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Thread: Mirror RF Rokkors + 2xTC a stupid idea?

  1. #1

    Mirror RF Rokkors + 2xTC a stupid idea?

    Moderator: I originally posted this under the "SONY" subforum but I now realize that this post is better off here. Please remove my old post. I've made a few alterations to the new post as well.

    I recently managed to buy the following mirror lenses in very good shape:

    Minolta RF Rokkor 250/5.6
    Minolta RF Rokkor 500/8
    Minolta 2x Tele Converter 200-L

    The 200-L TC was especially made for longer "L" lenses but there was also a version made for shorter "S" lenses (the 200-S). I've heard that these TC's should be of quite high optical quality.

    I'm dying to try out the lenses on a Sony NEX-5N that I hope to buy in the near future.

    Do you think that the 500mm mirror lens + 2x TC on a NEX could be useful? An equivalent of 1500mm/f16 is quite long and slow.

    What about the 250+TC combination? 500/11.2 in a slightly smaller package than the 500/8. There has to be a slight image degradation compared to the 500/8 right? And camera+adapter+TC+lens sounds complicated...

    I wonder if any of the above combinations can be used handheld, it could be tricky to get sharp pictures without a tripod I guess. Even with the 500/8 alone.

    I have very high hopes for the 250/5.6 as a tool for street photography. This lens is tiny. Too bad that it is so rare and expensive!

  2. #2
    New Member williamkazak's Avatar
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    May 2010
    Lansing, Illinois
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    Re: Mirror RF Rokkors + 2xTC a stupid idea?

    Wild. Let us see the results when you get them. I currently have a 300mm F5.6 Celestron mirror lens. It is very compact and useful hand held but I imagine it would not be too useful with a 2x because of "shake" and flare and optical degradation. I had a Nikon 500mm F8, which was very hard to work with because the depth of field was so shallow and the shutter speed needed to "stay up there" to prevent shake.
    Here is a picture of "Rocko" hand held 500mm F8 with the Nikon Reflex mirror lens.

  3. #3
    Super Duper
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    Shashin's Avatar
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    May 2011
    Florida, USA
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    Re: Mirror RF Rokkors + 2xTC a stupid idea?

    Well, you can always try it and see you can get results that please you. I suspect you are not going to like the contrast coming off that combination. The mirror lens is an obstructed system and so the secondary mirror takes a bunch on energy out of the center of the Airy disk, making relatively low contrast. At its working aperture, the lenses can be very nice for their size. At the smaller aperture caused by the converter, I think you will find them disappointing. Still, with high contrast targets and some processing, you may get some fun results.

    The smaller f/5.6 lens will most likely be worse because the central obstruction will be relatively larger compared with the f/8. This would be the difference in diameter of the clear aperture to the secondary mirror.

    You only have yourself to please. Have fun.

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