Review on 📷 Lightdow 420-800mm f/8.3 Super Telephoto Lens + T-Mount for Canon EOS Rebel and DSLR Cameras – Zoom in on Distant Moments by Cameron Kennedy

For the price, and given that this is a slow lens and requires a very stable mount (and possibly pole tracking), I'd say it's about what you'd expect. Consider that a lens with this focal length, aperture, and greater clarity costs 100x more, so it's worth shooting with very bright objects like the moon or sun, or being static enough to be a target for a slow shutter speed to fix. Images attached to this 800mm lens from a Canon 450D, on a tripod (no tracking). One uncut shows how much of the frame is filled with the moon, the other is cropped for a better close-up.