My 70-200 f4L backfocuses, what can i do?

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

--

Click to expand...

Shooting at rulers or flat test charts held at an angle does not
always work consistently. The AF points in the camera cover a much
wider area than that represented by a single line on a ruler or
test chart. You need a good high-contrast target for the AF point.
The best target is a flat surface at 90 degrees to the camera wide
enough to give the camera's focus point a solid target with good
contrast and good lighting - then the AF system should give
consistent results.

Using a small AF target like a line on a ruler or test chart is why
most of these 70-200 lenses backfocus at 70mm and less so at 200mm
or even work ok at 200mm. At 70mm you have low magnification and
the AF system sees a small target so the system misses and
generally backfocuses. At 200mm you have much more magnification
and the target line is more distinct and the AF system gets better
contrast and will generally focus better. Oly's lens was the
opposite (better at lower end) and the image jumped in the
viewfinder which is weird and probably indicates a real problem.

Check out this webpage:

http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm

You can also look at my test target which works well. I have since
made a bigger test chart with a wider center target that works even
better and gives very consistent results with all my lenses:

http://www.pbase.com/wrwood/test_images

Another good method is to line up 7 coke cans or something similar
in a straight line and shoot at the middle can from a 45 degree
angle. This also gives the AF point a good solid target and will
immediately show you misfocusing.

Another critical test in my opinion is to shoot at text to be sure
the lens focuses consistently up/down and left/right all the way
across the entire image. Find a big poster or open a good quality
magazine full width and attach it to a flat board. Shoot at 90
degrees to the camera. The text should be equally sharp top/bottom
and left/right. I had one 70-200L that showed blurry text on the
left 1/3 of the image. This problem is very hard to see in real
life photos because you can miss it thinking the blur is due to the
DOF.

On all tests shoot off a solid tripod in good light, preferrably
outside. Poor lighting will also produce inconsistent results.
One test is not enough to conclude that your lens is defective.
Test several times in different lighting.

Regards,

Bill Wood
Fountain Hills, AZ

Click to expand...

PaulyOly said:

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

Click to expand...

Click to expand...

Mine would jump after the second time i would half press the
shutter, if i focused on something far away and then something
close it wouldn't always jump, but if i refocused on the close
object twice it would jump as if to say, hey i'm allready focused
on that stupid! Just wanted to make that clear. I didn't pull
mine out of the box and go straight to testing it either, used it
for a week off and on, it wasn't untill the straight on shots of
the daisy shooting on a tripod in good light that i decided to test
it.
--

Click to expand...

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

--

Click to expand...

Shooting at rulers or flat test charts held at an angle does not
always work consistently. The AF points in the camera cover a much
wider area than that represented by a single line on a ruler or
test chart. You need a good high-contrast target for the AF point.
The best target is a flat surface at 90 degrees to the camera wide
enough to give the camera's focus point a solid target with good
contrast and good lighting - then the AF system should give
consistent results.

Using a small AF target like a line on a ruler or test chart is why
most of these 70-200 lenses backfocus at 70mm and less so at 200mm
or even work ok at 200mm. At 70mm you have low magnification and
the AF system sees a small target so the system misses and
generally backfocuses. At 200mm you have much more magnification
and the target line is more distinct and the AF system gets better
contrast and will generally focus better. Oly's lens was the
opposite (better at lower end) and the image jumped in the
viewfinder which is weird and probably indicates a real problem.

Check out this webpage:

http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm

You can also look at my test target which works well. I have since
made a bigger test chart with a wider center target that works even
better and gives very consistent results with all my lenses:

http://www.pbase.com/wrwood/test_images

Another good method is to line up 7 coke cans or something similar
in a straight line and shoot at the middle can from a 45 degree
angle. This also gives the AF point a good solid target and will
immediately show you misfocusing.

