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EF 50/1.8 AF Experiment?



 
 
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  #21  
Old December 21st 09, 12:22 PM posted to rec.photo.digital.slr-systems
Chris Malcolm[_2_]
external usenet poster
 
Posts: 3,142
Default EF 50/1.8 AF Experiment?

Wilba wrote:
Chris Malcolm wrote:
Wilba wrote:

The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.


But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy
images to work with, how /could/ the system nail the focus in difficult
conditions?


It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there
a consequence of either hypothesis that could be disproved empirically?


The AF sensors pay no attention to the aperture at which you're going
to take the picture. They do their work before the lens is stopped
down. Their construction gives them an effective aperture of their
own. Often this is around f6. That means that when the largest
aperture of a lens is smaller than that they can't get enough light to
work properly. That's why generally speaking you can't make reflex
lenses autofocus, because for technical reasons their best compromise
aperture is often smaller than that, e.g. 500mm f8.

More expensive DSLRs will also have larger aperture AF sensors at the
central position, e.g. around f3, with which they'll be able to get
focus in lower light with lenses which with max apertures which open
that far. It also improves the focus on very fast lenses with
spherical aberration and corresponding aperture related focus drift,
such as the old spherical type of 50mm f1.4 lenses.

Since the DOF gets very thin indeed at wide apertures and close
portrait type distances, which is often what is going on in a dimly
lit interior, the slightest error in AF will leave the image blurred
at the point you wished to focus on, and sharp nearby. For example in
a portrait you might have focused on the eyes, and find that the eyes
aren't in focus, but the tip of the nose, or the ears, are. The reason
for that is often that when DoF gets so sharp it becomes smaller than
the small residual error in the AF of your camera, i.e. your camera
has a slight front or back focus in the AF sensor plane calibration
which is larger than the DoF at these wide apertures.

If you find a systematic error of this type in your camera than you
either must switch to manual focus, or compensate yourself, e.g. by
holding down focus on the eyes and then simply moving your head back
or forwards a few cm to take up the systematic error.

Usually the more expensive DSLRs have better AF sensors so they can
focus better in lower light. The wider aperture AF sensors are also
able to get a tighter focus for wide aperture low light work because
the AF sensor itself has effectively a shallower DoF. That will also
rein in some of the aperture related focus drift of wide aperture
spherical lenses.

The more expensive DSLRs are also sometimes able to read lens-specific
focus compensation factors from the lens, and use that to trim out
systematic errors in autofocus for that specific lens.

The most expensive DSLRs go one better than that. They have user
trimmable tables of focus compensation for specific lenses in order to
get better focus with the more awkward lenses in the more awkward
situation, in which the AF will have slight lens-specific systematic
focus errors.


Thanks for your effort. Unfortunately, there is no answer to my question
within it. :- )


Your qestion doesn't make sense because you don't understand enough
about what might be going on with your specific camera and your
specific focus difficulties. Your questions need to be revised in the
light of an improved understanding, part of which must come from doing
some experiments of your own to discover exactly what with your
specific camera and focus problems the most important problems
are. For example, your problems could be simply not enough light for
your camera's AF sensors to work properly. If so there's nothing you
can do with the way you use your lens to improve that. But there are
several ways of helping your AF to work better in poor light. On the
other hand your difficulties could be due to a small AF calibration
error which starts to matter under those circumstances with your
lens. If so there are a number of things you can do about that.

But it's not worth going into all the details of all the possibilities
until you have found out more about which particular limitation of the
several possibilities your camera and lens are coming up against.

--
Chris Malcolm
  #22  
Old December 21st 09, 10:33 PM posted to rec.photo.digital.slr-systems
Alan Browne
external usenet poster
 
Posts: 12,640
Default EF 50/1.8 AF Experiment?

On 09-12-21 0:40 , Wilba wrote:
Alan Browne wrote:
Wilba wrote:


Those shots were focussed using contrast detection. Any error you might
perceive is of the order of the typical shot-to-shot variation.

That softness may fall outside the AF hysteresis band.


More information please.


In order to avoid hunting near focus, the system is designed with an
error band such that once the focus lies within that band the focus
action (control loop) can stop. Otherwise there could be hunting. For
most lenses, the sharpest focus falls somewhere inside the hysteresis
band. With your 50, the AF might determine the focus as in there or
slightly to either side making the focus error range larger. This due
to the softness wide open. The control loop must have several stop
(exit) conditions including 'best case' (to cover this case as well as
dim light).

