focus problems

[Irv Negrin]

I mentioned in an earlier thread that I felt the focus problems some have been experiencing where more related to subject matter than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a slight shift in focus point. Both should be on the dog's face as it fills a good part of the frame. Why is the first way out of focus and the second nearly perfect. Could it be the first tried to focus directly on the nose or left side of the face which is not square to the camera. The second probably focused on the left side of the face which is pretty square to the camera. I've gotten many out of focus shots of this dog so the only conclusion I can draw is his hair color and texture does not reflect well enough for the focus system to behave properly, regardless of ambient light level. It seems to be getting confused because lock is always achieved yet sometimes wrong. Because of the angle of the shot, the in focus plane is only on the top left and right of the picture, so is unlikely due to a misaligned focus point. 420ex was used for both pictures.

I did do some testing with the focus point above theory (which would be on the right in these pictures but still got intermittent out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun filled room while the second was at night in the same room lit with a 60 watt lamp only. I took many pictures in both settings and experienced no out of focus problems whatsoever. Internal flash was used for both pictures.

Irv

 

[BryanS]

Have you tried macro mode when in that close? I stand by my theory that because of parallax issues, that change is necessary when inside of 3 feet or so.

Bryan

I mentioned in an earlier thread that I felt the focus problems
some have been experiencing where more related to subject matter
than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a
slight shift in focus point. Both should be on the dog's face as
it fills a good part of the frame. Why is the first way out of
focus and the second nearly perfect. Could it be the first tried
to focus directly on the nose or left side of the face which is not
square to the camera. The second probably focused on the left side
of the face which is pretty square to the camera. I've gotten many
out of focus shots of this dog so the only conclusion I can draw is
his hair color and texture does not reflect well enough for the
focus system to behave properly, regardless of ambient light level.
It seems to be getting confused because lock is always achieved yet
sometimes wrong. Because of the angle of the shot, the in focus
plane is only on the top left and right of the picture, so is
unlikely due to a misaligned focus point. 420ex was used for both
pictures.

I did do some testing with the focus point above theory (which
would be on the right in these pictures but still got intermittent
out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun
filled room while the second was at night in the same room lit with
a 60 watt lamp only. I took many pictures in both settings and
experienced no out of focus problems whatsoever. Internal flash
was used for both pictures.

Irv

 

[Irv Negrin]

I could see macro mode helping since it would limit the error by setting the focus plane at the max of 2.3 feet specified which could be within the DOF when shooting at 3 ft resulting in an overall good shot. I've also had similar results from a further distance which macro mode wouldn't help.

What's interesting about these two pictures is that they were both taken with exactly the same settings but the autofocus gets one wrong and the other right. What is it seeing differently? If I could understand that than I could compensate to get more consistent results at all distances.

Thanks,
Irv

Bryan

I mentioned in an earlier thread that I felt the focus problems
some have been experiencing where more related to subject matter
than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a
slight shift in focus point. Both should be on the dog's face as
it fills a good part of the frame. Why is the first way out of
focus and the second nearly perfect. Could it be the first tried
to focus directly on the nose or left side of the face which is not
square to the camera. The second probably focused on the left side
of the face which is pretty square to the camera. I've gotten many
out of focus shots of this dog so the only conclusion I can draw is
his hair color and texture does not reflect well enough for the
focus system to behave properly, regardless of ambient light level.
It seems to be getting confused because lock is always achieved yet
sometimes wrong. Because of the angle of the shot, the in focus
plane is only on the top left and right of the picture, so is
unlikely due to a misaligned focus point. 420ex was used for both
pictures.

I did do some testing with the focus point above theory (which
would be on the right in these pictures but still got intermittent
out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun
filled room while the second was at night in the same room lit with
a 60 watt lamp only. I took many pictures in both settings and
experienced no out of focus problems whatsoever. Internal flash
was used for both pictures.

Irv

 

[Irv Negrin]

The dog pictures where taken with a focal length of 31 so I estimate was about 5 to 6 feet away. If you get too close, he thinks you want to play and start licking the camera No macro in this situation.