Another critical test in my opinion is to shoot at text to be sure
the lens focuses consistently up/down and left/right all the way
across the entire image. Find a big poster or open a good quality
magazine full width and attach it to a flat board. Shoot at 90
degrees to the camera. The text should be equally sharp top/bottom
and left/right. I had one 70-200L that showed blurry text on the
left 1/3 of the image. This problem is very hard to see in real
life photos because you can miss it thinking the blur is due to the
DOF.

On all tests shoot off a solid tripod in good light, preferrably
outside. Poor lighting will also produce inconsistent results.
One test is not enough to conclude that your lens is defective.
Test several times in different lighting.

Regards,

Bill Wood
Fountain Hills, AZ

Click to expand...

wu chou said:

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

--

Click to expand...

Shooting at rulers or flat test charts held at an angle does not
always work consistently. The AF points in the camera cover a much
wider area than that represented by a single line on a ruler or
test chart. You need a good high-contrast target for the AF point.
The best target is a flat surface at 90 degrees to the camera wide
enough to give the camera's focus point a solid target with good
contrast and good lighting - then the AF system should give
consistent results.

Using a small AF target like a line on a ruler or test chart is why
most of these 70-200 lenses backfocus at 70mm and less so at 200mm
or even work ok at 200mm. At 70mm you have low magnification and
the AF system sees a small target so the system misses and
generally backfocuses. At 200mm you have much more magnification
and the target line is more distinct and the AF system gets better
contrast and will generally focus better. Oly's lens was the
opposite (better at lower end) and the image jumped in the
viewfinder which is weird and probably indicates a real problem.

Check out this webpage:

http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm

You can also look at my test target which works well. I have since
made a bigger test chart with a wider center target that works even
better and gives very consistent results with all my lenses:

http://www.pbase.com/wrwood/test_images

Another good method is to line up 7 coke cans or something similar
in a straight line and shoot at the middle can from a 45 degree
angle. This also gives the AF point a good solid target and will
immediately show you misfocusing.

Another critical test in my opinion is to shoot at text to be sure
the lens focuses consistently up/down and left/right all the way
across the entire image. Find a big poster or open a good quality
magazine full width and attach it to a flat board. Shoot at 90
degrees to the camera. The text should be equally sharp top/bottom
and left/right. I had one 70-200L that showed blurry text on the
left 1/3 of the image. This problem is very hard to see in real
life photos because you can miss it thinking the blur is due to the
DOF.

On all tests shoot off a solid tripod in good light, preferrably
outside. Poor lighting will also produce inconsistent results.
One test is not enough to conclude that your lens is defective.
Test several times in different lighting.

Regards,

Bill Wood
Fountain Hills, AZ

Click to expand...

Click to expand...

alekas said:

How did you find out that lens was made in 2002?

I finally received my 70-200 4L, run AF test and shoot about 100
pictures in "real life" conditions - the lens is backfocusing
really badly. I'm going to send it for replacement - I don't
believe it's going to help, but I'll try one more time.

Alex

wu chou said:

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

--

Click to expand...

Shooting at rulers or flat test charts held at an angle does not
always work consistently. The AF points in the camera cover a much
wider area than that represented by a single line on a ruler or
test chart. You need a good high-contrast target for the AF point.
The best target is a flat surface at 90 degrees to the camera wide
enough to give the camera's focus point a solid target with good
contrast and good lighting - then the AF system should give
consistent results.

Using a small AF target like a line on a ruler or test chart is why
most of these 70-200 lenses backfocus at 70mm and less so at 200mm
or even work ok at 200mm. At 70mm you have low magnification and
the AF system sees a small target so the system misses and
generally backfocuses. At 200mm you have much more magnification
and the target line is more distinct and the AF system gets better
contrast and will generally focus better. Oly's lens was the
opposite (better at lower end) and the image jumped in the
viewfinder which is weird and probably indicates a real problem.

Check out this webpage:

http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm

You can also look at my test target which works well. I have since
made a bigger test chart with a wider center target that works even
better and gives very consistent results with all my lenses:

http://www.pbase.com/wrwood/test_images

Another good method is to line up 7 coke cans or something similar
in a straight line and shoot at the middle can from a 45 degree
angle. This also gives the AF point a good solid target and will
immediately show you misfocusing.

