This is a Geek Article. Many of you don't understand the term 'Geek' properly, so perhaps this will help. As the graph shows, if you aren't both intelligent and obsessed with photo gear, you won't enjoy this article.
I've tried hard to find whom to credit for this, but haven't been able to. If you know, please let me know so I can credit this brilliant work.
Left to right: Canon 16-35 f/2.8 II, 16-35 f/4 IS, 17-40 f/4. Can you spot the one with the wrong hood? The intern obviously couldn't.
As is so often the case, I bit off more than I wanted to chew when I came back from vacation. The Canon 16-35mm f/4 IS lens had just been released, a few copies were in stock, and I thought I'd do a nice quick test. But one of the reasons I'd wanted an optical bench was because I don't trust Imatest results with wide-angle lenses. At 16mm, even with the very largest test charts, we're testing at about 4 feet shooting distance.
So I after I did our standard Imatest on the 16-35 f/4 IS, I wanted to repeat the results on our optical bench. Of course, I don't have a big database of optical bench results to compare against like I do with Imatest. So I had to do optical bench tests on some other wide zooms for comparison purposes. Then I had to do some more comparison with other lenses to see if the variations we were seeing on the optical bench were simply a new, higher resolution testing method, or if they were telling me something about variation with wide-angle zoom lenses. (Both things were true.) Anyway, the testing I thought would take a week has taken three.
I realize some of you just want to see the usual Imatest results on a group of these lenses since that's what you're used to seeing. Others are also interested in the optical bench results showing how the lenses resolve at infinity, rather than just close up. And of course there are a few of you who want all the gory details of Geekiness that the optical bench reveals. So I'll try to present this in three parts: the Imatest results first, the optical bench optical test results second, and the geeky stuff third. It's a buffet; just grab what appeals to you.
Like a lot of photo history buffs, I've been quite excited about Lomography's new iteration of the Petzval lens in 85mm focal length. For those of you who don't know about the Petzval lens, I wrote about it a few years ago. It really has a rather a fascinating story.
Since writing that article, I've been rather obsessed by this lens. I own several of them, made in the late 1800s, but I haven't been able to adapt them to work on a modern camera. Now Lomography has reproduced the Petzval lens in a nice brass housing, for either Canon or Nikon mounts. Our first copies arrived yesterday and I grabbed them for a bit before they headed out the door.
Well, I have to admit this has been a fun series. I've learned a whole lot. That's what makes this so fun -- I get some results I don't understand, get some help figuring out what is going on, and before I know it, I've learned something that explains other things I haven't been able to understand.
In the second part of this series, we started a database of sensor stack thickness and exit pupil distances, hoping that it would help people decide which lenses would adapt best to which cameras. (And, of course, determine which lenses would not adapt well to which cameras.) A number of people have added information to the database since it was first posted -- enough to make it pretty useful.
Since the database is now large enough to be useful, I thought it would be a good idea to make a summary of what we know about lenses and sensor stacks. The best thing about all this, for me at least, is that it lets us make some generalizations about which lenses would be expected to have problems on which cameras.
A couple of weeks ago I got an email asking if we would be willing to take some lenses, remove the electronics, fix the aperture wide-open, and permanently lock them at infinity focus. It seems the person who needed this done was having trouble finding a legitimate repair shop or service center that was willing to do it.
Well, illegitimate is our specialty, so I started negotiations about just how exorbitant a fee we would charge for this work. We quickly arrived at a fair price (no money, but we get to take pictures) and yesterday received brand new copies of the Canon 100mm f/2 and Sigma 35mm f/1.4 Art to work on. If you're the kind of person who slows down to view car wrecks or spent $200 on fireworks for the 4th of July holiday, you might like this.
(For those of you who aren't American, the 4th of July is when we celebrate our Independence by getting sunburned, making burnt offerings of animal parts in our backyards, and then eating said offerings. During the entire day, we drink massive quantities of American beer and once it gets dark we shoot off massive quantities of Chinese fireworks. All too often, the results of mixing alcohol and explosives prove that Darwin was correct -- but hey, that's what celebrating is all about, right?)
If torn apart camera lenses make you squeamish, then you won't like this, and I suggest you not read further. You won't miss learning anything; it's just for fun. As best I can determine, this post has absolutely no practical use whatsoever. It's just something to amuse and entertain those of you who are amused and entertained by such things.
A couple of years ago I gave a talk on the history of lens design at the Carnegie-Mellon Robotics Institute. The faculty members were kind enough to spend the day showing me some of their research on computer-enhanced imaging. I'm a fairly bright guy with a doctorate of my own, but I don't mind telling you by the end of that I was thoroughly intimidated and completely aware of my own limitations. Continue reading →
We're growing, which means, we're hiring. Lenrentals is a fantastic place to work. We believe in working hard, having fun, and giving our customers the best possible experience. Our team members get great benefits, including health, dental, paid vacation, and 401(k), not to mention - FREE RENTALS! Continue reading →
When you run a rental house, you basically function as a torture-test lab for equipment. For many years I've put out a Repair Data list annually, showing which photography equipment is more likely to fail than others. I get asked to do the same thing for video equipment, but I usually just shrug and say it's not necessary. I can sum it up simply.
If the product is new and exciting it will probably fail.
If the company is new and cutting-edge, the product will probably fail.
This sounds like a generalization, and it is. It also sounds like an exaggeration, and it's not. New, cutting-edge video equipment from new, cutting-edge companies has an extremely high failure rate. For a lot of these products, nearly 100% fail within a few months. Continue reading →