Two D60's, both with focusing problems.

[Pete Stone]

You certainly COULD have hunting problems if the camera thinks the AF position is shifting, despite how the lens tries to achieve AF ( via pulse detection or any other means ).
Pete

 

[Thanh Tran]

Cirkitdude,

Your shot has f3.5
but David's shot had f1.4

Regards

Thanh

David,

Two cameras with exactly the same problem? One supposidly
calibrated by Canon and the same problem still? This is really
strange. What rotten luck. My D60 seems to focus perfectly.

I think your test may have been a little flawed for two reasons.

Handholding certainly leads to a small (but real) change in
distance between the focus point and the sensor plane between the
time of focus lock (half shutter press) and the time of image
capture, not to mention any camera movement due to the mirror flip.
Crouching also is a very difficult position to hold really steady.

Second, the angle between your camera and the tape can only lead to
enhanced possibilities for experimental error. It would certainly
be hard for you and/or the focus sensor to decide on exactly
where the focus point is supposed to be, because of the angle.

I would suggest trying the "carpet" test. Keep your focus object
exactly perpindicular to the ruler, carpet, or whatever you are
using to judge front/rear focus. Also, keep your camera/sensor
plane exactly in normal incidence with the focus object.

I tried a test this a.m., shown here. Best I can tell, my D60 is
spot on in focus. Zoom in and check out the carpet just to the
right of the bottom of the cereal box. I focused on the small
print just above "Ingredients". Note that this is a jpg image, so
the small text is a little distorted, but you can clearly see from
the carpet where the focus plane is - it seems to be exactly where
it should be... the front plane of the box.

http://www.pbase.com/image/3077764

 

[Cirkitdude]

What you describe below (a lens malfunction) is different from what you described in your original post (a manufacturing mismatch between body and lens). Certainly, an USM lens can have focus malfunctions, one possible scenario was in my post... I'm sure there are others. A modern AF lens is a very complicated piece of equipment.

What I was disagreeing with was your description of how focus is achieved as an explanation for the problem which started this thread... and the statement that a lens/body must somehow be calibrated together to account for manufacturing variances. This could cause readers to unnecessarily send in camera and lenses for "calibation".

I would agree that the original poster could have a malfunctioning lens. This seems even more likely since he sees the same problem on two D60s and after repair... all with the same lens. However, I think he just needs to have the lens repaired/replaced, not have it calibrated/adjusted to his body. That was my only point.

Thus if the lens is a little out of whack, an active feedback
control system will null out any mismatch error with the lens... it
will keep pulsing the lens until focus is achieved (minimizing the
error).

If the system was open-loop, as you describe, accurate focus across
many lenses would be hopeless... there is no way to control
manufacturing tolerances to those levels.

It is highly unlikely that this is a lens-camera combination
problem. The only way one can imagine the lens causing this
problem is if it has an electronics problem causing the stepper
motor to oscillate between front and rear focus... thus a lens
failure, not a combination failure.

What I'm saying is that maybe the 50 1.4 lens is off, and the D60
camera body is fine. I'd check it with some other fast lenses. It
would also be interesting to check the camera/lens combo at
infinity to see what the lens indication is ( how far off the mark
is the inf. mark on the barrel ). Possibly the CMOS sensor is off,
but Canon's check on the AF sensor distance reads as OK. Pete.
http://www.petestone.com

Read my post for a possible cause:

http://www.dpreview.com/forums/read.asp?forum=1019&message=3019725

Pete - you are pointing out that both the lens aned the body need
to be sent in for adjustment.

I think that the interface between the camera and the lens is what
is the Canon standard/specification is, and both the body and the
lens need to follow it. Consider what would happen if you have a
set of lenses and 2 bodies - which pair would you adjust ? Buying
a new lens would possibly cause a new "readjustment" of the body,
which would then cause problems with the other lenses in the set.

The treatment of the body and lens as a pair seems an unworkable
solution.

Paul.

