Of Lenses and Cameras

Or, not letting obsession get the best of you...


Photography has always appealed to people with an outsized appreciation for gear. The finely wrought lenses and camera bodies which enable this passionate endeavor of ours present an evocative counterpoint to photography itself - where the rendering of an image is the thing. Many photo hobbyists become far more focused on the equipment side of the practice than to the pursuit of emotive images. Some fall so deeply into that rabbit hole that that is all they see. They live in a world of arcane measurement. They obsess over the most minute performance faults. They hold manufacturers at fault for failing to achieve industrial perfection.

Nothing wrong with that, I suppose. At least as long as one can continue to make the distinction between photography - the capturing of images - and the gear which makes it possible.

I'm certainly of the camp that loves fine things. Whether it be an Anschutz rifle, a BMW motorcycle, an Omega Speedmaster watch, an Apple computer, or a Leica M camera - there is a certain undeniable joy that comes with operating a finely-manufactured piece of equipment. There is a pleasure that transcends the purpose of the thing itself.

But even enjoying these things, I try and keep things in perspective. Notwithstanding its storied past, I recognize that the trigger on the Anschutz rifle I buy today is subject to a degree of manufacturing tolerance. And that my particular sample may be a tinge better or a tinge worse than that of the fellow who bought one last week.

That's okay. Perfection is a state of mind, not something you'll find on the factory floor.

All of which is to say, I've always looked on with bemusement at those who like to photograph brick walls, trying to ascertain resolution deficiencies in their lenses; or finely-graduated yardsticks, figuring to find fault in a camera's focusing mechanism. To each their own. But that's not my idea of photography.

Me, I just shoot a bunch of pictures, normal pictures of people and such, and if most of them seem okay, that's good enough.

Having said all that, I certainly acknowledge that a small percentage of of gear will fall outside the manufacturer's intended performance tolerances. Especially with a high-end manufacturer, who probably is dealing with tighter tolerances than their less expensive competition, consistently hitting that exact-center-of-the-target mark can be a challenge. Perfection is a tough thing with which to wrestle.

Which brings me to a confession: Over the last couple of days I've done a bunch of those very same gear-obsessed tests that I have long eschewed. The obsessive-compulsive, anal-rententive gear whores out there would be proud.

There was, I would protest though, a purpose.

As a bit of backdrop, I would note that I bought an 85/1.4 Nikkor some years back. As many of you know, this is a renowned lens, one intended for use wide-open, with glorious bokeh. Over on Nikon Cafe they call it "The Cream Machine." It's one of those rare non-Leica lenses which follows the Leica gestalt. You can happily use all the apertures you paid for, not just those you stopped down a few clicks.

Alas, mine seemed a bit soft.

Nearly a year ago I came across a new product called the "Lens Align Pro," a device for verifying focus accuracy in DSLR's. After noting several very positive reviews by photography people I respect, I went ahead and ordered it. It's one of those things that is simple in concept, but brilliant in execution. It's way more expensive than it ought to be - just because it IS simple. What you're paying for is that slap-yourself-in-the-forehead, why-didn't-I-think-of-that bit of epiphany. I rationalized the cost by simply contrasting it against the glass that I've invested in over the years. Compared to that this little device was a trifle.

More importantly, it worked.

Within ten minutes I was able to confirm that that 85/1.4 Nikkor of mine was front-focusing a significant amount. A quick trip to the menus on my D3 and a tweak to the AF Fine-Tune setting for that lens... problem solved.

Fast forward ten months and back to my Leicas, the real story here.

When my M9 arrived I mounted my Summicron 50 on it. This was the lens I had purchased along with my M6, my first Leica years ago, and that 50 had been my happy companion over many miles. But like the wife cast aside for the exciting new mistress, when the M8 came along that Cron had been superceded by a newer and prettier 50, a chrome Lux ASPH. For three years that new Lux shared all the honors with an also-new 28 Cron. The Summicron 50 sat on the shelf.

Even mistresses eventually grow familiar, though. And so with the return of full-frame I figured it was right to go back to the lens that had started it all. Even if just for a little while.

