10D Back Focus

Yeah... about a LENS. Show me some where it involves the 10D. I can show you MANY, MANY posts by you which are negative when it concerns the 10D.
Remeber I'm using the 1v, I love it a lot, I prefer Canon 1v more
than Nikon F5.

I love my Nikon F100, I prefer it more than the EOS 3.

As I said before, I love good things, no matter what brand it is.
So I wonder why you have such a "thing" for the 10D since you participate so heavily in the "10D focus issues" threads almost to the point of exclusivity.
 
My post is a counter balance to your post, so we are helping others to get more balanced information, we both are great contributors.

I'm not negative, I hope my effort would let Canon eventually solve the 10D problem, then I would buy one without hesitation, may be the day when I buy one you will say "Uh, let's see, 10D is the best, even francis bought one!". But I can'y predict that day anyway, may be I buy the 3D instead.
Yeah... about a LENS. Show me some where it involves the 10D. I can
show you MANY, MANY posts by you which are negative when it
concerns the 10D.
Remeber I'm using the 1v, I love it a lot, I prefer Canon 1v more
than Nikon F5.

I love my Nikon F100, I prefer it more than the EOS 3.

As I said before, I love good things, no matter what brand it is.
So I wonder why you have such a "thing" for the 10D since you
participate so heavily in the "10D focus issues" threads almost to
the point of exclusivity.
--
Go ahead, never look back
 
Of course freedom of speech reigns here, but that is tied to responsibility as well. Without a detection strategy, the hysteria of the unknown takes over. "Do I have this problem?" replaces "I have a problem." Such uncertainty is a drain on everyone and benefits no one.

As an example, I ask myself "Do I have this problem?" Maybe. I check using the best method I can. It is THERE. I send it into Canon. They "repair" it and I check again. It is STILL THERE.

What is still there is the same thing that was there initially, except that was not IT but my own lack of diagnostic skills. Back and forth it goes.

Another approach in case of uncertainty would be to post suspect images here and ask, as several posters have requested. If you are still uncertain, send the camera to Canon for their opinion. If they say its good, look for the "problem" elsewhere.

Both the Sony 707 and 717 had problems from the manufacturer. However, that forum developed a good pattern to check and ultimately saved users from worry (and Sony a bundle in unnecessary checks). The real problem was solved.

So, let's see some real-world images with some consistency.

Laurence
I'm not negative, I hope my effort would let Canon eventually solve
the 10D problem, then I would buy one without hesitation, may be
the day when I buy one you will say "Uh, let's see, 10D is the
best, even francis bought one!". But I can'y predict that day
anyway, may be I buy the 3D instead.
Yeah... about a LENS. Show me some where it involves the 10D. I can
show you MANY, MANY posts by you which are negative when it
concerns the 10D.
Remeber I'm using the 1v, I love it a lot, I prefer Canon 1v more
than Nikon F5.

I love my Nikon F100, I prefer it more than the EOS 3.

As I said before, I love good things, no matter what brand it is.
So I wonder why you have such a "thing" for the 10D since you
participate so heavily in the "10D focus issues" threads almost to
the point of exclusivity.
--
Go ahead, never look back
--
http://www.pbase.com/lmatson/sd9_images
http://www.pbase.com/sigmasd9/root
http://www.beachbriss.com (eternal test site)
 
Dear Francis,

I think you miss my points and please calm down. I didn't ask him to shut up, did I? :-)

His post certainly doesn't harm me a bit and I am not trying to harm him with my post either. I'm just suggesting him to do something that I think will be best for him. Is that not what I'm supposed to do in this forum?

If you've read my previous messages (a long time ago), you will know that I actually welcome posts which report problems of our equipment. In a way, these posts will alert us of potential problems of our equipment as well as allowing us to know them better.

The problem here is that Dan doesn't have the necessary equipment/facility to perform a proper test (he admitted that in his original post) and most of us are miles away (some, like you and me, are half a globe away) and couldn't really help much.

So, you tell me, what else is better to Dan than sending his camera + - lenses for proper assessment and repair by qualified people at Canon Service?