I think your test may have been a little flawed for two reasons.

You may think so. Canon does not. They tested the body using a VERY
similar technique, found it to be out of spec and adjusted it. I
have to assume it left both the Canon factory and CPS in perfect
adjustment. It appears to be falling out of adjustment during
shipping. That is THIER opinion at the moment.
By the way, I only did the test after I noticed that all of the
pictures I had taken appeared to be out of focus. The problem is
with the camera/lens, not the test.

David Jay

--
pete stone

--
pete stone

--
pete stone

 

[Thanh Tran]

Pete,

I agree that there might be someting wrong in the lense that cause the focus failed, as the closed AF system gives up after several attempts.

Here I have something I just wonder:

20 hours life for the USM motor? (you said in your post)
= 72000 secs

Every picture might take about 3 times for focus lock and composing.

Each time of focusing probably takes about a sec (if not hunting)

so with 72000 secs you can take probably 72000 / 3 = 24000 pictures

If you take 200 pics a day, that's gonna be 120 days less than a year?

Thanh

Thus if the lens is a little out of whack, an active feedback
control system will null out any mismatch error with the lens... it
will keep pulsing the lens until focus is achieved (minimizing the
error).

If the system was open-loop, as you describe, accurate focus across
many lenses would be hopeless... there is no way to control
manufacturing tolerances to those levels.

It is highly unlikely that this is a lens-camera combination
problem. The only way one can imagine the lens causing this
problem is if it has an electronics problem causing the stepper
motor to oscillate between front and rear focus... thus a lens
failure, not a combination failure.

What I'm saying is that maybe the 50 1.4 lens is off, and the D60
camera body is fine. I'd check it with some other fast lenses. It
would also be interesting to check the camera/lens combo at
infinity to see what the lens indication is ( how far off the mark
is the inf. mark on the barrel ). Possibly the CMOS sensor is off,
but Canon's check on the AF sensor distance reads as OK. Pete.
http://www.petestone.com

Read my post for a possible cause:

http://www.dpreview.com/forums/read.asp?forum=1019&message=3019725

Pete - you are pointing out that both the lens aned the body need
to be sent in for adjustment.

I think that the interface between the camera and the lens is what
is the Canon standard/specification is, and both the body and the
lens need to follow it. Consider what would happen if you have a
set of lenses and 2 bodies - which pair would you adjust ? Buying
a new lens would possibly cause a new "readjustment" of the body,
which would then cause problems with the other lenses in the set.

The treatment of the body and lens as a pair seems an unworkable
solution.

Paul.

I think your test may have been a little flawed for two reasons.

You may think so. Canon does not. They tested the body using a VERY
similar technique, found it to be out of spec and adjusted it. I
have to assume it left both the Canon factory and CPS in perfect
adjustment. It appears to be falling out of adjustment during
shipping. That is THIER opinion at the moment.
By the way, I only did the test after I noticed that all of the
pictures I had taken appeared to be out of focus. The problem is
with the camera/lens, not the test.

David Jay

--
pete stone

--
pete stone

--
pete stone

 

[Pete Stone]

I never suggested a mismatch, only a possible problem with the lens rather than the body, and the fact that it might be better to send BOTH in so that BOTH could be checked individually to get to the bottom of the problem quickly. Obviously, both lens and camera have to be in tolerance for the AF system to work. I never used the term "manufacturing missmatch".Pete

What you describe below (a lens malfunction) is different from what
you described in your original post (a manufacturing mismatch
between body and lens). Certainly, an USM lens can have focus
malfunctions, one possible scenario was in my post... I'm sure
there are others. A modern AF lens is a very complicated piece of
equipment.

What I was disagreeing with was your description of how focus is
achieved as an explanation for the problem which started this
thread... and the statement that a lens/body must somehow be
calibrated together to account for manufacturing variances. This
could cause readers to unnecessarily send in camera and lenses for
"calibation".

