Pentacon Six to Canon problem - misfocused

[pepes]

I have problem with lens from P6 adapt to Canon EOS - adapter with AF confirm
I own Canon EOS 1100D - when use M42 lens like Pancolar, flektogon - AF confirm M42 adapter - focusing is very well.

I have problem with correct focusing - AF reduction beep when is focused (image in viewfinder is relative sharp) but final image on LCD is not right focused , I must turn focusing ring few degrees to left - anyone help with this problem ?)

I try P6 lens Biometar 80, Flektogon 50, Sonnar 180 - same result.

Adapter is china from Ebay .
I ordered now origin adapter from pentacon to M42 (next I must add M42 to CAnon adapter) - I try when item arrived and post result

[ManualFocus-G]

This is likely to be an adapter chip which isn't calibrated to your body, much the same as you can buy a lens which isn't calibrated properly to a body. I usually get around this by ordering adapters with an EMF chip, which you can micro-adjust to suit your camera.

[buerokratiehasser]

I dunno, the af confirm sees the imaeg just as it will be shot.
or main sensor, it's all a question of matching distances) If it works with other lenses the sensors (
or main sensor, it's all a question of matching distances) probably are not mis-calibrated too much.

What I heard is that the sensors are optimised for some average aperture A, 4 or 2.8 may be common (more like 4 with digital and its slow lenses).

I havent really thought this through but perhaps with the larger dimensions of MF, more light gets through and you have resulting bigger aperture (I know that F-stops are exposure invariant but it's not relevant how much light hits the area, but where the AF sensor is located relative to the middle)

Can you try focusing with stopped down lens and tell us if that changes anything?

[ManualFocus-G]

Focusing stopped down won't prove much as far more of the image will be in focus anyway.

Chipped adapters for Canon EOS bodies have always been hit or miss in my experience. As I say, the programmable ones are much better, but I tend to rely on my naked eye with plain adapters (easier on full frame than crop of course tho!).

[pepes]

Now I try Flektogon 4/50 P6, I stand camera to tripod, I try focusing on good contrasty object - AF reduction beep .Take shot. I look on picture - misfocused. I try on F4, F5.6 and f8 too - result is same misfocused image

I switch on Live View (on LCD image is misfocused) I turn focus ring to left and image on LCD is perfectly sharp - final picture is perfect.

I try short distance object and infinity object too - it is same on AF confirm.

Next week waiting delivery for original reduction P6 to M42 . I post result with this one

[visualopsins]

EDIT! THIS IS WRONG! see next post: pepes, some AF chip (Dandelion) can be programmed to correct AF indication to match focus in live view (correct focus) by using camera's AF adjustment. Check documentation for your AF chip.

[visualopsins]

Note focus adjustment problems are most evident when using fast wide-angle lenses, because focus differences are large compared to adjustment differences.


A. When using non-P6 adapter and using Live View to focus, the resulting image is in focus.

B. When using non-P6 adapter and using the viewfinder to focus, the resulting image is in focus.

3. When using P6 adapter and using Live View to focus, the resulting image is in focus.

4. When using P6 adapter and using the viewfinder to focus, the resulting image is in focus.

If 3 and 4 are true, then B cannot be true. That leaves 3 and 4, which indicate the focus screen needs to be shimmed (or shim removed) so viewfinder focus will match Live View focus.

[ManualFocus-G]