Are Your Focus Problems Real?

In answering one reader’s question today I had a small Aha! moment.

Basically, we have a lot of nitpicking going on (dynamic range, focus precision, etc.), coupled with a lot of “why doesn’t it just do what I want it to (automatically)?” More of those questions are coming from the full frame, high megapixel world than the small sensor, low megapixel world.

And that’s what caused my Aha!

Back in the 35mm film days many of you grew up with, the “good enough” thing was handled through auto exposure in the camera and then your print lab fixing that ;~). Many were using 35mm f/2.8 or slower lenses, which would tend to make small focus misses fit within the depth of field you’d see in the 6” print the lab handed you.

While the majority were in that one-hour print phase, the high-practice pros were using slide film with medium format or larger cameras. Any miss, when looked at with a Lupe on a whitebox, showed up. At Backpacker in the late 90’s, for instance, we’d put enthusiast 35mm slides, pro 35mm slides, pro 120/22 slides, pro 4x5” slides, and even pro 8x10” slides on the lightbox, then look closely trying to determine which photo was best to use in the magazine (particularly for cover images). The differences were dramatic. The bigger the format we looked at, the better the attention to detail and getting every bit right seemed to be. Almost without exception. 

There was a reason for that. First, 4x5” slide film was expensive, slow to work with in the field, and big enough to show any mistake readily. You didn’t dare make mistakes, or else you were wasting a huge amount of time and money. Plus, the payoff: a 4x5” slide on a lightbox looked far more impressive via the naked than the 35mm slide next to it.

One thing I haven’t written about in awhile is the difference between a 1” or even m4/3 camera and full frame cameras. It’s sort of the same thing as my Aha! Using a 1” or m4/3 camera for web-sized work has some things working for it that can let you ignore a slight focus miss. (I hesitate to get deep into the “equivalence” discussion, but you can read more on sansmirror (read that article and the next one after it). 

Relevant aside: dpreview just published their Sony A6700 review, and in it they did their usual “bicycle test” for autofocus. For the weave test, dpreview’s words are “passes this test with flying colors.” Only problem with that:? Not a single image is “in focus.” The camera was clearly focusing forward of the biker’s head. Perhaps you’ll judge that to be acceptable, but this is where myths like "Sony focuses perfectly” begin. 

Almost all of the “missed focus what am I doing wrong” questions I’m fielding these days are from full frame, high megapixel count cameras with their output looked at pixel level. Unlike dpreview, they insist that the pupil of the eye must be in focus or else the “camera is not focusing correctly."

Now, if you’re trying to create work that competes with the top-practicing pros, okay, let’s do that kind of examination and see what will help you get there (hint: it’s usually not a new camera). 

But for most of those that are coming to me for help, they’re asking for top-level results done totally with automation and no user discipline. And then their usual stated output is social media! 

I’d suggest to that group that they don’t need a high megapixel count camera. They need a one-hour lab producing small prints ;~). I’d further suggest that they should be probably examining their work at no more than 4K (certainly nothing more than 12mp). That’s one-quarter the size they’re capturing, and four times the size they’d put on social media. 

Guess what? A lot of "focus problems" just go away when you do that! 

So to answer today’s headline: yes, your focus problems probably are real, but are they important enough to be meaningful? It’s in that dichotomy that most of the “focus problem” discussion seems to be falling these days. Dpreview’s consistent overstatements about focus performance don’t help. Pixel peeping when you’re not printing at full 300 dpi size probably doesn’t help, either. 

Ask yourself what’s your output, and what’s your desired goal. If you’re printing big and want to be heralded as perfect craftsman, then nailing focus is just one of your problems. If you’re posting on social media, a lot of focus transgression can be tolerated, and the smaller the image sensor, the more likely you have a deeper depth of field to start with. 

 Looking for gear-specific information? Check out our other Web sites:
DSLRS: | mirrorless: | Z System: | film SLR: all text and original images © 2023 Thom Hogan
portions Copyright 1999-2022 Thom Hogan
All Rights Reserved — the contents of this site, including but not limited to its text, illustrations, and concepts,
may not be utilized, directly or indirectly, to inform, train, or improve any artificial intelligence program or system.