Michael Geschlecht Posted October 11, 2019 Share #21 Posted October 11, 2019 (edited) Advertisement (gone after registration) 27 minutes ago, maximilianm3 said: I would agree with you that at 0.65m focus on the lens the rangefinder thinks it's 1m. However this doesn't explain the trickery of the round goggle which definitely moves the rangefinder patch in the viewfinder vertically and horizontally when adjusted with the three little screws.... so what exactly is it's purpose if not to suggest that 1m is actually 0.65m? I think the square goggle doesn't do anything to the fixed and movable rangefinderpatches. Hello Maximillianm3, Welcome to the Forum. What the "goggles do to the rangefinder system is EXPAND their angle of travel. whatever their angle of travel was before: With the "goggles" it becomes "angle multiplied by 1.5" So, if the far to near travel was Infinity to 1 meter without the "goggles": Then the new travel becomes Infinity to 0.67 meters with the "goggles". Which, with all of the rounding for convenience that is done, becomes 0.65 meters. Altho, with some lenses, the actual measurement might be a little closer. Best Regards, Michael Edited October 11, 2019 by Michael Geschlecht 1 Link to post Share on other sites More sharing options...
Advertisement Posted October 11, 2019 Posted October 11, 2019 Hi Michael Geschlecht, Take a look here goggled v ungoggled 35mm lenses. I'm sure you'll find what you were looking for!
luigi bertolotti Posted October 11, 2019 Share #22 Posted October 11, 2019 (edited) Very intersting discussion, and compliments to Michael for his clear explanations : I think that to anyone now is clear one basic fact : GOGGLES DO SIMPLY EXPAND THE ANGLE OF VIEW (reduce the dimension) of the two images (the "large one" - VF and the "small one" - RF window projected); they don't do any "trick" about the coincidence mechanism activated by roller-cam-mirrors etc. Now… .. let's elaborate a little on the 1m - 0,7 - 0,65 question (Michael tell me if i write something wrong… ) 1) M3 rangefinder had (nominally) the capability to measure from 1m to infinity 2) A standard 35mm lens of that era (example, first BM Summaron 35 3,5 ungoggled) focused accordingly : from 1 meter to infinity, with an angular movement of the helicoid of 115° around (I've just measured mine) 3) The goggled version focused from 0,65... with the SAME angular movement (again, just checked my goggled Summaron 3,5) 4) So, helicoid slope was DIFFERENT (and the RF cam too) 5) Then, M2 was introduced, with a new rangefinder capable of focusing to 0,7m (optically and mechanically, the same specs as today's one.. apart refinements) 6) So they introduced lenses with focus from 0,7m , and capable of activating the new 35mm frame of M2 (Summaron 2,8, Summicron ; Summaron 3,5, though made in M2 version, kept the 1m minimum distance.. went out of production no much more than 1 year after M2 intro, anyway..) 7) Leitz did keep the goggled versions on pricelist , because thousands of M3 were in use, and manufactured for many years after M2 intro. 8) BUT, given that new ungoggled 35mm lenses with 0,7 focua were made, they could standardize the focus helicoid (and RF cam) in goggled/ungoggled lenses: good for manufacturing. 9) Which explains the intro of goggled lenses with 0,7 instead of 0,65 marked as minimum distance 10) Goggled Summilux kept the 0,65 mark, on the contrary (the ungoggled version kept the 1m minimum focus : only the Aspherical Unluckily, I cannot verify directly my 8) assertion… I haven't a goggled 35 with 0,7 and cannot verify if the angular movement when focusing is the same as, for instance , my Summicron 35 1st version : but looks to me a logical fact (neither I can verify if focus movement extends a bit further the 0,7 mark (it does not in my Summicron 1st) Edited October 11, 2019 by luigi bertolotti 2 Link to post Share on other sites More sharing options...
bayernfan Posted October 12, 2019 Share #23 Posted October 12, 2019 (edited) 7 hours ago, Michael Geschlecht said: The actual movement of the roller & the cam on the lens: Are at the point where they are measuring at an image plane at a distance of 1 meter. 6 hours ago, maximilianm3 said: Scratch that as you are right: all it does is reduce what is in the rangefinder patch from a 50mm view to a 35mm.... Ok, so the goggle's round RF optic changes the RF image magnification to correspond with the 35mm field of view (FOV) produced by the square VF optic. This must mean that ratio of travel (.65 : 1) is a direct consequence of the FOV de-magnification ratio (approx 35 : 50). So let's take it a step further. In my mind, the Leitz engineers set about to demagnify the 50mm FOV to a 35mm FOV. Demagnifying the VF image required the RF image to be demagnified (to correspond correctly with 35mm viewfinder FOV). Now here is what is key, the change in rangefinder window magnification meant that the movement of the RF cam no longer corresponded to 1m to inf (as perceived through the VF). Hence, the helical change to correct this discrepancy and then 0.65m to retain the original angular displacement of a 1m to inf lens. 😁 Edited October 12, 2019 by bayernfan Link to post Share on other sites More sharing options...
