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Wierd (at least for me) problem yesterday

So I was out shooting a swimsuit model yesterday (for fun - not profit) and had something happen that I have never seen happen before with my 1DsMkII. I am presuming my fat fingers had something to do with the problem, but haven't had this problem before. Closest thing I could find in manual was maybe related to AF point selection, but not quite a match. Had camera since Nov 2004, so I would think I would have had it show up before now if it was just me, but it could be just I was off normal yesterday.

Please take into account I usually shoot in the studio usually off a tripod hooked up to studio lights, but I do some outdoor stuff every once in awhile, although usually airplanes and flowers.
I have been trying to get just a swimsuit model to pose for me for about 6 months and a good outdoors location shoot for almost a year with lots of Murphy strikes. So even though overcast and rain threatened I was going to take some pictures...
{trivia note: This will seem strange to some, but I have no problem getting n___ (unclothed) fetish models, but getting just a good swimsuit model is like pulling teeth}

The Problem:
I was using an off-center focus point (farthest out), but every once in awhile it would jump to another focus point at least in the viewfinder. Usually the center point (which makes me think I was hitting a button), but not always. Sometimes it would sit at the point for awhile, but sometimes it would be a quick ghost image before returning to the selected point. It seemed to focus at the desired point versus the shown point at least from what I could see through view finder. It may have been a case of just staying on the good focus point though. I had to do a lot of focus and shift because the AF points don't go out far enough.

The problem did almost always (or maybe always) occur in Vertical (portrait) orientation. I sometime shot vert with horz grip if a quick shot, but switched to vert grip when shooting a sequence - problem occurred in both grip positions.

It never jumped away from center focus point if I had selected that one.


A secondary symptom (probably unrelated, but just in case) is a lot of the exposures were off and I usually don't have that high of a percentage off in Av mode. Most were over exposed, but a small number were under exposed. I was paying attention to exposure compensation as I have accidently shifted it in the past, but did not see any shift this time except when doing deliberately near end of shoot to cpensate for backlight sunset.

I think it was my fingers, maybe, but if it was I can not figure out how to avoid in the future. Looked through manual and did not see where to turn off specific buttons. I need the focus point select and the shutter in both vertical and horizontal modes. And the fact it only seemed to happen in Vert mode has me a touch worried.

Any suggestions as to what I was doing wrong and more importantly how to prevent from happening in future? I will of course be trying to figure it out on my own, but directions to look would help.



Trivia:
- I was outdoors in mostly overcast skies.
- Camera in Av mode, but sometimes Manual (hard to use in constantly changing lighting conditions, but I tried a couple of times any way)
- Lenses used 85/1.2, 28-70/2.8L and 70-200/2.8L
- Problem not observed as much with 70-200, more often with 85 and only slightly less with 28-70. I suspect more use of horizontal orientation with 70-200 and more vertical with 85 and 28-70 as reason.
- Started with 550EX flash mounted, but the idiot who owns the camera forgot to bring the spare batteries sitting on the shelf to be grabbed going out the door. Took flash off after batteries failed. 4 packs of freshly charged batteries and then I went and left them at home.

-- On the good side I got a few good shots (at least from initial review late last night) and the model (and I) had fun, which is most important. The camera issue is puzzleing though.
 
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Hi, Tim:

Your description is consistent with the operation of Custom Function 17-1 or 17-2. Here's how we described it in the "Camera Handling & Maximum Image Quality" PDF, available here:

http://photoworkshop.com/canon/EOS_Digital.pdf

Custom Function 17 allows the photographer to create a cluster of active focusing
points during manual focusing point selection.

• C.Fn 17-0 forces the camera to evaluate only the manually selected focusing point or
points. This is often the best choice when working with average subjects.

• C.Fn 17-1 expands the active focusing area by a radius of 1 point around the manually
selected focusing point, creating up to 7 active focusing points. The camera always
tries to use the manually selected focusing point, but when it can’t, it can choose one
of the other 6 active focusing points if there is readable subject detail under one of
them. This option is intended to increase the odds of getting sharp photos with small,
fast moving subjects such as birds in flight. However, it can sometimes cause critical
focus to shift slightly ahead of or behind relatively large 3-dimensional subjects like
human beings. We suggest practicing with C.Fn 17-1 repeatedly until you get a feel for
what it can and cannot do in your specific applications.

