Kanykei Posted February 28, 2020 Share #1 Posted February 28, 2020 Advertisement (gone after registration) Hi there Can anybody please explain what these numbers mean on the rear coma adjustment ring on Miyazaki lens Specifically what happens on these?: -- infinity -- 5 -- 3 -- 2 -- 1 Thank you in advance! 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! 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/306912-urgent-please-help-ms-sonnetar-73-mm/?do=findComment&comment=3921171'>More sharing options...
Advertisement Posted February 28, 2020 Posted February 28, 2020 Hi Kanykei, Take a look here urgent please help MS sonnetar 73 mm. I'm sure you'll find what you were looking for!
Ecar Posted February 28, 2020 Share #2 Posted February 28, 2020 In a nutshell, the coma adjustment ring is meant to maximise the lens' optical performance by minimising coma at the selected (focus) distance. This is achieved by slightly shifting the rear block - thereby effectively changing the nominal focal length. All nice and good in principle, BUT in practice (without getting into details) it also affects the ability to achieve proper focus through the rangefinder. In consequence, if the lens is not perfectly calibrated -- and anecdotal evidence suggests that most of them are not -- you will experience back or front focus, depending on the coma ring setting and the effective focus distance. From your selected setting, you then need to learn how the lens behaves to compensate by either nudging the focus ring or slightly rocking your body. Btw, this trait is shared, to varying degrees, with all Sonnar lenses. The difference here - and with a couple of other Miyazaki lenses that feature this kind of adjustment ring - is that the amount and direction of focus shift may vary as you turn the coma adjustment ring. In my experience, the "middle" setting of 3m and is what works best for "general photography". No such issues, of course, when using a camera body equipped with LV/EVF. Link to post Share on other sites More sharing options...
adan Posted February 28, 2020 Share #3 Posted February 28, 2020 This is a "manual" floating element, similar to the manual FLEs in the more recent Hasselblad/Zeiss wide-angles (40mm and 50mm). Not really different than the FLE's in some Leica lenses (75 APO-Summicron-ASPH-M, for example) - except that by making it manual, rather than having it automatically adjust with movement of the main focus ring, it is less expensive to build and calibrate. On this Hasselblad 40mm FLE, for example, there is a similar ring - but installed more conveniently on the outside of the lens: https://www.kenrockwell.com/hasselblad/40mm-f4-cf.htm INF _ 2 _ 0.9 _ 0.5m It optimizes the lens formula (spacing of the lens elements) for different focus distances. I.E. if your subject is between roughly 4 and 2 meters away, set the "coma adjustment ring" to "3" (or between 3 and 5, or between 3 and 2) for best performance in the picture corners, remount the lens, and then focus as usual. Link to post Share on other sites More sharing options...
NigelG Posted February 28, 2020 Share #4 Posted February 28, 2020 Further to my reply before by email - I have tracked down a copy of the elusive English translation of the instructions - which still remain a little cryptic. Mine are in London not NYC but this copy is clear enough I hope. Basically from how I interpret the hand notes - the coma variation ring should only be adjusted between 1 and infinity when using mirrorless cameras . I take that to mean also using an EVF/live view on an M. This is to minimise aberrations at the preferred focus point from near to far. Position 3 is the default which gives “good” correction but not the best. I now think the additional note implies that for front/back focus calibration the ring should be moved +/- 1mm about position 3. Im happy to be corrected as I’ve ended up only using this lens with the EVF as focussing was so variable. 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! 1 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/306912-urgent-please-help-ms-sonnetar-73-mm/?do=findComment&comment=3921489'>More sharing options...
NigelG Posted February 28, 2020 Share #5 Posted February 28, 2020 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! 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/306912-urgent-please-help-ms-sonnetar-73-mm/?do=findComment&comment=3921491'>More sharing options...
Kanykei Posted March 2, 2020 Author Share #6 Posted March 2, 2020 (edited) Dear all Thank you very much for all of the responses! It was a huge help! I could not thank right away because I am a newbie in this forum and can make only one entry or message in 24 hours I have personal messaged NigelG - thank you Andy - thank you very much for all quick replies Thank you Ecar! Edited March 2, 2020 by Kanykei 1 Link to post Share on other sites More sharing options...
AndreasG Posted March 2, 2020 Share #7 Posted March 2, 2020 Advertisement (gone after registration) vor einer Stunde schrieb Kanykei: I could not thank right away because I am a newbie in this forum and can make only one entry or message in 24 hours That is strange, even as a newbie you can post as much as you want, the forum does not limit you? Anyhow, welcome here! Link to post Share on other sites More sharing options...
Kanykei Posted March 2, 2020 Author Share #8 Posted March 2, 2020 18 minutes ago, AndreasG said: That is strange, even as a newbie you can post as much as you want, the forum does not limit you? Anyhow, welcome here! It does at least it did limit, saying I can't make more than one entry in 24 h I will try responding though now. Let's see Link to post Share on other sites More sharing options...
Kanykei Posted March 2, 2020 Author Share #9 Posted March 2, 2020 Oh It works now! Link to post Share on other sites More sharing options...
NigelG Posted March 2, 2020 Share #10 Posted March 2, 2020 It would be great if any other users can confirm my attempted decoding of the handwritten note re the coma adjustment - am I right in thinking it can be the focus point adjustment if used very very carefully around the start point.... I think I was moving it too far and ending up with a lens that focuses at minimum distance but is way off at distance...a problem I had with a Hexanon Limited 50 f1.2 that I eventually passed back to the dealer (and obviously now regret) Link to post Share on other sites More sharing options...
Kanykei Posted March 2, 2020 Author Share #11 Posted March 2, 2020 (edited) 2 minutes ago, NigelG said: It would be great if any other users can confirm my attempted decoding of the handwritten note re the coma adjustment - am I right in thinking it can be the focus point adjustment if used very very carefully around the start point.... I think I was moving it too far and ending up with a lens that focuses at minimum distance but is way off at distance...a problem I had with a Hexanon Limited 50 f1.2 that I eventually passed back to the dealer (and obviously now regret) Nigel , I think your decoding of the instructions was right to the point. Infinity - 1 -- only for mirrorless camera's. I have got in touch with a person who spoke personally to Miyazaki in Tokyo about Ms Sonnetar 73 mm and Mr Miyazaki said use 3 almost for ALL purposes Edited March 2, 2020 by Kanykei 2 Link to post Share on other sites More sharing options...
farnz Posted March 3, 2020 Share #12 Posted March 3, 2020 13 hours ago, Kanykei said: Nigel , I think your decoding of the instructions was right to the point. Infinity - 1 -- only for mirrorless camera's. I have got in touch with a person who spoke personally to Miyazaki in Tokyo about Ms Sonnetar 73 mm and Mr Miyazaki said use 3 almost for ALL purposes I'm glad you found the answer, Kanykei, and sorry I wasn't able to help more through the private messages. Pete. Link to post Share on other sites More sharing options...
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