There may also be more mechanical slop built in to the lens to allow for
a smaller motor to drive it. That's harder to pinpoint.
  #23  
Old December 22nd 09, 12:04 AM posted to rec.photo.digital.slr-systems
Wilba[_3_]
external usenet poster
 
Posts: 572
Default EF 50/1.8 AF Experiment?

Chris Malcolm wrote:
Wilba wrote:
Chris Malcolm wrote:
Wilba wrote:

The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy images to work with, how /could/ the system nail the focus in
difficult conditions?

It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there
a consequence of either hypothesis that could be disproved empirically?

The AF sensors pay no attention to the aperture at which you're going
to take the picture. They do their work before the lens is stopped
down. Their construction gives them an effective aperture of their
own. Often this is around f6. That means that when the largest
aperture of a lens is smaller than that they can't get enough light to
work properly. That's why generally speaking you can't make reflex
lenses autofocus, because for technical reasons their best compromise
aperture is often smaller than that, e.g. 500mm f8.

More expensive DSLRs will also have larger aperture AF sensors at the
central position, e.g. around f3, with which they'll be able to get
focus in lower light with lenses which with max apertures which open
that far. It also improves the focus on very fast lenses with
spherical aberration and corresponding aperture related focus drift,
such as the old spherical type of 50mm f1.4 lenses.

Since the DOF gets very thin indeed at wide apertures and close
portrait type distances, which is often what is going on in a dimly
lit interior, the slightest error in AF will leave the image blurred
at the point you wished to focus on, and sharp nearby. For example in
a portrait you might have focused on the eyes, and find that the eyes
aren't in focus, but the tip of the nose, or the ears, are. The reason
for that is often that when DoF gets so sharp it becomes smaller than
the small residual error in the AF of your camera, i.e. your camera
has a slight front or back focus in the AF sensor plane calibration
which is larger than the DoF at these wide apertures.

If you find a systematic error of this type in your camera than you
either must switch to manual focus, or compensate yourself, e.g. by
holding down focus on the eyes and then simply moving your head back
or forwards a few cm to take up the systematic error.

Usually the more expensive DSLRs have better AF sensors so they can
focus better in lower light. The wider aperture AF sensors are also
able to get a tighter focus for wide aperture low light work because
the AF sensor itself has effectively a shallower DoF. That will also
rein in some of the aperture related focus drift of wide aperture
spherical lenses.

The more expensive DSLRs are also sometimes able to read lens-specific
focus compensation factors from the lens, and use that to trim out
systematic errors in autofocus for that specific lens.

The most expensive DSLRs go one better than that. They have user
trimmable tables of focus compensation for specific lenses in order to
get better focus with the more awkward lenses in the more awkward
situation, in which the AF will have slight lens-specific systematic
focus errors.


Thanks for your effort. Unfortunately, there is no answer to my question
within it. :- )


Your qestion doesn't make sense because you don't understand enough
about what might be going on with your specific camera and your
specific focus difficulties. Your questions need to be revised in the
light of an improved understanding, part of which must come from doing
some experiments of your own to discover exactly what with your
specific camera and focus problems the most important problems
are. For example, your problems could be simply not enough light for
your camera's AF sensors to work properly. If so there's nothing you
can do with the way you use your lens to improve that. But there are
several ways of helping your AF to work better in poor light. On the
other hand your difficulties could be due to a small AF calibration
error which starts to matter under those circumstances with your
lens. If so there are a number of things you can do about that.

But it's not worth going into all the details of all the possibilities
until you have found out more about which particular limitation of the
several possibilities your camera and lens are coming up against.


I'm not having focus difficulties. The question is stated in the 5th
paragraph. All the rest is preamble.


  #24  
Old December 22nd 09, 12:15 AM posted to rec.photo.digital.slr-systems
Wilba[_3_]
external usenet poster
 
Posts: 572
Default EF 50/1.8 AF Experiment?

Alan Browne wrote:
Wilba wrote:
Alan Browne wrote:


That softness may fall outside the AF hysteresis band.


More information please.


