Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 71,872   Posts: 1,583,444   Online: 1177
      
Page 1 of 2 12 LastLast
Results 1 to 10 of 13
  1. #1
    Steve Smith's Avatar
    Join Date
    May 2006
    Location
    Ryde, Isle of Wight
    Shooter
    Medium Format
    Posts
    8,706
    Images
    122

    Sigma 600mm Mirror Lens - Has anyone used one?

    I acquired a Sigma 600mm mirror lens this weekend. I don't know if I will give it much use but it looks like a fun thing to own. Has anyone else got such a thing or has used one in the past?

    It comes with a set of rear mount filters and is currently fitted with a clear 'filter'. I recall reading that it needs a clear piece of glass in the filter position if no other filter is being used in order to maintain focus. Is this correct?


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  2. #2

    Join Date
    May 2005
    Location
    Daventry, Northamptonshire, England
    Shooter
    35mm
    Posts
    7,152
    Steve, a great find. 600mm is pretty powerful and the "cats" are as I understand it much lighter and smaller than a comparable 600mm conventional lens. In my albeit sparse reading about "cats" I cannot ever recall seeing a N.B. in any book reminding potential users to ensure that a clear filter was fitted.

    Fine if you have one but hopefully it's not required. If it is then I wonder what the optical science is that means one is essential?

    pentaxuser

  3. #3
    flash26c's Avatar
    Join Date
    Mar 2009
    Location
    Oregon
    Shooter
    Medium Format
    Posts
    108
    I own one for a Nikon. Haven't used it much but it did it's job when I did. Shallow DOF and not much light getting thru to focus unless it's bright out. I heard the same about the filter. Never tryed without.

  4. #4
    Steve Smith's Avatar
    Join Date
    May 2006
    Location
    Ryde, Isle of Wight
    Shooter
    Medium Format
    Posts
    8,706
    Images
    122
    This one is f8. The viewfinder seems bright enough to focus in decent daylight.

    The instruction booklet suggests that it can be used hand held but I think I would prefer a tripod.


    Steve.
    "People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.

  5. #5

    Join Date
    Nov 2004
    Posts
    1,178
    I have one in OM fit, but it came without any filters.It has not seen much use but produced an interesting result when used to photograph a boat in that the reflections off the waves were unusual.
    Since you have the filter it can be used but I am encouraged by the following that having no filter should still be OK, except the focus is changed:
    http://photo.net/classic-cameras-forum/00YBg4

  6. #6
    narsuitus's Avatar
    Join Date
    Nov 2004
    Shooter
    Multi Format
    Posts
    571
    I do not have the Sigma 600mm mirror lens but I do have a 1000mm mirror lens and a 500mm lens that require a filter in the filter slot for it to focus correctly. The way I understand it is if a filter is not in place, the infinity focus will be off. For example:

    1. If you manually focus on an object that is at an infinite distance, the distance scale on the lens will not be lined up with the infinity marking.

    2. If you rotate the focus ring to the infinity position and point your camera toward a star cluster, the star cluster, which should be in focus, will actually be out of focus.

    However, using the lens without the filter in place has no affect on the image quality.

    http://www.flickr.com/photos/11336821@N00/7798937038/
    Attached Thumbnails Attached Thumbnails IMG_4545b sml.JPG  

  7. #7
    lxdude's Avatar
    Join Date
    Apr 2009
    Location
    Redlands, So. Calif.
    Shooter
    Multi Format
    Posts
    6,756
    I have a 500mm/f8 Tamron SP with matched 2X converter.

    I really enjoy it. It's light and compact, and produces sharp images with good contrast.

    Negatives of mirror lenses are: the "donut" look to out of focus highlights and busy/double line bokeh in backgrounds with distinct detail, caused by the secondary mirror's position in the light path; lower contrast due to having an obstruction in the light path; generally smaller maximum aperture; a fixed aperture opening which means no way to increase DoF, plus difficulty getting precise exposure setting with all-mechanical cameras unless in-between shutter speeds can be set as on the Nikon F2.
    Positives include compactness and light weight (except the Vivitar Solid Cat, which is mostly a solid piece of glass); close focusing (mine goes to 1:3, and 1:1.5 with the 2X), which makes for some intriguing "nearly-macro" shots; less magnification of camera vibration due to short length and ability to attach the camera to the tripod directly. (Mine also has a tripod collar- I've used both setups and haven't seen a difference. But the lens is only about 3.75 inches long at infinity anyway, excluding the the hood). Finally, cost. A high quality regular telephoto will cost more than a comparable quality mirror lens.