I fell in love again. I had forgotten how stirringly beautiful that 50 Cron rendered images. Putting it on the M9 had reminded me.

Days passed. And I needed to shoot an event at work. The conference room had crappy fluorescent lighting. And not nearly enough of it. I needed something fast. So back to the mistress I went.

Hmm. You shoot 150 images and you usually get an idea of things. My idea was that these weren't what I expected. Despite the slow shutter speeds and the capture-the-moment hair trigger requirement, too many seemed just a little soft. Something that had never happened with that 50 Lux before.

Thought turned to worry. And that to wonder. And then I fell down the rabbit hole.

On Saturday I pulled out my M9, that once-used Lens Align Pro, two tripods, and a handful of M lenses. I set the tripods three feet apart, a distance just beyond their minimum focusing requirement. I carefully set up the Lens Align Pro. I screwed a 1.25 magnifier into the viewfinder window. I mounted the camera and took a baseline shot to ensure everything was in alignment. And then, for each lens, I took six carefully-focused shots at its maximum aperture and six more at its next-to-maximum aperture. I deliberately re-focused between each shot, moving the rangefinder back and forth, seeking perfect focus, just like I do when taking real pictures. And I placed a Post-It note on the Lens Align Pro device so I'd have a permanent record of the shot details.


Making sure everything is aligned.



The test setup



Reading the results


I did this for my 35 Lux ASPH, my 50 Lux ASPH, and my 50 Cron. Then I moved the tripods another foot apart, to accomodate my last two lenses - the Noct, and my 90 Elmarit - and took the frames for those. Then I loaded the images onto my computer to take a look.

I was aghast. My M9 was front-focusing on everything save the Noct, which was seriously back-focusing. I went to bed thinking I'd be sending the camera to New Jersey.

On Sunday I decided to do some more tests. It would be another day before I could ship it, after all.

Once again I pulled out the tripods, the Lens Align Pro, my lenses, and both my M8 and M9. In the three years I had shot with it I never had the sense that my M8 had ever been off in any way. And so I was most curious to see how it compared to what I had seen on my M9.

I repeated all the shots, with all the same lenses, from the day before. First with the M8. Then again with the M9.

I did one more thing. Since I seemed to have a problem with front-focusing on my M9, I wondered how tweaking the focus ever so slightly would affect what I was seeing. So when that 50 Lux was mounted, after taking the normal, perfectly-focused shots, I also took a dozen shots with the rangefinder turned just a smidge towards the rear, towards infinity. Just a hair, just enough to come off perfect-focus.

The results were enlightening.

Having loaded everything into a spreadsheet...



I was able to draw some conclusions.

That last raised what seems to me to be the most important question here: At what point does any of this become meaningful? The great benefit of the Lens Align Tool is that it allows the most subtle gradations of measurement. But since manually focusing a lens involves a mechanical linkage, not to mention my own imperfect 56-year-old eyes, when do you decide that a problem truly exists?

The conclusion I've drawn is that my M9 is fine, as was my M8 before it. Leica may or may not deliberately inject a tinge of front-focus into their rangefinder calibration. I dunno. What I do know is that the shot-to-shot variation I see when trying to measure it is larger than any perceived level of error. If anything, I have a renewed respect for the inherent accuracy of Leica's rangefinder design. It's really quite amazing that these things work as well as they do.

And so out of the rabbit hole I climb.

I do take away a few other things, though. My Noct most definitely back-focuses to an unacceptable degree. That explains the too-many-soft-shots I always got with that lens, something I just attributed to its character. And my 90 Elmarit front-focuses way too much. both those lenses will be going back to New Jersey for re-calibration.

And my 35 Lux ASPH clearly exhibits focus shift, something a lot of folks deny, but something that is inherently part of this lens' design. In my case it starts out as very modest front focus at f1.4, moving to very slight back-focus at f2. That's optimized behavior for this lens, in my opinion. And it's something I had long inferred from my sample. Now I can actually see it.

And now I shall be glad to get back to taking real pictures, of real people and real things.