DSLR manual focusing issues

"Peter Chant" wrote in message
...
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

You can get viewfinder magnifiers for the K20D, some like them.

On Sun, 23 Aug 2009 00:05:31 +0100, Peter Chant
wrote:

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.

Not awkward at all if it's available right in the viewfinder too. As in
most all P&S cameras with an EVF.

H. Stiles wrote:
On Sun, 23 Aug 2009 00:05:31 +0100, Peter Chant
wrote:

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.

Not awkward at all if it's available right in the viewfinder too. As in
most all P&S cameras with an EVF.

The focus precision we're talking about lies well within the immense DOF
that you get with the typical P&S lens and tiny sensor combo.

On Sun, 23 Aug 2009 10:53:33 -0400, Alan Browne
wrote:

H. Stiles wrote:
On Sun, 23 Aug 2009 00:05:31 +0100, Peter Chant
wrote:

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.

Not awkward at all if it's available right in the viewfinder too. As in
most all P&S cameras with an EVF.

The focus precision we're talking about lies well within the immense DOF
that you get with the typical P&S lens and tiny sensor combo.


You've obviously never used many P&S cameras, and certainly not in
telephoto, macro, and tele-macro modes where the DOF is every bit as
shallow as any dSLR's. EVFs work fine for focusing with shallow DOFs. The
EVF dot-pitch is just right in most all P&S cameras to work as a "reverse
effect" micro-prism focusing aid even when not using magnified
manual-focusing modes. I discovered a unique ability of EVFs about 9 years
ago. Unlike a micro-prism ring in an OVF, where the little triangles in it
scintillate if anything moving across it is out of focus, if any edges or
textures are making the EVF's pixels scintillate then I know that those
areas are in perfect focus. The exact opposite of how an optical
micro-prism focus aid works. The finer in-focus edges and textures cause
the pixels to rapidly change in luminosity as they pass between individual
EVF pixels. Out of focus areas do not cause this due to the wider range of
tones on the blurred edges and textures as they pass between EVF display
pixels. Also not unlike how the more accurate (as opposed to less accurate
phase detection) contrast detection focusing works, but I do it with my eye
and using the EVF, instead of depending on the camera software and sensor
to do the same when auto-focusing.

Sony even expounded on this unusual but subtle principle of EVFs in some of
their cameras a couple years ago, by including an option to color-highlight
any edges and textures that cause this scintillating effect when in perfect
focus in manual-focus modes. For manual focusing I'm able to detect exact
focus across any area of the whole FOV at once, not just one little
micro-prism ring in the center of an OVF. Anyone with a perceptive eye can
do the same in any camera with an EVF. It takes practice to watch for this
effect but once you learn to recognize when it happens and what it looks
like this tool/method is always at your disposal for perfect and fast
manual focusing in EVF equipped cameras. Once I taught myself this and
other new ways of using EVF displays (having previously used OVFs all my
life) I find EVFs more accurate and faster for focusing and more useful and
brighter than any OVF on any camera I've ever used. No contest at all.

You're never going to be able to convince me otherwise when I already know
all of the above from personal experience. From your comment it's obvious
that you don't possess the same -- experience.

H. Stiles wrote:
On Sun, 23 Aug 2009 10:53:33 -0400, Alan Browne
wrote:

H. Stiles wrote:
On Sun, 23 Aug 2009 00:05:31 +0100, Peter Chant
wrote:

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.
Not awkward at all if it's available right in the viewfinder too. As in
most all P&S cameras with an EVF.
The focus precision we're talking about lies well within the immense DOF
that you get with the typical P&S lens and tiny sensor combo.


You've obviously never used many P&S cameras, and certainly not in
telephoto, macro, and tele-macro modes where the DOF is every bit as
shallow as any dSLR's.

No. Now, please run along. This is a dslr group.

Bruce wrote:


You asked for "any thoughts apart from getting a split screen?"

Well, there is a simple answer. Get a split screen. The Katz Eye™
screen will be familiar to anyone who has used a 35mm film SLR with a
split image/microprism collar focusing screen, and it should eliminate
the focusing errors that occur when focusing manually. Cost $105.

http://tinyurl.com/9bvmjc
or:

http://www.katzeyeoptics.com/item--P...prod_K10D.html

But I guess you didn't want to hear about that. ;-)

Interesting site. Not cheap, I wonder how they compare to the pentax ones,
not that I could find a pentax one with a quick google. Worth considering.
I must compare the existing viewfinder with my ME Super.

Pete


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

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. 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.

I don't beleive so, I took slides and also when scanning zoomed right in.
If I'd had simplar problems with previous cameras I would have noticed.


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

Alan Browne wrote:

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.


Why is that? Backlash in the lens?

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.

Something to watch out for, thanks.

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

Paul Furman wrote:



Are you using the AF confirm light?

Sometimes. To be honest I've been shunning my MF lenses, although faster
than my autofocus ones because of the focusing issues. Anti-shake plus AF
zoom in poor light conditions seems to get a better result than faster
manual lens plus anti-shake in poor light. Perhaps poor light has
something to do with it.

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

Alan Browne writes:
No. Now, please run along. This is a dslr group.

BTW, anyone know why the name of the group is "...slr-systems", and not
just "...slr"? The former seems an oddly awkward and clumsy name.

-Miles

--
I'd rather be consing.