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 →
The first post I made on sensor-stack thickness wallowed deeply in PhotoGeekery. This one is meant to be of practical use so I'll try to leave the Geek stuff out. We'll start with the simple facts.
1) There are several pieces of glass right in front of the sensor of every digital camera.
2) The thickness of this layer varies from less than 1mm to slightly more than 4mm depending upon the camera.
3) The thickness of the stack can affect the optics of a lens mounted to that camera.
There is some confusion on when this stuff matters so I'm going to attempt to accomplish two things with this post. First, we'll do a general summary of when it might matter. Second, we'll start a database of information that's not readily available so those who are interested can come back to this page and find out if a certain camera-lens combination might have a problem. Continue reading →
Single glass piece from the sensor stack of a Canon (left) and Micro 4/3 (right) camera. Image credit Aaron Closz.
NOTE: This is a Geek Post. If you aren't into geeky photo measurements, or into adapting lenses from one brand of camera to another, you'll not be interested.
A year or two ago, I wrote a blog post where I basically showed lenses shot on adapters on other cameras aren't acceptable for testing. If you run them through Imatest the results aren't accurate. I suggested that reviewers shouldn't test lenses on adapters, although obviously adapters are a great way to use interesting lenses to take pictures. Continue reading →