kcnarf Posted September 28, 2011 Share #1 Posted September 28, 2011 Advertisement (gone after registration) Sein Reid in his Luminous Landscape comments on the Ricoh GXR and new M mount adaptor says he is hoping for a future autofocus version. How would that be possible with a manual lens? Unless the sensor unit were motorized for focussing movement. How feasible is this? Link to post Share on other sites More sharing options...
Advertisement Posted September 28, 2011 Posted September 28, 2011 Hi kcnarf, Take a look here Autofocusing an M lens?. I'm sure you'll find what you were looking for!
andybarton Posted September 28, 2011 Share #2 Posted September 28, 2011 You would need for Leica to make an autofocus lens for it. Maybe next Photokina and the mirror-less option? Link to post Share on other sites More sharing options...
luigi bertolotti Posted September 28, 2011 Share #3 Posted September 28, 2011 ...in theory they COULD envision a GXRM-AF module in which all the bayonet mount does move along the axis, moving with it the attached lens (probably keeping care you HOLD the lens and keeps the body moving... is lighter than many M lenses... ) ... funny to think of... I doubt they wiil do... Link to post Share on other sites More sharing options...
adan Posted September 28, 2011 Share #4 Posted September 28, 2011 Probably not hard at all to make the front of the module itself (carrying the lens mount) move in and out several mms, controlled by the camera's AF-detect from the sensor. Something Ricoh can do with no input from Leica at all. For longer lenses, it might require prefocusing manually to a range - a 90mm requires a cm or so of travel to get down to 1 meter, so one would need to set it to, say, 2 meters on the lens scale to get AF from 2m to 1m, and set it to infinity for AF from infinity down to 2 meters. But the wideangles only need to move a couple of mms. It could probably focus a 21 down to 1 foot. It's not really much different from the way Contax managed to autofocus their older manual lenses with the Contax AX (motorized moving film plane) - except that moving the front is probably simpler than moving the sensor (with all its electronic connections) - and Ricoh wouldn't have to worry about moving a ground-glass and mirror box as well. The AX also required setting manual focus to a range for longer lenses, since it was limited to about 1cm of travel. Link to post Share on other sites More sharing options...
Dannybuoy Posted September 28, 2011 Share #5 Posted September 28, 2011 Blimey. Imagine how slow auto focus would be on Leica lenses... It take brute force to focus my 90mm Summicron by hand. You'd need a powerful motor to focus that. The battery would take some serious punishment too. Link to post Share on other sites More sharing options...
Ronan Posted September 28, 2011 Share #6 Posted September 28, 2011 You would need for Leica to make an autofocus lens for it. Maybe next Photokina and the mirror-less option? Focusing sensor. Moves back and forth. Link to post Share on other sites More sharing options...
John McMaster Posted September 28, 2011 Share #7 Posted September 28, 2011 Advertisement (gone after registration) And that would negate all the performance benefits of floating lens elements ;-( john Link to post Share on other sites More sharing options...
Tom M Posted September 28, 2011 Share #8 Posted September 28, 2011 Blimey. Imagine how slow auto focus would be on Leica lenses... It take brute force to focus my 90mm Summicron by hand. You'd need a powerful motor to focus that. The battery would take some serious punishment too. Zeiss has done it successfully with their Contax N. Link to post Share on other sites More sharing options...
hoppyman Posted September 28, 2011 Share #9 Posted September 28, 2011 Zeiss has done it successfully with their Contax N. Not really Tom! I had that discontinued system. Kyocera had some excellent design features in the N and the G systems but the focus mechanisms in the lenses have to be very different for autofocus. Aside from any other considerations the mechanism must be physically much lighter and easier to turn or the motor and battery demands would be huge of course. For the Zeiss labelled lenses a comparison of the current manual focus designs for M and dSLRs to the discontinued N lenses would show the differences very clearly. Link to post Share on other sites More sharing options...
jaapv Posted September 28, 2011 Share #10 Posted September 28, 2011 I think the most that we might hope for, at least the autofocus minded amongst us and the older users that start to notice the effect of age on eyes, is a focus confirmation LED like the Olympus OM 40. However this presupposes a sensor that is AF capable or a contrast sensor type addition to the existing rangefinder, which would not be more accurate, probably less so, than the current RF. It would be helpful though for visually impaired users. Link to post Share on other sites More sharing options...
