Some Day You Got to Do It: Calibrating Lenses with FocusTune & LensAlign


Today is the day it finally has to happen: I’ve got to calibrate my Canon camera and lenses. Yes, I admit it, I have been running all these tests without going through the hassle of this exercise. Luckily for me, hardly any tests were done using my Canon 5D III and I have been shooting a lot with manual focus glass anyways.

But later today the by now familiar UPS driver will bring the long-awaited Sigma 50mm f/1.4 ART lens and the Sigma USB dock and I need to be sure that all my autofocus lenses are going to behave nicely on my Canon.

Also, during a shoot a few days ago, I was diligently focusing my 135mm f/2 on the left eye of the model at aperture f/2. Lo and behold, consider the shock when I noticed on the computer screen that the right eye was in perfect focus but the left eye wasn’t.

I bought the LensAlign kit from Michael Tapes a while back and also purchased his FocusTune software, knowing this day of reckoning would arrive. But my whole being resisted actually settings things up and running the tests.

One: I’m kind of peeved that with modern camera advances we actually have to deal with more crap that has little to do with actual photography. I for one experience no joy taking pictures of a ruler and I prefer to just use my camera for taking pictures of beautiful things or things I hope to make beautiful. Rulers aren’t among my choice subjects.

Two: I don’t have a scientific bone in my body. I’m curious, I ask questions, but repetitive testing in a disciplined manner isn’t my thing. I’m a journalistic hack, not a lab rat. I shudder at the thought of all these lenses, all these focal lengths and all these micro-adjustments.

Still, there is a price to pay for being able to rely on your gear in the field. I guess I’ve always been pretty lucky, as I never noticed any autofocus problems with my Canons before.

And in a way it compares to the film days, where during a professional photography course I had to spend considerable time studying the various chemical components of film, paper and darkroom solutions. That wasn’t my thing either.

I do appreciate digital and all the advances it has brought. I never liked developing film and was too impatient in the darkroom. Since I had to set it up and break it down every time, I focused on quantity instead of quality and still see the poor results of that whenever I look at prints I made a few decades ago. So, digital is right for me.

Thus I dutifully calibrate my monitors, back up my digital files multiple times, clean my sensors and will now get to work on fine tuning my Canon camera and lenses. It’s the grungy side of digital for me, a price to pay for the otherwise vast improvements the medium offers.

Running the Tests

So, here we go. Gotta find that Lens Align kit in the closet and open up FocusTune on the computer.

Found the kit. Put it together. That was easy. Brought me back to my youth, sitting at the kitchen table way back in Holland, assembling kit cars or tanks or airplanes or aircraft carriers, with all those tiny plastic planes. Sorry, got carried away.

Time to head over the Michael Tapes site to read up on how to use LensAlign and make it work with FocusTune. Will be back after the break.

Well, not really a break. I watched some videos with Michael explaining his system and how to go about the process. Then I followed his instructions, switching lenses, twiddling with the Canon menus and frequently pressing the buttons in the wrong order.

But I got there. It’s basically a two-step process. First you go through some rough moves, taking five pictures each at settings from -20 adjustment to +20 in 5-step increments. The software shows you at which settings focus is best, but since your increments are so large, you then have to narrow it down. So, you go in 1-step increments around the point where focus was sharpest. That way you narrow it down to one number you enter in the camera for that particular lens.

It’s repetitive, but actually pretty much a breeze. Since each test requires five pictures at each increment, that’s 90 pictures per lens. The zoom lenses on the newer Canons can have separate calibration settings for the long and the short end, so each zoom requires 180 pictures. Thus, in quick succession I have today taken about 800 shots of exactly the same thing from exactly the same vantage point. Exciting.

Most of my lenses were pretty well set from the get-go, which again explains why I didn’t really see anything wrong with most of my shots in terms of autofocus. The lens most out of whack was indeed the 135mm f/2 which needed to be set at a correction of -12. The 85mm f/1.8, the 40mm pancake and the 50mm f/1.4 needed -11, -9 and -8, respectively. Of the zooms, the 24-70mm f/2.8 II needed -5 at the wide end and -2 at 70mm. The 70-200mm f/4 needed no adjustments.

I did test my Sigma 35mm f/1.4 ART and it showed it needed -2, but I’ll wait for the Sigma USB dock to arrive this afternoon to finalize the Sigma settings.

Unfortunately, I’m all alone at the moment at the vast premises of Photographic Wanderings, so I can’t pursue my favorite pastime of focusing on one eye with a wide-open lens and see what’s in focus on the final image. That’s left for the weekend.

And an exciting weekend it promises to be. I still have the Zeiss Otus on loan until Tuesday and can now shoot it side-by-side with the Sigma 50mm ART that’s arriving later today. My report will follow next week.

Now I have to clean up all those lenses standing around on my desk.

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