I suppose it's only fitting...#@$%%# BACKFOCUS!!!

[Mark Gillett]

Clutching at straws! Who knows, I just can't see how the thing will look in focus and then change to OOF. I would love to get hold of the camera just to reassure me there was something wrong with it.

M

Have you EVER seen a dioptric that's out of whack make an out of
focus image look focused? I haven't.

All it does it make things look more blurry.

The least blurry image still happens at the proper focus.

At least that's been my experience.

maybe your little dioptric adjustment knob is incorrectly
positioned? Have you adjusted this at all?

--
http://www.outboundmusic.com
Your link to independent music!

--
http://www.pbase.com/markgillett

 

[Victor Engel]

Yes, and your red rectangle hits the tree edge at the bottom!

If that's a tree edge, sure. I thought that was the ground. By tree edge, I thought you meant the vertical trunk.

 

[Ed Rotberg]

--
= Ed Rotberg =

'A waist is a terrible thing to mind'
http://www.edrotberg.org/gallery

 

[Mark Gillett]

No worries.

Yes, and your red rectangle hits the tree edge at the bottom!

If that's a tree edge, sure. I thought that was the ground. By tree
edge, I thought you meant the vertical trunk.

--
http://www.pbase.com/markgillett

 

[Vern Stevens]

My purpose for doing that was not to exercise good photographic technique. It was to test just how out of focus the center point was when focused from the wide end of the lens.

VES

Don't do that. Ever. If you're gonna try something like that,
focus at 200mm, then zoom out to 70mm. NOT the other way around.

 

[Vern Stevens]

It's not focusing left of, right of or anything like that. If you look at the depth of the shot, the left of or the right of each of those shots represents BEHIND the focus point, not actually left or right of it.

VES

It doesn't seem to happen the same way all the time. The first
shot looks like it chose left of center (possibly for the more
painted then chipped section). The first rock is totally out of
focus, the second rock is focused on the more contrasty v cutout of
the rock. However, the squirrel shot seems to me to be focused on
the right of the squirell on the more contrasty small tree branch,
which actually starts off slightly in front of the squirrel. This
would only seem to support the focus area being larger than the red
rectangle theory.

Rgds
KR

 

[Vern Stevens]

Nothing in my case since it's all under warranty. Well, except I have to pay the shipping to them. The pay for shipping back to me.

VES

as in the clear examples I have shown in posts down on the thread
tree here. Also, the same thing was happening to my 70-200 4L yet
much worse and in all aperatures. Upon capturing the lens chose a
different focus point than what is confirmed by the focus points
and seen in the viewfinder.
I sent mine back to Canon, as I mentioned to DavidP ealier, and
they did an excellent job of calibrating. Now, WISIWIG!
Tell them to take thier time and recalibrate, which is what I did;
and now I am what's called 'a happy camper'.

--
'Deceive, Inveigle, Obfuscate.' - The X-Files (Teliko)

http://www.pbase.com/vsteven

 

[Vern Stevens]

As I said in the first post, all of these shots were taken with the center point selected, and no recomposing of the frame. There is NO way the tree would have been within the center focus point.

Another user posted the focus point overlay in a followup response.

VES

Can you post the pic with focus points?

When you focus check that the desired focus point is what the
sensor has picked up rather than assuming that is the case. They
can often be fooled.

M

Can you post the pic with

Well, after several shots, including the one below, I have pretty
much determined that my 70-200L 2.8 IS and my 10D make a nice
backfocusing couple. I suspect my 17-40L does it as well, just not
quite as easy to tell.

The following shot was done with the center focus point selected,
no recomposing of the frame. The chainsaw blade SHOULD have been
my focus point...



Full Image here: http://www.pbase.com/image/23652114/original

As you can see, the tree behind the stump and the ground behind the
blade are in focus, the stump, the chainsaw and it's weilder, all
in the same plane, are not in focus.

Time to call Canon.

VES

--
'Deceive, Inveigle, Obfuscate.' - The X-Files (Teliko)

http://www.pbase.com/vsteven

--
http://www.pbase.com/markgillett

--
'Deceive, Inveigle, Obfuscate.' - The X-Files (Teliko)

http://www.pbase.com/vsteven

 

[Vern Stevens]

Apparently there WAS enough contrast, that's why it locked. How the
hell was the camera to know the photographer was aiming for the
blade not for the objects behind it ???

