BF issue on my A700, send it in for repair?

Hi Folks,


I need some assistance please? I think I have a BF issue with my A700. I have sample images that I will be posting up to show you and I would like your opinion please on the following:

1. AF tolerance acceptable/unacceptable? I know/understand that all devices has a +/- tolerance level, let me know if the "issue" I'm having is within this tolerance?

2. In real life life photos and next "test" images, how badly on a scale of 1-10 would this affect my images?

3. Should I send it in for service?


The test was performed on a tripod with the camera's sensor plane as parallel to the subject as possible. The subject was at the same height and 2 second shutter with cable release was used. Yes, I didn't forget, SSS was turned off for all of these shots.

Subjects three (3) energizer batters in a 45 degree line away from the camera and the the left battery the closest to the lens and the right batter furthest away from the lens. SPOT AF with CENTER AF sensor used and AF was on the center battery. Each battery was spaced about !" from each other.

Please reply and let me know your thoughts?

One thing to be careful of - the center AF sensor is very large (around the size of the center circle). So some of the sample pics may well have just been the camera picking up the most contrast in the far battery and hence focusing there instead. Perhaps try to move the batteries further apart to be sure? Good luck!

Originally posted by ab012 One thing to be careful of - the center AF sensor is very large (around the size of the center circle). So some of the sample pics may well have just been the camera picking up the most contrast in the far battery and hence focusing there instead. Perhaps try to move the batteries further apart to be sure? Good luck!

Hi Bernard,

Thank you for the reply. I wanted to keep the batteries about 1" apart because, I'm noticing some OOF with my portrait shots, I would SPOT AF on the model's eye, recompose/frame the picture and the shot would be OOF at the model's eye, her nose would be PIN sharp or her ear would be, but not the eyes? I was hoping the batteries spacing 1" apart would be really helpful in determining if this is a BF issue or not?

Let me re-phrase the question this way? If the AF (spot) is so large, what is the best way for me to compose a portrait shot so that the model's eye is PIN sharp, I would love to make the model's eye as big as the the "circle" in the vf but shot's composition would be changed?

If you can provide a "workaround" for my portrait shots, without necessitating me to have my camera sent in that would be great...


Thanks!

OK here's the thing to do. First is more testing, set up some cereal boxes or business cards with about 1" forward and backward spacing-check for BF again. Make sure you are in AF-A or AF-S and center AF point. You can move the cards/boxes forward and back to see where the focus plane lies. Usually the focus plane is from the card and back, I perfer to have a little more in front about 30% distance in the front and 70% in the back.

You should also check to see if center AF point is lined up, tape somthing to a window and see when the center spot looses focus by moving to the left/right/up/down of the item on the window-this way you can measure the size of the focus area and see if it's lined up.

Test various lenses and keep track of the results or you'll drive yourself crazy.

As a side note, if you are doing shots like this (model shots with critical focus area) a matte screen really helps then you can use MF. I had one in my 7D and will most likely put one in my A700.


If you find the focus to be "off" you can adjust it (I can help you if you want) or send it in.

Garth

Funny, I am having noticeable BF & inconstant focus issues as well. I was testing my 100 macro last night. I would put my square exactly in the center of something, take a photo, and notice that it was just slightly oof, with the sharpest behind it a bit. I aso have a problem believing that the center sensor is as big as the circle; even then, my targets were centered and had no reason to be off. (looks exactly like the wide-open 50mm shots).

I will give some more tests tonight (I am sure i have some playing cards somewhere), but I am really sick of this. When you pay this much for a camera, it is not to much to ask for it to work right....

Are you using fluorescent lamps in your tests?
I had try some conditions tonight and my camera are consistent BF over fluorescent light.
I will try more tonight. Someone have this problem in same condition?

I don't know, here I have more problems with distant elements.