bayernfan Posted October 12, 2019 Share #24 Posted October 12, 2019 Thank you everyone for your participation and insight. This has been a very enlightening conversation. Link to post Share on other sites More sharing options...
luigi bertolotti Posted October 12, 2019 Share #25 Posted October 12, 2019 (edited) 10 hours ago, bayernfan said: In my mind, the Leitz engineers set about to demagnify the 50mm FOV to a 35mm FOV... in YOUR mind… … but what was actually in the mind of Leitz engineers ? One can only guess… And this is my guess, not necessarly right, of course, and mainly based on the fact that the first goggled lens has been the Summaron 3,5, alens that already existed in SM, re-engineered in BM in 1954 (M3 intro) with a new Mount and the std. 1m min. focus. - Someone had this brilliant idea of goggles to enlarge FOV to 35 (not 100% new… the old NOOKY was a sort of goggle, for near distance focusing) - Design the goggle unit in itself.. a rather simple optical schema (two negative lenses) : it can work, in theory, without any need to modify the focusing range 1m - infinity. - But the goggle unit, in their mind, had to be ATTACHED to the lens' body (removable in case, and they did) … and here mechanical problems arise, looking at how the std. Summaron 3,5 body is made : the rotating barrel (for focusing) makes most of the lens' length.. the fixed part, onto which one must attach the goggle, is just 4mm long (out of the camera) .. too thin to assure a solid attachment.. and btw it bears also the DOF scale… 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! - A completely different approach : attach the goggle not to the lens but to the camera… using the accessory shoe… a 90° flip for inserting..bah.. not elegant … shoe can be useful for meter or flash… and not fine mechanically (a "heavy" unit linked to a "tiny" support…) : discarded solution. - Solution : attach the goggle to a longer non rotating barrel : ok.. we have to design it, engineer etc... and there is a basic requirement : KEEP THE GLASS CELL OF THE SUMMARON AS IS : otherwise, it would be a completely new and costly design, not to speak of two different glass assemblies for , at the end, the same lens . costly and absurd by principle. - So they designed this new barrel, with room to attach the goggle, and putting the writings where they can be decently read : it is very worth noting that in the same year the DR Summicron was introduced, with a very similar design of the goggle attachment. - Problem : being the lens cell the same, in practical terms you have a Summaron with (roughly said) a "virtual extension ring" : engineers had to play, on the design table, with focus helicoid, positioning of the lens cell, RF cam, shims maybe, to find a good solution : it resulted in a minimum focus distance of 0,65 (which, in user view, is a plus) - So, an engineering-driven need (attach the goggle) resulted into an add-on value (the lens has a nearest minimum focus vs. the previous one) : and this "0,65" became the standard fo the future goggled lenses (which weren't yet designed at that time : Summaron 2,8, Summicron, Summilux). This is my basic idea : the 0,65 was NOT a marketing driven decision but a (useful) consequence of a design-driven decision. The intro of M2 with its "0,7 RF" changed someway the game, but was well integrated in the previous "goggle strategy" (the goggled 35s were marked 0,7, accordingly with designed-for-M2 standard) Sorry for the long speech : but this is one of the many fascinating stories of a great company in its Golden years. I don't know if in some publications (Viewfinder mag ?) the story of the goggled 35s has been reported, with informations from then-insiders (Puts does not say much on the matter) : I'd be very curios to know, in case. Edited October 12, 2019 by luigi bertolotti 1 Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! - A completely different approach : attach the goggle not to the lens but to the camera… using the accessory shoe… a 90° flip for inserting..bah.. not elegant … shoe can be useful for meter or flash… and not fine mechanically (a "heavy" unit linked to a "tiny" support…) : discarded solution. - Solution : attach the goggle to a longer non rotating barrel : ok.. we have to design it, engineer etc... and there is a basic requirement : KEEP THE GLASS CELL OF THE SUMMARON AS IS : otherwise, it would be a completely new and costly design, not to speak of two different glass assemblies for , at the end, the same lens . costly and absurd by principle. - So they designed this new barrel, with room to attach the goggle, and putting the writings where they can be decently read : it is very worth noting that in the same year the DR Summicron was introduced, with a very similar design of the goggle attachment. - Problem : being the lens cell the same, in practical terms you have a Summaron with (roughly said) a "virtual extension ring" : engineers had to play, on the design table, with focus helicoid, positioning of the lens cell, RF cam, shims maybe, to find