    The Tamron is said to be one of the best of the mirror lenses, and I certainly find sharpness and contrast to be good. I don't know how your Sigma stacks up.

    I avoid the donut and double-line look by careful selection of background and/or foreground. The narrow depth of field is a plus in this, as extremely out-of-focus images in a background tend to blur to near non-definition. A very bright out-of-focus highlight, however, will be larger though dimmer the more it is out of focus, and can present problems. A uniformly lit out-of-focus area will not show the donut effect. I have also had success with uniformly mottled light/dark backgrounds looking good. Placing a subject against a uniform sky, stretch of calm water or area in shadow also works well.

    I bought my lens mostly for shots of very distant objects at infinity, excluding closer objects, and for those shots foreground/background issues are eliminated. Also at long distances, issues of contrast and resolution compared to top-notch regular telephotos are less important. Subject contrast is usually reduced anyway, so a little lower contrast still looks natural. Same with resolution at those distances- atmospherics usually affect resolution anyway.

    I don't mind the slowness- f/8@500mm, f/16@1000mm with the 2X. Depth of field is so shallow even at those apertures, and I'm (usually) not hand-holding anyway.


    Always use one of the filters. The filter is part of the optical formula so it is important that it be used.
    Last edited by lxdude; 08-19-2012 at 11:29 PM. Click to view previous post history. Reason: amended for accuracy
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  8. #8

    Join Date
    Aug 2006
    Location
    Hamilton, Ont, Canada
    Shooter
    Large Format
    Posts
    1,086
    What lxdude said, except that I was under the impression that DOF at f8 was what it was at f8. I don't think the mirror lens has less depth of field, than any other lens, but that the transitions may appear more abrupt. After all 500mm on 35 mm film has 6 inch of DOF at 30 feet. Mine is fitted to a Contax mount and I leave it on Aperture Priority and use appropriately fast film. A shutter speed of 1/500 or faster and you are good to go, handheld or bean bag.
    "There are a great many things I am in doubt about at the moment, and I should consider myself favoured if you would kindly enlighten me. Signed, Doubtful, off to Canada." (BJP 1914).

    Regards
    Bill

  9. #9
    rmolson's Avatar
    Join Date
    Feb 2006
    Location
    Mansfield Ohio
    Shooter
    Medium Format
    Posts
    307
    Had one as I remeber there is no adjustment for changing the f/stop.But what threw me for awhile was the fuzziness caused,by heat waves in the summer. You definatley can see that with a 500mm lens

  10. #10
    lxdude's Avatar
    Join Date
    Apr 2009
    Location
    Redlands, So. Calif.
    Shooter
    Multi Format
    Posts
    6,756
    Thanks for bringing up those points, Bill.

    Yes, you're right about DoF being the same.
    My comments on DoF were subjective. To clarify: For me, the Dof is usually a good tradeoff at f/8- enough for fairly close work, but shallow enough to lose distracting backgrounds pretty easily. I would seldom want less for the shots I make at short range though, f/5.6 being about 4.3 inches at 30 ft., and the extra stop meaning a large increase in size and weight. So the larger aperture lenses aren't that useful to me, and the smaller maximum aperture is not a deficit.

    You're right about hand-holding too. I've also hand-held, and it's certainly doable. I used to take pictures at air shows a lot, and the cat was great for that. It's a breeze to pivot holding it, as what weight it has is held close in. 400 ISO Provia and go. Pushing it, or using 400 ISO negative film's latitude would allow a higher shutter speed, though I just used Provia 400 at rated speed. It seemed easier for me to get a hand-held shot of a moving object than a stationary one. I used a monopod sometimes, but I usually ended up just hand-holding with good results. A bean bag on top of the car worked great, too.
    I seldom shoot non-stationary objects these days, so I use a tripod to get maximum resolution. I might use it handheld again though, so I amended my post.
    Last edited by lxdude; 08-19-2012 at 11:32 PM. Click to view previous post history.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

Page 1 of 2 12 LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin