Autofocus with the FA 31mm and FA 43mm limiteds
Steve
Half Backs: K10+BG,DA16-45, DA50-200
Backs: LXs,Super As and lots of A, M & K lenses
Impact Subs: 28mm Shift, K 135-600 (the Banahan of Pentax zooms ), 400-600 Reflex
The green hexagon flickers a lot more with these lenses - so that I can't take the pictures (if in AF.S). This is especially true for quite close subjects (single portraits) in low light.
Got both and neither given me any problems. Nor have I seen anything about either lens having AF issues.
Steve
Bodies: K20D (2), K10D, Super A, ME Super, Auto 110 SLR, X70, Optio P70
Pentax Glass: DA* 300, DA* 60-250, DA* 50-135, DA* 16-50, DA 70 Ltd, FA 31 Ltd, DA 35 Ltd, DA 18-55 (2), DA 12-24, DA 10-17, M 200, A 35-70, M 40, M 28, Converter-A 2X-S, 1.4X-S, AF 1.7, Pentax-110 50, Pentax-110 24
Other Glass: Sigma 105 macro, Sigma-A APO 75-300
Flash: Metz 58 AF-1 P, Pentax AF160FC ringflash, Pentax AF280T
Do you think it is possible that front/back focus problems could cause the green focus indicator to flicker?
The green hexagon flickers a lot more with these lenses - so that I can't take the pictures (if in AF.S). This is especially true for quite close subjects (single portraits) in low light.
That will be because you are swaying backwards and forwards. The depth of field in the viewfinder and to the AF sensors will be very thin. If you sway a centimetre the camera may loose focus lock. Hold the camera steadier, steady yourself, brace yourself, use a tripod and control your breathing. Don't know if you've ever been shooting but you can steady your aim quite a bit by controlling your breathing.
The green hexagon flickers a lot more with these lenses - so that I can't take the pictures (if in AF.S). This is especially true for quite close subjects (single portraits) in low light.
That will be because you are swaying backwards and forwards. The depth of field in the viewfinder and to the AF sensors will be very thin. If you sway a centimetre the camera may loose focus lock. Hold the camera steadier, steady yourself, brace yourself, use a tripod and control your breathing. Don't know if you've ever been shooting but you can steady your aim quite a bit by controlling your breathing.
Do you think it is possible that front/back focus problems could cause the green focus indicator to flicker?
No. Once the AF has locked on something, it won't try to "change it's mind"
K.
It is an illusion that photos are made with the camera… they are made with the eye, heart and head. Henri Cartier-Bresson
Lots of film bodies, a couple of digital ones, too many lenses (mainly older glass) and a Horseman LE 5x4.
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I have now checked the lens focus with a simple focus test chart and made an adjustment of -2. It was slightly front focussing.
It occurs to me that if I am taking a picture of a person (not an obedient model) at close range, then there would be combined swaying between me and the object - even if seated.
I tested the lens in the sun today and all seemed well - it took a little while to focus, but the af indicator didn't flicker so I wasn't prevented from taking shots. So either (a) good light, or (b) a still subject sorted this out.
The af problem I am sensing may be just the swaying combined with the FA 43mm not focussing as fast as my DA 40, which I understand is a fast lens.
So the new request is: any tips on slightly moving subjects at close range in low light?
I realise this may be some kind of holy grail of focussing...
Which focus mode are you using? Do you get the problem with AF-S or AF-C?
K.
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38 posts
16 years
London
I have heard this mentioned before, but I have much more difficulty auto-focussing with these lenses than other lenses such as the DA 21mm and the DA 40mm.
Does anyone have any tips or workarounds to improve focus performance?
For instance, I have read that some people improve the FA 31mm flare performance by adding a stop down ring or filter rings as a makeshift hood. Would this also improve auto-focus?