Thanks, Irv

Bryan

I mentioned in an earlier thread that I felt the focus problems
some have been experiencing where more related to subject matter
than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a
slight shift in focus point. Both should be on the dog's face as
it fills a good part of the frame. Why is the first way out of
focus and the second nearly perfect. Could it be the first tried
to focus directly on the nose or left side of the face which is not
square to the camera. The second probably focused on the left side
of the face which is pretty square to the camera. I've gotten many
out of focus shots of this dog so the only conclusion I can draw is
his hair color and texture does not reflect well enough for the
focus system to behave properly, regardless of ambient light level.
It seems to be getting confused because lock is always achieved yet
sometimes wrong. Because of the angle of the shot, the in focus
plane is only on the top left and right of the picture, so is
unlikely due to a misaligned focus point. 420ex was used for both
pictures.

I did do some testing with the focus point above theory (which
would be on the right in these pictures but still got intermittent
out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun
filled room while the second was at night in the same room lit with
a 60 watt lamp only. I took many pictures in both settings and
experienced no out of focus problems whatsoever. Internal flash
was used for both pictures.

Irv

 

[Irv Negrin]

I meant 21, oops typo.

Thanks, Irv

Bryan

I mentioned in an earlier thread that I felt the focus problems
some have been experiencing where more related to subject matter
than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a
slight shift in focus point. Both should be on the dog's face as
it fills a good part of the frame. Why is the first way out of
focus and the second nearly perfect. Could it be the first tried
to focus directly on the nose or left side of the face which is not
square to the camera. The second probably focused on the left side
of the face which is pretty square to the camera. I've gotten many
out of focus shots of this dog so the only conclusion I can draw is
his hair color and texture does not reflect well enough for the
focus system to behave properly, regardless of ambient light level.
It seems to be getting confused because lock is always achieved yet
sometimes wrong. Because of the angle of the shot, the in focus
plane is only on the top left and right of the picture, so is
unlikely due to a misaligned focus point. 420ex was used for both
pictures.

I did do some testing with the focus point above theory (which
would be on the right in these pictures but still got intermittent
out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun
filled room while the second was at night in the same room lit with
a 60 watt lamp only. I took many pictures in both settings and
experienced no out of focus problems whatsoever. Internal flash
was used for both pictures.

Irv

 

[BryanS]

Irv,

If you were around 3 feet away or closer, I might have some evidence of the problem. With 21 focal length, that's a real possibility that you were that close, since this is pretty wide.

Check out the following:

http://www.dpreview.com/forums/read.asp?forum=1010&message=735230

Here, I have evidence that the focus point when that close is very high and to the left in the frame. Switching to Macro mode fixes the probem.

Thanks.

Bryan

Thanks, Irv

Bryan

I mentioned in an earlier thread that I felt the focus problems
some have been experiencing where more related to subject matter
than lighting or focus point. Check this link for some examples:

http://albums.photopoint.com/j/AlbumIndex?u=1434696&a=10844220

The two dog pictures where taken one after another with just a
slight shift in focus point. Both should be on the dog's face as
it fills a good part of the frame. Why is the first way out of
focus and the second nearly perfect. Could it be the first tried
to focus directly on the nose or left side of the face which is not
square to the camera. The second probably focused on the left side
of the face which is pretty square to the camera. I've gotten many
out of focus shots of this dog so the only conclusion I can draw is
his hair color and texture does not reflect well enough for the
focus system to behave properly, regardless of ambient light level.
It seems to be getting confused because lock is always achieved yet
sometimes wrong. Because of the angle of the shot, the in focus
plane is only on the top left and right of the picture, so is
unlikely due to a misaligned focus point. 420ex was used for both
pictures.

I did do some testing with the focus point above theory (which
would be on the right in these pictures but still got intermittent
out of focus when shooting the dog.

The first Buzz Lightyear was taken during the day in a bright sun
filled room while the second was at night in the same room lit with
a 60 watt lamp only. I took many pictures in both settings and
experienced no out of focus problems whatsoever. Internal flash
was used for both pictures.

Irv