a good solution : it resulted in a minimum focus distance of 0,65 (which, in user view, is a plus) - So, an engineering-driven need (attach the goggle) resulted into an add-on value (the lens has a nearest minimum focus vs. the previous one) : and this "0,65" became the standard fo the future goggled lenses (which weren't yet designed at that time : Summaron 2,8, Summicron, Summilux). This is my basic idea : the 0,65 was NOT a marketing driven decision but a (useful) consequence of a design-driven decision. The intro of M2 with its "0,7 RF" changed someway the game, but was well integrated in the previous "goggle strategy" (the goggled 35s were marked 0,7, accordingly with designed-for-M2 standard) Sorry for the long speech : but this is one of the many fascinating stories of a great company in its Golden years. I don't know if in some publications (Viewfinder mag ?) the story of the goggled 35s has been reported, with informations from then-insiders (Puts does not say much on the matter) : I'd be very curios to know, in case. ' data-webShareUrl='https://www.l-camera-forum.com/topic/302296-goggled-v-ungoggled-35mm-lenses/?do=findComment&comment=3834777'>More sharing options...
bayernfan Posted October 12, 2019 Share #26 Posted October 12, 2019 Thank you for your detailed insights Luigi. Always enjoy chatting with you about these early lenses. 1 Link to post Share on other sites More sharing options...
Michael Geschlecht Posted October 13, 2019 Share #27 Posted October 13, 2019 (edited) Advertisement (gone after registration) On 10/11/2019 at 5:22 PM, luigi bertolotti said: Very intersting discussion, and compliments to Michael for his clear explanations : I think that to anyone now is clear one basic fact : GOGGLES DO SIMPLY EXPAND THE ANGLE OF VIEW (reduce the dimension) of the two images (the "large one" - VF and the "small one" - RF window projected); they don't do any "trick" about the coincidence mechanism activated by roller-cam-mirrors etc. Now… .. let's elaborate a little on the 1m - 0,7 - 0,65 question (Michael tell me if i write something wrong… ) 1) M3 rangefinder had (nominally) the capability to measure from 1m to infinity 2) A standard 35mm lens of that era (example, first BM Summaron 35 3,5 ungoggled) focused accordingly : from 1 meter to infinity, with an angular movement of the helicoid of 115° around (I've just measured mine) 3) The goggled version focused from 0,65... with the SAME angular movement (again, just checked my goggled Summaron 3,5) 4) So, helicoid slope was DIFFERENT (and the RF cam too) 5) Then, M2 was introduced, with a new rangefinder capable of focusing to 0,7m (optically and mechanically, the same specs as today's one.. apart refinements) 6) So they introduced lenses with focus from 0,7m , and capable of activating the new 35mm frame of M2 (Summaron 2,8, Summicron ; Summaron 3,5, though made in M2 version, kept the 1m minimum distance.. went out of production no much more than 1 year after M2 intro, anyway..) 7) Leitz did keep the goggled versions on pricelist , because thousands of M3 were in use, and manufactured for many years after M2 intro. 😎 BUT, given that new ungoggled 35mm lenses with 0,7 focua were made, they could standardize the focus helicoid (and RF cam) in goggled/ungoggled lenses: good for manufacturing. 9) Which explains the intro of goggled lenses with 0,7 instead of 0,65 marked as minimum distance 10) Goggled Summilux kept the 0,65 mark, on the contrary (the ungoggled version kept the 1m minimum focus : only the Aspherical Unluckily, I cannot verify directly my 😎 assertion… I haven't a goggled 35 with 0,7 and cannot verify if the angular movement when focusing is the same as, for instance , my Summicron 35 1st version : but looks to me a logical fact (neither I can verify if focus movement extends a bit further the 0,7 mark (it does not in my Summicron 1st) Hello Luigi, Point #8: With the "ungoggled" lens that focuses to 0.7 meters the rangefinder cam has to be different so that it can read the M2 & later "M" model rollers correctly from Infinity to 0.7 meters. While both the original 35mm, F3.5, Summaron that brought up the 50mm frame & used an auxiliary accessory shoe mounted viewfinder & the "goggled" lens that we are writing about here only require a cam that reads to 1 meter. The original 35mm, F3.5, Summaron that did NOT have "goggles" focuses from Infinity to 1 meter. Which means that with these various 35mm, F3.5, Summaron lenses there has to be some sort of different internal connection between the focusing cam that reads to 1 meter & its focusing barrel & the focusing cam that reads to 0.7 meters & its focusing barrel since the same number of degrees of barrel rotation bring the 2 different lenses to the same 0.7 meter focal plane. Or closer. Some 35mm, F2, Summicrons with "goggles" that have markings that stop at 0.7 meters do focus to 0.65 meters. And some even focus a little closer. Best Regards, Michael Edited October 13, 2019 by Michael Geschlecht Link to post Share on other sites More sharing options...
