Rookie and Autofocus

Macmook

Tenebrous
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Aug 23, 2011
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This may seem like sacrilege and I hate to admit it, but I am having difficulty with AF when wide open. (please don't group me with certain well known PP pundits) I'm certain that user error contributes significantly to the degree of the issue. But unless the focus object is decidedly larger than the center focus box I have too high a number of unfocussed images.

For me autofocus while wide open is fairly inconsistent if the focus target is vertical and is just slightly larger than the focus box. I have repeatedly locked onto objects behind the target with perfect focus and the target not. Generally speaking, in all cases the in actual focus plane is somewhere within 6-10 feet behind the target. In each case I thought the positive acknowledgement was for the centered target. (I rarely change focal points for other than totally static subjects)

I realize I can lock focus, etc. I could also measure or use a rangefinder to estimate distance, but I'm not in a studio and only a fair judge of distance. (something I have repeatedly attempted to cultivate and only marginally improved) Regardless these are work arounds or would dramatically force me to alter my shooting behavior (not necessarily a bad thing).

I am not blaming the equipment. Perhaps the student has more to learn. I also hope not to (re)start any debate about the suitability/features/comparisons, etc. I am just commenting on the difficulty a new owner (me) is having adapting the the manner in which the X100 acquires and locks on target.

Productive tips would be greatly appreciated.

Regards,

Alex
 
The auto-MF

The auto-MF

I had similar problems and have decreased them by using the camera in MF mode and activating AF by pressing the AFL/AEL button.
 
Can't you reduce the size of the focussing point on the x100? I would do this, and see if it helps...
 
Can't you reduce the size of the focussing point on the x100? I would do this, and see if it helps...

Yes, you can (for AF-S mode). Press the AF button on the back left of the camera, and use the jog dial on the upper right to reduce or enlarge the focus box. Reducing it does help.

Edit: At present, you can't change the focus box size in MF mode. I'm hoping this changes in a future firmware release. I use MF most of the time but occasionally will switch to AF-S when the camera is having trouble getting focus lock in "manual" focus mode.
 
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update...

i noticed that the op has sold his x100, on another site...i doubt that he is checking in here for answers.
 
got my x100 yesterday, played with it a bit yesterday and today. tough test this evening, shooting some friends at a backyard from a friend's place and then at a very dim candle lit restaurant. AF had a pretty rough time nailing the correct focus spots, but when it did....


rgz by Marcelo Colmenero, on Flickr

note to self: remember to use uv filters as lens cap and only that. i never shoot with filters on and that kind of ghosting reminded me why...
 
I find the AF to be dead on...

I think I'm a bit too used to focusing with rangefinders, much easier to find a contrast spot and get focus right.

Yesterday I was trying to get focus using AF-S to shoot two friends in a dark bridge, with some contrast areas (light reflex on her chest, i confess :D) AF could find focus, and it's really spot on


belle by Marcelo Colmenero, on Flickr

but when I tried taking a shot of them leaning against the wall i was getting the red focus fail box all the time.. switched to MF and EVF but it was quite slow/hard to focus, so I ended up missing it as it was taking a bit much time and we were all eager to get back home. in the photo the scene looks somewhat bright, but it was VERY dim lit at the time, only with the glow from the streetlights below.


sapeca by Marcelo Colmenero, on Flickr

I got the camera this tuesday, so still i'm very raw (no pun intended). Still gotta find my ways with it, still devouring the threads on tit :)
 
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Yes, you can (for AF-S mode). Press the AF button on the back left of the camera, and use the jog dial on the upper right to reduce or enlarge the focus box. Reducing it does help.

Wow! Thanks! I've been trying to figure that out (although, I didn't look at the manual.. ) I just wish it'd work for the ovf too, seems to only work for the evf. :(
 
It is true that when the contrast is challenging, EVF with the smallest possible focus region in AF-S has the best success rate.

I tend to focus and recompose. But at f 2 in low light focus and recompose is not a universa solution.
 
In general switch from ovf to evf in low light gives u a better chance for the af to get it right.

Gary
 
Steve, are you sure you're not using the camera's AF like a phase-detect system in your DSLR? That is, don't focus on object edges. Rather, focus on object surface structures which fill the entire AF frame.
 
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