First Learn The Rules | New Orleans photography

July 17, 2011 - 3:48 pm

steve fleming - I read this again today, and I really must say yes the painting reminded me of a lonely cowboy but it was a really nice cowboy. But I never realized it was supposed to be overlooking the pacific ocean with mist and weather. I feel like a cad but then again that is sort of my job.
On another front, Christine is the most professional person I ever had the great fortune to work with, she promised me some quality work and delivered in a fashion that I was totally not used to. Plus she took some fabulous photos of me, so email her and get her to work her photo magic for you. Steve Fleming

Lesson 2.1: Histogram

Sunday, August 8, 2010

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

Here’s how all of the individual tiles stack up to represent this image in my histogram:
Screen-shot-2010-08-06-at-3.59.08-PM

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

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

And its resulting 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.

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

Wednesday, August 26, 2009

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, 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.

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

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!

3 comments

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 4: exposure review

Saturday, July 4, 2009

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

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 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

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3 comments

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!

Protected: kids, summer, pool, photos and golf

Monday, June 22, 2009

defocusing

Friday, April 24, 2009

defocus
verb ( -focused , -focusing or -focussed, -focussing) [ trans. ]
cause (an image, lens, or beam) to go out of focus : the filter lets you defocus all or part of an image.

•••

At the beach, for example, on vacation: why focus? Watching my husband toss a football to our son requires (of me) very little focus, yet captivates me completely. Dreamy recollections of a beach vacation don’t necessarily rely on the crisp details I demand of a lens.

Find it in the “first learn the rules, then learn to break them” chapter.

1 comment