Another critical test in my opinion is to shoot at text to be sure
the lens focuses consistently up/down and left/right all the way
across the entire image. Find a big poster or open a good quality
magazine full width and attach it to a flat board. Shoot at 90
degrees to the camera. The text should be equally sharp top/bottom
and left/right. I had one 70-200L that showed blurry text on the
left 1/3 of the image. This problem is very hard to see in real
life photos because you can miss it thinking the blur is due to the
DOF.

On all tests shoot off a solid tripod in good light, preferrably
outside. Poor lighting will also produce inconsistent results.
One test is not enough to conclude that your lens is defective.
Test several times in different lighting.

Regards,

Bill Wood
Fountain Hills, AZ

Click to expand...

Click to expand...

Click to expand...

Weew said:

My 4L is working very good now, no back focus problem, no front
focus problem, just have the problem to stop using it!

alekas said:

How did you find out that lens was made in 2002?

I finally received my 70-200 4L, run AF test and shoot about 100
pictures in "real life" conditions - the lens is backfocusing
really badly. I'm going to send it for replacement - I don't
believe it's going to help, but I'll try one more time.

Alex

wu chou said:

Bill,

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

Click to expand...

Click to expand...

Click to expand...

alekas said:

How did you find out that lens was made in 2002?

I finally received my 70-200 4L, run AF test and shoot about 100
pictures in "real life" conditions - the lens is backfocusing
really badly. I'm going to send it for replacement - I don't
believe it's going to help, but I'll try one more time.

Alex

wu chou said:

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

William R Wood said:

wu chou said:

I just ordered EF 70-200mm/f4L two days ago, and it is on its way
to my home. I am wondering what is the best (may be just the
easiest) way to test the lens to see if it is normal.

Any help on how to test this lens will be appreciated. But simple
less time consuming method is prefered, since I am still learning
the rope,

--- wuchou.

--

Click to expand...

Shooting at rulers or flat test charts held at an angle does not
always work consistently. The AF points in the camera cover a much
wider area than that represented by a single line on a ruler or
test chart. You need a good high-contrast target for the AF point.
The best target is a flat surface at 90 degrees to the camera wide
enough to give the camera's focus point a solid target with good
contrast and good lighting - then the AF system should give
consistent results.

Using a small AF target like a line on a ruler or test chart is why
most of these 70-200 lenses backfocus at 70mm and less so at 200mm
or even work ok at 200mm. At 70mm you have low magnification and
the AF system sees a small target so the system misses and
generally backfocuses. At 200mm you have much more magnification
and the target line is more distinct and the AF system gets better
contrast and will generally focus better. Oly's lens was the
opposite (better at lower end) and the image jumped in the
viewfinder which is weird and probably indicates a real problem.

Check out this webpage:

http://www.hkdotnet.com/FrancisPhotographyChannel/AF_Test/index.htm

You can also look at my test target which works well. I have since
made a bigger test chart with a wider center target that works even
better and gives very consistent results with all my lenses:

http://www.pbase.com/wrwood/test_images

Another good method is to line up 7 coke cans or something similar
in a straight line and shoot at the middle can from a 45 degree
angle. This also gives the AF point a good solid target and will
immediately show you misfocusing.

Another critical test in my opinion is to shoot at text to be sure
the lens focuses consistently up/down and left/right all the way
across the entire image. Find a big poster or open a good quality
magazine full width and attach it to a flat board. Shoot at 90
degrees to the camera. The text should be equally sharp top/bottom
and left/right. I had one 70-200L that showed blurry text on the
left 1/3 of the image. This problem is very hard to see in real
life photos because you can miss it thinking the blur is due to the
DOF.

On all tests shoot off a solid tripod in good light, preferrably
outside. Poor lighting will also produce inconsistent results.
One test is not enough to conclude that your lens is defective.
Test several times in different lighting.

