ON THE LEVEL
By MICHAEL PERKINS
IT’S NOW QUITE EASY TO HAVE YOUR CAMERA OR EDITING SOFTWARE correct for things you should have done before the image was made. Most of the times, these fixes cure more than curse, some of them genuinely helping a shooter extend his skills or fine-tune his control. However, in the case of one of the most common post-pic fixes, the “straighten” slider, you’re potentially messing with picture quality, to fix a problem that, quite honestly, shouldn’t have existed in the first place.
Consult every, and I mean every basic camera tutorial going back a hundred years or more. Many timely tips in such books have vanished or evolved over time, but the simple admonition to keep your shot level has remained unchanged since the dawn of photo time. So why do cameras and software even offer straightening as an option?
If you take the cynical view, the existence of this fix suggests that camera manufacturers assume that enough people will routinely take crooked pictures that, of course, they need something to tilt their images back to normal. Because, if that’s not true, then why does the fix even exist?
Here’s the critical point about straightening: it does not maintain sharpness like simply cropping a photo to a smaller size does. To restore your image to a rectangular shape after you’ve rotated it left or right to level it, your camera (or software; both do it the same way) must trim part of the picture and resize it, producing a lower total number of pixels in the “corrected” photo but within the same space as the original one. And there’s just no way to do that without degrading the sharpness.
Some straightenings, if conservative, may not fuzz up your photo as much as some more extreme adjustments. The above image was shot literally on the run during a tour, but it needed just slight adjustment, and so retained most of its sharpness after I ran it though a second editing program. However, you really have to love a shot to go to those extremes to save it.
Thing is, you can bypass this entire problem simply by shooting a level picture. Now, I won’t bore you with a list of just how many really easy ways there are to ensure this. But since sharpness makes at least the top five list of things that most people want from a picture, why not take a pass on all the post-mortem fixes by doing one of the simplest possible things in photography more often?