In order to avoid hunting near focus, the system is designed with an error
band such that once the focus lies within that band the focus action
(control loop) can stop. Otherwise there could be hunting. For most
lenses, the sharpest focus falls somewhere inside the hysteresis band.
With your 50, the AF might determine the focus as in there or slightly to
either side making the focus error range larger. This due to the softness
wide open. The control loop must have several stop (exit) conditions
including 'best case' (to cover this case as well as dim light).


Thanks, no worries with all that, I just hadn't heard the term before.

What you say fits with my thinking, the problem is finding a way to test the
theories.

There may also be more mechanical slop built in to the lens to allow for a
smaller motor to drive it. That's harder to pinpoint.


It sure feels and sounds like a crude sloppy mechanism with the 50/1.8, and
I'm sure that has a lot to do with people inferring that that causes the
focus performance they observe.


  #25  
Old December 22nd 09, 04:08 AM posted to rec.photo.digital.slr-systems
rwalker
external usenet poster
 
Posts: 484
Default EF 50/1.8 AF Experiment?

On Mon, 21 Dec 2009 14:04:56 +0800, "Wilba"
wrote:

snip


Yeah, we're not all called Bruce.

Only the philosophers.
  #26  
Old December 25th 09, 10:34 PM posted to rec.photo.digital.slr-systems
Paul Furman
external usenet poster
 
Posts: 7,367
Default EF 50/1.8 AF Experiment?

Wilba wrote:
The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2) erratic
focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are not
able to provide the required accuracy and control of motion of the focus
ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have fuzzy
images to work with, how /could/ the system nail the focus in difficult
conditions?

It would be interesting to see what happens when the AF sensors have sharper
images to work with (e.g. at f/2.8 or f/4), but my 450D refuses to AF when
the DOF preview button is pressed, so I can't test that. External aperture
perhaps?

Any ideas for how these competing hypotheses could be tested? Is there a
consequence of either hypothesis that could be disproved empirically?


If you are using the center AF point, sharpness shouldn't be a problem.
In fact the shallower DOF should improve accuracy.

One factor could be the phenomenon where focus shifts when stopping
down, but I suspect they've included corrections for that in the
firmware. There could also be issues with curvature of field, if you are
concerned about something off to the side, etc.

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

all google groups messages filtered due to spam
  #27  
Old December 25th 09, 11:56 PM posted to rec.photo.digital.slr-systems
Wilba[_3_]
external usenet poster
 
Posts: 572
Default EF 50/1.8 AF Experiment?

Paul Furman wrote:
Wilba wrote:

The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy images to work with, how /could/ the system nail the focus in
difficult conditions?

It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there a
consequence of either hypothesis that could be disproved empirically?


If you are using the center AF point, sharpness shouldn't be a problem.


I can interpret that to mean several different things. What do you mean
exactly?

In fact the shallower DOF should improve accuracy.


I think that's part of why the "crude mechanism" theory is so popular, but I
can't think of any way to test it. I'm not interested in theory or
speculation except that which leads to an experiment which proves something.

One factor could be the phenomenon where focus shifts when stopping down,
but I suspect they've included corrections for that in the firmware.


If that were a factor I would expect to see a consistent mis-focus, but
that's not what I get.

There could also be issues with curvature of field, if you are concerned
about something off to the side, etc.


I'm not. :- )


  #28  
Old December 26th 09, 04:39 AM posted to rec.photo.digital.slr-systems
Paul Furman
external usenet poster
 
Posts: 7,367
Default EF 50/1.8 AF Experiment?

Wilba wrote:
Paul Furman wrote:
Wilba wrote:
The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy images to work with, how /could/ the system nail the focus in
difficult conditions?

It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there a
consequence of either hypothesis that could be disproved empirically?

If you are using the center AF point, sharpness shouldn't be a problem.


I can interpret that to mean several different things. What do you mean
exactly?


Sharpness shouldn't be a problem in the center. I was doing some lens
tests with macro stacking software and just for curiosity tried some
really fast primes, much closer than they were designed for, not
reversed or anything... and was amazed that the center performance was
excellent wide open. That quickly degraded to 'hideous' outside the
middle third though.
http://www.flickr.com/photos/edgehil...7603231101723/

If you have extension tubes or a bellows, try it at extreme closeup.
That's a good way to make flaws much more obvious. It may not apply to
normal operation though.

In fact the shallower DOF should improve accuracy.


