Table of Contents
introduction
specs
reviews
Minolta Rokkor RF 250mm f/5.6 mirror lens
see also:
super telephoto mirror lenses
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
Minolta Flashback
Rokkorphile - 250mm on MFT
http://oldlenses.blogspot.com.au/2014/02/minolta-rf-rokkor-x-250mm-f56-another.html