I thought I'd ask this here since a lot of the members are friendly and knowledgeable. I thought I understood the crop factor of my Canon 40D but I guess I don't as I got my hand slapped in a flickr discussion.

I have a Canon 28-135 lens and a Canon EF-S 10-22 lens among others. From what I understand, on a non EF-S lens, at 28mm, the camera crops in 1.6 cutting off the outer edges. I would always use this math: 28x1.6=44.8. I always though that the real world focal distance was 44.8.

Am I mistaken?

If I shoot a Canon EF-S 17-55 f/2.8 @ 55mm, the actual focal distance is 55, but if I shoot a Canon EF 24-105 f/4L @ 55, the actual focal distance is 88?