Are some mirror lenses better than others?

Discussion in 'Digital Cameras' started by Paul Ciszek, Jul 10, 2012.

  1. Paul Ciszek

    Paul Ciszek Guest

    Of the 500mm lenses for sale on Amazon, the only name I have heard of
    before is Vivitar, and it is also the cheapest. The most expensive is
    Rokinon, but I have no reason to believe it is any better than Opteka,
    which seems to be the only one reviewed by very many people. A couple
    of others are mentioned in the fora on, but I don't know
    who sells them. Anyway, can anyone recommend a good 500mm mirror lens?
    Paul Ciszek, Jul 10, 2012
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  2. Paul Ciszek

    Guest Guest


    Guest, Jul 10, 2012
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  3. Chris Malcolm, Jul 10, 2012
  4. Paul Ciszek

    RichA Guest

    Most of them are clones of each other, old mangin mirror designs from
    the 1970's. Only standouts I am aware of:
    Tamron's long discontinued and increasingly expensive 350mm f5.6
    Questar Corporation's 700mm mirror from the 1980s. Also expensive
    when they turn up.
    Some telescope mirror lenses (some, not all, mind you) from Meade and
    Orion Telescopes (Sky Watcher derived) are pretty decent, but long
    focal length and slow focal ratio.
    RichA, Jul 10, 2012
  5. Paul Ciszek

    Bruce Guest

    Vivitar's 'Solid Catadioptric' 600mm is also a good performer, but it
    is heavy.
    Bruce, Jul 10, 2012
  6. Paul Ciszek

    RichA Guest

    I tried one. It's wasn't that good and had bad absorbtion of light
    owing to the fact it is solid. Also, Maksutovs don't perform at 100%
    until they reach the same temp as the environment they are being used
    in. Take one from a warm environment to the cold, it's mirrors start
    changing "size" and it screws up the image. They typically take 30min
    to an hour or more to reach thermal equalibrium.
    To be good, a Maksutov (the basic design) needs to have as small a
    secondary mirror as will permit a fully-illuminated a sensor. Today,
    these mirrors could be redesigned with smaller secondary mirrors
    because they might not be used on a FF sensor. In astronomy, a hybrid
    design, a "Maksutov-Newtonian" is a better overall performer
    (contrast, etc) because the design permits the secondary to be small,
    but that design is too large to be a workable camera lens, unless you
    like challenges. A large secondary mirror/aluminized spot results in
    more light being diverted from the diffraction disk to the diffraction
    rings (Airy disk) which renders contrast low. Some of the
    photographic units had secondary mirrors as large as 50% of the
    diameter of the main mirror which means a contrast loss of at least
    30%, before scattering at each reflection-transmission surface were
    taken into account. However, if they are compared to an older
    refractive telephoto lens that suffered from chromatic aberration,
    contrast loss in it due to unfocused red and blue light might have a
    worse effect. This problem was largely eliminated with ED glass.
    RichA, Jul 10, 2012
  7. Paul Ciszek

    Paul Ciszek Guest

    I have found Orion telescopes for sale; are you saying that Orion also
    makes mirror lenses? I can't find those.
    Paul Ciszek, Jul 10, 2012
  8. Paul Ciszek

    Paul Ciszek Guest

    I read somewhere that the Vivitar name was sold, and is now used to market
    crappy lenses.

    The thermal problems could be easily solved by making it out of borosilicate
    glass (aka pyrex) which I thought was SOP for large optics anyway.
    Paul Ciszek, Jul 10, 2012
  9. Paul Ciszek

    RichA Guest

    No, they make only telescopes, but the mirror-lens units are
    (optically) very similar to camera lenses. Generally, they are much
    better optically (they have to be since people magnify the latent
    image they produce with an eyepiece) than run of the mill camera
    lenses. They can be adapter directly to cameras.
    However they are not suitable for hand-held shooting or for moving
    -Images are inverted unless you use a special correction prism.
    -Focusing is fine but slow, using a focusing knob instead of twisting
    a barrel.
    -Focal ratios are high, like f/13 to f/15 which is very slow for a
    camera lens. There are compressor lenses which can drop that to f/7.5
    or so, with a "same percentage" reduction in effective focal length so
    a 1500mm f/13 lens becomes a 900mm f/7.5. They function like tele-
    converters only the other way round.
    -Cost versus performance is low. They are inexpensive and interesting
    to play with.

