Archived posting to the Leica Users Group, 2006/12/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Frank, it would make no sense to limit flash sync to 1/250 sec if the shutter isn't providing the exposure timing. If the shutter were functioning only as a dust cover and the exposure duration were determined only by an electronic signal control a flash sync could be provided at 1/8000 sec. Of course there are contrarians on this list who might claim the 1/250 sec limit is another example of Leica's engineering incompetence when 1/8000 sec is possible. Doug Herr Birdman of Sacramento http://www.wildlightphoto.com On Dec 26, 2006, at 7:30 PM, Frank Filippone wrote: > OK.. I went there and read the following under M8 tech specs at the > Leica USA site.... > --------------------- > To quote....... > Shutter: > Micro-processor controlled metal-blade slotted shutter with vertical > movement. > Shutter Speeds > In automatic mode (A) steplessly from 32 s to 1/8000 s. Using manual > setting 4 s to 1/8000 s in half steps. > B for long exposures of any duration. > Shutter action optimized for minimum noise. Driven by an electric motor > -------------------- > Having read that, I will repeat that the shutter in the M8 is only for > a dust ( and overload) sensor cover. It does nothing for the > exposure. Let me explain..... > > The sensor is gated fully under electronic digital control. It has > nothing to do with a mechanical part anywhere in, round or under > the camera. It is both easier to do it this way, it works, it needs > no calibration, and it is cheap to make. It is totally > electronic. > > The shutter COVER, or what you might call a shutter, does not do > anything to the exposures. If it did, Leica would have to make an > infinitely variable shutter accurate to 1/8000 of a second, and keep > it in calibration. Ain't going to happen. Nikon proved that > in the 8008 and other cameras. > > I think it is important that users know what they are getting in an M8 > or other digital camera ... this mechanical shutter is > probably ( maybe, maybe not) timed to open and close in some > relationship with the exposure. It does not matter how long the > shutter is open; as long as it is long enough for an exposure to be > recorded. It can be a LOT longer the light is gated by a > digital signal, not a mechanical device. Very similar to the baffle > shutter in a Hasselblad 500 series. > > Notice carefully that Leica never claims that the shutter speed is > mechanical nor do they claim the shutter is timed for any time > duration... They claim the shutter is a vertically moving metal > blade slotted shutter. The shutter speeds are the ones that are > timed with specs on them. There is a big difference between the > shutter speeds that affect the exposure, and the shutter that only > covers the sensor. What I called a baffle. > > dPreview does not add any information. I am sure they are nice guys, > but technically, anyone that claims the reason a M8 can have > higher synch speed than a M7 is because of a different shutter is just > plain not correct. The synch is digitally controlled as are > the gating functions of the sensor. There is no mechanical > association in a M8. There is in any previous film oriented M ( or > LTM).. > > BTW, if you owned a M8, you could easily prove me wrong.... Try the > shutter at different speeds with no lens. You should see the > light baffle open and close faster with increasing speed, like a real > shutter does. You do not have to be 100% accurate, you only > need to note if the thing stays open longer with increasing exposure > time.... It should be pretty obvious. > > If there is some evidence that the M8 has a mechanically timed > exposure, I still have not seen it......If you, or someone else on > this list, own a M8, check out the shutter /baffle/ whatever you want > to call the thing that moves out of the way to allow the > light to hit the sensor. Then we have some form of data that is not > marketing speak..... > > I would promise to eat a bug if I am wrong, but Cal Worthington has > already done that one..... > > Frank Filippone > red735i@earthlink.net > > > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > >