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Malaxos1
15th of June 2004 (Tue), 01:31
I went into a camera store here in Portland that sells mostly used stuff. I did get a verylarge camera bag that hold my 2 DSLRs with battery grips a few lenses, strobo, flash and all other accerssories. I did have to get a large lens case for my 70-200L as that was the only thing that couldn't fit in the bag. I got it all for $40.

Anyway, I asked if he had any EF lenses. He told me that he did have a few in the back that he was selling for a friend. He said he had a 100-300L for $1,700 and a 100mm f2 USM lens for $175. I asked to see the 100 and was impressed with the speed and sharness as well as contrast that I got in my test shots. This was when I was pointing the lens toward the front door where there was more light. I told the guy I really liked it and then turned the lens towards the back of the store where it was a little darker but not too dark. The lens wouldn't focus at all, it did lock focus but I could see that the focal point was somewhere in the middle between me and the back wall that I was focusing on. I then handed him the lens and told him that I wasn't interested and left.

What was the problem? Was it an older lens that was finicky with the D60? Could just be that the camrea was having trouble? I could have used any of my other lenses and would not have had the same trouble. whta gets me is that it did lock focus on something in the middle where I wasn't focusing...Dean

topeju
15th of June 2004 (Tue), 01:51
I told the guy I really liked it and then turned the lens towards the back of the store where it was a little darker but not too dark. The lens wouldn't focus at all, it did lock focus but I could see that the focal point was somewhere in the middle between me and the back wall that I was focusing on. I then handed him the lens and told him that I wasn't interested and left.

Was there anything to provide a contrasty enough subject on the back wall?

scottbergerphoto
15th of June 2004 (Tue), 06:02
The Canon AF system makes some compromises in low light AF to give you more accurate AF in other situations. Some lenses will perform better then others. For a very detailed explanation by Chuck Westfall of Canon read This (http://www.robgalbraith.com/ubbthreads/showflat.php?Cat=&Number=245591&page=0&view=collap sed&sb=5&o=&fpart=1&vc=1).
Regards,
Scott

CyberDyneSystems
15th of June 2004 (Tue), 07:34
Also.. the D60 though a fine camera.. was known to be less than stellar in low light as far as AF goes...

robertwgross
15th of June 2004 (Tue), 09:51
When they redesigned the D60 to make the 10D design, I think the first thing they improved was the dim-light autofocus system.

Some parts of the autofocus system are in the body, and some parts are in the lens. Does anybody here have a good explanation of the entire autofocus process? The D60 emits a white light during dim-light shooting.

---Bob Gross---

Malaxos1
15th of June 2004 (Tue), 10:47
Thanks for the feedback. There was enogh contrast, I have used the D60 in much lower light than that. The problem that I had wit the whole thing is that with my other lenses, if there was a problem with there not being enough contrast it wouldn't lock fpucus. This lens did and it wasn't at the distance I was trying to fucus on.

Anythoughts on the 100mm f2 USM lens? It seemed very nice and I may consider one for portraits...Dean

scottbergerphoto
15th of June 2004 (Tue), 11:07
When they redesigned the D60 to make the 10D design, I think the first thing they improved was the dim-light autofocus system.

Some parts of the autofocus system are in the body, and some parts are in the lens. Does anybody here have a good explanation of the entire autofocus process? The D60 emits a white light during dim-light shooting.

---Bob Gross---\
Bob,
My link above gives a detailed explanation of the Canon AF system. Here it is again:
http://www.robgalbraith.com/ubbthreads/showflat.php?Cat=&Number=245591&page=0&view=collap sed&sb=5&o=&fpart=1&vc=1
Scott