Isn't that why they put the AUTO in autofocus? If I'm given a reference point with which the aim the camera, say that little center autofocus square in the viewfinder, and I point that square at something that I want in focus, isn't it it's job to know that's what I"m pointing at? Otherwise, why have autofocus, or an autofocus selection point?

it is, look above and look at other posts here - more people
stressed that this particular situation was most likely very
confusing for the system...

And that may be the problem. More people saying the same thing may be correct. But more in and of itself is not a sign of credibility.

VES

 

[Sonny]

Here is my experience with my 10D regarding focussing. Please read.

http://forums.dpreview.com/forums/read.asp?forum=1019&message=6782080

Sonny T. Senser
http://www.sonnyphoto.com

 

[Vern Stevens]

Anyone who looked at the actual sensor overlay that another user posted, assuming that is an accurate representation of the sensor size, can easily see the log and the sawdust beneath it were NOT in the sensor area. Now if that overlay does not represent the actual size, and it's even bigger than that, perhaps so, but I don't think that is the case.

Regardless of the sensor size, big or small, I think it would have been smart for Canon to make the reference in the viewfinder the same size so people don't have to guess what's being covered and what's not being covered by the sensor.

VES

If there's not enough contrast, the AF shouldn't lock. It should
blink the green light, and refuse to fire a shot (in one-shot mode).

This would happen if there was not enough contrast in the pic or
the sensor was the size of the red square. We all know that is not
the case so can we not accept what it has done. It looks fairly
obvious to me.

Isn't the camera smart enough to recognize when there's not enough
contrast?

As above!

Apparently not. Even the 1D suffers from this . . . . apparently
not as frequently as the 10D, though.

I know not.

I agree that the tree stump would make a better AF target. But
it's plain stupid that the camera will mis-focus by such a large
amount and not know it. Of course, the extra-large AF sensor of
the 10D is largely to blame for this issue in this particular image.

Take the actual sensor size into acount and it has not mis focussed.

What I find difficult is that the taker of the photo could not see
that it was locking on to the wrong subject just by looking into
the view finder.

My 1D makes that shot for sure and probably my 10D get that shot
too. Maybe the lens is the problem. Try on diff. body to test the
lens.

--
http://www.outboundmusic.com
Your link to independent music!

--
http://www.pbase.com/markgillett

--
'Deceive, Inveigle, Obfuscate.' - The X-Files (Teliko)

http://www.pbase.com/vsteven

 

[Charles Carroll]

which is what you demonstrated.

 

[Vern Stevens]

I'm shooting real world shots, just like most advocates of the "there's no aF problem" crowd suggest, and apparently "THESE" real world shots aren't what they want either.

Now, that aside, let me see if I understand what some folks are saying.

I should shoot a picture of some object that will encompass the entire AF sensor (although you really can't tell how big it is by the reference in the viewfinder) in good light and if that doesn't focus properly, then I have a problem?

But otherwise, if I EVER want to shoot a subject that may not be covered by the entire sensor or that may not be in optimal lighting circumstances, it's a cr*p shoot that the subject will be in focus.

Is autofocus that undependable? It didn't seem to be with my 28-135 IS.

VES

 

[Ed Rotberg]

It's not black and white like that. You want to verify if you have a problem with your lens/camera. Test the lens/camera on something that can plainly indicate if there is or is not a problem with that.

NO AF SYSTEM IN THE WORLD is foolproof. There are "real world" situations that are easy for AF systems, some that are pretty much impossible, and everything in between. They are ALL "real world" photo situations. If you want pro quality results, you have to get beyond the point where you expect that the AF system will work in every situation, reading your mind as to what you want it to focus on. It can't.

The unfortunate part here is that you have chosen some of the more difficult photo situations. I don't say that your first post was that difficult, but you could have helped your system in that case by focusing on the carving or the man and then recomposing. Instead you chose a much smaller, lower contrast object to focus on. You opened the door for error that you did not have to open. I can't explain the rocks - I have no idea how close you were to them.

The wire cage is a classic problem for auto focus (and cleary not BACKFOCUSED), as is the squirrel through a whole passel of tree branches. This would be one indication that your lens is not backfocusing. The wire case shows nothing in the "back" as in focus.

If you want a point and shoot camera you probably should not have bought the 10D. That said, any point and shoot you buy will have similar limitations with regards to autofocus. In fact they will have more limitations. You might not notice them as much because the P&S digitals have such a large DOF almost all the time.

Learn how to help your camera to find the right focus. The more thinking you do behind the the camera, the better "thinking" your camera can do for you.