I think that's part of why the "crude mechanism" theory is so popular, but I
can't think of any way to test it. I'm not interested in theory or
speculation except that which leads to an experiment which proves something.


Lots of ways to test. Do a series at the same spot but defocus manually,
first several starting from infinity, then several from closest focus,
then from just slightly off in each direction. Do that for something up
close then something 30 feet away.

You could try your stopped down theory by putting a piece of black paper
with a hole punched on the front, but might try testing first that it
doesn't make things less sharp due to non-optimal aperture placement.
Put the paper aperture in the right place in back and the lens becomes
telecentric, meaning light rays travel straight out the front and the
field of view is no wider than the front element.


One factor could be the phenomenon where focus shifts when stopping down,
but I suspect they've included corrections for that in the firmware.


If that were a factor I would expect to see a consistent mis-focus, but
that's not what I get.


The pattern could be complex though... depending how much you are
stopped down, maybe depending if it's close up or infinity...


There could also be issues with curvature of field, if you are concerned
about something off to the side, etc.


I'm not. :- )




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

all google groups messages filtered due to spam
  #29  
Old December 26th 09, 11:11 AM posted to rec.photo.digital.slr-systems
Wilba[_3_]
external usenet poster
 
Posts: 572
Default EF 50/1.8 AF Experiment?

Paul Furman wrote:
Wilba wrote:
Paul Furman wrote:
Wilba wrote:

The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy images to work with, how /could/ the system nail the focus in
difficult conditions?

It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there
a consequence of either hypothesis that could be disproved empirically?

If you are using the center AF point, sharpness shouldn't be a problem.


I can interpret that to mean several different things. What do you mean
exactly?


Sharpness shouldn't be a problem in the center. I was doing some lens
tests with macro stacking software and just for curiosity tried some
really fast primes, much closer than they were designed for, not reversed
or anything... and was amazed that the center performance was excellent
wide open. That quickly degraded to 'hideous' outside the middle third
though.
http://www.flickr.com/photos/edgehil...7603231101723/


No, it is a problem for the nifty fifty. You can see it in the shots I
posted a while back -
http://www.users.on.net/~alanw/Usene...ewFullsize.jpg (3.6MB)
http://www.users.on.net/~alanw/Usene...ewFullsize.jpg (3.4MB)

If you have extension tubes or a bellows, try it at extreme closeup.
That's a good way to make flaws much more obvious. It may not apply to
normal operation though.

In fact the shallower DOF should improve accuracy.


I think that's part of why the "crude mechanism" theory is so popular,
but I can't think of any way to test it. I'm not interested in theory or
speculation except that which leads to an experiment which proves
something.


Lots of ways to test. Do a series at the same spot but defocus manually,
first several starting from infinity, then several from closest focus,
then from just slightly off in each direction. Do that for something up
close then something 30 feet away.


What consequence of which theory would this test, and how?

You could try your stopped down theory by putting a piece of black paper
with a hole punched on the front, but might try testing first that it
doesn't make things less sharp due to non-optimal aperture placement.


How could I do that?

Put the paper aperture in the right place in back and the lens becomes
telecentric, meaning light rays travel straight out the front and the
field of view is no wider than the front element.


You lost me somewhere there. :- )

Put the external aperture _behind_ the lens? And light comes out the
_front_?! I don't get it. :- )

One factor could be the phenomenon where focus shifts when stopping
down, but I suspect they've included corrections for that in the
firmware.


If that were a factor I would expect to see a consistent mis-focus, but
that's not what I get.


The pattern could be complex though... depending how much you are stopped
down, maybe depending if it's close up or infinity...


Yeah, let's just stick with what happens wide open.


  #30  
Old December 26th 09, 06:02 PM posted to rec.photo.digital.slr-systems
Paul Furman
external usenet poster
 
Posts: 7,367
Default EF 50/1.8 AF Experiment?

Wilba wrote:
Paul Furman wrote:
Wilba wrote:
Paul Furman wrote:
Wilba wrote:

The Canon EF 50mm f/1.8 II "Nifty Fifty" has a reputation for two
shortcomings, 1) softness at wide apertures (OK from f/2.8), and 2)
erratic focus under difficult conditions (low light, shallow DOF).

Many people claim that 2) is a result of the crudeness of the cheap
focussing motor and electronics in the lens, that those components are
not able to provide the required accuracy and control of motion of the
focus ring.

