01-02-2011, 07:44 AM
[quote name='larsrc' timestamp='1293808601' post='5297']
What lenses exist in EF/FD/M42 mount with a thread diameter down towards 37mm?
I have this 8x tele-extender with 37mm inner thread that I got surprisingly good result with on my old compact, and I would like to play around with it some more.[/quote]
I think you're wayyy better off getting an old native lens in the desired focal length than hoping for a 8x TC on a 37mm (read small aperture) lens.
Even the best lenses (e.g. over $5000) take visible IQ hits with a 2x extender that's made for those lenses. So an 8x TC on an arbitrary 37mm diameter (cheap and slow) lens should put you back in the field of cheapish compacts.
But here's a synthesised list of 37mm diameter lens configurations (in the typical f numbers) that you should look for:
180mm f/5.6 or slower
140 f/4 or slower
100 f/2.8 or slower
70 f/2 or slower
50 f/1.8 or slower
Since a 8x TC is really demanding on IQ and also reduces the apertures massively, I think a 100 2.8 lens should be a good bet. They're usually sharp, compared to wider angle lenses and with a 8x TC it should give you an effect of a 800mm f/22.
Also search on ebay for cheap f/11-16 type refractive zoom lenses. For example:
http://shop.ebay.com/?_from=R40&_trksid=...800mm+lens
GTW
What lenses exist in EF/FD/M42 mount with a thread diameter down towards 37mm?
I have this 8x tele-extender with 37mm inner thread that I got surprisingly good result with on my old compact, and I would like to play around with it some more.[/quote]
I think you're wayyy better off getting an old native lens in the desired focal length than hoping for a 8x TC on a 37mm (read small aperture) lens.
Even the best lenses (e.g. over $5000) take visible IQ hits with a 2x extender that's made for those lenses. So an 8x TC on an arbitrary 37mm diameter (cheap and slow) lens should put you back in the field of cheapish compacts.
But here's a synthesised list of 37mm diameter lens configurations (in the typical f numbers) that you should look for:
180mm f/5.6 or slower
140 f/4 or slower
100 f/2.8 or slower
70 f/2 or slower
50 f/1.8 or slower
Since a 8x TC is really demanding on IQ and also reduces the apertures massively, I think a 100 2.8 lens should be a good bet. They're usually sharp, compared to wider angle lenses and with a 8x TC it should give you an effect of a 800mm f/22.
Also search on ebay for cheap f/11-16 type refractive zoom lenses. For example:
http://shop.ebay.com/?_from=R40&_trksid=...800mm+lens
GTW