Archived posting to the Leica Users Group, 2015/11/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]An excellent description of the mechanism.... and especially the variants. Yes, rather difficult to implement.... especially if you wanted to be 100% compliant with all lenses of any age........ Frank Filippone Red735i at verizon.net The Leicaflex (original) used a sloped cam outwardly similar to an M lens' focussing cam. The body's axial cam follower (at the top of the mirror box) read this cam as actual lens aperture (for the non-TTL meter, much like the Nikon F rabbit ears). The Leicaflex SL and SL2 use a second sloped cam, similar to the first but at the bottom of the mirror box, that indicated aperture relative to full aperture for TTL metering (like auto-indexed rabbit ears or Nikon's AI tab). The R cam (R3 onward) a.k.a. 3rd cam used a rotational cam that indicated both actual aperture and aperture relative to maximum. It would be messy to sort these out in an adapter. Doug Herr > >One word answer..... No. > >The easy part is the auto aperture.... which is a simple linear >actuator requirement. The hard part will be the transfer of set >aperture to the body. >I have forgotten ( if I even ever knew) how the Leicaflex transferred >Aperture information to the body, but I do not think it was >electrical... I think it was a mechanical linkage.... >That could be done with a pretty simple resistive element..... If this >were implemented, it would mean Aperture Priority only..... ( metering >system adjusts shutter speed to get proper exposures) > >Again, my Analog Circuit Design background allows me to think of >this... it does not mean Leica agrees..... > >Frank Filippone >Red735i at verizon.net > > > >Is there any technical reason why this is difficult (Auto Exposure >feature for R lenses)? Nikon DSLR AF lenses work fine on the Nikon 1 >mirrorless systems, with both AF and AE (most features) enabled via an adapter. >Cheers >Jayanand > >On Tue, Nov 3, 2015 at 5:37 AM, Frank Filippone <red735i at verizon.net> wrote: >> If it were as easy as a simple tube, which is the adapter without the >> auto feature, there is no reason that it would not have been >> available now. It is so trivial, that the Chinese copy cats have >> probably already >done it..... >> ( somewhat tongue in cheek.)... Checking after I wrote that, I found >> that Novoflex has the adapter ( dumb, no auto feature), called the >> LET/LER. So you can use your R lenses on your SL body, as soon as >> they >ship them..... >> >> That is the primary reason I think that it will the Auto feaqture..... >> that it is taking a year to come out..... >> >> I have no real info, nor am I on the inside track at Leica..... I am >> purely speculating... >> >> But if it did have the Auto feature, it would be the single most >> brilliant implementation Leica has had since the LTM to M adapters..... >about 1953. >> >> Frank Filippone >> Red735i at verizon.net >> >> >> >> Actually I was told by a Leica rep at PhotoExpo that the R adapter >> would not have an auto stop down mechanism. Of course he could be >> wrong, or they might reconsider.... >> >> On Mon, Nov 2, 2015 at 6:01 PM, Frank Filippone <red735i at verizon.net> >wrote: >> >>> There is no published information that the R to TL adapter has or >>> has not the auto stop down abilities. >>> >>> The R to M adapter plus the M to TL adapter, which they now >>> recommend until the one piece adapter becomes available, does not. >>> >>> Frank Filippone >>> Red735i at verizon.net >>> >>> The facht that the R adapter tube does not stop down R lenses seems >>> a problem to me, however perfect this camera would be. >>> >>> >>> Cedric Agie >>> Brussels