Don't just sit here, telling me my suggestion's wrong. Please tell me what your recommendation to Dan to solve his problem is? Continuing to engage in the heated arguement here (that's my impression a least) or going back to Canon Service?

To be honest, Dan appears to me to be rather convinced that his 10d back focuses, no matter what other people say. That's fine to me. He has the right to do so and as a matter of fact, I don't have any judgement on whether his 10d back focuses or not from the limited information available.

However, I do think that there is no point for Dan to continue to argue here (especially when he has seemingly made up his mind and when a few people lose their cool, did you? :-)) and his interest is best served by sending his camera + - lenses back to Canon Service. Don't you think so?

You know, I don't have telepathy and so when people consult me over the internet, after giving out some general advices, I would usually ask them to go to see a doctor locally rather than giving uninformed recommendation.

I know you;re very concern and you're trying to be helpful to Dan, but that's not reasons for losing your cool.

I'd be most grateful if you could enlighten me on a better way to help Dan.
Some people share their happiness of getting good 10D and good
shot. Should they keep silent rather than post here?

Some people share their unhappy experience of bad 10D, there is
nothing wrong with them.

Their post help others a lot to hear balance information for future
buyer. The only bad thing is people post troll or fake information
to mislead other people. Do you want they keep silent and let other
uninformed?

They post here and they can get comments from others, we see others
are querrying his finding and this help him to rectify anything
that might be wrong. His post at least no harm to you, right!
 
Ben Strasser wrote:
".... Also we tend to expect that a lens on a
35mm camera is the same when we mount it on a 10D - it is not. A
28mm wide-angle lens on a 35mm camera is more like a normal lens on
a 10D and has a whole different DoF......"
Ben, it is a complete misconception that the lens is somehow altered when it is mounted on a 10D.
Neither the focal length, or the DOF is altered in any way.

I explained this to dan yesterday, if you would like to read it, it is up this thread and is titled, Re: You're kidding, right?.
 
Hi Andy. Are you talking the image of the inclined chart? I agree that it is not perfectly aligned (But the focal point was on the center line of the chart. If you look at the "distribution" of the focused area, it's clearly behind that center line, I was able to see that in the view finder and correct it by turning the focus ring). Anyway, that was why I decided to not used the incline and just shoot the chart straight on in the 2nd and 3rd images (the link for the 3d img was wrong, see my other post of the corrected link). Again I was able to see it in the view finder that the image wasn't quite focused when the camera fininshes auto-focusing. Then I manually compensate for that in the 3d image. when looking at the images on the monitor, the 3rd one is noticeably sharper.

I noticed the problem after looking at some portrait images the my friend and I took while trying out the camera. We found that almost all of the images that were taken with F4& 200mm (we were trying to get a blurred background) were noticeably not well focused. The shutter speed was always > 1/500 since we were in bright daylight.

I called Canon this morning, they asked me to send it to Irving CA repair center. Anyway, I believe that some cameras (10d) do have real focusing issues, although the actual % of 10Ds have this problem my be low, but it may be significantly higher vs other camera models.

If I could choose again, I would still get the 10D, the price/value ratio is excellent. But I think I'd probalby choose a local store with a good return policy instead of buying it online.

Edgar
A setup problem.

Note that the center of the paper and image is distinctly blurry,
while the text on the left is clearer, and the text on the right is
clearer still, and in fact well within reasonable tolerance, with
zero being on the near side of the area in focus.

The chart would appear to not be flat, or otherwise mis-aligned.

Now for the question I ask a lot. What drove you to this test? Do
you have examples of photos that you would normally take that
exhibit a problem? If so, send it in for calibration. If not,
give up on the testing and accept good photos.

