Review on TYCKA 420-800mm f/8.3 DSLR Camera Lens: Ultra-Telephoto Manual Zoom for Shooting the Moon and Birds - Telescope SLR Lens (Canon T-Mount) for EOS Rebel T3-T7i, SL1, SL2, 5D-7D, 60D-80D II/III/IV by William Stevenson

I have used this lens on a Canon Rebel SL1 and it is one of the most difficult lenses to use because although the adapter allows the lens to fit the camera, it snaps it does not place, so zooming and focusing may cause the lens to accidentally fall off. However, the lens has a few flaws in the way it works. I couldn't figure out how to focus my zooms until I watched an overview video of how to use the lens and found that the focus ring was stuck so I had to force it to rotate hoping not to damage it. Another problem I encountered. When I came across the lens I received was that it appears to have a built in bloom filter. This is much worse in night shots when you can see a lot of ghosting in the images, so much so that even focusing doesn't help. But for $100 the thing works fine during the day but still nothing I would stick to when shooting. for higher quality images.