LeicaPassion Posted May 14, 2015 Share #21 Posted May 14, 2015 Advertisement (gone after registration) A bird photographer showed me how to reduce vibration. With a solid tripod and ball head, pull down on the camera to take up any slack and then release the shotter with your finger. Do not use a cable release. When framing the shot, compensate for the slack. With the 560 lens it worked like a charm. Quote Link to post Share on other sites More sharing options...
Advertisement Posted May 14, 2015 Posted May 14, 2015 Hi LeicaPassion, Take a look here MR 500 mm Telyt on M. I'm sure you'll find what you were looking for!
CheshireCat Posted May 14, 2015 Share #22 Posted May 14, 2015 (edited) I think Mirror Lock Up + Electronic First Curtain is enough. 1:1 crops with and without EFC, Tamron 500 SP. Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Edited May 14, 2015 by CheshireCat Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/244684-mr-500-mm-telyt-on-m/?do=findComment&comment=2815761'>More sharing options...
pop Posted May 14, 2015 Share #23 Posted May 14, 2015 I think Mirror Lock Up + Electronic First Curtain is enough. 1:1 crops with and without EFC, Tamron 500 SP. Which mirror? Quote Link to post Share on other sites More sharing options...
CheshireCat Posted May 14, 2015 Share #24 Posted May 14, 2015 Which mirror? 5D2... just an example of what a good mirror lens can do if properly used. I don't have the lens with me at the moment, so I cannot provide an example on the M. Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 28, 2015 Share #25 Posted May 28, 2015 The Zuiko 500mm has been serviced and s/b back next week when will try it it on my Leica 'T' … but I think it might be a rare prototype lens because service agency repair description on pro forma invoice states: "Dismantled lens unit, repaired focus levels, cleaned and polished iris blades, cleaned and reset castings, rebuilt aperture control mechanism, cleaned mirrors and elements, refitted helical, reset stops and adjusted focus" dunk Quote Link to post Share on other sites More sharing options...
bocaburger Posted May 28, 2015 Share #26 Posted May 28, 2015 I had the Leinolta, I had a late Nikkor, I had the Tamron SP, all pretty much the same. My no-brand cheapo I have now is just as good as the others were, that is to say, it's a very sharp but f/8 500mm lens with donut bokeh and no IS. Quote Link to post Share on other sites More sharing options...
gvaliquette Posted May 28, 2015 Share #27 Posted May 28, 2015 Advertisement (gone after registration) The Zuiko 500mm has been serviced and s/b back next week when will try it it on my Leica 'T' … but I think it might be a rare prototype lens because service agency repair description on pro forma invoice states: "Dismantled lens unit, repaired focus levels, cleaned and polished iris blades, cleaned and reset castings, rebuilt aperture control mechanism, cleaned mirrors and elements, refitted helical, reset stops and adjusted focus" dunk I think you just got a generic, canned response that they send back with any and all repair pro formas. I have never, ever, seen / heard of a catadioptric lens with a diaphragm! However, I do not know if there is a technical reason why it cannot be built. Does anyone know? Please enlighten us! Guy Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 28, 2015 Share #28 Posted May 28, 2015 I think you just got a generic, canned response that they send back with any and all repair pro formas. I have never, ever, seen / heard of a catadioptric lens with a diaphragm! However, I do not know if there is a technical reason why it cannot be built. Does anyone know? Please enlighten us! Guy Of course it's a standard blurb used with all their repair invoices … but maybe reflects the fact that they do not repair many mirror lenses … but could also be indicative that the tea lady also prints out the invoices Ref iris diaphragms on mirror lenses: IIRC back in the 80s one of the independent lens manufactures sold a mirror lens which had a lens diaphragm. There are several different mirror lens designs; astronomical telescopes are made with at least four. dunk 2 Quote Link to post Share on other sites More sharing options...