Andy
chart position in a 45 degree incline (cropped to reduce size)
http://www.pbase.com/image/16831161/original

chart positioned straight up (parrell to the lens), shot with auto
focus.
http://www.pbase.com/image/16831498/original

chart positioned straight up (parrell to the lens), manually
adjusted focus ring after camera auto-focused
http://www.pbase.com/image/16831498/original

The lens used is 70-200F4, camera mounted on tripod, 2m from
subject. I contacted onecall.com for an exchange, however the
person that I talked to said that if Canon does't acknowledge that
there's a defect, I'll have to pay a 15% restocking fee. So if
anyone who doesn't think that the focus issues are real, I can give
you the $220 (15%*$1499) if you are willing to exchange your good
10D with mine :)


Edgar
For all who doubt 10D's have focus problems here is a photo to
view. Since I dont have all of the fancy technical equipment that
Canon has I set up a very simple focus test.

The image was shot with the 10D mounted on a tripod and at 45
degrees. I used a Canon f4L lens. The center of the picture is
immediately to the left of the tip of the pen. I used the center
focal point of the camera only.

The pityful thing about this image is that I just got my camera
back from the Canon New Jersey repair facility. This picture
represents the degree of quality and customer service that Canon is
building into their product. The bottom line is there is no excuse
on Canon's part for selling a $1500 camera body that wont focus,
especially after it undergoes warranty repair at their own facility.

http://www.pbase.com/image/16753690
 
Alan,

You are correct, the lens is not altered (physically), the focal length remains the same, the f-stops remain the same but I will differ with you on the DoF. What determines if a lens is a wide-angle, normal or telephoto is the focal length in relation to the diagonal of the image plane.
35mm film plane is 24x36mm with a diagonal of 42mm normal lens is 50mm
6x7 medium film plane is 60x70mm or 92mm diag. normal lens is 90mm

10D film plane is 23x15mm or 23mm diag. a normal lens would be about this focal length.

The crop factor is 1.6 according to Canon reads like this: "(35mm-equivalent focal length is equal to approx.1.6 times the marked focal length.)" which means a 50mm lens on a 35mm camera has the focal length of 80mm on a 10D. The image produced on the 23x15mm sensor would be the same image produced by an 80mm lens on a 35mm camera. I think you would agree that as the focal length of the lens increases the DoF of the lens decreases. I hope you would agree with me that a "normal" lens is defined by the diagonal of the image plane. Taking that a step further, focal length (basic) is determined by the distance from the front lens element to the image plane. If the focal length is the same (meaning the distance from the front lens element to the image plane) and only the image sensor changes size, there is a magnafication factor of 1.6 times the "normal" view of 35mm camera, then that lens has become a telephoto.
35mm camera is the same when we mount it on a 10D - it is not. A
28mm wide-angle lens on a 35mm camera is more like a normal lens on
a 10D and has a whole different DoF......"
Ben, it is a complete misconception that the lens is somehow
altered when it is mounted on a 10D.
Neither the focal length, or the DOF is altered in any way.
I explained this to dan yesterday, if you would like to read it, it
is up this thread and is titled, Re: You're kidding, right?.
 
Ben,

The field of view of a 50mm lens mounted on a 10D, is the same as an 80mm mounted on a 35mm. So in that sense, you are getting a magnafied shot.

However, it is only a crop, the center 62%, of a 35mm frame. It is no different that taking a 35mm negative and cropping the center 62%. Cropping the negative didn't alter the DOF.
I started a thread on this subject, its titled "Lenses And The D10".

The fact that I inadvertantly called the 10D, a D10, seems to be of interest to some. Appearantly I rub some folks the wrong way.
35mm camera is the same when we mount it on a 10D - it is not. A
28mm wide-angle lens on a 35mm camera is more like a normal lens on
a 10D and has a whole different DoF......"
Ben, it is a complete misconception that the lens is somehow
altered when it is mounted on a 10D.
Neither the focal length, or the DOF is altered in any way.
I explained this to dan yesterday, if you would like to read it, it
is up this thread and is titled, Re: You're kidding, right?.
 