I would agree that the original poster could have a malfunctioning
lens. This seems even more likely since he sees the same problem
on two D60s and after repair... all with the same lens. However, I
think he just needs to have the lens repaired/replaced, not have it
calibrated/adjusted to his body. That was my only point.

 

[Pete Stone]

My exprience is that the AF ultrasonic motor is actually used far less than this. 3 seconds is WAY longer than my AF usually takes! I have already replaced 2 motors in EF lenses ( 70-200 & 300 2.8 )The ultrasonic motor's life came from a press release that Canon issued about a new type of ultrasonic motor developed for their copiers that achieved far greater life than the previous 20 hr average. Pete

Pete,
I agree that there might be someting wrong in the lense that cause
the focus failed, as the closed AF system gives up after several
attempts.

Here I have something I just wonder:

20 hours life for the USM motor? (you said in your post)
= 72000 secs

Every picture might take about 3 times for focus lock and composing.

Each time of focusing probably takes about a sec (if not hunting)

so with 72000 secs you can take probably 72000 / 3 = 24000 pictures

If you take 200 pics a day, that's gonna be 120 days less than a year?

Thanh

 

[Pete Stone]

Here's a link you might like to see:
http://www.photoscene.com/sw/tour/inside.htm

Check out in particular the description of the photocoupler as described by Chuck Westfall.
Best wishes, Pete.

Thus if the lens is a little out of whack, an active feedback
control system will null out any mismatch error with the lens... it
will keep pulsing the lens until focus is achieved (minimizing the
error).

If the system was open-loop, as you describe, accurate focus across
many lenses would be hopeless... there is no way to control
manufacturing tolerances to those levels.

It is highly unlikely that this is a lens-camera combination
problem. The only way one can imagine the lens causing this
problem is if it has an electronics problem causing the stepper
motor to oscillate between front and rear focus... thus a lens
failure, not a combination failure.

What I'm saying is that maybe the 50 1.4 lens is off, and the D60
camera body is fine. I'd check it with some other fast lenses. It
would also be interesting to check the camera/lens combo at
infinity to see what the lens indication is ( how far off the mark
is the inf. mark on the barrel ). Possibly the CMOS sensor is off,
but Canon's check on the AF sensor distance reads as OK. Pete.
http://www.petestone.com

Read my post for a possible cause:

http://www.dpreview.com/forums/read.asp?forum=1019&message=3019725

Pete - you are pointing out that both the lens aned the body need
to be sent in for adjustment.

I think that the interface between the camera and the lens is what
is the Canon standard/specification is, and both the body and the
lens need to follow it. Consider what would happen if you have a
set of lenses and 2 bodies - which pair would you adjust ? Buying
a new lens would possibly cause a new "readjustment" of the body,
which would then cause problems with the other lenses in the set.

The treatment of the body and lens as a pair seems an unworkable
solution.

Paul.

I think your test may have been a little flawed for two reasons.

You may think so. Canon does not. They tested the body using a VERY
similar technique, found it to be out of spec and adjusted it. I
have to assume it left both the Canon factory and CPS in perfect
adjustment. It appears to be falling out of adjustment during
shipping. That is THIER opinion at the moment.
By the way, I only did the test after I noticed that all of the
pictures I had taken appeared to be out of focus. The problem is
with the camera/lens, not the test.

David Jay

--
pete stone

--
pete stone

--
pete stone

 

[Mark J.]

David,

I'm not questioning at all your observations, but in previous discussions here about this sort of problem, it's been suggested that the best test is to set up multiple surfaces (cereal boxes and Zip drive diskette cases have been used, for example) at regular intervals around the distances you wish to test so that the faces of these objects are all parallel to the focus plane, and shoot your test images.

Crouching low over a tape extending away from you ensures that whatever point the camera uses to try and achieve focus will encompass a range of distances rather than a single distance parallel to the focus mechanism/focus plane.

Do mean one end of the tape was at your feet, and it was extending
directly away from you? And you focused at the 1, 3, 6, 9-foot
marks on the tape?

