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Author » 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.
MTF Charts for 24mm Lenses

Equipment

Practical Use of Field Curvature: Wide and Telephoto Primes

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We introduced evaluating field curvature with 35mm f/1.4 lenses, then looked at how those differ from slower 35mm primes and zooms at the same focal lengths. Then we got into some practical stuff, showing how field curvature gives you useful information for 50mm lenses. Today we’re going to look at 24mm and 85mm prime lenses for a couple of […]

Equipment

Finally, the Nikon Z 24-70mm f/2.8 S Lens Teardown

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Just so you know, my original title was “Lens Disassembly is a Complicated Profession. Don’t You Agree?” The editor said nobody would know what the post was about. But I promise, you’ll see by the end of this; lens disassembly is a complicated profession. We were interested in this disassembly, and by interested, I mean both […]

Canon RF 7-200mm Teardown

Equipment

The Not Very Long Awaited Teardown of the Canon RF 70-200mm f/2.8 IS

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Long ago, a visiting Canon engineer put a box on my workbench, grinned, and said: “You’re going to like this.” Then he pulled out a mock-up of the RF 70-200mm f/2.8 IS lens, and my jaw dropped. I’ve been doing this stuff for a long time. My jaw drops very infrequently. My only comment was, “That’s […]

Lenses and Optics

Practical Use of Field Curvature Graphs – the 50mm Primes

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In my last two posts (1,2), I’ve been using field curvature graphs to look at how lenses behave as you stop them down. It’s been a fairly limited data set; basically 35mm prime lenses and some zooms at 35mm. I’m going to keep going with this topic and today look at a different focal length […]

Geek Articles

Stopping Down Some Bargain Primes and Zooms

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In my last post, we looked at how the field curvature of some really excellent 35mm f/1.4 primes affected what happens when we stop down the lens. The takeaway message is that as you stop down, things change a bit differently with the different lenses, but by f/5.6 they were similar. Still slightly different, but […]

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