One of the few Olympus film lenses I kept was the 500mm f8 mirror reflex. It is sharp and contrasty and quite expensive when new, having tried cheaper mirrors you could certainly tell the difference - however it was far easier to focus on a proper OM film body, just about as fast as any long lens. I have used it as a 1000mm f16 with a 2x multiplier (4/3 equiv 2000mm) on 4/3, however it is a good test of a tripod - forget image stabilisation and there is rarely a day when haze makes the combination useable. As a result I just have the basic lens these days. If you have something vaguely static and have the time to bracket focussing it is fine. At least there is no ca!
Probably best used when all else fails on long distance birding, inaccessible nesting sites etc.
I havn't tried it on the M1 yet, to date it has hung on 4/3 E-n bodies as they had bigger and clearer viewfinders than the E-nn species.
I did have a manual focus 300mm prime with a decent aperture, but manually focussing was still too hit and miss for practical bird work.
The new lens sounds like the only realistic option, depending on the price.
Last edited by iveljay : Tuesday 29th September 2015 at 16:16.