Canon Digital Slr Body Used
How will using a non-digital lens with a digital body change the quality?

I have older Vivitar lens that I’d like to use with my new digital SLR Canon EOS xTi camera. I will be trying to mount using a t-adapter. These are nice lenses that have been taken care of but will the quality be different if I don’t use a digital lens for my digital SLR?

There is no difference between a digital or “non-digital” lens, design wise. Nothing has been done to the glass or element design. The real differences have to do with the size of the image projected to the film or sensor. The “film” camera has to cover the whole of a 36x24mm frame, with no distortion, focus or colour. Most “digital” cameras only have to cover the smaller APS-C, 23.7 x 15.7 mm frame … so using a lens designed for the larger format will work fine on a DSLR, but if you try the reverse, your 36x24mm frame will experience some vignetting.

Your manual focus lens probably not have the necessary components to allow you to use your XTi’s sophisticated light meter