    There were some "camera" type Maksutov telescopes made by Meade and
    Celestron in the 1980's but I'd avoid them.

    Same with the old, heavy Russian units, avoid them.
    RichA, Jul 10, 2012
  10. Paul Ciszek

    Chemiker Guest

    The brands Phoenix, Opteka, and some others are made by Samyang of
    Korea. I have one under the Opteka name, and I find little to
    recommend. Contrast is poor, DOF is (naturally) almost non-existent,
    bokeh is typical Cialis circles, "macro" really isn't. 500-1000mm
    means a 500 mm lens with a poor 2x teleconverter. They run about $125,
    and are best avoided. Also the larger unit, IIRC a 500 f/6.3, and an
    800mm f/8.

    Chemiker, Jul 10, 2012
  11. Paul Ciszek

    RichA Guest

    No, with the tolerances where they are, Pyrex too changes shape enough
    when changing temp to effect the image. Zerodur is a glass that
    won't, or silica (quartz) but you won't find either in inexpensive
    scopes or camera lenses.
    RichA, Jul 11, 2012
  12. Paul Ciszek

    RichA Guest

    You'll never escape that with a mirror lens. Good thing is that you
    don't see the circular defocus patterns in every mirror lens shot.
    See below. I would like to say however, that the refractive lenses
    from Samyang (85mm, 35mm, 14mm, 8mm) are all a bargain and very good.
    RichA, Jul 11, 2012
  13. Paul Ciszek

    PeterN Guest

    I have a good 500mm Nikkor, that I no longer use since I got my 80-400.
    It comes in a leather case and the front lens cap is missing. I have had
    it since about 1972.
    PeterN, Jul 11, 2012
  14. Paul Ciszek

    Wally Guest

    Yow, the lens causes hexagonal pupils.

    Wally, Jul 11, 2012
  15. Paul Ciszek

    Paul Ciszek Guest

    Paul Ciszek, Jul 11, 2012
  16. Paul Ciszek

    Paul Ciszek Guest

    Now, that is a very nice shot. As for the "donuts", I figure if the
    focal length of the mirror lens is half a meter, and everything I am
    taking telephoto pictures of is, say, a hundred meters away, that
    should not be a problem, should it?
    Paul Ciszek, Jul 11, 2012
  17. Paul Ciszek

    Paul Ciszek Guest

    You looking to sell it? And what sort of mounting does it use?
    Paul Ciszek, Jul 11, 2012
  18. Paul Ciszek

    Martin Brown Guest

    It isn't wise to take anything the RichA troll says about kit reviews.
    If you had been reading this group for a while you would know that.

    The Vivitar Series 1 kit was the result of a misplaced decimal point and
    the early kit was exceptionally good optically. The marketeers then
    traded on the brand name for a while but with inferior products late on.

    These days how one behaves will depend very much on how well it was
    looked after and modern lens designers have better tools. It would help
    to give you better advice if you made it clear whether you are looking
    for a long lens for wildlife, industrial or astronomical photography.

    Of the cheaper ones the Russian made MTO 1000 f10 Mak is probably the
    about the best. At least good specimens of it are.
    Martin Brown, Jul 11, 2012
  19. Paul Ciszek

    Bruce Guest

    Don't forget the 24mm, and the fact that the Samyang/Rokinon/Bower
    85mm, 35mm and 24mm lenses all have a maximum aperture of f/1.4.

    The 85mm f/1.4 is an exceptional performer that is only just bettered
    by the new Nikon 85mm f/1.4G costing over four times more.
    Bruce, Jul 11, 2012
  20. Paul Ciszek

    RichA Guest

    Actually, closer to six times as much, $1700 versus $300.
    RichA, Jul 11, 2012
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