Roger Cicala
I'm Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.
Posts by Roger Cicala · page 18 of 39
Some Holiday Lens Mutilation
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…
Geeks Go Wild: Data Processing Contest Suggestions
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…
Only You Can Prevent Movi Fires
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…
Sensor Stack Thickness: When Does It Matter?
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…
The Glass in the Path: Sensor Stacks and Adapted Lenses
* 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’m Gonna Party Like It’s 1995
I doubt any of you remember it, but 1995 was the coming out party for Digital SLRs. There had been digital cameras before then. There had even been digital SLR cameras of a sort – modified cameras tethered to a hard drive — before then. But in 1995 camera makers released digital SLR cameras for the…
Comparing Rangefinder and SLR 50mm Lenses. (Version 0.7)
Well before our Imagemaster optical bench was delivered, I knew what I wanted to do first: compare some Leica lenses with the best SLR lenses on a level playing. I did one comparison involving Leica lenses a long time ago, but Leica lenses are difficult to test in our Imatest lab. It’s nothing to…
A Data Processing Contest
OK, when I introduced our new optical bench, I mentioned that it generates a lot of data. We gathered data for a nice comparison test (I mean who wouldn’t want to know how the Zeiss Otus and Sigma 50mm f/1.4 Art stack up against some nice Leica 50mm lenses). Since then I’ve spent about 20 hours…
Introducing the Optical Bench
Note: This is a Geek article. If you aren’t into geeky stuff, you won’t be into this. _“We take a step back so that we may leap further.” African proverb_ I wrote a post a couple of weeks ago about our first copies of the Sigma 50mm Art lens, and promised to follow up when we got more samples.…
MTF – The English Translation
This post contains absolutely no mathematics. Explaining MTF without math is sort of like doing a high-wire act without a net. It’s dangerous, but for any number of reasons is more likely to keep the audience interested. ## Why Am I Doing This Again? I wrote an article on reading MTF charts several…
Yet Another Sigma 50mm Art Post
I suspect I’ll never be on any manufacturer’s “early review copy” list for new lenses. There are already plenty of good early lab reviews on the eagerly awaited Sigma 50mm f/1.4 Art lens at SLRGear, Lenstip, and DPReview, among others. So when we received our first Sigma 50 f/1.4 Art lenses for…
A Look at Stopping Down
We all know that aberrations affect points of light off-center, making them blurred. We all know that some aberrations are worse the farther away from center we go. And we know that some aberrations are improved when we reduce the aperture. Some of us even know the various rules-of-thumb for what…