Oh, I heard that if a Canon 75-300mm is use with a canon digital camera, the subject or object you're trying to take apear 3 times closer?..
You can use it with the 5D and Xti I'm sure. The 5D is a full frame sensor so you get exactly the same image as a 35mm film, but the XTi (Rebel is it?) has a sensor which is smaller than the 5D and it will crop the image ... not zoom by a factor of 1.3..
Can I clarify? Can I use my old manual Canon Rebel lenses with one of the new Canon Digital Rebel cameras?..
Manual Rebel lens? The 35mm Rebels have an EF mount (ElectroFocus, a.k.a. autofocus). EF and EF-S lenses will work on the digital Rebels. To use older FD manual focus lenses requires an adapter, and a lot of patience. See: http://photonotes.org/articles/eos-manual-lenses/..
Thanks for your feedback. I have EF lenses for my 35mm Canon Rebel that I don't want to waste so it would be terrific to buy just the basic Digital Rebel XT and use some 35mm lenses on it. I think that's the point I got from you, so thanks...
EF lenses will work fine. Just keep in mind the 1.6x crop factor for the digital Rebels...you may want to buy something wider than you already have...
Can you explain the 1.6 crop factor to an amateur?..
I have just acquired a pentax k100d super dslr can I get a lense adapter so I can use my vivitar 80-200mm m/md lense on it?..
The crop factor is a result of the sensor being smaller than a "full frame" sensor or the 35mm film frame. While lenses don't change in focal length, the smaller frame size is multiplied more to get to viewing or print sizes compared to a full frame. The sensor crop works like if you took a 4x6 "print" and trimmed an inch or so off each side. You take that small center portion of the image and enlarge it back to 4x6, the subject is going to be larger. It looks pretty much like it could have been taken with a longer lens if you would have had that subject size initially. What this means is that "perspective" doesn't change, you get a 50mm image when using a 50mm lens, just that it seems to be what you would have gotten with a lens 1.5x (most non-Canon) or 1.6x (Canon) longer in focal length.
For the most part the crop factor perspective changes won't impact most users in general use situations, it's meant the camera makers have needed to develop less expensive wide angles (as wides seem longer) and the user has had the advantage of telephotos "acting" longer on the long end...