Hi Laurence -

For you and all the others who think those with focus problems are needlessly whining let me say this:

I would much rather have a camera that functions properly. I sent my camera back today. I spent in excess of $120.00 on shipping and insurance. I bought the camera approximately one month ago. I used it the first weekend I owned it and have not been able to use it since. There is nothing I would like more than to have my 10D focus accurately so that I can enjoy the camera and bring something to the forum besides concern over Canon's quality control. I gave Canon my cold hard cash because of the perception they build a quality product. I am anxiously awaiting to see if they resolve the issue in good faith.
Dan,

I tried to phrase my comments carefully. I did not want to imply
that you do not have a problem. I feel, however, that by
continuously bringing these focussing problems here to your forum,
you all contribute to an atmosphere where people who have normal
cameras wonder what is wrong with them.

If you have a specific issue, take it up with Canon. Everyone else:
get out and take great pictures. The water's fine.

No one, including someone who loves his SD9, wishes an atmosphere
insecurity and wild testing on another forum.

Laurence

--
http://www.pbase.com/lmatson/sd9_images
http://www.pbase.com/sigmasd9/root
http://www.beachbriss.com (eternal test site)
 
Hi Olga -

I think you may have a point. When you look carefully at the focus test the 28-70 looks to be focusing a little inside the depth of field, though certainly not as much as one third. The 70-200 mm lens is not focusing within the depth of field at all. I sent the 700-200 mm lens along with the camera. I believe I may have a compound issue which is throwing off the results of the 70-200mm lens significantly.
Dan,

Do you only have those 2 L lenses? The reason I ask is because I
have a few lenses, 28-135IS, 50mm f1.8, 20mm, 75-300IS, Sigma
15-30, all of which work great with my 10D.

Then I bought the 70-200L f4 which I received on Friday. It's on
its way back to the vendor for an exchange. If the replacement is
going to be back-focusing as badly as the first one, it will be
returned for a refund.

(My example of back-focusing is here:

http://www.pbase.com/image/16805422 )

If you note a lot of the complaints about focusing in the forum,
starting with Mac's ruler test suggestion that started this spiral
of tests and complaints, you will find that the one common factor
in most cases has been the 70-200 lens.

Just food for thought...

Olga
 
Ben,

The field of view of a 50mm lens mounted on a 10D, is the same as
an 80mm mounted on a 35mm. So in that sense, you are getting a
magnafied shot.
However, it is only a crop, the center 62%, of a 35mm frame. It is
no different that taking a 35mm negative and cropping the center
62%. Cropping the negative didn't alter the DOF.
I started a thread on this subject, its titled "Lenses And The D10".
The fact that I inadvertantly called the 10D, a D10, seems to be of
interest to some. Appearantly I rub some folks the wrong way.
Unfortunately whilst in some ways you are right, you also have to remember that DOF represents an "acceptable" range of focus, for a given print size at normal viewing distance based on a given CoC. In getting to that given print size, the cropped image needs to be magnified more than it does with a full frame 35mm negative. This does mean that dof is different on a crop factored camera.

Simon
 
I seem to be having this same conversation on two different threads, but thats OK, I can multi-task.

Any given lens, will provide the same DOF for the same f-stop wether it is mounted on a 10D, or a 35mm camera body. The confusion comes about when we talk about "effecvtive focal length".

Lets discuss a 50mm lens. That 50mm lens has a 50mm focal length, it doesn't matter wether it is mounted on a 10D or a 35mm, that lens will provide the same DOF on both cameras.

That 50mm lens mounted on a 10D, has the same field of view as an 80mm lens mounted on a 35mm body. It is because of the reduced field of view on the 10D, that people say that the 50mm lens has an "effective focal length" of 80mm.

So, mount that 50mm on a 10D, take a picture, print it on standard 35mm size media, and you have what is in affect, an 80mm telephoto shot. But you dont have an 80mm lens, you have a 50mm lens.

Now if you compare the DOF of a 50mm lens on a 10d, (remember it provides an 80mm field of view on the 10D), to an 80mm mounted on a 35mm body,(that lens provides an 80mm field of view on the 35mm body), the DOF on the 10D appears to be increased by a factor of 1.6 for the same image.
Unfortunately whilst in some ways you are right, you also have to
remember that DOF represents an "acceptable" range of focus, for a
given print size at normal viewing distance based on a given CoC.
In getting to that given print size, the cropped image needs to be
magnified more than it does with a full frame 35mm negative. This
does mean that dof is different on a crop factored camera.

Simon
 
I think we both agree with this:
The field of view of a 50mm lens mounted on a 10D, is the same as
an 80mm mounted on a 35mm. So in that sense, you are getting a
magnafied shot.
Again, I agree with you on this point also. Just as a 35mm negative is a crop of a medium format 2-1/4x2-3/4 negative (6x7). The 90mm being a normal lens on a 6x7 and a telephoto on a 35mm. Also a magnified shot.
However, it is only a crop, the center 62%, of a 35mm frame. It is
no different that taking a 35mm negative and cropping the center
62%.
This is where we part company and can only agree to disagree. The DoF scale on my medium format 6x7 camera with the "normal" 90mm lens shows less DoF at the same f-stop than my 50mm "normal" lens on my 35mm camera. You are correct that cropping the negative does not change the DoF but the focal length in relation to the image plane does, in my opnion, change the DoF.
Cropping the negative didn't alter the DOF.
I started a thread on this subject, its titled "Lenses And The D10".
The fact that I inadvertantly called the 10D, a D10, seems to be of
interest to some. Appearantly I rub some folks the wrong way.
Not me, I enjoyed our conversation. Who knows, maybe Canon has a left handed version of the 10D that they call the D10.
35mm camera is the same when we mount it on a 10D - it is not. A
28mm wide-angle lens on a 35mm camera is more like a normal lens on
a 10D and has a whole different DoF......"
Ben, it is a complete misconception that the lens is somehow
altered when it is mounted on a 10D.
Neither the focal length, or the DOF is altered in any way.
I explained this to dan yesterday, if you would like to read it, it
is up this thread and is titled, Re: You're kidding, right?.
 
What I did was using the same chart and focus the black line manually with my own eyes and hand.. make note of the distance. Second time use auto focus and make note of the distance on the scale. The distance is the same for manual or auto.

I think that shows the auto focus works properly...The number 2 and 3 on each side of the black line doesn't have the same sharpness but who cares I think it's an optical effect from the lens itself.
For all who doubt 10D's have focus problems here is a photo to
view. Since I dont have all of the fancy technical equipment that
Canon has I set up a very simple focus test.

The image was shot with the 10D mounted on a tripod and at 45
degrees. I used a Canon f4L lens. The center of the picture is
immediately to the left of the tip of the pen. I used the center
focal point of the camera only.

The pityful thing about this image is that I just got my camera
back from the Canon New Jersey repair facility. This picture
represents the degree of quality and customer service that Canon is
building into their product. The bottom line is there is no excuse
on Canon's part for selling a $1500 camera body that wont focus,
especially after it undergoes warranty repair at their own facility.

http://www.pbase.com/image/16753690
 
I seem to be having this same conversation on two different
threads, but thats OK, I can multi-task.
Any given lens, will provide the same DOF for the same f-stop
wether it is mounted on a 10D, or a 35mm camera body.
Not quite. You aren't accounting for all the variables that go into calculating DoF:

"When a lens is focused on an object, there is some distance in front of the object and some behind which will also be acceptably sharp. This zone of sharpness which includes the subject is called the depth of field.

Photography, Phil Davis, 1972."

The key adjective in there is "acceptably". The acceptability is defined based on a given CoC and a given print size at a given viewing distance.

