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-   -   HELP! AF issues with 50-200 on E-M1ii (http://e-group.uk.net/forum/showthread.php?t=46000)

pdk42 28th August 2017 12:35 PM

AF issues with 50-200 on E-M1ii
 
I've noticed that my 50-200 tends to miss focus (I think front-focusing) when the subject is distant. It's fine at closer distances. If I manually focus then it's fine, as it is if I use the "Pre-AF" function on the camera with the distance set to its maximum.

I could try focus calibration I guess, but I'm concerned that would throw off focus on near subjects.

Thoughts?

Ross the fiddler 28th August 2017 01:05 PM

Re: AF issues with 50-200 on E-M1ii
 
Quote:

Originally Posted by pdk42 (Post 426068)
I've noticed that my 50-200 tends to miss focus (I think front-focusing) when the subject is distant. It's fine at closer distances. If I manually focus then it's fine, as it is if I use the "Pre-AF" function on the camera with the distance set to its maximum.

I could try focus calibration I guess, but I'm concerned that would throw off focus on near subjects.

Thoughts?

Maybe you're experiencing issues I had (with the 40-150 Pro +MC14) & the cross PD-AF sensing is larger than you're allowing for (being larger than indicated in the display & EVF). Or maybe not.
Can you show us the scene (image) with what you're trying to focus on? The front focussed image & with a small crop enlarged would be good.

EDIT: You may still need to adjust Fine AF though.

pdk42 28th August 2017 01:12 PM

Re: AF issues with 50-200 on E-M1ii
 
Quote:

Originally Posted by Ross the fiddler (Post 426070)
Maybe you're experiencing issues I had (with the 40-150 Pro +MC14) & the cross PD-AF sensing is larger than you're allowing for (being larger than indicated in the display & EVF).
Can you show us the scene (image) with what you're trying to focus on?

EDIT: You may still need to adjust Fine AF though.

Thanks Ross. I don't have immediate examples at hand, but I tried to take some shots of a distant helicopter yesterday that showed the problem pretty clearly (or not clearly, if you see what I mean!). The subject was against a clear blue sky (I know, a rarity in Blighty) ao I don't think it's AF area related. Other examples I've had have been on landscape shots with distant tress with nothing in a nearer focal plane to upset the AF. I'll take some shots later and post to show some examples.

Ross the fiddler 28th August 2017 01:15 PM

Re: AF issues with 50-200 on E-M1ii
 
Quote:

Originally Posted by pdk42 (Post 426071)
Thanks Ross. I don't have immediate examples at hand, but I tried to take some shots of a distant helicopter yesterday that showed the problem pretty clearly (or not clearly, if you see what I mean!). The subject was against a clear blue sky (I know, a rarity in Blighty) ao I don't think it's AF area related. Other examples I've had have been on landscape shots with distant tress with nothing in a nearer focal plane to upset the AF. I'll take some shots later and post to show some examples.

That sounds like you need to do those adjustments. Maybe do the tele end for longer distance subjects & the wide end with closer subjects. When doing my 50-200 SWD lens on the E-M1 I only needed to do the tele end. It may be fine after the adjustment for closer subjects still. I think you'll need to suck & see.

Ricoh 28th August 2017 01:23 PM

Re: AF issues with 50-200 on E-M1ii
 
It's a while since I've thought about the 'dreaded' AF lens system... as a consequence I can't remember if the lens 'acquires' focus wide open, then stops down immediately prior to exposure. Is that correct? If so it could be 'focus shift' as a consequence of stopping down, closing the aperture.

GyRob 28th August 2017 06:13 PM

Re: AF issues with 50-200 on E-M1ii
 
Yes sounds correct to me .
Rob.


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