Shutterfinger

What's the Most Valuable Thing to Learn?

It's that time of year. Even though I'm a street photographer at heart, even I can't help but be moved by the crispness in the air and the colors of fall. That's what I wanted to express in this photograph. In this case, capturing it was more a matter of composition than technique.

I recently had a friend mention that she had bought a digital camera and wanted to learn how to use it. It was a point-and-shoot, so I asked what she meant by "how to use it." Its operation didn't seem particularly complicated. She replied that she wanted to learn how to use it to take pictures that were better than just snapshots. It was her impression that this required a more intimate knowledge of how to use a camera than she possessed. She wondered what suggestions I had to help her.

I have to admit I was stumped. It's not as if I know nothing about photography. The problem was where to begin. Should I explain apertures, shutter speeds and ISOs? Do I explain focal length, angle of view and depth-of-field? Would understanding all of this really improve her abilities? As important as technical knowledge may be, it's only a means to an end, and not necessarily the only means either.

On a whim, I tried a metaphor: "It's sort of like learning to play an instrument," I said. "The learning gets a lot easier when you know what style of music you're trying to play. If you're familiar with the style then you can concentrate one learning the technique it takes to play it."

This idea seemed to make sense to her, but whether it will help her improve her photography neither of can say for now. Knowledge, even if useful, still has to be applied. Still, it seems to me that the most important way to improve your skill as a photographer is to have some sense of what you're trying to achieve or say; a sense, even if vague, of how you'd like a picture to look and how to get your camera to produce what you want. Without this you're basically just snapping the shutter and hoping for the best.

So that's what I consider the most valuable thing to learn. What about you? What, other than this incredibly thought-provoking blog*, has been the most important factor in your own growth as a photographer? What's the most valuable tip you would pass on to a friend of yours who wants to get better?

*I'm being ironic and self-deprecating here.

A Follow-up To Focusing Foibles

It occurred to me that after going on at length about the challenges of focusing with wide aperture primes on APS-size DSLRs I should provide a few visual examples of what I'm talking about. If this proves to be of any interest to you then I'd encourage you not to simply take my word for it. Try doing a similar test for yourself to see if your results are like mine. Whatever the result, you'll learn something about how your fast lenses perform and how to interpret what you see through your camera's viewfinder.

The photo above shows what happened when I focused my Canon 50mm f/1.4EF at the 10cm mark on this ruler. I shot at maximum aperture. The ruler was held in place by a clamp on a light stand and was parallel to the floor. My camera was on a tripod, pointed downward at a 45 degree angle.

Two things are evident: First, the point of sharpest focus is a bit closer than 10cm. I'd estimate it at roughly 9.5cm. Given that the actual focus point may have been slightly different than what's indicated in the viewfinder, this isn't bad.

The second thing you notice is that the out-of-focus area in the background has a green tinge while the foreground has a magenta tinge. That, my friends, is chromatic aberration in action. It would be harder to see with a multi-colored, textured subject but on a subject like this it's hard to miss.

This second photo shows what happens when I stop down to f/5.6. As you would expect, the greater depth-of-field renders the 10mm mark more than acceptably sharp. But also notice that the overall zone of focus has shifted back, away from the camera. That's focus shift. As for the chromatic aberration effect, it's still evident but less obvious. Once again, keep in mind that I intentionally shot this subject this way so that you could see both effects. The 50mm f/1.4 EF is one of Canon's best lenses, so it would be a mistake to interpret these results as "defects."

The bigger point I'd like to make--one that I realized only after comparing the photos to what I saw in my EOS 30D's viewfinder--is that even though I was focusing the lens at maximum aperture, the way most people do, the image I saw through the viewfinder looked more like the image shot at f/5.6. In other words, I saw four more stops of depth-of-field than there actually was.

No wonder it's so hard to manually focus a DSLR with a standard autofocus screen! The reduced magnification with APS-sized DSLRs only adds to this handicap. As for the so-called depth-of-field preview button, my experience is that all it does is darken the viewfinder. What you see through the viewfinder is seldom even close to what you get. I can't speak for all DSLRs, but of the ones I've used, the rear LCD gives you a much better idea of what the actual image will look like than the optical viewfinder.

Make of this what you will. My personal conclusion is that when a particular depth-of-field and pinpoint focus are necessary you'd be wise not to take what you see in your viewfinder too literally. When possible, bracket your apertures and your point of focus. Since one of the advantages of digital shooting is that there's no incremental cost to shooting more pictures you might as well take full advantage of it.

As for all of you Luddites out there who are still shooting film cameras with manual focus lenses and manual focusing systems, you wipe that smug smile off your face right this minute!

Addendum: I don't want to give the impression that I'm singling out APS DSLRs for criticism based on their viewfinders. The same criticism could just as easily be directed at 35mm rangefinders or twin-lens reflexes. In both cases, what you see is not what you get. The one difference with APS DSLRs though, is that you're more likely to assume their viewfinders work exactly the same as with 35mm SLRs. They don't. In some cases it's not even close. So if you really need to check for depth-of-field or the lack of it, check the LCD, not the viewfinder.

The Elusive Quest for Accurate Focus

This photo works partly because I managed to focus on the bridge of the sunglasses and to keep it there even after I stopped down a bit. As this post explains, accurate focus is sometimes easier said than done.

Caution: Don't read this if you're already happy with the results you get with your DSLR or if you never use lenses with an aperture faster than f/4. If you do read further, then don't blame me if become obsessed with finding ways to wring the last iota of focusing accuracy out of your camera. You have been warned.