Having said all of that, your camera may indeed have a focus problem. Personally, however, I just couldn't be certain given the shots you have posted so far. If it were my camera, I would want to convince myself that the camera/lens is or is not at fault. Yes, I would pick the easiest case for the camera so I could determine that WITHOUT A DOUBT. If it's the camera or lens , return it or get it serviced and move on.

However, if the camera/lens combination work properly, then you have to go back and examine problem photos and try to LEARN from them what went wrong and why. Add that information to your technique and use this approach to help make you a better technical photographer. It will stand you in good stead with whatever equipment you are using.

I'm sorry if I sound harsh. I certainly am not trying to do so. I just can't be certain that you have an equipment problem given these photos.

= Ed =

I'm shooting real world shots, just like most advocates of the
"there's no aF problem" crowd suggest, and apparently "THESE" real
world shots aren't what they want either.

Now, that aside, let me see if I understand what some folks are
saying.

I should shoot a picture of some object that will encompass the
entire AF sensor (although you really can't tell how big it is by
the reference in the viewfinder) in good light and if that doesn't
focus properly, then I have a problem?

But otherwise, if I EVER want to shoot a subject that may not be
covered by the entire sensor or that may not be in optimal lighting
circumstances, it's a cr*p shoot that the subject will be in focus.

Is autofocus that undependable? It didn't seem to be with my
28-135 IS.

VES

--
= Ed Rotberg =

'A waist is a terrible thing to mind'
http://www.edrotberg.org/gallery

 

[keef]

when i am taking pictures that do not want to run away from me, I always press the shutter half way 2 or 3 times. I think auto focus is pretty magic, but needs a bit of help from the carefull spelled out spell.

also, another interesting thing: some people zoom in focus, zoom out, click. Perhaps with old manual focus lenese this was ok, but with my L gear zooming scre.ws up the focus, so you ALWAYS need to refocus.

any way, thats what i do . . .

http://www.waddo.net

keith

 

[Mark Rodrigues]

David, do you work for Exxon? I was at an SAP course in Philadelphia with an engineer from Exxon a few months back.

I don't know what your excuse is, but mine's that I'm a petroleum
engineer, and we're always having to (try) to explain things that
just don't make sense.

A recent example. Drilled a well the other day. The well was
updip of a well that had produced gas (with some condensate). We
took pressure data in the well when we logged it. The pressure
data across the sand had a pressure gradient that was indicative of
a gas reservoir (though with quite a bit of condesnate).

So, we concluded that this would be a gas well.

When it was completled, it was an oil well. Go figure.

The only explanation possible is that we're in a completely
different sand lobe than the downdip well.

Things are not always what they appear.

We just all like discussing it, really.

--
http://www.outboundmusic.com
Your link to independent music!

 

[DavidP #28649]

SAP? Isn't that an accounting type of program?

Nope, though I used to work for Shell.

David, do you work for Exxon? I was at an SAP course in
Philadelphia with an engineer from Exxon a few months back.

--
http://www.outboundmusic.com
Your link to independent music!

 

[Mark Rodrigues]

Geez, I would expect that given the cost of the 10D, the AF system would be at least as foolproof as the next SLR in its class - but according to this logic this is not the case.

I guess we all bought some really, really, non foolproof cameras - funny though that Canon can fix it then.

There is absolutely no way that the shot that Vern posted should have the focal plane where it is if the camera/lens pair is working properly together.

I know that sometimes an SLR will focus on something else in the shot that draws the AF's "attention", but in Vern's shot there is absolutely no reason for the AF to have selected the particular plane that it did given his intended focal point and the content of the image.

NO AF SYSTEM IN THE WORLD is foolproof. There are "real world"
situations that are easy for AF systems, some that are pretty much
impossible, and everything in between. They are ALL "real world"
photo situations. If you want pro quality results, you have to get
beyond the point where you expect that the AF system will work in
every situation, reading your mind as to what you want it to focus
on. It can't.

The unfortunate part here is that you have chosen some of the more
difficult photo situations. I don't say that your first post was
that difficult, but you could have helped your system in that case
by focusing on the carving or the man and then recomposing.
Instead you chose a much smaller, lower contrast object to focus
on. You opened the door for error that you did not have to open.
I can't explain the rocks - I have no idea how close you were to
them.

The wire cage is a classic problem for auto focus (and cleary not
BACKFOCUSED), as is the squirrel through a whole passel of tree
branches. This would be one indication that your lens is not
backfocusing. The wire case shows nothing in the "back" as in
focus.