But I wonder if 2) is actually a result of 1) - if the AF sensors have
fuzzy images to work with, how /could/ the system nail the focus in
difficult conditions?

It would be interesting to see what happens when the AF sensors have
sharper images to work with (e.g. at f/2.8 or f/4), but my 450D refuses
to AF when the DOF preview button is pressed, so I can't test that.
External aperture perhaps?

Any ideas for how these competing hypotheses could be tested? Is there
a consequence of either hypothesis that could be disproved empirically?
If you are using the center AF point, sharpness shouldn't be a problem.
I can interpret that to mean several different things. What do you mean
exactly?


Sharpness shouldn't be a problem in the center. I was doing some lens
tests with macro stacking software and just for curiosity tried some
really fast primes, much closer than they were designed for, not reversed
or anything... and was amazed that the center performance was excellent
wide open. That quickly degraded to 'hideous' outside the middle third
though.
http://www.flickr.com/photos/edgehil...7603231101723/


No, it is a problem for the nifty fifty.


Huh? "No" what? It's not sharp in the center?


You can see it in the shots I posted a while back -
http://www.users.on.net/~alanw/Usene...ewFullsize.jpg (3.6MB)
http://www.users.on.net/~alanw/Usene...ewFullsize.jpg (3.4MB)

If you have extension tubes or a bellows, try it at extreme closeup.
That's a good way to make flaws much more obvious. It may not apply to
normal operation though.


This will tell you if it's sharp in the center.


In fact the shallower DOF should improve accuracy.

I think that's part of why the "crude mechanism" theory is so popular,
but I can't think of any way to test it. I'm not interested in theory or
speculation except that which leads to an experiment which proves
something.

Lots of ways to test. Do a series at the same spot but defocus manually,
first several starting from infinity, then several from closest focus,
then from just slightly off in each direction. Do that for something up
close then something 30 feet away.


What consequence of which theory would this test, and how?


Testing the 'slop' theory. To see if it stops at different positions on
repeated runs of the same movement or different movements.


You could try your stopped down theory by putting a piece of black paper
with a hole punched on the front, but might try testing first that it
doesn't make things less sharp due to non-optimal aperture placement.


How could I do that?


Just side by side comparison shots to see if the new aperture makes
things softer.


Put the paper aperture in the right place in back and the lens becomes
telecentric, meaning light rays travel straight out the front and the
field of view is no wider than the front element.


You lost me somewhere there. :- )

Put the external aperture _behind_ the lens? And light comes out the
_front_?! I don't get it. :- )


Heh, sorry, off on a tangent. The idea is that adding an aperture like
that can do weird things, so maybe not sharper than stopping down the
lens' own aperture and who knows, maybe softer than wide open.


One factor could be the phenomenon where focus shifts when stopping
down, but I suspect they've included corrections for that in the
firmware.

If that were a factor I would expect to see a consistent mis-focus, but
that's not what I get.


The pattern could be complex though... depending how much you are stopped
down, maybe depending if it's close up or infinity...


Yeah, let's just stick with what happens wide open.


But you wanted to test if things improved stopped down. If I understand
correctly, the view in the optical viewfinder and presumably what the AF
sensors see, is already stopped down to maybe f/2.8; it doesn't benefit
from faster lenses, due to obstructions I guess. So there is already
some potential for focus shift there... but as you say, that should be
consistent, so again this points toward slop in the mechanism. If you
tested various final taking apertures, at least that's some kind of data
pointing to whether that might be playing a role.

The simplest test is that focus chart manually focused then stop down to
various amounts & see if the focus shifts. It will get wider DOF but
might not be centered if you count from each side. Then see if the AF
places the focus differently from the manual fixed focus test at
different apertures. If there is focus shift and the camera firmware is
correcting for it, there should be little differences in where the
camera decides to focus.

PS I still don't get how the AF calibration thing works on the cameras
that have that. I can see one master set screw for coordinating the
distance of the AF sensors to match the distance to the picture sensor
and or viewfinder ground glass but calibrating differently for different
lenses would seem to me to have to be relying on this idea of focus
shift when stopping down. If so, that's going to have to be checked at
various apertures to establish a curve for the correction, not just one
test shot. Does that make sense?

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

all google groups messages filtered due to spam
 




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