Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Canon EOS dSLR

Thread Tools Search this Thread
Old Apr 17, 2003, 1:47 PM   #1
Junior Member
Join Date: Apr 2003
Posts: 8
Default 10D Focus Problems

I've spent the last week testing my new 10D. I love the camera feel and ease of operation but am very confused about the whole probem with auto focus.

First, my two year old Sigma 28-105 lenses had to go back to my dealer for "re-chipping" as to avoid an Error 99 message.

I've been using a Canon 28-80 4.0 lens that came with an older EOS that seems to be a bit cheaply made and I've had BIG problems with focusing. I then went to the shop that I purchased my 10D at and tried several other lenses, Canon and Sigma, and found no clearly better focusing lens - sometimes it was good, othertime not so.

Today, I borrowed a new Sigma 28-80 to experiment with the sharpness settings in the studio and outdoors to see if that would help. It seemed to a bit, but I'm still blown away that an issue of focus should ever come up. Isn't that the most basic of essentials when designing a camera? Again, I love this camera, but I don't believe I have to spend a week trying to figure out if I'm going to keep it. I won't have my Sigma lenses back from re-chipping for a couple weeks and am worried that I'll have to bail.

Does anyone have any thoughts/advice on the use of sharpness as a focusing aid or any hints, words of encouragement, or perhaps a short poem to help me out?


Usher is offline   Reply With Quote
Sponsored Links
Old Apr 17, 2003, 2:04 PM   #2
Join Date: Jun 2002
Posts: 1,141

Hi Usher,

You didn't specify the exact nature of the "focus problem" you were having. Was is simply inconsistent focus, or was it front focusing or back focusing, etc.

The most frequent issue people have with several of Canon's newer systems is the issues caused by having multiple focus points. I think the camera is shipped as a default using all seven focal points. This works great for AI servo focusing, but not well at all for photographing static subjects. What usually happens is that the point of focus the camera selects and the point of focus desired by the photographer are rarely in concert.

If the issue is inconsistent focus, try changing to the central point and see if this doesn't make a considerable difference. Even with my EOS-1D, if I have multi-point focus activated for still subjects, the focus is inconsistent. For AI servo where subjects are moving, the multi-point feature on both my 10D and 1D work perfectly. But for still subjects, the center point focus is definitely the way to go.

Hopefully, that's the issue you are dealing with. If not, you may have a problem with the camera which can be corrected, but it may be easier to simply exchange it for one which works correctly.

Sharpness is applied post capture by the electronics, and should not have any bearing at all on focus.

Lin Evans is offline   Reply With Quote
Old Apr 17, 2003, 9:36 PM   #3
Junior Member
Join Date: Apr 2003
Posts: 8


Thanks for your reply. It is your dedicated work and postings on this and other cameras that was a huge influence on my purchase decision.

I'm not certain if I'm getting "front" or "back" focus. Most of the time I was hand selecting the focus point and training it on the subjects eyes - the most important part of any portrait. I'm thinking I was on the AI focus, not AI servo for most of the experiments, but today I was on One Shot with the new lens. That may have helped. When you say use the "central point" do you mean the very center square of the focus selection? I use rule of third most of the time and hope to use the side focus areas, but if you think using just the center one, pre-focusing and the recompose may help I'm willing to try. My dealer told me that when my Sigma lenses come back that if I continue to have problems he will switch me to another body to see if I've gotten a "lemon".

Thank again and keep up the good work - we all appreciate it.

Usher is offline   Reply With Quote
Old Apr 18, 2003, 9:02 AM   #4
Senior Member
Join Date: Dec 2002
Posts: 5,803


Other can probably add more here. I believe the center focusing point has more capabilities than the other focusing points. I think that translates into better detecting of focus on both vertial and horizontal based contrast (i.e. horizontal or vertial lines.) So it might work better (at least for the test) to use focus lock based on the center point and then compose the picture as you like and take the picture.

You can test if you are consistantly front/back focusing fairly easily. I talked about this in a different post. Do realize that it's camera & lens dependent. I saw test pictures which showed a lens worked great on a specific 10D, but badly on a D30, a different lens worked opposite and a 3rd worked great on both (all with the same cameras.) This is a type of problem which never should have happened. It really starts to make me wonder about whole EOS mount system in general. How is this problem even possible? From what I've seen with the Nikon D100 problem, if the camera had back/front focusing problems, it did it consistantly with all lenses.

Here is what I posted about testing for it:

If you want to test for front/back focusing this is easy. (This is from my memory, I believe I read this on dpreview's forums, but maybe another. I go to so many... It's a great way to learn about lenses.) The way I've heard which seems the most logical is to focus on a ruler laying at an angle away from you. Focus on the middle of it using the smallest DOF you can get with the given light (and I'd also use the lowest ISO to make sure that doesn't effect anything.) Then look at the picture. If it focuses correctly at a variety of zoom distances (and apetures?) then you're camera is doing it right.

I've also heard of using the bar codes on cerial boxes set in a stair pattern 1 inch apart.... also using the bar codes on rolls of film. You want something with some contrast to make the focusing easy.
eric s is offline   Reply With Quote
Old Apr 18, 2003, 9:10 AM   #5
Senior Member
Join Date: Aug 2002
Posts: 610

Try on some Canon USM lenses, 28-105mm, 28-135mm IS, 50mm 1.4. I think you find the 10D works well with these lenses, AF is extremely fast.

Canon USM lenses work better with Canon cameras, the Canon lens you mentioned is the biggest disapointment of Canon, loudsy design, plastic mount and if I'm correct and made in Taiwan, in my opinion it should not allowed in the Canon lenses family. Canon contract some company to make these lenses so they can sell them with the entry of their SLRs as package. The Sigma lens is not impressive either, made in Japan, but the results may not acceptable in most cases, AF is slow and noisy.

You will also see AF will work a whole lot better on Canon L series, especially the one with larger aperture (such as F/2.8 and above).
tuanokc@hotmail.com is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

All times are GMT -5. The time now is 12:26 AM.