If you want a point and shoot camera you probably should not have
bought the 10D. That said, any point and shoot you buy will have
similar limitations with regards to autofocus. In fact they will
have more limitations. You might not notice them as much because
the P&S digitals have such a large DOF almost all the time.

Learn how to help your camera to find the right focus. The more
thinking you do behind the the camera, the better "thinking" your
camera can do for you.

Having said all of that, your camera may indeed have a focus
problem. Personally, however, I just couldn't be certain given the
shots you have posted so far. If it were my camera, I would want
to convince myself that the camera/lens is or is not at fault.
Yes, I would pick the easiest case for the camera so I could
determine that WITHOUT A DOUBT. If it's the camera or lens ,
return it or get it serviced and move on.

However, if the camera/lens combination work properly, then you
have to go back and examine problem photos and try to LEARN from
them what went wrong and why. Add that information to your
technique and use this approach to help make you a better technical
photographer. It will stand you in good stead with whatever
equipment you are using.

I'm sorry if I sound harsh. I certainly am not trying to do so. I
just can't be certain that you have an equipment problem given
these photos.

= Ed =

I'm shooting real world shots, just like most advocates of the
"there's no aF problem" crowd suggest, and apparently "THESE" real
world shots aren't what they want either.

Now, that aside, let me see if I understand what some folks are
saying.

I should shoot a picture of some object that will encompass the
entire AF sensor (although you really can't tell how big it is by
the reference in the viewfinder) in good light and if that doesn't
focus properly, then I have a problem?

But otherwise, if I EVER want to shoot a subject that may not be
covered by the entire sensor or that may not be in optimal lighting
circumstances, it's a cr*p shoot that the subject will be in focus.

Is autofocus that undependable? It didn't seem to be with my
28-135 IS.

VES

--
= Ed Rotberg =

'A waist is a terrible thing to mind'
http://www.edrotberg.org/gallery

 

[Ed Rotberg]

Mark,

You say there is absolutely no way it should have been fooled. Reasons were given. Sorry if you don't understand the what has already been posted.

= Ed =

I guess we all bought some really, really, non foolproof cameras -
funny though that Canon can fix it then.

There is absolutely no way that the shot that Vern posted should
have the focal plane where it is if the camera/lens pair is working
properly together.

I know that sometimes an SLR will focus on something else in the
shot that draws the AF's "attention", but in Vern's shot there is
absolutely no reason for the AF to have selected the particular
plane that it did given his intended focal point and the content of
the image.

NO AF SYSTEM IN THE WORLD is foolproof. There are "real world"
situations that are easy for AF systems, some that are pretty much
impossible, and everything in between. They are ALL "real world"
photo situations. If you want pro quality results, you have to get
beyond the point where you expect that the AF system will work in
every situation, reading your mind as to what you want it to focus
on. It can't.

The unfortunate part here is that you have chosen some of the more
difficult photo situations. I don't say that your first post was
that difficult, but you could have helped your system in that case
by focusing on the carving or the man and then recomposing.
Instead you chose a much smaller, lower contrast object to focus
on. You opened the door for error that you did not have to open.
I can't explain the rocks - I have no idea how close you were to
them.

The wire cage is a classic problem for auto focus (and cleary not
BACKFOCUSED), as is the squirrel through a whole passel of tree
branches. This would be one indication that your lens is not
backfocusing. The wire case shows nothing in the "back" as in
focus.

If you want a point and shoot camera you probably should not have
bought the 10D. That said, any point and shoot you buy will have
similar limitations with regards to autofocus. In fact they will
have more limitations. You might not notice them as much because
the P&S digitals have such a large DOF almost all the time.

Learn how to help your camera to find the right focus. The more
thinking you do behind the the camera, the better "thinking" your
camera can do for you.

Having said all of that, your camera may indeed have a focus
problem. Personally, however, I just couldn't be certain given the
shots you have posted so far. If it were my camera, I would want
to convince myself that the camera/lens is or is not at fault.
Yes, I would pick the easiest case for the camera so I could
determine that WITHOUT A DOUBT. If it's the camera or lens ,
return it or get it serviced and move on.

However, if the camera/lens combination work properly, then you
have to go back and examine problem photos and try to LEARN from
them what went wrong and why. Add that information to your
technique and use this approach to help make you a better technical
photographer. It will stand you in good stead with whatever
equipment you are using.

