DSLR manual focusing issues

Auto focus works fine, but manual focusing, with either autofocus or manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing screen was
out of position it would be consistent. Any thoughts apart from getting a
split screen? PEntax k20d if that makes any difference. I never had this
problem on my MZ-5n despite lack of split screen on that camera.


--
http://www.petezilla.co.uk

Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing screen was
out of position it would be consistent. Any thoughts apart from getting a
split screen? PEntax k20d if that makes any difference. I never had this
problem on my MZ-5n despite lack of split screen on that camera.

Could it be that the ease with which you can inspect every photograph
at the highest possible resolution means that you simply now have much
higher standards of sharpness and focus than you used to in film days?
That's what happened to me. I also found to my great surprise that no
matter how hard I tried, when working with critically sharp DoF, I was
unable to nail focus completely accurately by manual methods. Using a
tripod and taking several seconds over it I'd get it right about one
time in three, whereas autofocus would nail it spot on in a fraction
of a second.

The difference is simply that in film days I'd rarely print as large
as 12"x8", but now I check sharpness down to pixel level, a much
higher standard. As a result I've also had to improve my camera
steadying skills a lot too.

--
Chris Malcolm

Chris Malcolm wrote:


Could it be that the ease with which you can inspect every photograph
at the highest possible resolution means that you simply now have much
higher standards of sharpness and focus than you used to in film days?
That's what happened to me.

me too

But, on the reverse side, the manual focus screens with their
microprism certer areas really did, for static subjects, always
get it right, on my Minolta SRT101 and SRT201 cameras. This is
even with Tech Pan film and the 50mm lens at f/8.


The difference is simply that in film days I'd rarely print as large
as 12"x8", but now I check sharpness down to pixel level, a much
higher standard. As a result I've also had to improve my camera
steadying skills a lot too.


With my calibrated 30D and 24-105 f/4L lens, and with truly flat subjects,
truly perpendicular to the line of sight, autofocus works perfectly.

BUT ... it does not get it uniformly right for most of my subjects,
which are 3D in nature (pun intended, I'm a nature photographer), since they
are often either smaller than the center focus spot and it may focus on
the background, or if there is even a single tree limb in front, it may
focus on that. I've learned to autofocus on some large object that I know is
big enough and the right distance, then move the camera to the
desired subject. This often works better.

Doug McDonald

Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing screen was
out of position it would be consistent. Any thoughts apart from getting a
split screen? PEntax k20d if that makes any difference. I never had this
problem on my MZ-5n despite lack of split screen on that camera.

I too have some "almost" in focus shots when I shoot manual even with
the super acute matte screen designed for high speed lenses. (The
screen increases contrast for focusing). So I've been using AF more
often which I dislike as I'm usually on a tripod with a geared head - so
pointing the AF sensor right and re-composing is a pain.

One "trick" that seems to help is to focus beyond the desired focus
plane and slowly focus back to no further than when the desired area
comes into focus.

IOW avoid bringing the focus closer and then going back out again.
Avoid the old "rocking" technique.

Further, I believe the longer you try to get focus the less likely you
are to get it - an eye fatigue or other physiological issue, perhaps.

Perhaps a Katz-eye or other split prism VF is in order. However this
also may have an effect on exposure readings.

Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing screen was
out of position it would be consistent. Any thoughts apart from getting a
split screen? PEntax k20d if that makes any difference. I never had this
problem on my MZ-5n despite lack of split screen on that camera.

Are you using the AF confirm light?


--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Paul Furman wrote:
Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or
manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing screen
was
out of position it would be consistent. Any thoughts apart from
getting a
split screen? PEntax k20d if that makes any difference. I never had
this
problem on my MZ-5n despite lack of split screen on that camera.

Are you using the AF confirm light?

In my case, not often, as the AF sensor might not be pointed at where I
want focus during manual focus.

Alan Browne wrote:
Paul Furman wrote:
Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or
manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing
screen was
out of position it would be consistent. Any thoughts apart from
getting a
split screen? PEntax k20d if that makes any difference. I never had
this
problem on my MZ-5n despite lack of split screen on that camera.

Are you using the AF confirm light?

In my case, not often, as the AF sensor might not be pointed at where I
want focus during manual focus.

Live view zoomed in is great for tripod work, even though it doesn't go
to full pixel zoom.

--
Paul Furman
www.edgehill.net
www.baynatives.com

all google groups messages filtered due to spam

Paul Furman wrote:
Alan Browne wrote:
Paul Furman wrote:
Peter Chant wrote:
Auto focus works fine, but manual focusing, with either autofocus or
manual
lenses does not seem to. I've tested and the point that is in focus is
sometimes in the right place, sometimes before and sometimes after the
desired position. It seems to be inconsistent, if the focusing
screen was
out of position it would be consistent. Any thoughts apart from
getting a
split screen? PEntax k20d if that makes any difference. I never
had this
problem on my MZ-5n despite lack of split screen on that camera.

Are you using the AF confirm light?

In my case, not often, as the AF sensor might not be pointed at where
I want focus during manual focus.

Live view zoomed in is great for tripod work, even though it doesn't go
to full pixel zoom.

Alas, I don't have live view. Perhaps on a future body.

Peter Chant wrote in
:

Auto focus works fine, but manual focusing, with either autofocus or
manual lenses does not seem to. I've tested and the point that is in
focus is sometimes in the right place, sometimes before and sometimes
after the desired position. It seems to be inconsistent, if the
focusing screen was out of position it would be consistent. Any
thoughts apart from getting a split screen? PEntax k20d if that makes
any difference. I never had this problem on my MZ-5n despite lack of
split screen on that camera.



Get a camera with magnified live view.

Rich wrote:

Peter Chant wrote in
:

Auto focus works fine, but manual focusing, with either autofocus or
manual lenses does not seem to. I've tested and the point that is in
focus is sometimes in the right place, sometimes before and sometimes
after the desired position. It seems to be inconsistent, if the
focusing screen was out of position it would be consistent. Any
thoughts apart from getting a split screen? PEntax k20d if that makes
any difference. I never had this problem on my MZ-5n despite lack of
split screen on that camera.



Get a camera with magnified live view.

It does that. Rather awkward compared to using a viewfinder.

--
http://www.petezilla.co.uk