Yep.Crouched down low though.
David Jay

Regards,

Mark J.

--
EOS 1D ~ 28-70mm f/2.8 L ~ 100-400mm f/4.5-5.6 L IS ~ 20-35mm f/3.5-4.5 ~ 550EX

 

[DavidP #28649]

And it's probably not the lens. Not if Canon verified it on their lens, too.

I saw similar results on my 1D.

http://thewilkinsons.crosswinds.net/frontfocus/ff.htm
seems to suggest a problem with certain lenses

http://thewilkinsons.crosswinds.net/frontfocus/ff.htm
shows that even one of the "good" lenses also front-focuses.

BTW, if you want a solution to this problem, put an ST-E2 on your camera (or use the AF-assist of your 550-EX flash). This results in perfect focus each time.

I sent my camera back once to CPS, but they didn't fix it, apparently. I haven't sent it back yet.

Hope yours gets fixed soon.

Not subtle at all. I'm talking 1" to 5" out of focus. ie: Focused
on 36" and 33" is sharp, 36" is blurry. Every time. Surely this is
unuseable.
This test is very simple yet the results are obvious and
undeniable. I posted my results only as a "heads up" for other D60
owners. Use the information as you like. I do suggest testing your
cameras though, using your largest aperture lens shot wide open.
David Jay

--
http://www.davidjayphotography.com

--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise

 

[DavidP #28649]

Did they say WHY it's possible to fall out of adjustment during shipping?

This is very disconcerting to me. Just how careful do you have to be with these bodies not to upset the AF-adjustments?

You may think so. Canon does not. They tested the body using a VERY
similar technique, found it to be out of spec and adjusted it. I
have to assume it left both the Canon factory and CPS in perfect
adjustment. It appears to be falling out of adjustment during
shipping. That is THIER opinion at the moment.
By the way, I only did the test after I noticed that all of the
pictures I had taken appeared to be out of focus. The problem is
with the camera/lens, not the test.

--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise

 

[Don Lashier]

I have visions of missing loctite and then jiggling in the back of a UPS truck for 20 hours, let alone multiple 2 foot drops on converyors - that's why I'm having Canoga send my replacement via next-day air. But Greg said they ship these ground all the time and never have a problem (but then again, maybe my experience contradicts that).

• DL

Did they say WHY it's possible to fall out of adjustment during
shipping?

This is very disconcerting to me. Just how careful do you have to
be with these bodies not to upset the AF-adjustments?

 

[Russell Stewart]

Did they say WHY it's possible to fall out of adjustment during
shipping?

This is very disconcerting to me. Just how careful do you have to
be with these bodies not to upset the AF-adjustments?

If your concerned about shipping have a read of this, the thought or 25 foot falls for my D60 makes me cringe!

http://www.dpreview.com/forums/read.asp?forum=1019&message=3005826

 

[DavidP #28649]

I sent mine next-day Fedex. It was returned next-day UPS to me (though they sent it on a Friday, for Monday arrival).

I have visions of missing loctite and then jiggling in the back of
a UPS truck for 20 hours, let alone multiple 2 foot drops on
converyors - that's why I'm having Canoga send my replacement via
next-day air. But Greg said they ship these ground all the time and
never have a problem (but then again, maybe my experience
contradicts that).

--
The Unofficial Photographer of The Wilkinsons
http://thewilkinsons.crosswinds.net
Photography -- just another word for compromise

 

[Cirkitdude]

Thanks for that piece of info.

Yup, f3.5. That's as wide open as the ole 28-135 IS will go. Now what does this have to do with the testing procedure (other than the obvious difference in DOF, which has nothing to do with the discussion here)?

Your shot has f3.5
but David's shot had f1.4

Regards

Thanh

David,

Two cameras with exactly the same problem? One supposidly
calibrated by Canon and the same problem still? This is really
strange. What rotten luck. My D60 seems to focus perfectly.