CheshireCat Posted May 28, 2015 Share #29 Posted May 28, 2015 "Dismantled lens unit, repaired focus levels, cleaned and polished iris blades, cleaned and reset castings, rebuilt aperture control mechanism, cleaned mirrors and elements, refitted helical, reset stops and adjusted focus" Which basically means that what they actually performed is any combination of the above copy&paste'd procedures, including none of them Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 28, 2015 Share #30 Posted May 28, 2015 Which basically means that what they actually performed is any combination of the above copy&paste'd procedures, including none of them No … doesn't mean that dunk Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted May 28, 2015 Share #31 Posted May 28, 2015 (edited) Hello Everybody, I think the manufacturer Dunk was writing about is a German Company that made the mirror lens in the 1970's or 1980's. The mirror has an iris which pivots from the center of the lens & extends to the outside edge of the lens element. The iris blades always block a part of the lens from the center to the edge. As the iris opens up further it blocks off more of the lens between the center & the edge. It worked similarly to a fan which you might have in your hand on a hot Summer Day & open more or less as needed. This creates the correctly panel to move the air appropriately as you wave the fan. I think the name of the Company started with a "Z". It might have been "Zorkendorfer". Best Regards, Michael Edited May 28, 2015 by Michael Geschlecht 2 Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted May 28, 2015 Share #32 Posted May 28, 2015 Hello Again Everybody, I have found that the biggest cause of unsharpness in working with a mirror lens is usually not the lens itself. Rather it is forgetting that this little, light lens is in reality a really long, light lens & needs to be treated as such. The small size & lightness that makes it so easy to use multiply the photographers need to steady it. Many photographers realize they can often improve many of their photographs significantly by putting the camera & lens on a tripod with any camera/lens combination. Even with wide angle lenses. This is more so the case with a mirror lens. The lens under discussion here is a 500mm lens. The fact that its light path is folded back & compressed doesn't make the parameters for steadying it any less. The lightness which makes it easier to handle also multiplies the need to compensate for the lack of weight when using this lens. Tiny movements of the lens/camera are multiplied significantly. It might be interesting to see the difference in results after attaching this lens to a big, steady tripod & attaching a stationary weight directly to the camera/lens. Not a weight hanging in the air. Don't forget a gentle release at a high shutter speed , etc. Best Regards, Michael 1 Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 28, 2015 Share #33 Posted May 28, 2015 (edited) Thank you Michael … I plan to use the Olympus 500mm mirror lens on a hefty Berlebach tripod with an equally solid mount to ensure it's as stable as possible . Yes, photographers underestimate the fact that mirror lenses require a very stable mount to ensure shake free, sharp images … thus lens reviews/tests might not always show their true imaging potential. Also, the relatively 'thin' mirrors need time to acclimatise to ambient atmospheric temperature . Astronomers are very aware of this fact and would not expect their reflector 'scopes to reach optimal imaging stability until after 30 to 40 minutes from set-up time ... and many astro 'scopes incorporate miniature battery powered fans to facilitate 'cooling' and neutralising convection currents which can play havoc with the image . These factors are TTBOMK never fully discussed /documented in reviews of photographic mirror lenses. Best wishes dunk Edited May 28, 2015 by dkCambridgeshire Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted May 30, 2015 Share #34 Posted May 30, 2015 Hello Dunk, "TTBOMK"? Best Regards, Michael Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 30, 2015 Share #35 Posted May 30, 2015 Hello Dunk, "TTBOMK"? Best Regards, Michael HI Michael, 'TTBOMK' = 'to the best of my knowledge'. Best wishes dunk 1 Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted May 30, 2015 Share #36 Posted May 30, 2015 Hello Everybody, 1 other thing about a mirror lens that people sometimes forget is: Any perceived movement at the front of the lens is optically multiplied by a factor of more or less 3. Meaning: If the front of the lens wobbles 1mm (Not an unlikely occurrence in many hand held situations) then the actual movement in optical terms is as if the front had moved 3mm. This multiplies the image loss from instability accordingly. This, of course, is again multiplied by the image magnification of the specific focal length itself. This factor of 3 is only for regular mirror lenses such as the Leitz/Minolta 500mm: Lens = 121mm long. Optical register SL/R Mount = 47mm. 121mm + 47mm = 168mm X 3 (Folding of optical path) = 504mm. Mirror lenses which have been designed to be physically shorter such as the Vivitar 600mm Solid Cat have a larger factor than 3. Best Regards, Michael 1 Quote Link to post Share on other sites More sharing options...
gvaliquette Posted May 30, 2015 Share #37 Posted May 30, 2015 Michael, Dunk: That is a very strange diaphragm mechanism implementation, opening from the center! Was it mounted on the primary or the secondary mirror? Either way, it would not increase the depth of field, as the diameter of the cone of light (entrance pupil) would not be reduced. It would only serve to reduce the shutter speed and magnify the "donut bohke" effect, neither of which is really welcome. It would also be rather complex mechanically. On the other hand, a diaphragm placed in front of the primary mirror, and closing in conventionally from the edges, would narrow down the entrance pupil and increase the depth of field. But it would be physically large. Am I making sense, or did I miss something? Thanks. Guy Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 30, 2015 Share #38 Posted May 30, 2015 Posted result using the Zuiko 500mm / Leica T http://www.l-camera-forum.com/topic/245734-leica-t-with-olympus-zuiko-500mm-mirror-lens/ Guy, I'm still trying to find out more about the variable aperture mirror lens which was sold in UK during the 80s … may have been available in two focal lengths and unlikely to have been the model that Michael refers to. The lens I recall was made in the far east and was listed at a budget price. dunk Quote Link to post Share on other sites More sharing options...
dkCambridgeshire Posted May 30, 2015 Share #39 Posted May 30, 2015 The mirror lens with the variable aperture was the Japanese made OHNAR 300mm f5.6 - f16 with a 9 element configuration. dunk 1 Quote Link to post Share on other sites More sharing options...
Michael Geschlecht Posted June 1, 2015 Share #40 Posted June 1, 2015 Hello Everybody, We are actually talking about 3 different configurations all together: What Dunk mentioned in Post #28 above is a mirror lens with a set of donuts (Waterhouse Stops). Each donut has an outside diameter the size of the front element of the mirror lens. The inside diameters of the various Waterhouse Stops are centrally located circular openings of various sizes. The appropriate donut is placed in front of the front element to change the F stop to what is required. These were common in 19th Century photography for lenses of that time which did not always have Internally Adjustable Irises. What I described in Post #31 above would most likely create a somewhat different bokeh. It would most likely not effect depth of field. The Warehouse Stops in Dunk's Post #28 would. The 300mm lenses mentioned by Dunk in his Post #39 above were made by a number of Manufacturers & imported by a number of Importers under a variety of names. They were not always stellar performers. Best Regards, Michael 1 Quote Link to post Share on other sites More sharing options...
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