Feedback wanted: Calling all 85L owners, wish-listers, & critics

I love my canon 85 1.2. Best lens I own and is always on my camera. Although, can't wait to see a Sigma 85 art!

Poe wrote in post #17876802
There might be a magnification factor I need to account for since the LED is not sufficiently far away from the subject. Below is the chart with the data I collected.

Hosted photo: posted by Poe in
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forum: Canon Lenses

Difficult to say. At f/11 you'd obviously expect a fair bit of depth of field, such that even an out of focus point would still be pretty small (43 pixels diameter seems large). But, if the focal plane was fairly close to the camera then you will obviously have pretty shallow depth of field.

I know that many of the traditional calculations for, say, DOF, become inaccurate at smaller focussing distances. What was your camera to subject distance in this test?

Also, if you focus on the LED, how large is it? I suspect it effectively needs to be a point source for this experiment to give meaningful results. I.e. a single fibre optic wide may be better. Or perhaps put the LED behind a sheet of card with a pin hole in it (I'm not sure if that may result in any diffraction issues though).

Subject distance was about 32" from sensor plane. The LED was a little more than 38" behind the subject. Here's the test shot at f/11.

I would rather Canon make a f/1.4 version that comes close in sharpness to the Otus while keeping the weight (and cost) down. I've owned the f/1.2L II version of it and it was just not that usable till f/1.6 to f/2, which sort of negates the benefits of having a f/1.2 aperture.

Poe wrote in post #17878525
Subject distance was about 32" from sensor plane. The LED was a little more than 38" behind the subject. Here's the test shot at f/11.

Fairly close to the camera then (and the LED was quite a long distance behind the subject, relative to the camera to subject distance). I'd suggesting finding fibre optic or the pin hole method I suggested. I am interested though - I think this is a really good experiment you're trying.

frankchn wrote in post #17878553
I would rather Canon make a f/1.4 version that comes close in sharpness to the Otus while keeping the weight (and cost) down. I've owned the f/1.2L II version of it and it was just not that usable till f/1.6 to f/2, which sort of negates the benefits of having a f/1.2 aperture.

Yea, that's kinda how I feel. There's little point in having an uber wide aperture lens if it's not really that great until it's stopped down. That said, most of Canon's recent lens releases have been excellent, so maybe it's not unreasonable to hope they could build new versions of the f/1.2 lenses that were much improved (both are ~10 years old, IRC).

I think an 85f1.0. Even if it is about 3k, would make a good alternative to the 200f2 to get full body pictures with some nice isolating DoF.

Moncho wrote in post #17895305
I think an 85f1.0. Even if it is about 3k, would make a good alternative to the 200f2 to get full body pictures with some nice isolating DoF.

But, given the results from other ulta-fast (<= f/1.0) lenses I've seen, it'd probably be softer than a soft thing on a soft day. Wide open anyway. It would certainly also be a highly specialised and unusual lens - and not a replacement for the current 85L.

Moncho wrote in post #17895305
I think an 85f1.0. Even if it is about 3k, would make a good alternative to the 200f2 to get full body pictures with some nice isolating DoF.

sploo wrote in post #17895556
But, given the results from other ulta-fast (<= f/1.0) lenses I've seen, it'd probably be softer than a soft thing on a soft day. Wide open anyway. It would certainly also be a highly specialised and unusual lens - and not a replacement for the current 85L.

It's nice to dream. I could see astrophotographers being interested in such a lens if it corrects coma really well.

Frankly I've been really interested lately in evaluating the change in blur discs for f-stops less than 2.8, as well as understanding any behind-the-scenes raw data manipulation by current production camera bodies to account for light loss at f-stops less than 2.8 as well (i.e. DxOMark's 'f-stop blues' article here. Would be nice if they kept those charts updated). My 135 ZF.2 seems to not have any big difference in background blurring ability between f/2.0 and f/2.2, but for an unknown reason sharpess and brightness (i.e. vignette) take a hit at f/2.0 versus f/2.2