I think your test may have been a little flawed for two reasons.

Handholding certainly leads to a small (but real) change in
distance between the focus point and the sensor plane between the
time of focus lock (half shutter press) and the time of image
capture, not to mention any camera movement due to the mirror flip.
Crouching also is a very difficult position to hold really steady.

Second, the angle between your camera and the tape can only lead to
enhanced possibilities for experimental error. It would certainly
be hard for you and/or the focus sensor to decide on exactly
where the focus point is supposed to be, because of the angle.

I would suggest trying the "carpet" test. Keep your focus object
exactly perpindicular to the ruler, carpet, or whatever you are
using to judge front/rear focus. Also, keep your camera/sensor
plane exactly in normal incidence with the focus object.

I tried a test this a.m., shown here. Best I can tell, my D60 is
spot on in focus. Zoom in and check out the carpet just to the
right of the bottom of the cereal box. I focused on the small
print just above "Ingredients". Note that this is a jpg image, so
the small text is a little distorted, but you can clearly see from
the carpet where the focus plane is - it seems to be exactly where
it should be... the front plane of the box.

http://www.pbase.com/image/3077764

 

[Cirkitdude]

That's a very interesting web site... I enjoyed it. Thanks. It's great to get a chance to see the inner workings of something like USM lenses.

However, if you intended it to shed some light on the discussion of focus problems, unfortunately it doesn't. What the photocoupler discussion describes is how the USM stepper motor works and how the onboard lens electronics sense the focus ring movement. Remember, the focus sensor and the focusing electronics/software are in the camera, not the lens. The focusing "decisions" are made in the camera. This was the control system I was describing, not the mechanical movement system in the lens. The system described in the web site is simply the electronics which activate the stepper motor and then sense the focus ring movement... it is not making focus decisions.

I will say, the one thing this web site does shed some light on is, as I stated earlier, modern AF lenses are very complicated beasts. Certainly, there are lots of things to go wrong. But, focusing decisions are controlled in the camera.

My disagreement with your original post was not that a problem might exist in the lens, it was with your statement:

If the lens has an internal AF error, the camera AF can be correct,
but the ultrasonic motor "moves" to the wrong position.

This is not consistent with modern feedback control systems, and certainly not the way the D60 focus system works. Any error generated because the motor "moves" to the wrong position would show up on the camera AF sensor and new instructions would be issued to the lens... this process continues until the lens is in a focus state that the camera AF decides is "best focus".

I have no disagreement with another of your statements that sending in both camera and lense might save time by having both checked. But it seems to me one could do that at home by simply trying a different lens and determining if the problem is the camera AF out of calibration or a faulty lens.

Regards.

Check out in particular the description of the photocoupler as
described by Chuck Westfall.
Best wishes, Pete.

Thus if the lens is a little out of whack, an active feedback
control system will null out any mismatch error with the lens... it
will keep pulsing the lens until focus is achieved (minimizing the
error).

If the system was open-loop, as you describe, accurate focus across
many lenses would be hopeless... there is no way to control
manufacturing tolerances to those levels.

It is highly unlikely that this is a lens-camera combination
problem. The only way one can imagine the lens causing this
problem is if it has an electronics problem causing the stepper
motor to oscillate between front and rear focus... thus a lens
failure, not a combination failure.

The way the Canon EOS System functions, at least with the
Ultrasonic lenses, is that the camera body tells the lens AF motor
how may "pulses" and in which direction to move the lens assembly.
If the lens has an internal AF error, the camera AF can be correct,
but the ultrasonic motor "moves" to the wrong position. Many Pro's
have had to send in their fast EF teles for adjustment after heavy
use ( and abuse! ) to correct AF error in the lens itself.

