does anyone know the reason why the m-lenses and actually all rangefinder lenses have the aperture ring in the front of the lens? does it have to with the non-retro-focus construction of rangefinder lenses? it is a bit confusing in the beginning, but easy to get used to.

-- stefan randlkofer (geesbert@yahoo.com), December 01, 2001

Answers

Most current M lenses have the diaphragms either at midships or just fore of the rearmost element. The placement of the aperture ring is not indicative of the exact location of the diaphragm. It is most likely an ergonomic consideration or at worst simply a convention which has carried on throught the system's evolution.

-- Jay (infinitydt@aol.com), December 01, 2001.

Since the focus ring moves the lens elements, and the diaphram is within the elements, the diaphram ring has to remain with the part of the lens that has the elements--the section ahead of the focus ring. . . unless you're making a lens with a complex linkage for auto- diaphram and metering, in which case you might put the diaphram ring anywhere you want, you're making so many extra pieces, anyway.

-- Michael Darnton (mdarnton@hotmail.com), December 01, 2001.

As I understand it, automatic diaphragm SLRs (i.e. all SLRs after 1970 or so) need to stop down after the shutter release is pressed. So it is advantageous for the aperture ring to be next to the body to effect the necessary mechanical linkage.

Rangefinders, on the other hand, need to communicate focusing distance information to the body (the rangefinder). So the focus ring is next to the body for the cams to engage.

-- Mani Sitaraman (bindumani@pacific.net.sg), December 01, 2001.

Simple... Because the focus ring is at the back! ;-)

-- Jack Flesher (jbflesher@msn.com), December 01, 2001.

I don't known why the aperture ring is in front, but after using Nikon and Contax lenses where the aperture ring is right up against the body, I much prefer the Leica approach. It justs feels natural to reach out to set aperture and back in to foucs with my left hand. It's a real plus for the system, in my view.

-- Dan Brown (brpatent@swbell.net), December 01, 2001.

With two control rings, you can have only two choices, either aperture ring at front, or at rear.

With zoom lenses, there are three rings, there will be more combinations available....

-- martin tai (martin.tai@capcanada.com), December 01, 2001.

Some historical perspective. The original screw-Leica had the focusing scale on the body (about as far back as you can go!) and the aperture on the front of the lens around the front element. Which set a "standard" of sorts. The Contax had the focusing helical built into the body for normal and wide lenses, and the aperture around (or later, NEAR) the front element, as well.

The very early SLRs (Contax S and Pentax) followed the 'standard' since that's what people were used to. So did the first line of Canon SLR lenses (FL).

Nikon moved the aperture ring to the back when they introduced the F, because they were already thinking about linking the aperture ring to a meter (remember the prong on the aperture ring?) and the meter would be on/in the body. If the aperture ring was at the front, the linkage would have to travel the whole length of the lens, and since Nikon's linkage was EXTERNAL, that would have meant shafts and rods on the outside of the lens (!!) Do-able - but WHY?

Canon followed suit in about 1970 with the FD lens line. Eventually all the 35mm SLR makers (including Leica and excepting Olympus, who were tring to make their SLR as 'M'-like as possible) did the same. Some 3rd party pre-set lenses kept the ring up front, too. (viz. my old Spiratone 28mm).

So basically the aperture atarted at the front and moved to the back only when SLR makers need to add metering connections - something that never affected the M.

-- Andy Piper (apidens@denver.infi.net), December 01, 2001.

Andy, not necessarily

My Zeiss Ikon Contaflex Super B is a automatic/manual SLR with meter coupling. It's aperture ring is IN FRONT OF focusing ring.

IMO, the following are similar questions

• Why some focusing ring turns clockwise, other turns counter clock wise ?
• Why some film cartridge load at the right, some loaded at the left ?
• Why some car has steering wheel at left, other at right ?

-- martin tai (martin.tai@capcanada.com), December 01, 2001.

Martin - I don't see the contradiction.

As I said, "Eventually all the 35mm SLR makers (including Leica and excepting Olympus, who were trying to make their SLR as 'M'-like as possible) did the same."

The last Zeiss Ikon cameras included the Icarex, which switched to Pentax screw-mount and a REAR aperture ring. So Zeiss, too, "EVENTUALLY ...did the same". Shortly thereafter Zeiss got out of making 35mm cameras altogether.

"So basically the aperture atarted at the front and moved to the back only when SLR makers NEEDED (emph. added) to add metering connections - something that never affected the M."

Zeiss apparently never felt the need, at least until the line was nearly dead anyway. Those companies that DID feel the need moved the location of the aperture ring - for rational, not arbitrary, reasons. Including the (sort of) resurrected Zeiss/Yashica/Contax SLRs.

Leica set a standard that lasted for 30 years, until the new technological needs of the SLR brought change - aperture ring in front, focus ring/scale at back. This was also not arbitrary - the aperture blades for the original f/3.5 lens were right behind the front element, so the front was the most logical and cost-effective place to put the aperture control. Once the rangefinder was added, it made even more sense, since, as Mani points out, the main lens/camera connection had to do with focusing, not aperture setting. A Leitz or Zeiss engineer of 1935 would have thought it nuts to worry about an aperture/camera connection (well, maybe there were a few visionaries...)

I just wanted to make Stefan aware that "aperture at the front" is how it all started. It's the SLRs (with a few duly noted exceptions) that have departed from that original standard - for logical engineering reasons of their own.

Leica S and M (and most other rangefinders) have never waivered.

-- Andy Piper (apidens@denver.infi.net), December 02, 2001.

andy- my zeiss ikon voigtländer icarex 35 s mb (what a name!)has a bayonet mount, aperture on the back. does that mean, they went back to pentax tm afterwards or is this a later model. mine comes in a good condition (~9) with zeiss 2.8/50 color pantar and a scoparex 3.4/35. does anyone know whether this is something special or valuable? it was kept in a ever ready case and has the original caps.

-- stefan randlkofer (geesbert@yahoo.com), December 02, 2001.

Stefan: A link to the screw-mount version of the Icarex. I don't really know the relative rarity of the different models of Zeiss/Ikon/ Voigtlander.

-- Andy Piper (apidens@denver.infi.net), December 02, 2001.

If you mount a summitar 50/2 on your screw-mount, you can see the f numbers in the viewfinder.

-- John Fleetwood (johnfleetwood@hotmail.com), December 02, 2001.

I think the Rollei made lenses for Rolleiflex 600x SLR and the Carl Zeiss lenses for Hasselblald 500c SLR have the aperture ring at front.

-- G. S. Ling (gsling@hotmail.com), December 03, 2001.

The camera designer can put the aperturing control anywhere they like. even outside of the lens barrel:

• On top of camera: Minox 110S
• On camera front, Rollei 35
• Even at bottom side of camera: Rollei 16S

-- martin tai (martin.tai@capcanada.com), December 03, 2001.

Some Schneider & Rodenstock lens for view camera have done away with aperture ring all together, for example Schneider Super Symar 120mm/f5.6, Rodenstock Apo Grandagon 45mm/f4.5 etc. These lenses have Rollei electronic shutter. The aperture and shutter is controlled via a Rollei LensControl unit, with LCD display.

-- martin tai (martin.tai@capcanada.com), December 05, 2001.