Resolution Tests
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,…
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…
I Sing of OLAF . . .
I have a couple of things to talk about today. First, is to announce the winner of our name the new machine contest. Second is to answer about 1,000 people’s questions regarding optical testing and adjustment. ## The New Machine’s New Name First, if you don’t known what we are naming then you can…
Examples Using an Optical Testing Station
OK, I’ve done a couple of posts about critical focus for testing, and setting up an optical testing station. This post will provide some demonstrations about actually using it. I’m going to use lenses that we optically adjusted back into proper alignment as examples. I’m doing this because it’s a…
Setting Up an Optical Testing Station
There are a lot of right ways to do optical testing. The gold standard is to put the lens on a $150,000 optical bench or run it through a well-equipped Imatest lab. But unless you have an optical bench or Imatest lab handy, that’s not practical. We have to optically test around 400 lenses a day,…
Why You Can’t Optically Test Your Lens with Autofocus
By far the most common email and PM I get basically says, “I think my lens is optically out of sorts. What do you think?” The second most common is, “So what’s the best way to optically test my lens without a ton of equipment.” Years ago I wrote an overly long post about testing lenses, but it was…
Sony A7R: A Rising Tide Lifts All the Boats?
I have to admit I didn’t get too worked up when the Sony A7 and A7R were released. The last time I wrote about Sony it was how there were so few lenses for the NEX system years after introduction. So now we’re going to a system requiring a whole new lens mount. Sure the camera’s specs were…
There Is No Perfect Lens Test, Either
In my last article, I wrote about the fact that every copy of a given lens has some bit of sample variation. This affects lens reviews, whether lab-based or photography-based, because the copy they tested will be just a bit different from the copy you buy. I suggested, that if you want to get a…
There Is No Free Lunch, Episode 763: Lens Adapters
Lens adapters can be useful things sometimes, letting you mount one brand of lens on another brand of camera. One thing that has always bothered me, though, is the idea of doubling the number of lens-mount interfaces. When you look at the thick metal pieces on the front of the camera and the back…
Sigma 120-300 f/2.8 OS Sport Part 1: Features and Optics
OK, I’m not sure what the official name of the new 120-300mm f/2.8 lens is. I think Sport is probably best, since it’s got that designation in the new Sigma lineup. On the Sigma website it gets called the OS S. The guys around here call it the 120-300 A1, since it’s one of the lenses that go…
Finally Got Around Touit
I was lucky enough to be invited to New York for Zeiss’ Touit lens release and they were kind enough to loan me a 32mm f/1.8 lens in Sony E mount to experiment with. Unfortunately being away during our busiest repair season got me behind and I’ve only just now had a chance to experiment with the…