• C.Fn 17-2 performs a little differently according to the camera model. With the original
EOS-1D and EOS-1Ds, the camera decides whether or not to expand the focusing area
by a radius of 1 or 2 focusing points around the manually selected focusing point
based on the focal length of the lens in use as well as the subject’s degree of
movement. The photographer has no control over it other than lens selection. With the
Mark II cameras, on the other hand, C.Fn 17-2 expands the active focusing area by a
radius of 1 point around the manually selected focusing point at focal lengths up to
200mm, or by a radius of 2 points when the focal length is greater than 200mm,
regardless of the degree of subject movement.

Note: In theory, Custom Function 17-1 or 17-2 slightly reduces AF speed because of the
extra calculations involved. However, expanding the active focusing area often
increases the odds of finding a readable subject when subject size is small, or low in
contrast. We encourage you to experiment with all C.Fn 17 settings to determine which
setting is best for your specific needs.

Hope this helps!

Best Regards,

Chuck Westfall
Director/Media & Customer Relationship
Camera Marketing Division/Canon U.S.A., Inc.
 
Chuck,
thanks for responding,

I was thinking it might be that custom function, but that would not explain the jump from outer-most AF point to the center point. It would explain the one point over occasions though and I seem to remember I have it set for the 7-point version of the function. I just rarely see it do any jumping of AF points except when in all-point mode, but then in the studio I am usually using the center point if selecting single point.

I suppose it is possible I was maybe having a combination problem as I thought the jump to center problem might be caused by pre-selected AF point jump (cF-18 I think), but the one point jump was throwing me off.

Is there a way to kill only the WB button (which works the AF point pre-select) so I can't accidently set that one off - if that is the other half of the problem (both vert and horz grip). I know I have never set the pre-selected to anything other then the default center point.

Lastly, any idea why it was happening in portrait orientation and not landscape? (at least not observed)

As soon as I get home I will try to find out which setting my camera is on just to make sure.
Update: CFn 17-1 and CFn 18-2 so one point jump definately 17-1 setting.
 
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>>Is there a way to kill only the WB button (which works the AF point pre-select) so I can't accidently set that one off<<

No.

>>Lastly, any idea why it was happening in portrait orientation and not landscape? (at least not observed)<<

It may have had something to do with the contrast characteristics of the subject matter. Remember that the outer focusing points are single-axis arrays. When the camera is aimed vertically, the orientation of the outer focusing points is horizontal, and vice versa. In either case, the outer points may have a tough time locking onto subjects that are parallel to them. This is usually not a problem for the central focusing points because they are cross-type with fast lenses like the ones you were using.

Best Regards,

Chuck Westfall
Director/Media & Customer Relationship
Camera Marketing Division/Canon U.S.A., Inc.
 
Thanks Chuck,
Makes sense for why the one point switch,

I also discovered by playing with the camera last night that my thumb goes over the WB button more so in portrait mode when using the vertical grip buttons, which explains the higher incidence of switch to the center point. Even when deliberately paying attention I did not feel the button much with my thumb except when deliberately tightening my grib, so maybe it is a touch too sensitive. My thumb doesn't go anywhere near it in horizontal orientation normally except when I am going between back dial and AF point selection button. Which I was doing frequently on Sunday out of habit in normally using the quick dial in manual mode.

Don't take me too serious on this last question, but... If I sent it in for servicing could I have them disable the vertical grip WB button? :)

So I think the problem identified as user derived and I just need to keep it in mind under similar circumstances. I am just finding it amazing that I have used this camera for 20 months, taking definately over 50,000 images with it (I lost count somewhere after 30k - filled up 4x250GB drives and a lot of DVD so far) and I am just now noticing this.

I also am worried that anxiety in personal life is manifesting itself as worrying about camera more then normal. At least I am making some posts to the forum, even if it is just my idiocy at work. At least I knew it was probably me this time.

Anyway many thanks,
 
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