Clik here to view.
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...
View ArticleClik here to view.
Some M-Mount Field Curvatures
I haven’t posted very much lately. We’ve had some new equipment installed and we’ve been doing a LOT of testing as we develop our new database of lenses on the optical bench. As the database fills out...
View ArticleClik here to view.
Just The Lenses: Canon vs Nikon Zooms at 70mm
It’s impossible to accurately compare lenses from different mounts using any form of Computerized Target Analysis testing (methods like DxO or Imatest). Target analysis tests an entire system (camera...
View ArticleClik here to view.
Just the Lenses: Canon and Nikon Mount 35mm f/1.4s
As I discussed in the last post, it’s impossible to accurately compare lenses from different mounts using any form of computerized target analysis testing (methods like DxO or Imatest). Target analysis...
View ArticleClik here to view.
Field Curvature and Stopping Down
Ignorance more frequently begets confidence than does knowledge. Charles Darwin What I know that I don’t know doesn’t cause me much trouble. I don’t know the formulas for 7th order optical aberrations...
View ArticleClik here to view.
Just the Lenses: Canon and Nikon Mount 85mm f/1.4 (and 1.2) Primes
We’ll continue our Just the Lenses posts with the 85mm wide-aperture prime lenses. We’ll get through all of the wide aperture primes eventually, for those of you who like this series. If you haven’t...
View ArticleClik here to view.
Quick Zeiss 85mm Otus MTF Charts
Well, we finally got a few copies of Zeiss’ newest Big Ass Lens, the 85mm f/1.4 Otus in Friday afternoon. I didn’t have time to do a whole lot with them other than take a few shots, and run them...
View ArticleClik here to view.
A Brief 400mm Comparison
Canon shooters have a bit of 400mm excitement right now. The biggest news, of course, is the release of the 100-400mm f/4.5-5.6 IS II lens, replacing the original version that's had a very long,...
View ArticleClik here to view.
The Nikon 300mm f/4E PF ED VR Test: Or Why I Don't Test Just One Copy
As most of you know, we generally test multiple copies of a lens when we evaluate it, simply because we are so aware of copy-to-copy variation. But I got caught between a rock and a hard place this...
View ArticleClik here to view.
Just the Lenses: Tamron 15-30mm f/2.8
Our Just the Lenses posts are optical tests where we compare various lenses on the optical bench. Unlike DxO or Imatest test results, no cameras are involved, eliminating one of the major variables....
View ArticleClik here to view.
Canon 11-24 f/4 L MTF Tests
I'll be honest. I'm pretty excited about the Canon 11-24mm f/4 L lens. I love shooting ultra-wide and the chance to shoot this wide with a rectilinear lens on a full-frame camera has me pretty excited....
View ArticleClik here to view.
A Quick Zoom Variation Demonstration
Sometimes I put up posts basically because I find myself answering the same email over-and-over. One of the emails I get a lot is: "I want the best copy of the xxxx zoom lens." People get irritated...
View ArticleClik here to view.
Just the Lenses: Sigma 24 f/1.4 Art Comparison
Most of you know I've been very impressed with Sigma's new Art lenses. Their 35mm f/1.4 Art I still think is the sharpest 35mm prime lens made. The 50mm f/1.4 Art is also superb. When I heard about the...
View ArticleClik here to view.
Sony FE 90mm f/2.8 G OSS Resolution Test
We got a pre-release set of Sony FE 90mm f/2.8 G OSS Macro lenses in for preliminary testing last week, and I was kind of excited about this lens for a couple of reasons. First it simply gives me a...
View ArticleClik here to view.
Measuring Lens Variance
Warning: This is a Geek Level 3 article. If you aren't into that kind of thing, go take some pictures. I've been writing and discussing the copy-to-copy variation that inevitably occurs in lenses since...
View ArticleClik here to view.
Variance Measurement for 35mm SLR Lenses
Last week we posted optical bench MTF and copy-to-copy variation measurements for 50mm SLR lenses. We're going to continue that series this week with the same measurements for the 35mm lenses. This set...
View ArticleClik here to view.
Variation Measurements for Wide-Angle Lenses
When we started this series, we introduced our methods using 24mm lenses, then followed up with looks at the 50mm and 35mm groups. Today we're going to go back to the wide-angle lenses; the ones we...
View ArticleClik here to view.
Variation Measurements for Telephoto Lenses
We're nearing the end of the Varation series for prime lenses. If you are joining in late, you may want to go back to the original article for an introduction into the methods used. Today will look at...
View ArticleClik here to view.
A Quick Guide to Teleconverters
Teleconverter use and compatibility can easily get confusing. I'd like to shed some light on the subject for those looking to get more length out of their lenses without the extra weight or cost....
View ArticleClik here to view.
Supertelephoto MTF Curves
Brandon has accomplished much during his summer with us, including several things I never thought we'd be able to do. One of those things was measuring the MTF of supertelephoto lenses on our optical...
View Article
