ProfHankD

The closer-to-universal focal reducer mount is Canon FD.  However, there are fewer adapters commercially available. Both Nikon F and M42 are common, but Minolta MD isn't -- although I made a ...

Ah, but that's a useful experience because it trained you that it is much better to think a little and write code that's correct the first time, rather than writing junk and hoping to debug it ...

There's SA (spherical aberration) that puts halos around bright things, but it looks quite sharp to me in the center of your wide-open shots.  Far off-axis, SA isn't the problem. That's about when ...

You're absolutely right -- these are highly valued . However, I have really serious doubts as to them earning the reputation, especially on FF. It has been my experience that having the name ...

Look again. The front twig is quite a bit more out of focus in the SMC shots... just as the twigs behind are much more in focus in the SMC shots.  You just missed focus. No big deal; it is very ...

You really need to figure-out how you like to view the world.  For example, I have always tended to think in 28mm, although, like most people, I've been tending toward somewhat longer lenses as I ...

Looks like you missed focus pretty badly with the SMC -- the twigs behind are in much better focus in those shots. In fact, the color fringing in the second shot is at least partly longitudinal CA ...

Ooops. Try again: http://forum.mflenses.com/1977-pop-photo-normal-lens-tests-32-of-them-t18107.html

Don't have anything nice handy. Here's a calibration image: And here's one shot sitting on a table in the hallway of the Marksbury building (where my lab is): Obviously, there are IQ issues here. ...

You can find a complete set of tests at this mflenses post Have to agree about the Pentax flare numbers, although Pentax coatings didn't produce top scores for transmittance. There also is ...

I think a magnified picture-in-picture would be a great addition to peaking. Even better, Sony could have the option of making the area magnified be precisely the eye that it was tracking.... ML ...

A bird's eye lens is a very close relative to a fisheye lens, but uses a reflective optic to provide a 360-degree view. I've built a number of such things other the years. For example, here's a ...

If things showing peaking are from 4 to 6 feet away, the middle distance is 5 feet. DoF is basically an exponential function on distance, so you get a larger distance behind the focus point in ...

I've probably explained this a dozen times here, but the trick is to understand what peaking does. Peaking DOES NOT show what is in best focus. All it does is highlight any areas that meet a ...

I bet the lack of raw is because that lens is doing some nasty stuff that they fix in firmware postprocessing.

Not having raw actually increases the motivation for somebody to hack it, but this is...

This isn't really a 4K camera... it's an outstanding 1080 that lets you master in over-sharpened, artifacted, 4K. That's actually fine; there's a market for that. As for being a bridge, well,...

I'm not one of those people who really gets upset by a scratch or ding on an external part of camera equipment... as long as the glass is clean and everything works, I'm happy. Still, some old ...

AiryDiscus: Not familiar with stop shift theory (the slides didn't quite do it for me either), but I'm certainly aware that position of the stop can play a huge role in controlling aberrations. Is...

Apparently not a compression artifact!  KARWY didn't fix it, but would have it it was a compression artifact, thus, it isn't a compression artifact.... Don't know what it is.

Welcome back, Hasselblad!

It might still be too expensive for me to buy, but at least it's a product I wish I could afford. ;-)

(Although I still wish they'd actually do a medium-format sensor...