Andy, if I understand your test, you used the Brevis at F4 (on a F1.4) lens. That in itself is not a fair comparison as the DOF at F4 is much, much deeper than at F1.4. I am concerned that some folks are being "scared" by this, without understanding perhaps the conditions of the test.
I compared the Brevis at f4 and f1.4 against the poc20 at f4 and f1.4, so the only difference was that the cam went to 3db gain on the poc20. With the Brevis when I went from f4 to f1.4 I saw negligible change in the dof, not so with the poc20, it's much more apparent.
It's also critical to isolate the 35mm lens from the rest of the test conditions...for example the haze at full open aperture.
True and I've compared the diffusers on the Nikon lens, it's just that I can't mount the Nikon on my adapter. The difference between the Nikon and the Takumar (both f1.4s) is not visible next to the difference in bokeh caused by the diffuser. I'm not sure how the lens would affect haze at open aperture, I see no difference between them. I thought the haze was entirely down to the diffuser, maybe you've seen something else?
Also, I've observed with my spinner (mechanically blasted spinning diffusor) that "good" bokeh at F1.4 with my lens, that is, specular highlights showing the blade pattern of of the aperture on a fully open lens is impossible. They're just mush until the lens is stopped down to F8 or so. Remember that's on a high diffusion (2.5 f/stop) diffusor.
It depends on the diffusion to light loss ratio of the diffuser. POC20 is pretty good in that respect, maybe your high diffsion spinner had to much light loss and that's what rendered it impossible, I think it is possible with the poc20.
But it's true I've noticed the same thing the circles start turning to mush with the lens open, I think that happens when the light loss overcomes them, but with poc20 you still get virtually solid circles on bright lights, as shown in my demo, they look better at f2. With poc20 you don't need to go to f8 to get them.
I've deliberately shot at F4 on my Minolta F1.4 to get a much larger field of focus, and the difference between F1.4 and F4 is very large.
With the Brevis as I open from f4 to f1.4 I see no change in the dof but I do see the ghost of the disc expand around a highlight. That'swith my Nikon 50mm f1.4.
As far as haze, I honestly have not seen any of this, on any of the cams I tested. It makes me wonder if there is a reflection issue with your adapter. I'm interested to see the same test but at F1.4 with both diffusors.
Ummm the video already includes that comparision, freeze frame and read the text at the bottom. I compared f1.4 against f1.4 and f4 against f2 I think. The second shot Brevis at f1.4 is much hazier than the third shot poc20 at f1.4.
After I ordered the Brevis I went back and looked at your demo footage. It looks hazy to me. The HVX squeeze dolly shot on the watering can looks very hazy to me. When I say haze I mean on out of focus areas. Would probably look better with some colour correction, and the light looked pretty flat as well. But I can definitely see a difference in apparent haze between poc20 and Brevis, just look at the example I posted.
Francois - not to put words in your mouth, but you're seeing the same differences I'm seeing between straight Brevis and extra diffusion in your own tests?