Summary: Fun to play with. Take some getting used to since this is old school manual all the way. Stick on a strong tripod with remote shutter release and be patient with focusing. This will take some time (and luck) to get just right. No electronics in this. Set camera on manual and no lens modes. On a Lumix G5 and using the extender this will reach out to 2000mm. This is in no way a $20,000 lens and has the expected visual quirks.
Summary: This is tele optics for little money. It is manual focus so a tripod is absolutely required....along with patience. With that said, it's good for long distance wildlife photography at a cheap price. Someone suggested taking multiple pictures after you focus. Step forward, step back and one of the three may be in focus. Seems well made, but its a mirror lens and that has limitations. I think I may aim it at the moon and see how it does.
Summary: I have always wanted an affordable really long telephoto lens and have nearly bought mirror lenses in the past. I was prepared to be disappointed at this price, but the lens is quite sharp in it's very narrow zone of sharp focus. Because mirror lenses have no variable aperture an inherent limitation of them is that you have no control over depth of field - and there is precious little of that at long focal lengths even at f6.3.
Summary: I was looking forward to receiving this product but was to be severely disappointed. This is supposed to be a T-Mount lens but the supplied T-Mount did not fit the lens (although did fit the camera). Did contact the supplier who responded promptly asking for photographs of the components but as the supplier is in America I decided that returning the item was the only solution.
Summary: First, it came from the USA resulting in paying import taxes, even though I paid the UK office of amazon, to avoid these. Second, it's a chinese product, with problematic junctions. Even though it's supposed to be compatible with Sony A350, it's not compatible with auto zoom, making VERY DIFFICULT to zoom exactly on the object, which is also in a long distance. I've tried numerous pictures, only a couple came out acceptable. Everything else was for garbage!
Summary: Depth of field is almost zero, light input is low, quality of manufacture is good, OK for moon shots. If you want a lens that is needed for the occasional distance shots then buy it, the times 2 option is not worth it.
Summary: This lens is difficult but not impossible to use on my Canon D500 needs to be very secure on a tripod to enable good focus(manual only) The lens is superb when combinesd with the Kenko Lens2scope and Canon adapter.
Summary: Opteka 500mm f/6.3 Telephoto Mirror Lens for Nikon D40, D40x, D50, D60, D70, D70s, D80, D90, D100, D200, D300, D700, D7000, D5000, D3000 & D3100 Digital SLR Cameras (Purchased on 10/25/2010) by Opteka 500mm leans This reflex mirror lens is excellent for the price The amateur Photography will be well pleased With it, It important you have an excellent tripod to Mount the camera went fitted with the lens The manual focusing wants' sum getting use to But praxis makes...