maximilianm3 Posted October 13, 2019 Author Share #28 Posted October 13, 2019 The focusing cam of the goggled Summaron 3.5 is sloped whereas the normal version is flat I believe..... Luigi kindley posted some photos of his Summarons. Is there really a difference in thicknes/lenght of the whole lens or does it just look like that because of the thick 'gogglemount'. What about the faster versions? Link to post Share on other sites More sharing options...
a.noctilux Posted October 13, 2019 Share #29 Posted October 13, 2019 24 minutes ago, maximilianm3 said: ... What about the faster versions? I have the two versions (M3 "goggled" and "M2", they are of same thickness) Summicron and Summaron 2.8 same thickness for "M3 type" or "M2 type". Summicron 28mm... Summaron 2.8 are 1mm more 29mm thick. Link to post Share on other sites More sharing options...
bayernfan Posted October 14, 2019 Share #30 Posted October 14, 2019 7 hours ago, maximilianm3 said: The focusing cam of the goggled Summaron 3.5 is sloped whereas the normal version is flat I believe..... Luigi kindley posted some photos of his Summarons. Is there really a difference in thicknes/lenght of the whole lens or does it just look like that because of the thick 'gogglemount'. What about the faster versions? I own both versions, I'll check tomorrow. Link to post Share on other sites More sharing options...
a.noctilux Posted October 14, 2019 Share #31 Posted October 14, 2019 10 hours ago, a.noctilux said: I have the two versions (M3 "goggled" and "M2", they are of same thickness) Summicron and Summaron 2.8 same thickness for "M3 type" or "M2 type". Summicron 28mm... Summaron 2.8 are 1mm more 29mm thick. Update with digital caliper : - Summicron "M3" and "M2" at infinity lock = 28.5mm ± 0.3mm * - SAMWO Summicron "M3" at 0.65m setting = 30.7mm ± 0.2mm - SAWOM Summicron "M2" at 0.7m setting = 30.4mm ± 0.2mm * Not too far from Wiki figures (28.4mm) Link to post Share on other sites More sharing options...
Ernstk Posted February 6, 2021 Share #32 Posted February 6, 2021 15 hours ago, Steven said: I do want to inform you though that my lens focuses perfectly through the RF. From 1.4 to 2, the alignment of the RF is absolutely perfect. From 2.8 to 4, I notice a very slight focus shift, but nothing that makes it unusable for most subjects, and nothing out of the ordinary since many lenses, including more recent asph 35 lux have focus shift at these aperture. Past 5,6, I don’t notice any focus shift anymore, but that’s probably due to the extended depth of field. Are you saying that you can see a focus shift in the rangefinder images? At f1.4 and f2, the ragefinder aligns perfectly but beyond that, to f5.6, there is a misalignment in the rangefinder? Ernst Link to post Share on other sites More sharing options...
roelandinho Posted February 6, 2021 Share #33 Posted February 6, 2021 1 minute ago, Steven said: I am saying that when using the range finder patch, up to f2.8 the focusing process is very precise. Between 2.8 and 5.6, if I focus on an eye with the RF patch, it will be right behind the eye that there is focus. After 5.6, the focus shift is probably still happening but with the dof being larger, I don't see the effect. Does that sound weird ? No, this sounds exactly like what you can expect. Most Leica 35mm lenses I have tried behave this way. Link to post Share on other sites More sharing options...
Ernstk Posted February 6, 2021 Share #34 Posted February 6, 2021 1 hour ago, Steven said: Does that sound weird ? Between 2.8 and 5.6, or at any other aperture, it will still look in focus on the RF patches? Ernst Link to post Share on other sites More sharing options...
Ernstk Posted February 6, 2021 Share #35 Posted February 6, 2021 1 minute ago, Steven said: I need to do more testing before answering something stupid. What about image quality between modified version and non goggles version ? Any thoughts on that ? If they're the same lens, i.e. both v1 or both v2, then there shouldn't be any difference. They're the same optically. Ernst 1 Link to post Share on other sites More sharing options...
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