DR Summicron, how does it work?

[rover]

Is it RF coupled in the close range?
How?
When you move to the close range does the coupling roller (I think that is how they couple) shift out to fool the camera into thinking that there is still room to focus closer?
I know how the lens is operated, but don't understand how it works. 😕

 

[SolaresLarrave]

According to the directions on my M3, the lens is pulled out (slightly) so that the focusing ring goes to the other side of the focusing mark. Then you put on the goggles... and I think that's how's done.

As for the RF roller going any further... I guess that's what happens.

In any case, I don't think I answered your question, so now we're two people expecting a reply! 🙂

 

[phototone]

The Dual-Range Summicron works like this.

For normal use, you mount it and use it just like any normal Summicron. To take closer-up shots, you turn the focusing ring to its closest focusing distance where it hits a stop. You then pull the ring towards the front of the lens, until the stop clears and you can rotate beyond the stop, you release the ring, and then mount the close focusing goggles on the lens, these cover the viewfinder and rangefinder windows, and re-align them to show the correct view in the close-focusing range. Yes the rangefinder couples, as the coupling cam is stepped, and kind-of reverts back towards infinity, and the compensation for this is in the goggles, which re-position the focusing patch to compensate for the closer distance. You can only focus close with the goggles on, and you can only focus the normal range with the goggles off. Foolproof. The close range is parallex corrected. But......it is not "close" in the same sense that a "macro" lens on a SLR is close. I think the closest distance with the goggles on is 19 inches.

 

[laptoprob]

Completely correct, Phototone.
The effect in the camera is that the second (close) focusing cam pushes the focusing system just like the fitst cam. No further.
What changes is the distance of the lenshead to the camera. At infinity any cam of every lens is flush with the lens bayonet mount, at 3/4 ft. the cam of a 50mm lens is about 2mm into the camera. In close focus this is the same.
However, since the two cams are one piece of brass, the second cam (the second half of the circle) is 3,4mm further into the camera. That is corrected by pulling the lens out: at 30"close folusing range the camera is fooled to think the lens is again at infinity. The goggles correct this, as well as parallax.
All this means the DR can't be used on a CLE due to the internal light meter.

My DR is still for sale: http://www.rangefinderforum.com/forums/showthread.php?t=6081
I don't know how to make one of those nifty shortcuts in text...

Rob

 

[rover]

Gentlemen, thank you very much for your answers, and Rob, believe me, I know about your DR, haven't stopped thinking about it since I saw it. 😉

 

[Kris]

Another GAS attack Ralph? Are you going to collect all types of Summicrons?

😀

 

[rover]

My GAS has been out of control lately Kris. Here is my 50mm collection

Canon 50/1.2
Canon 50/1.4 (to be picked up next week)
Canon 50/1.5 (sweet little lens)
Canon 50/1.8
Jupiter 8
Leitz 50/2 Summicron, tabbed type 3 (very very nice lens)
Leitz 50/2 Summicron, collapsible (and asking for an M3)

I am thinking that with a Rigid or DR my collection will be complete (that is sooooo sad🙁).
And of course I have not yet shot them all (sadder) but I have time, I plan on being around for a while.

 

[Doug]

All this means the DR can't be used on a CLE due to the internal light meter.

Hi Rob, thanks for the explanation, but could you clarify the above? There is surely no physical interference with the CLE meter, which is located in the camera floor and reads off the shutter/film. Certainly the CL meter might physically interfere, as its cell is on a stalk like the M5. If it's just that the lens partly occludes the shutter from the view of the CLE's meter cell, then this is inconvenient but doesn't make the lens unusable if you use manual shutter speeds.

But the (focused) closeup range of the DR Summicron is unusable on the CLE because the goggles don't line up with the CLE's viewfinder and RF windows, correct? 🙂

 

[laptoprob]

Hi Doug,
ofcourse the close-up goggles do not match the CLE. Problem is however the close focusing cam extends further into the body of the camera. My M2 is almost empty until the shutter curtain, the CLE has its meter sitting in the lower part of the camera.
The normal focusing cam is in the top part of the camera, the other, close focus, cam is in the lower half. The normal cam just misses the internal meter, ofcourse. The close focus cam hits it frontally.
Makes sense?
I got a regular rigid, that's why my DR is for sale.

Rob.

 

[Doug]

Interesing! Wouldn't have thought there could be any interference... thanks!