Edmontonion needs expert opinion on XTi

Hey guys,

I had recently shipped my XTi to Canon to check out a backfocus issue I had with the body and they shipped it back (after 4 weeks) to tell me nothing is wrong.

I pretty much can't shoot with any aperture wider than 4 without noticing backfocus.

Is there any local repair shop that will give me a 2nd opinion? I don't want to ship it out to Canon Ontario(sent to calgary the first time) and shell out another 60$ to do so. Or perhaps a local shooter here on the forum that can take a few shots and give me their thoughts?

The only other thing I can think of is to go about my shooting and saving all the pictures to a CD and sending the CD to Canon for their thoughts before sending the camera in again.

I will post some pictures when i get home.

THe only other thing I can think of is I am a total n00b and don't know how to use AF.

From what I understand, the AF needs contrast in order to focus properly

one of the tests I did was as follows

_______________ background (was black)

O O 2 white batteries

O 1 random battery I found (energizer)

the camera backfocussed off the energizer onto the 2 white batteries.

I realized this morning the energizer and background was fairly similar in color and maybe the camera picked out the white batteries because they contrasted heavily with the rest of the scene.

I also did some tests with paper with text on it on a tripid with mirror lock and a remote, which turned out to be quite a bit more accurate.

thanks for bearing with me, I am just really furstrated!

could it be that it might be the lens and not the body that's back focussing?

I thought that was the issue, but this is my 2nd copy of the 50mm F1.4 and my 50mm 1.8 SEVERLY backfocussed when I had it.

I've also seen it on the kit lens, although it hasnt seen much use.

the BF is most prevalent on wider apertures. 2.8 and lower. generally speaking.

blam wrote in post #2361325
....
The only other thing I can think of is to go about my shooting and saving all the pictures to a CD and sending the CD to Canon for their thoughts before sending the camera in again.....

When I was debugging an over exposure problem with Canon, The second time I sent in a CD with 6 example pix. When I did so, it prompted a call with a tech and I got to talk to a real person I was able to clearly explain the problem to the tech. It got resolved. Sometimes a pic is worth a 1000 words as the saying goes.

i dont think you ever mentioned which focus point you used. im assuming center focus point?, no?

I used the centre focus point

gjl711 wrote in post #2361425
When I was debugging an over exposure problem with Canon, The second time I sent in a CD with 6 example pix. When I did so, it prompted a call with a tech and I got to talk to a real person I was able to clearly explain the problem to the tech. It got resolved. Sometimes a pic is worth a 1000 words as the saying goes.

I think I will try that....take a lot of photos (real life) and preserve the EXIF and AF point data and put them on a CD and send the CD out to Canon in Ontario this time and wait for them to call me. I don't want my camera being sent out again for nothing.

I've heard better things about them over the Calgary location.

blam wrote in post #2361601
I used the centre focus point


I think I will try that....take a lot of photos (real life) and preserve the EXIF and AF point data and put them on a CD and send the CD out to Canon in Ontario this time and wait for them to call me. I don't want my camera being sent out again for nothing.

I've heard better things about them over the Calgary location.

I don't think that they will do anything with the pics by themselves unless they have a RMA and the hardware as well. I worked with Canon service and when asked to send in my lens, I also supplied the data clearly showing the issue. I think that's what prompted the call. After talking to the guy for about 10 minutes or so I was able to clearly explain that my problem happened once every 20/30 pics so a quick plug into their test bench might not show the problem but after shooting for a while it would crop up. They were then able to determine that the aperture mechanism was in the process of failing and they replaced the unit. It has worked flawlessly since. So call service, explain the issue, they will issue the RMA and send in pics clearly showing the problem. Might even take a screen shot which shows the focus point selected and the focus being elsewhere.

RMA?

the Calgary location wasn't a very good experience to start with...

2 weeks for them to even open my package, and another 2 to tell me there was nothing wrong. never got any phone calls or anything from them to let me know they received it, looked at it, found nothing or even that they shipped it out.

at least if I send the CD in before hadn with the focus points (in a screen shot) they will see that the focus is off. I don't think I should be paying the hefty shipping fee to get the package to them either. (55$ to ship and insure) I already paid it once and I do not want to pay it again for something that should have been fixed.

blam wrote in post #2361681
RMA?

the Calgary location wasn't a very good experience to start with...

2 weeks for them to even open my package, and another 2 to tell me there was nothing wrong. never got any phone calls or anything from them to let me know they received it, looked at it, found nothing or even that they shipped it out.

at least if I send the CD in before hadn with the focus points (in a screen shot) they will see that the focus is off. I don't think I should be paying the hefty shipping fee to get the package to them either. (55$ to ship and insure) I already paid it once and I do not want to pay it again for something that should have been fixed.

Hmmm... When I sent in my lens the second and third times, Canon sent me the shipping label. Maybe if you let them know that this was not fixed and try the other location. 4 weeks sounds quite excessive though.
EDIT::Whoops RMA = returen material autherization. Its the sheet they send you when you call that you fill out and send back.

have you also tried manually focusing? and when you do, does it give you the confirmation beep at the correct focus? if so, then its definitely an AF problem. your camera needs to be recalibrated.

ahhh.

I will keep the shipping slip in mind. I am definatly not shelling out another penny to ship this for warrenty work

thanks for the help.

roeddel wrote in post #2361877
have you also tried manually focusing? and when you do, does it give you the confirmation beep at the correct focus? if so, then its definitely an AF problem. your camera needs to be recalibrated.

can you tell me how this is done?

I know with my 50mm F1.4 I can manual focus after I autofocus.

I dont know anything about this beep you speak of though

set your lens to MF, find a good contrasty subject -- preferrably something that has a line -- then half press the shutter release button and manually focus. your camera WILL beep when it finds absolute focus. you may have to go back and forth on the subject until you hear the confirmation beep. you will also see the center focus point blink red when it finds absolute focus.

You might want to also set it so that only the center focus point is used as well. This will eliminate any shenanigans from the camera trying to pick the best point.

roeddel wrote in post #2362350
set your lens to MF, find a good contrasty subject -- preferrably something that has a line -- then half press the shutter release button and manually focus. your camera WILL beep when it finds absolute focus. you may have to go back and forth on the subject until you hear the confirmation beep. you will also see the center focus point blink red when it finds absolute focus.

Thanks I will give that a try and report back!