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 Kevin Ayala

I've read a lot of reviews about these lenses and the only thing critical is that this is clearly a manual lens so you have to focus it manually. However, the lens is best used with a tripod and timer/remote control for better image stability. This would be the perfect 5, but it works best with a tripod and a timer/remote. A bit awkward as I don't want to take my tripod everywhere lol.