Regards,

Bill Wood
Fountain Hills, AZ

Click to expand...

Click to expand...

Click to expand...

alekas said:

All lenses I bought and keep are "second copy".

And again - what's the point to buy $600 lens and then send it to
Canon for the adjustment immediately (and pay on top of the price a
shipment to Canon)? And usually Canon requesting to send a camera
with lens for the adjustment - I don't want to be w/o camera for
2-3 weeks and I don't want to get back the "adjusted body" which
does not focus correctly with the rest of my lenses

I paid my money and I'm expecting to get a good copy. If it's not
true I may try as many times as I want (as long as the store is
reimbursing the shipment charges and does not refuse to continue
this game with me). I checked out and I have email from J&R - they
are going to reimburse the shipment charges for the defective lens.
So I think I'll try at least once - hope I'm receiving a good copy

Alex

Weew said:

My 4L is working very good now, no back focus problem, no front
focus problem, just have the problem to stop using it!

alekas said:

How did you find out that lens was made in 2002?

I finally received my 70-200 4L, run AF test and shoot about 100
pictures in "real life" conditions - the lens is backfocusing
really badly. I'm going to send it for replacement - I don't
believe it's going to help, but I'll try one more time.

Alex

wu chou said:

Bill,

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

Click to expand...

Click to expand...

Click to expand...

Click to expand...

wu chou said:

I may be wrong here. I got the impression from the lens manual that
printed " @CANON INC, 2002". The lens box also seems on the shelf
for some time, again this is speculation. The lens is marked "made
in Japan". The lens body is painted with yellow-gray color paint.
It doesn't look like very polished from the outside. I saw a
picture of this lense in white color, which is better than mine.
There must be a date mark on when it is produced, but I haven't
found it.

Here are my first indoor shot of EF70-200mm/f4L with flash
http://www.pbase.com/image/27658318

and an outdoor flower shot (windy)
http://www.pbase.com/image/27653037

By the way, you might consider to send the lens to Canon Service
Center to repair, and the problem should be fixable. I will
consider that, since this is the only L- zoom lens that weighs
below 2lbs.

-- wuchou.

Click to expand...

Weew said:

alekas said:

All lenses I bought and keep are "second copy".

And again - what's the point to buy $600 lens and then send it to
Canon for the adjustment immediately (and pay on top of the price a
shipment to Canon)? And usually Canon requesting to send a camera
with lens for the adjustment - I don't want to be w/o camera for
2-3 weeks and I don't want to get back the "adjusted body" which
does not focus correctly with the rest of my lenses

I paid my money and I'm expecting to get a good copy. If it's not
true I may try as many times as I want (as long as the store is
reimbursing the shipment charges and does not refuse to continue
this game with me). I checked out and I have email from J&R - they
are going to reimburse the shipment charges for the defective lens.
So I think I'll try at least once - hope I'm receiving a good copy

Alex

Weew said:

My 4L is working very good now, no back focus problem, no front
focus problem, just have the problem to stop using it!

alekas said:

How did you find out that lens was made in 2002?

I finally received my 70-200 4L, run AF test and shoot about 100
pictures in "real life" conditions - the lens is backfocusing
really badly. I'm going to send it for replacement - I don't
believe it's going to help, but I'll try one more time.

Alex

wu chou said:

Bill,

Thanks so much for the help. I got my new EF 70-200mm/f4L lens
today. The lens was made in 2002, two years ago in Japan. I am not
sure if this is normal for new lens purchase.

Your jar test is a wonderful idea. I did it right away. So far, I
haven't seen the back focusing problem with this lens. But it maybe
just to early to say, since it is in my hand for less than three
hours.

----wuchou.

Click to expand...

Click to expand...

Click to expand...

Click to expand...

Click to expand...