I'm sorry if I sound harsh. I certainly am not trying to do so. I
just can't be certain that you have an equipment problem given
these photos.

= Ed =

I'm shooting real world shots, just like most advocates of the
"there's no aF problem" crowd suggest, and apparently "THESE" real
world shots aren't what they want either.

Now, that aside, let me see if I understand what some folks are
saying.

I should shoot a picture of some object that will encompass the
entire AF sensor (although you really can't tell how big it is by
the reference in the viewfinder) in good light and if that doesn't
focus properly, then I have a problem?

But otherwise, if I EVER want to shoot a subject that may not be
covered by the entire sensor or that may not be in optimal lighting
circumstances, it's a cr*p shoot that the subject will be in focus.

Is autofocus that undependable? It didn't seem to be with my
28-135 IS.

VES

--
= Ed Rotberg =

'A waist is a terrible thing to mind'
http://www.edrotberg.org/gallery

--
= Ed Rotberg =

'A waist is a terrible thing to mind'
http://www.edrotberg.org/gallery

 

[Vern Stevens]

It's not really that I mind people responding with good advice, even if it contains some harshness. The thing that bothers me more is when they seem to overlook things I say in my posts, such as my mentioning I never had this problem with the 28-135. I have shot over a thousand images, many tough situations like this, and that lens seemed to be able to handle it. Granted, the overall images are quite as crisp (in that areas that are in focus), nor is the color, contrast or bokeh is pleasing, but it seemed to focus where I wanted most all the time. Not all the time, but with a much more acceptable ratio to me than this lens is pulling off.

The wire cage is a classic problem for auto focus (and cleary not
BACKFOCUSED), as is the squirrel through a whole passel of tree
branches. This would be one indication that your lens is not
backfocusing. The wire case shows nothing in the "back" as in
focus.

I disagree that the wire shot doesn't show something "behind" or to the rear that is in focus. To the left, outside of the sensor area, there is a bit of the wire that is clearly sharp. That wire cage is round, and that bit of wire that is clearly in focus is (in terms of the focus point plane) behind the focus point. The part that was in focus had no more contrast or detail than the part I was aiming the sensor at.

If you want a point and shoot camera you probably should not have
bought the 10D. That said, any point and shoot you buy will have
similar limitations with regards to autofocus. In fact they will
have more limitations. You might not notice them as much because
the P&S digitals have such a large DOF almost all the time.

I already have a point and shoot camera. Even if you are going to be harsh, at least be helpful. This isn't a helpful statement, because I believe I have a reasonable expectation as to how the focus system should work. On that we probably disagree. This camera is not "new" to me. I have been using it since July without any complaints like this. The new thing is the lens (two actually 17-40L and 70-200L 2.8 IS).

Having said all of that, your camera may indeed have a focus
problem. Personally, however, I just couldn't be certain given the
shots you have posted so far. If it were my camera, I would want
to convince myself that the camera/lens is or is not at fault.
Yes, I would pick the easiest case for the camera so I could
determine that WITHOUT A DOUBT. If it's the camera or lens ,
return it or get it serviced and move on.

Trust me (or not) when I say, I get no pleasure from the idea of sending this off to Canon for 2-3 weeks to get it fixed. I would much rather it not be the camera or lens. But, I don't want to convince myself of anything other than what is the real problem. There is no bias in that. If I'm dead set on convincing myself it's not the camera or lens, that suggests bias which clouds the judgment. It suggests blinding oneself.

I'm sorry if I sound harsh. I certainly am not trying to do so. I
just can't be certain that you have an equipment problem given
these photos.
= Ed =

That's the interesting things, some, maybe even most people agree with you, while others seem to think there is a problem as well. As is the nature of polling opinions on the net, there is no clear answer to be derived from the information I have received.

Because I don't detail my exact technique, people look to that as a reason for the problem. It's not to say they may not be right, but one person seem to think I wasn't even looking through the viewfinder when I was taking the shot. I'm mean, come on!!!! Therefore, even if I detailed my technique for people to read, they probably would ignore it anyway, and still assume it was something I did, or just fail to digest it as some others did. This is not necessarily directed at you.

Okay, I will post a few more shots in a follow up to this response.... center focus point selected (which the only focus point I ever use really) and no recomposing (though i do that frequently when I shoot, when I don't have problems). No editing, except for adding the overlay on some shots.

Shots to follow without commentary, leave them up to viewer interpretation...

VES