How difficult could it be to design and fabricate a horizontal cloth focal plane type shutter that reaches speeds of 1/2000 second or greater when Hasselblad can do one for medium format?

-- chris chen (chrischen@msn.com), January 25, 2002

Answers

Not to be argumentative :) but why does the question of 1/2000 over 1/1000 crop up so often. I very rarely shoot over 1/500 and have never felt the need for 1/2000. IMO the M shutter speed range is well balanced and suits it's ideal type of use perfectly.

And as most M's at 1/1000 give around 1/700 you may only end up with 1/1500 from your 1/2000!

-- Giles Poilu (giles@monpoilu.icom43.net), January 25, 2002.

Giles - I suppose if you're shooting 100ASA in bright daylight, 1/2000 would get you down to f/4, which would reduce the depth of field on a wide angle lens a bit. 1/4000 would be even better!

As to the engineering side of it, I don't know.

-- rob (rob@robertappleby.com), January 25, 2002.

I'm an engineer, and many previous posts mention the physical impossibility of achieving such a "high" (low) speed. Given the size of a Hasselblad shutter, I see no physical reason why Leica cannot produce such a shutter relatively cheaply (diff. springs/governor). FWIW, I would use 1/1000, 1/2000 FAR more than B and 1 sec.

-- chris chen (chrischen@msn.com), January 25, 2002.

The Leicaflex had it already in 1964.

-- Frederik Boone (frederik.boone@harol.be), January 25, 2002.

The M shutter has probably been unchanged since the M3 (about 50 years ago) and I suspect it's very close to LTM Leicas. There is such a mystique about the shutter and its noise that I can understand Leica's reluctance to change it: A lot of Leica fans are still raging at the fact the changed the all metal rewind arm of the M3 to an arm with the plastic swiveling head with the M4... I don't even want to imagine the reaction of these hard core fans if they touched the shutter mechanism.

Leica has to do a tightrope balancing act between satisfying a large very conservative crowd of old fans and integrating new technologies. Decisions they make on this matter are more based on intuition than science: Sometimes they get it right sometimes they get it wrong.

This being said I would appreciate to have 1/2000th speed (I sometimes shoot at the limit 1/1000 and F16 when using fast films) and more importantly I would love to be able to have a higher flash sync. speed for flash filled pictures. If I really could not live without these features I would switch camera though (SLR, Hexar RF?).

-- Xavier C. (xcolmant@powerir.com), January 25, 2002.

Well, they could probably do it. It can be done by reducing the slit width. The shutter wouldn't necessarily have to move any faster. But at 1/1000, there is already a non-uniformity of exposure across the frame. At 1/2000, it might be worse.

-- Bob Fleischman (RFXMAIL@prodigy.net), January 25, 2002.

As already mentioned, both my SL and SL/2 have a top speed of 1/2000. I never use it for the same reason I never used 1/1000 on my M3...it won't be accurate enough with Kodachrome 25. I supposed I could have had DAG tell me what the real shutter speed was but I never needed it anyway.

I read that the M6 has lighter curtains and that the curtains are screwed to the drum rather than glued. This should provide a more accurate top speed than on older M's.

-- Bud (budcook@attglobal.net), January 25, 2002.

First of all if your M6 only reaches 1/700 at the 1/1000 setting it's because that's how it was set. Mine both hit 1/1000 (with the usual variance being about 1/900-1/1100) because I adjusted them myself. If you make it clear to whoever is servicing that you want it set up as close to 1000 as possible, there's no reason you shouldn't get it. Furthermore the shutter can be adjusted to reach 1/2000 as well, however since 500 and 1000 are tied together, you'd end up with a jump from 250-1000-2000 with 500 missing, and of course the meter wouldn't know you'd fooled with the speeds. A separate issue is the evenness of curtain travel. If you check an M shutter no matter how well it has been adjusted, there is nominally about a 2/3-stop variation from far left to far right at 1/1000. It's not a linear variation (fortunately), most of it occurs in the 1st and last couple mm (when the curtain starts and stops), with the majority of the frame exposed evenly. In practice the most noticeable areas are usually cropped out by a slide mount or in printing.

-- Jay (infinitydt@aol.com), January 25, 2002.

I wouldn't imagine it to be too difficult, considering Zeiss Ikon was able to achieve a top speed of 1/1250 back in 1936. As Charles Lennox posted in this old thread back in 2001:

"CONTAX - LEICA comparing shutter accuracy on the "CLASSICS" as a year's project - M3 and earlier VS same units produced by Contax, over same time frame: I have tested shutter accuracy on these old clunkers, involving 23 Leica and 28 Contax and the results are a story of remarkable inconsistancy! In general ALL of the Leica units, ranging from Superfine ++++ condition to just working, had a MEAN shutter differential of 47% against the cameras settings, on the SLOW side while on a similar batch of Contax units the measurements are very much superior, producing a MEAN differential of only 18% - the ancient Leica shutter design of processed fabric are from the stone ages, at best incapable of precision lasting into the 70 - 45 years that have passed since they came out of the factory. The Contax units, with metal shutter blades fared much better."