PaulyOly said:

Well after getting consistently blurry pics of flowers at 200mm and
not at say 135mm i decided to test it using a focus chart at a 45
degree angle, it seems to be bacfocusing very bad at 200mm. There
is no way i'm sending my camera to canon with this lens so will
they try to fix it without my camera? Or will they simply test it
and say there is nothing wrong with it? Maybe 17 street photo will
take it back even though i've had it for 16 days. I'll follow this
up with the chart pics.
--
http://www.pbase.com/paulyoly/root

Click to expand...

PaulyOly said:

This one backfocuses just as bad as the other and it does it at all
focal lengths. I had asked to replace it with the canon 100mm
macro and wrote that on the return form and still they sent me
another copy. I didn't even bother opening the lens hood this
time. Anyone with a digital rebel i would advise against buying
this lens as it appears to not work well with this camera. funny
how my 50 1.8 and 400 f5.6L both work great as well as the kit lens
of course. I'd would guess nothing is infocus past my focus point
until 1/4-1/2 inch. I wonder just how good a "good copy" of this
lens focuses with the digital rebel. I'm going to try and exchange
it again for a 100mm macro and battery grip, if they sold the 200mm
2.8 i would have exchanged for that.

Click to expand...

PaulyOly said:

I'm going to try and exchange
it again for a 100mm macro and battery grip, if they sold the 200mm
2.8 i would have exchanged for that.

Click to expand...

PaulyOly said:

When focusing the image in the viewfinder shakes when using this
lens, does anyone elses do this?

Click to expand...

PaulyOly said:

PaulyOly said:

Well after getting consistently blurry pics of flowers at 200mm and
not at say 135mm i decided to test it using a focus chart at a 45
degree angle, it seems to be bacfocusing very bad at 200mm. There
is no way i'm sending my camera to canon with this lens so will
they try to fix it without my camera? Or will they simply test it
and say there is nothing wrong with it? Maybe 17 street photo will
take it back even though i've had it for 16 days. I'll follow this
up with the chart pics.
--
http://www.pbase.com/paulyoly/root

Click to expand...

--
http://www.pbase.com/paulyoly/root



This one backfocuses just as bad as the other and it does it at all
focal lengths. I had asked to replace it with the canon 100mm
macro and wrote that on the return form and still they sent me
another copy. I didn't even bother opening the lens hood this
time. Anyone with a digital rebel i would advise against buying
this lens as it appears to not work well with this camera. funny
how my 50 1.8 and 400 f5.6L both work great as well as the kit lens
of course. I'd would guess nothing is infocus past my focus point
until 1/4-1/2 inch. I wonder just how good a "good copy" of this
lens focuses with the digital rebel. I'm going to try and exchange
it again for a 100mm macro and battery grip, if they sold the 200mm
2.8 i would have exchanged for that.

Click to expand...

PaulyOly said:

PaulyOly said:

Well after getting consistently blurry pics of flowers at 200mm and
not at say 135mm i decided to test it using a focus chart at a 45
degree angle, it seems to be bacfocusing very bad at 200mm. There
is no way i'm sending my camera to canon with this lens so will
they try to fix it without my camera? Or will they simply test it
and say there is nothing wrong with it? Maybe 17 street photo will
take it back even though i've had it for 16 days. I'll follow this
up with the chart pics.
--
http://www.pbase.com/paulyoly/root

Click to expand...

--
http://www.pbase.com/paulyoly/root



This one backfocuses just as bad as the other and it does it at all
focal lengths. I had asked to replace it with the canon 100mm
macro and wrote that on the return form and still they sent me
another copy. I didn't even bother opening the lens hood this
time. Anyone with a digital rebel i would advise against buying
this lens as it appears to not work well with this camera. funny
how my 50 1.8 and 400 f5.6L both work great as well as the kit lens
of course. I'd would guess nothing is infocus past my focus point
until 1/4-1/2 inch. I wonder just how good a "good copy" of this
lens focuses with the digital rebel. I'm going to try and exchange
it again for a 100mm macro and battery grip, if they sold the 200mm
2.8 i would have exchanged for that.

Click to expand...