinion.

A: Think about the question you originally asked me, the one I replied to with a link that landed you here. The questions I get are, “The moms using 28mm lenses at gymnastics meets are getting better pictures than I am with my 200 mm zoom — and my lens was more expensive and gets me way closer to my daughter than theirs does. WHY???”

See “camera shake/blur” in aperture.

Any of us can buy package of ballpoint pens at Target; it’s what we write with those pens that is uniquely ours.

It’s easy to cry “but technology!” now because crying “egads! I get it! I learned photography!” requires a lot of work. (A LOT. And a lot of knowledge. Education. And a hefty investment in gear. So the answer is no, I won’t shoot your sister’s wedding for 500 bucks! But I digress.) It’s easier to buy the camera and hope for the best than to keep reading and learn — finally, truly learn — how to use your camera.

For those of you who want better pictures, for those of you who want to make a smart purchase, for those of you who asked me why, keep reading.

Erase from your brain this notion of making a “correct” exposure. Correct exposure. Remember, we agreed for the sake of argument that you’re looking to create images that are first and foremost in-focus and not too bright (overexposed) or too dark (underexposed.) That’s why we made this agreement. Creativity will come later. Creativity comes once you’ve learned the rules. Sometimes creativity comes as a fluke, a mistake that actually looked pretty cool.

First learn the rules; then learn to break them.

Today is just review. Look over the exposure flowchart and get your brain thinking like a photographer. What kind of picture are you trying to take? Are you trying to show action? Freeze action? Isolate your subject from the background for a portrait? Look over the ways to make that happen. The more you see it, the sooner it will become second nature.

And then go enjoy the celebration — Happy birthday, America!!!

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 56mm, f4 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

 

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.5 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.5 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

 

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

 

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

 

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

 

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

Nikon D700, 28-70mm f/2.8 lens at 70mm, f5.6 @ 1/2 second, ISO 200, off-camera flash at 1/16 power + sparkler

[return to the PHOTO 101 Table of Contents]

July 4, 2009 - 10:04 pm

Jim - Trying to soak all of this up! Happy 4th!

July 4, 2009 - 10:27 pm

alexis - mommy, it’s blurry.

July 5, 2009 - 5:59 pm

christine - Sweetie, I know! it’s supposed to be blurry! :)

Lesson 3: aperture

Exposure = ISO + Aperture + Shutter Speed. Learn it, know it, live it.

Let me start by saying I don’t buy the top of the line camera body Nikon makes, especially since I’ve gone digital. Digital camera bodies are like computers; in a couple of years, newer, better technology will render today’s bodies almost useless. (Almost. But that’s a discussion for another day.) Lenses, on the other hand, hold their use and value. Lenses contribute more toward making a great photo than a camera body does.

I’d rather have a $1500 lens on a $500 body than a $5000 body with a $500 lens (well; ideally, I’d have a $1500 lens on a $5000 body.)

One of the most important considerations in buying and/or using a lens is aperture.

This is how I think of aperture: imagine a sheet of glass between you and your subject. That sheet of glass represents aperture when shooting wide open. There’s only that tiny stretch of depth across your frame that will be in sharp focus. This is known as shallow depth of field. I did my best to photograph an example of shallow depth of field using critical aperture (keep reading) where you can literally see the plane of focus:

Nikon D700, 70-200mm f/2.8 lens at 200mm, f5.6 (critical aperture) @ 1/1600 second, ISO 400

Nikon D700, 70-200mm f/2.8 lens at 200mm, f5.6 (critical aperture) @ 1/1600 second, ISO 400

Aperture, by definition, is the variable opening by which light enters a camera through a lens. Aperture is the lens opening or f/stop in a photographic equation. Aperture is the amount of light made available to the sensor to record an image.

So let’s review focal length just for a moment and return to the numbers printed on a lens: for example, my Nikon 105mm 1:2.8 lens. We know that the 105mm means focal length, but what does the ratio-looking 1:2.8 mean?

This number designates the widest aperture available for that lens and it’s written as a ratio because aperture is in fact a fraction (stay with me.) For example, my 105mm 1:2.8 lens can be shot wide open at f/2.8. Some zoom lenses will have numbers that look like this: 1:4-5.6 This number means that f/4 is the largest aperture available at the widest (wide angle) end but only f/5.6 at the longest (telephoto) end (say, for example, it’s a 70-200mm zoom, f/4 at 70mm and f/5.6 at 200mm is the widest aperture available for that lens.) My 70-200mm telephoto zoom lens has a 1:2.8 ratio; I can shoot wide open at f/2.8 no matter what focal length I’m at with this lens.  That’s a more in-depth explanation as to why, in an earlier lesson, I explained I can keep shooting wide or nearly wide-open with that lens as a toddler runs toward me without having to change my exposure settings.

This number is the crux of the issue of lens choice. All of my lenses are f/2.8 or f/1.2 — all of them. Lenses slower than f/2.8 are deal-breakers for me. It’s just the way I shoot. Perhaps you shoot differently; say you shoot landscapes at mostly f/22 and don’t have much use for a lens wide open. Perhaps you never shoot pictures indoors, so a lens that can perform in low-light situations isn’t of much use to you. That’s exactly my point, why I’m going to all of this effort to show you how to use your camera; it’s why I can’t tell you one way or another what camera-lens combo would be the best gear for you to buy. Remember Rilke?

Look at this aperture scale to help you visualize aperture as the amount of light splashing in through your lens toward your sensor:

f/1.2  f/2.8  f/4  f/5.6  f/8  f/11  f/16  f/22  f/32

f/1.2 f/2.8 f/4 f/5.6 f/8 f/11 f/16 f/22 f/32

Each stop on the aperture scale = one full stop of light.

Take our exposure equation that we learned last post:

Exposure = ISO (sensitivity to light) + Aperture (amount of light made available to record an image) + Shutter Speed (the length of time the light is made available to record an image)

How sensitive you’re making your camera to light + how much light you’re letting in and for how long. That’s it! That’s your exposure equation. How much light you’re letting in is controlled by aperture. Think of aperture as pouring light onto your sensor through your lens; at f/2.8, you’re just dumping it in wide open but by the time you stop down to f/22, you’re pouring it quite detailed through a small funnel.

Photography is, by definition, painting with light. Not enough light and you might as well take your ball and go home. Light gives a photographer options and options are the paint in a photographer’s hands.

Moving from f/2.8 to f/5.6 on the aperture scale is two full stops of light. In ISO terms, which you might be a little more familiar with if you’re using a point-and-shoot and ISO is really the only adjustment you make, that’s the equivalent of moving from ISO 400 to ISO 1600. Think of the difference in the quality of your images when you shoot on ISO 1600 as compared to ISO 400. (If you don’t already know this offhand, don’t worry; we’ll cover it.) If you’re starting at f/5.6, you’re going to have to make up that loss of light somewhere. Looking back at our exposure equation, there are only two other options: ISO or shutter speed. If you’re working with a long telephoto lens, you might not have as much wiggle-room to slow your shutter speed. That leaves you bumping up your ISO which might give you noisy or not so crisp and clear images.

There’s also the issue of performance. A “critical aperture” is the aperture at which a lens can be expected to best perform, and is generally two stops from the maximum (or largest) lens aperture. So if your largest aperture is f/1.2, then you can expect very good, clean, sharp images from shooting that lens at f/4; but if f/5.6 is your maximum aperture, you’ll have to stop that lens down to f/11 to achieve “critical aperture.” Scroll back up to the aperture chart and look at the circles, particularly at f/11 — visually compare the amount of light available at f/11 with the amount of light available at f/4 or even f/1.2. See my concern?