What I'm saying is that maybe the 50 1.4 lens is off, and the D60
camera body is fine. I'd check it with some other fast lenses. It
would also be interesting to check the camera/lens combo at
infinity to see what the lens indication is ( how far off the mark
is the inf. mark on the barrel ). Possibly the CMOS sensor is off,
but Canon's check on the AF sensor distance reads as OK. Pete.
http://www.petestone.com

 

[Malcolm Bader]

I tried this same test 10 times.
In the beginning I got out of focus shots. Some front focus, some rear.
Then I suspended the ruler a foot above the floor.
Now it focuses perfectly.
The cameras focus spot is wider than the ruler so the floor was interfering.
Try your test again.

Malcolm Bader

In the last week I've received two D60's from two retailers. I'm a
professional fashion photographer and shoot a lot of close-up
"beauty" with VERY shallow depth of field. Accurate focus is
critical.....obviously.
So I tested as follows: 50mm 1.4, wide open. Laid a tape measure
out on the floor, crouched down in front of it and shot at 0ft,
1ft, 3ft, 6ft, 9ft. First focusing manually and then repeating with
autofocus. Results: EVERY PICTURE OUT OF FOCUS. Manual in front,
auto behind. BOTH CAMERAS.
Overrnighted one body to CPS. They adjusted it and overnighted it
back to me today. Tested it again. Result. Exactly the same. Every
picture out of focus. Called CPS, spoke with tech, he assured me he
had adjusted it "spot on" 12 hours before. Its on its way back to
CPS for round 2.
Houston, we've got a problem.
David Jay
--

--
Malcolm

 

[David Jay]

Never use it. It's useless for the vast majority of images I do. The visual auto focus points are often ambigious and not nearly as refined as my eye. (Fortunately my right eye is nearly perfect [one click from center on the eyepiece adjustment] .I'd rather not discuss my left eye!).

Consequently I am not surprised that the auto focus is off.........for whatever reasons people might suggest. I DO care about the manual focus though. There is no ambiguity whatsoever FOR ME when I manual focus. The exact point of focus is crystal clear in the viewfinder. Even more so with the camera mounted on a sturdy tripod. The results are crystal clear as well: The focus is off with these two bodies and two off the shelf 50mm 1.4's.
David Jay

Addendum: Just tried a 85mm 1.8. WAY better than the 50 1.4's..........but still off. Unfortunately, " a miss is as good as a mile" when it comes to something as obvious as focus.
By the way, these lenses feel like cr&p. At least there cheap!
--
http://www.davidjayphotography.com

 

[Thanh Tran]

hi Cirkitdude

What I know is that with the F1.4, DOF is much shallower than that of F3.5 (you've already known), which I think contributes to the focus range. It makes the focus ability become more important.

Please correct me if I'm wrong.

Thanks

Thanh

Yup, f3.5. That's as wide open as the ole 28-135 IS will go. Now
what does this have to do with the testing procedure (other than
the obvious difference in DOF, which has nothing to do with the
discussion here)?

Cirkitdude,

Your shot has f3.5
but David's shot had f1.4

Regards

Thanh

 

[Thanh Tran]

What 3sec mean was that eveytime you half press the button, the AF - which is the USM, has to work. So I usually half press several time before I get a good compose, which could be three times.

Assume each time takes one sec (should be less than one sec if already focus), so you half press three times taking about 3 secs.

But 20 hours sounds really SHORT to me.

Thanh

Pete,
I agree that there might be someting wrong in the lense that cause
the focus failed, as the closed AF system gives up after several
attempts.

Here I have something I just wonder:

20 hours life for the USM motor? (you said in your post)
= 72000 secs

Every picture might take about 3 times for focus lock and composing.

Each time of focusing probably takes about a sec (if not hunting)

so with 72000 secs you can take probably 72000 / 3 = 24000 pictures

If you take 200 pics a day, that's gonna be 120 days less than a year?

Thanh

 

[Thanh Tran]

Thanks Pete

THanh

Here's a link you might like to see:
http://www.photoscene.com/sw/tour/inside.htm

Check out in particular the description of the photocoupler as
described by Chuck Westfall.
Best wishes, Pete.