adan Posted September 28, 2011 Share #11 Posted September 28, 2011 Wake up, people! Time for a strong cup of coffee before reading. Contax-Kyocera had TWO (2) different AF systems for their SLRs. The AX was an autofocus body for their manual-focus lenses, which moved the entire inside of the camera back and forth to focus a lens - which did NOT itself move. Lens weight was irrelevant, both because the lens did not move - and the mass that was being moved (mirror box, ground glass, prism, shutter, and film rails) likely weighed as much as most M lenses anyway. (Yes, it was a bit slow). http://www.ixbt.com/digimage/m39/contaxax.jpg It did present the problem, as John says, that floating elements were left in the "infinity" position. Unless one focused manually to approximately the right position, and let the autofocus fine-tune the focus from there. Not unlike Zeiss's Hassy FLE 50mm - where one manually sets the position of the floating element with a separate ring to the approximate distance ("Infinity-4m, 4m-1.2m, 1.2m-0.8m, 0.8m-0.5m") - and then uses the main focusing ring to actually focus. See image here: http://static.photo.net/attachments/classifieds/126/1268530-165721.jpg FLE ring at top - focus ring at bottom. Of course, there are lots of nice Leica M and R lenses that don't have floating elements anyway. The Contax N system came later, and did, as Geoff says, work like other AF SLRs - a motor moved a lightweight lens designed for AF. Link to post Share on other sites More sharing options...
stunsworth Posted September 28, 2011 Share #12 Posted September 28, 2011 Focusing sensor. Moves back and forth. Many, many problems. A dead end IMHO. How far would the sensor have to move to focus a 50mm lens from 1 metre to infinity, and how thick would the body need to be? As for longer lenses. the problem would be even worse. Link to post Share on other sites More sharing options...
hoppyman Posted September 28, 2011 Share #13 Posted September 28, 2011 About 5 or 6mm for the Summilux 50 ASPH and the Contax AX body of course was thicker to accomodate the moving sensor. I read 72mm. Still it might avoid the 1.21 gigawatt power source you might need to drive current M lenses to autofocus:eek: There's an awful lot of hypotheticals and improbables in this discussion! Link to post Share on other sites More sharing options...
luigi bertolotti Posted September 29, 2011 Share #14 Posted September 29, 2011 About 5 or 6mm for the Summilux 50 ASPH and the Contax AX body of course was thicker to accomodate the moving sensor. I read 72mm.Still it might avoid the 1.21 gigawatt power source you might need to drive current M lenses to autofocus:eek: There's an awful lot of hypotheticals and improbables in this discussion! True, and let's say that a "brutal" AF is out of typical "Leica way" ... if some manufacturer like Ricoh or Sony would one day make a camera which accepts M lenses and can A-focus with moving sensor or similar... I imagine the number of posts with heated comparisions like "my Summilux with AF on xxx and on M9 ... AH ! crop 100%... AH ! bokeh..." Link to post Share on other sites More sharing options...
AlanG Posted September 30, 2011 Share #15 Posted September 30, 2011 If a camera had an electronic shutter and phase detect on the sensor, such as the new Nikon N1 system, one would just need to move the sensor back and forth. This would be a fairly low mass and could move pretty quickly with minimal power. Consider if you set a 50mm lens at its closest focus position, the body would not have to be very thick for it to work. (The sensor could move forward to hit infinity.) As mentioned, longer lenses and floating element lenses may need to be roughly focused. One could also consider adding swing, tilt, rise, and fall to this mechanism. Link to post Share on other sites More sharing options...
jaapv Posted September 30, 2011 Share #16 Posted September 30, 2011 But it would not solve the problem of immobile floating elements Link to post Share on other sites More sharing options...
bill Posted September 30, 2011 Share #17 Posted September 30, 2011 I don't use shower gel in the bath I don't cut bread with a carving knife I don't try to drive my car across a river I don't wear tweed in the rain I don't expect my cat to work the remote I don't want my manual focus lenses made to autofocus A bodge is a bodge, however it is wrapped up. Regards, Bill Link to post Share on other sites More sharing options...
adan Posted September 30, 2011 Share #18 Posted September 30, 2011 But it would not solve the problem of immobile floating elements Correct. But only a tiny percentage of M-mount-compatible lenses out there have floating elements. Probably <1% counting adapted SM lenses, Canons, Nikkors, Zeisses, Voigtlanders - and even ALL of Leica's own M lenses produced prior to 2003. I don't want my manual focus lenses made to autofocus Nor do I. That's two opinions - now for the other 6,999,999,998. Link to post Share on other sites More sharing options...
jaapv Posted September 30, 2011 Share #19 Posted September 30, 2011 But a considerable percentage of my lenses has floating elements... Link to post Share on other sites More sharing options...
luigi bertolotti Posted September 30, 2011 Share #20 Posted September 30, 2011 Frankly said : if one day I feel the need to have AF... there are plenty of solutions to go, without involving my M lenses set.... to say, if (maybe, a vague thought of mine) I'd get a Nex 7 with a M adapter... well I'd consider to have also a kit zoom... is cheap, is AF... I'd much prefer this to some complicated way to have AF for my M lenses, that are not made for this, period. Link to post Share on other sites More sharing options...
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