The other factors you mention, I agree remain constant, regardless of which body you mount them to. But what cannot be ignored, is that to get the same given print size from the smaller sensor, you have to magnify the image more.
The confusion
comes about when we talk about "effecvtive focal length".
Lets discuss a 50mm lens. That 50mm lens has a 50mm focal length,
it doesn't matter wether it is mounted on a 10D or a 35mm, that
lens will provide the same DOF on both cameras.
No confusion with me, I know this.
That 50mm lens mounted on a 10D, has the same field of view as an
80mm lens mounted on a 35mm body.
Yes, doing ok so far...
It is because of the reduced
field of view on the 10D, that people say that the 50mm lens has an
"effective focal length" of 80mm.
Agreed. More accurately termed equivalent FOV.
So, mount that 50mm on a 10D, take a picture, print it on standard
35mm size media, and you have what is in affect, an 80mm telephoto
shot.But you dont have an 80mm lens, you have a 50mm lens.
No argument there.
Now if you compare the DOF of a 50mm lens on a 10d, (remember it
provides an 80mm field of view on the 10D), to an 80mm mounted on a
35mm body,(that lens provides an 80mm field of view on the 35mm
body), the DOF on the 10D appears to be increased by a factor of
1.6 for the same image.
The magnification required to bring the sensor captured image on the 10D up to the given print size for the comparison causes dof to be reduced. Think of it like this... The focal length or apertures haven't changed at all.

As you say, the image on the 10D is just a crop. Now, when you enlarge that crop up to give you the same given print size for the comparision, you enlarge slightly out of focus areas by 1.6x. This gives LESS apparent dof for the 10D. Not more.

If you don't believe me, go here, and play with this online calculator - plugging in values for 35mm, and for the 10D.

http://dfleming.ameranet.com/dofjs.html

Simon
 
I think your camera focused "right on"

Maybe I should spend more time shooting Rugs!!

My real life acton shots are spot on sharp, no problem...

Maybe the rug moved??

MK
For all who doubt 10D's have focus problems here is a photo to
view. Since I dont have all of the fancy technical equipment that
Canon has I set up a very simple focus test.

The image was shot with the 10D mounted on a tripod and at 45
degrees. I used a Canon f4L lens. The center of the picture is
immediately to the left of the tip of the pen. I used the center
focal point of the camera only.

The pityful thing about this image is that I just got my camera
back from the Canon New Jersey repair facility. This picture
represents the degree of quality and customer service that Canon is
building into their product. The bottom line is there is no excuse
on Canon's part for selling a $1500 camera body that wont focus,
especially after it undergoes warranty repair at their own facility.

http://www.pbase.com/image/16753690
 
Hi Mark -

Here is the real focus test. You apparently missed this:

http://forums.dpreview.com/forums/read.asp?forum=1019&message=5129295
Maybe I should spend more time shooting Rugs!!

My real life acton shots are spot on sharp, no problem...

Maybe the rug moved??

MK
For all who doubt 10D's have focus problems here is a photo to
view. Since I dont have all of the fancy technical equipment that
Canon has I set up a very simple focus test.

The image was shot with the 10D mounted on a tripod and at 45
degrees. I used a Canon f4L lens. The center of the picture is
immediately to the left of the tip of the pen. I used the center
focal point of the camera only.

The pityful thing about this image is that I just got my camera
back from the Canon New Jersey repair facility. This picture
represents the degree of quality and customer service that Canon is
building into their product. The bottom line is there is no excuse
on Canon's part for selling a $1500 camera body that wont focus,
especially after it undergoes warranty repair at their own facility.

http://www.pbase.com/image/16753690
 
That some pretty severe mis-focusing!

Out of sheer boredom I decided to do one of these focus tests. Didn't spend a lot of time on it, but found my 50/f1.8 and 24-85 seem to front focus a few milimeters, and my 70-200/f4 is either spot on or a couple milimeters back. Ok, now where are the instructions for the long exposure noise tests??? :)
Dan,

Do you only have those 2 L lenses? The reason I ask is because I
have a few lenses, 28-135IS, 50mm f1.8, 20mm, 75-300IS, Sigma
15-30, all of which work great with my 10D.

Then I bought the 70-200L f4 which I received on Friday. It's on
its way back to the vendor for an exchange. If the replacement is
going to be back-focusing as badly as the first one, it will be
returned for a refund.

(My example of back-focusing is here:

http://www.pbase.com/image/16805422 )

If you note a lot of the complaints about focusing in the forum,
starting with Mac's ruler test suggestion that started this spiral
of tests and complaints, you will find that the one common factor
in most cases has been the 70-200 lens.

Just food for thought...

Olga
 

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