photo:minolta250mmreflex
Table of Contents
Minolta Rokkor RF 250mm f/5.6 mirror lens
see also:
introduction
- this is a very popular and now expensive mirror lens
- this super telephoto lens introduced in 1979 is a catadioptric mirror lens, and as with all such mirror lenses, share the following characteristics:
- manual focus
- fixed aperture (in this case f/5.6)
- virtual elimination of chromatic aberration as uses mirror rather than lenses
- also means focus position for infrared photography is the same as for light photography
- central mirror:
- allows much more compact lens length as the optic path is reflected internally twice
- by necessity, blocks some of the light and thus causes:
- decrease in image contrast
- characteristic “doughnut” shaped bokeh imagery in out of focus areas
specs
- 250mm focal length and field of view (10° ??) at infinity focus
- fixed f/5.6 aperture
- 6 lens elements, 5 groups (multicoated)
- closest focus 2.5m (8.2')
- 62mm filter thread but mount turns when you focus + 39 mm rear filter
- 68mm diameter, 71mm long and 262g
- Ebay prices tend to be $600-1200
reviews
photo/minolta250mmreflex.txt · Last modified: 2014/05/17 22:34 by gary1