-- Chris Chen (Washington, DC) (furcafe@NOSPAMcris.com), January 25, 2002.

yes, the contax gave an accurate 1/1250 in 1937, and the univex mercury hit 1/1500 accurately in 1941. but they both did it by locking the two curtains together during travel, effectively eliminating the fade and timing problems that tend to be exacerbated at very narrow slit widths (the mercury also boosted the travel speed and only had an 18mm trip to make). it's not as easy to do with separately triggered curtains traveling 36mm.

:)=

-- Rick Oleson (rick_oleson@yahoo.com), January 25, 2002.

Thanks for the clarification, Rick. Would it be too hard for Leica to switch to a vertically-traveling shutter design (I wonder what the rumored M7 uses)?

-- Chris Chen (Washington, DC) (furcafe@NOSPAMcris.com), January 25, 2002.

Chris: RE vertical shutter - have you seen pictures of vertical shutter mechanisms? They often appear in camera brochures (possibly hard to come by in Krasno...).

Vertical shutters are very square in layout - there is the 35mm frame area, and then areas above and below the opening for the blades to 'hide' before and after exposure. (Think of a slide mount shape).

The Leica-M shutter, and the space available for it, is extremely horizontal, with space left on the SIDES for the shutter rollers - the space above and below the shutter opening are taken up with flash sync connections and other stuff.

To switch to a vertical shutter would mean a full-scale redesign of the body - and probably the rangefinder - and far less parts compatability with the M3/4/5/6. Konica, V'lander, and Contax have done it, but they were starting from a clean piece of paper and no doubt designed their RFs around a vertical shutter to begin with.

Re: 1/2000th in a horizontal shutter - as pointed out, the Leicaflexes have this (also Canon F1, Nikon F2/3, with metal foil 'sted cloth). My SL has a sync speed of 1/90 or 1/100, so the way Leica did it was to roughly double the curtain travel speed while keeping the minimum slit width about the same as the M. I forget the exact equations of physics, (let's see, force = mass x acceleration) but stopping a curtain travelling twice the speed would involve at least twice the 'shock' or camera shake - and noise - and there maybe a exponential in there some place. I.E. a noisier, shakier camera. I guess Leica figures its franchise is for quiet and smooth, not fast and furious.

My math tells me that the slit width for a 1/1000th second (Leica-M shutter) should be about 1.8mm - for 1/2000th this would reduce to 0.9mm. For 1/4000th - 0.45mm. A pretty skinny gap to keep consistant with clockwork.

I don't think anyone ever produce a regular production horizontal shutter with speeds above 1/2000.

RE: "I can't imagine why anyone would want a shutter speed faster than 1/1000"

I found the 1/2000 and 1/4000 settings the most useful things about my late Konica RF - it allowed me far more leeway with the aperture to soften backgrounds or use the 'peak' f/stop for sharpness (usually f/4 or f/5.6).

-- Andy Piper (apidens@denver.infi.net), January 25, 2002.

Andy: Actually, I'm the other Chris Chen, not the 1 who posted the question, & I have seen pictures of vertical shutters. But you're right--Leica is stuck w/a legacy mechanism. I guess I didn't think about Leica's need to share parts w/the rest of the M series (& TM Leicas, too!).

-- Chris Chen (Washington, DC) (furcafe@NOSPAMcris.com), January 25, 2002.

Whoops...Sorry Chris (D.C.) (Note to self: READ logons before answering posts!) Many manufacturers do stock multiple shutter versions - I just suspect Leica is too small a company to want to handle that extra cost.

Plus I think the rubber/cloth curtains probably help suppress shutter noise some, as well as the 1/1000 limitation.

Both reasons probably have some impact on why they're also using the same basic design for the M7 - even though, if they wanted an electronic shutter, it would have been miles cheaper to buy an off-the- shelf model from Seiko/Copal, instead of R&Ding a whole new design just to fit their current 'box'.

-- Andy Piper (apidens@denver.infi.net), January 25, 2002.

I think 1/2000 VS 1/1000 is more a marketing decision

A M8 with 1/2000 speed may creat a two tier M, the M with 1/2000 shutter and the "inferior" M6.M5,M4..."

There shall be a yahoo group dedicated only to M with 1/2000 sec etc,etc

Any M6 to see the M6 sudden drop in value and becomes second class ?

-- martin tai (martin.tai@capcanada.com), January 28, 2002.

I have read that the problem with higher shutter speeds is twofold, ie there are essentially 2 ways to get a higher speed and both introduce problems. The first method is to reduce the width of the gap between front and rear shutters. However, if the gap is too small you begin to get diffraction, the same as when you stop down to a very small appeture and of course this will reduce image quality. The second means is to increase shutter traverse speed and this is difficult to achieve with cloth blinds. ( Most if not all higher speed shutters I am familiar with use vertical travelling metal shutters - not sure about the few older SLR cameras which had high shutter speeds such as the Canonflex, but even the Contax rangefinder had a vertical travelling metal shutter.) Not sure where I read this, but for what it's worth it may give a good reason why Leica do not do it.

-- Peter (Peterm1@ozemail.com.au), January 28, 2002.

4000,4000,4000,4000 konica hexar rf

-- richard b (rubyvalentine@earthlink.net), January 28, 2002.