That's not entirely true the width of the slit depends on the timing between the release of the first and the release of the second curtain. There could there could easily be problems with calibrating that in a mechanical system.
At 03:10 PM 1/18/2002 -0500, you wrote: >Focal plane shutters depend on two things for their higher speeds. 1. The >maximum speed of the curtain. That is also the highest flash sync speed. 2. >The width of the slit. At speeds above the highest sync speed the second >curtain is released before the first is fully open, as the delay is reduced >the effective shutter speed goes up. > >So, with a focal plane shutter the highest speed should be every bit as >accurate as the highest sync speed. > >The inaccurateness of higher speeds is from leaf shutter mythology. I say >mythology because there is a variation of efficiency that has to be taken >into consideration when measuring the highest speeds. Many people who >checked their shutters didn't realize that and concluded that the speed was >not as high as marked. In fact except for lost of tension on very old >shutters every leaf shutter that I have tested was pretty accurate at the >highest speed when the compensation for efficiency was factored in. > >Ciao, >graywolf >[EMAIL PROTECTED] > > > >----- Original Message ----- >From: Frantisek Vlcek <[EMAIL PROTECTED]> >To: David A. Mann <[EMAIL PROTECTED]> >Sent: Friday, January 18, 2002 4:22 AM >Subject: Re: Is SMC 55/2 K the best Pentax standard lens? (and 28mm ?) > > > > > > I heard that most manual shutters can't get precise enough in the > > super high speeds. That Nikon FM2's shutter isn't much precise in the > > 1/4000, really like 1/3000 or so. Makes sense. That's why electronic > > shutters are for. >- >This message is from the Pentax-Discuss Mail List. To unsubscribe, >go to http://www.pdml.net and follow the directions. Don't forget to >visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
