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View Full Version : C/V 35/1.4 focus shift confirmation


Benjamin Marks
06-04-2010, 10:45
Well, I know that a lot of electrons have been spilled over whether the C/V 35/1.4 shifts focus as you stop down (and whether it matters). Seeing is believing. I put my new 35/1.4 SC (thanks Hiromu!) on an EP-2, focused wide open using the EVF in "focus magnification" mode and then stopped down the lens while looking through the EVF at a page of text about 2 feet away. You could see the zone of sharp focus moving backwards from the original point of focus so that by 5.6, all of the focused area was behind the original spot. It is actually not a problem with an EP-2 because you can focus stopped down, but I can see it being maddening on an RF camera, unless you knew your lens really well and compensated for it in actual use. I am very much looking forward to learning this lens. The EP-2 will actually be a great learning tool for this sort of lens because you can see what sort of adjustments are needed in real time.

Flame away.

Ben Marks

ferider
06-04-2010, 10:49
No flame.

But do also check the picture corners. While the center shifts, the original soft corners at f1.4 get in focus (non-planar focus plane).

And then, try the same with a pre-asph 50/1.4 Summilux or Noctilux, if you have one.

:)

Roland.

Andy Kibber
06-04-2010, 10:58
Which was the "correct" focus at two feet? The in-focus area at f/1.4 or f/5.6?

Benjamin Marks
06-04-2010, 10:58
Thanks, Roland, that's actually an excellent idea. I have a Noctilux and will report over the weekend regarding the same. Also want to try the C/V 40/1.4, the C/V 50/2 Heliar and the C/V 28/2.

Ben Marks

Benjamin Marks
06-04-2010, 11:02
Which was the "correct" focus at two feet? The in-focus area at f/1.4 or f/5.6?

I tried it both ways Andy. I originally focused at two feet with the lens wide open and then watched what happened as I stopped down without moving the camera. Then I refocused at 5.6 and opened the lens up a half stop at a time. While the shift was pretty dramatic at close distances, at 10 feet it was not so bad -- a matter of a few inches from 1.4 to 5.6. Still it would be enough to notice if you were taking a low-light portrait and focused on the subject's eye.

Ben