Generally speaking, the larger the f/stop (think of the size of the circle, not the number!) the better the lens. The larger the f/stop, the “faster” the lens.

Q: Why is f/22 smaller than f/2.8 when 2.8 is a smaller number than 22? It’s very confusing!

A: It is confusing. It’s math. “f/stop” is literally (speaking in mathematical terms) a fraction that indicates the diameter of the aperture (or lens opening). “f” stands for the “focal length” of the lens, “/” is “divided by” and the number indicates the stop. So a 28mm lens set at f/2.8 would be [focal length] 28 divided by 2.8 = 10. The diameter of that lens opening would be 10. A 28mm lens set at f/22 would yield a diameter of 1.27. So in this case, a circle with a diameter of 10 would be larger than a circle with a diameter of 1.27 — whew!

Or, you can simply commit to memory the size of the circles in the chart I drew, f/2.8 being much larger than f/22, each numbered stop along the way halving the light reaching the sensor. That’s what I did.:)

Q: Why does it go f/1.2 and then f/2.8? Shouldn’t it be f/1.4?

A: That’s a good question. Sometimes it does, some lenses are f/1.4. The numbers don’t quite line up perfectly with halving and doubling. Sometimes cameras factor in half-stops or thirds, producing far more numbers than I included on the scale above. You’ll see the same things happen next post when we get to shutter speed, moving from 1/60 to 1/125. Don’t get too hung up on it.

The numbers on the charts I’m giving you are considered the “whole stops.” It’s a good frame of reference for a beginner. Once you memorize those numbers, you’ll find it becomes second nature to move from whole to whole in calculating exposure. This is useful because if you are shooting f/5.6 at [shutter speed] 1/250 but you’d like to be shooting at f/2.8 to blur your background more, all you have to do is adjust your shutter speed two stops to the right to make up for shifting your aperture two stops to the left. So the exposure of f/2.8 at 1/1000 is equal to the exposure of f/5.6 at 1/250 for this particular photo. Both photos will look the same as far as brightness and contrast, but the image shot at f/2.8 will have less depth of field.

Here’s an example of changing shutter speed and aperture combinations to produce basically the same exposure. In this case, I wanted to illustrate the difference in depth of field (notice the backgrounds) with different apertures. I moved my aperture roughly 5 steps to the right on the scale above, so I had to move my shutter speed roughly 5 steps to the left to compensate for the loss of light in order to achieve the same basic exposure. I was using my 28-70mm lens and probably should have shot 4 photos, two at 28mm and two at 70mm but my model was in a hurry to get to her meet so I shot two frames at roughly “normal” focal length, the first to illustrate shallow depth of field and the second to illustrate great depth of field:

Nikon D700, 28-70mm lens at 48mm, f2.8 @ 1/800 second, ISO 400

Nikon D700, 28-70mm lens at 48mm, f2.8 @ 1/800 second, ISO 400

See those pretty little circles in the background above? That’s bokeh. Wide open apertures produce blurry backgrounds and beautiful bokeh and shallow depth of field (blurry background.)

Nikon D700, 28-70mm lens at 48mm, f18 @ 1/20 second, ISO 400

Nikon D700, 28-70mm lens at 48mm, f18 @ 1/20 second, ISO 400

F/18 renders great depth of field (focus plane extends much farther throughout the background.) However, depth of field does not always insure sharp focus. A corresponding shutter speed of 1/20 to make up for the loss of light when I moved to f/18 was clearly against the rules we learned in focal length — it’s not a “first learn the rules, then learn to break them” example, it’s an example to illustrate why paying attention to focal length and its relationship to shutter speed is important. Remember, I was handholding my lens (the body-lens combo weighs about 10 pounds) at 48mm with a shutter speed of 1/20 and result is screaming camera shake or blur. Look at these close-up crops of the same images from above:

Nikon D700, 28-70mm lens at 48mm, f2.8 @ 1/800 second, ISO 400

Nikon D700, 28-70mm lens at 48mm, f2.8 @ 1/800 second, ISO 400

 

Nikon D700, 28-70mm lens at 48mm, f18 @ 1/20 second, ISO 400

Nikon D700, 28-70mm lens at 48mm, f18 @ 1/20 second, ISO 400

Extra Credit: Let’s say that second image was shot at (I’ll put it into whole stops to make it easier for you) [aperture] f/16 and [shutter speed] 1/30. iTunes treat goes to the first person who can tell me (before I post the answer in the next topic) what my exposure on that second image SHOULD have been, assuming a shutter speed of 1/60.

Bueller? Bueller? Anyone? Anyone?

[return to the PHOTO 101 Table of Contents]

July 3, 2009 - 7:01 am

kate gardiner - i know! i know! :O) wink!

July 3, 2009 - 9:02 am

christine - if you are a pro who started giving ME advice back when we were both slaving away in that underground newsroom, you should probably get iTunes extra credit just on general principle! :) so in the spirit of keeping it fun for everyone, if you’re a pro with a link back to your portfolio, iTunes extra credit for any errors you find in my calculations and/or spirited discussions you stir up in the comment section. Offer not valid in West Virginia or states that prohibit such games. comments must be relevant to post topic. CGP reserves the right to remove comments without notice. pushers of prescription drugs that begin with a capital C need not apply.

July 4, 2009 - 1:41 am

Ray - Sorry. I must recuse myself. But I thought your post was extraordinarily well written.

Happy Independence Day.

July 5, 2009 - 10:20 am

Flash - Nice!

July 5, 2009 - 6:07 pm

christine - Ray, a writer couldn’t ask for a nicer compliment coming from you. Please don’t apologize for recusing yourself; I definitely don’t aim to teach you EVERYTHING I know, as I hope to land the job shooting you author photo when you publish your next book. :)

July 11, 2009 - 3:33 pm

Greg - Just out of curiosity.. in the “critical aperture” section you said that the best
performance can be excepted from the lens which has max aperture say 1.2, about two stops up (from this aperture)
Then you said that: we should expect the best performance at f4.0 which isn’t two stops. Each stop is about a previous number times 1.414.
F1.2 is half stop from 1.0.
So let’s imagine we talking about lens that has max aperture 1.4 instead of 1.2
1.4 * 1.414 = 2.0 (it’s actually 1.9796) but 2.0 is close enough. This is first stop.
Then: 2.0 * 1.414 = 2.8 second stop.
So the best performance for this lens is about 2.8 not 4.0.
For the lens with 1.2 max aperture the “critical aperture” should be a half stop less.
(which is about f/2.4)
Love your tutorial :grin:

July 12, 2009 - 10:33 am

christine - thank you, Greg! very well done. except that you forgot to link your portfolio to collect on your extra credit! :)

Lesson 2: exposure

So we’ve agreed that you’re looking to create technically correct images that are in-focus and not too bright (overexposed) or too dark (underexposed.) You’ve chosen a lens that gives you roughly the focal length you’re looking for depending on what you’re shooting.

Q: I chose a 105mm lens, but how do I get the flowers to go all blurry in the background when shooting portraits? I’ve got a 200mm lens so I can get close enough to him without getting wet, but how do I freeze the water that my son is splashing in the pool? My daughter is jumping on her bed; I have a 28mm lens. What do I use to make the other settings work so that I can freeze her in the air mid-jump?

A: Here’s the magic equation:

Exposure = ISO + Aperture + Shutter Speed

Here’s a flowchart to help get you thinking about what kind of images you want to make:

isoSSaperture

Learn it, know it, live it.

Next up: breaking down the details. Picking your own iso, aperture and shutter speed numbers is how a photographer differs from a camera. Knowing this, and what to look for in a camera and lens to help you, separates the men from machines.

[return to the PHOTO 101 Table of Contents]