I am very new to the site, but have been reading for hours. I am looking for the best vintage manual focus lens to look for on Ebay or other site that I can use with my Canon Rebel SLR. I am looking for a wide angle, and also if someone can explain what sort of adapter i would be looking for? Any suggestions would be of great help. I have a Sears No. 829476 MC 1:28 on my old Canon AE1 that I love and would be oh so happy if I could use it on my Digital SLR.
Welcome! To use that lens on your Rebel you will need an adapter with quality reducing glass, also changing your field of view. I think 1.3x on top of the 1.6x which the sensor size of your Rebel provides already. You suddenly have a "normal" lens with low quality rather than a high quality wide lens.
There are some other options giving you the equivalent of 28mm that should outperform you Sears lens quite easily, but they are not cheap. I would look into getting an Olympus Zuiko OM 21mm f2 if you can afford it. A simple adapter is like 10-50 dollars depending on if you want focus confirm or not and does nothing to degrade the image. But the lens is pricey, like 1000 dollars Someone else can maybe guide you in a cheaper direction if thats too much. Good luck!
Wide angle is one thing that you can't do well with vintage lenses on a modern crop-frame body. Because of the 1.6x effective focal length multiplier, even the best and widest older lenses turn into boring, non-wide focal lengths. If you want something similar to a 28mm on full-frame, you need an ~18mm lens on your DSLR (which severely limits your choices). The new generation of ultrawidewide zooms designed for crop-frame cameras are truly superb optics, and will let you get much wider (and sharper) pictures than are available from older lenses.
However, don't let that discourage you from using vintage lenses, of which there are many choices that are excellent for normal width, portrait, and macro (at a fraction of the cost of similar new optics). Ironically, lenses that fit Canon manual-focus cameras are about the only ones that you can't properly adapt to a Canon autofocus camera. Almost everything else (Nikon, Pentax screwmount, Olympus, Leica R, etc.) can be easily adapted with inexpensive, glassless adapters that preserve the full optical quality of the lens.
Someone else can maybe guide you in a cheaper direction if thats too much. Good luck!