The problem is with the terminology. It is spoken of as delay, because the shutter is tripped and a gear train delays the firing of the bulb until the right point. But that point is before fully open. M bulbs are normally fired 20ms before the shutter is fully open, F bulbs 5ms. So it is actually lead time, but spoken of as delay. Confusing isn't it?
-- graywolf http://www.graywolfphoto.com http://webpages.charter.net/graywolf "Idiot Proof" <==> "Expert Proof" ----------------------------------- William Robb wrote: > ----- Original Message ----- > From: "mike wilson" > Subject: Re: A few questions on a Zeiss Ikon,an old film and a studio > lighting peace > > >>> From: Paul Sorenson <[EMAIL PROTECTED]> > >>> Subject: Re: A few questions on a Zeiss Ikon, an old film and a >>> studio lighting >>> peace >>> >>> 1) The "F" and "M" are to match the shutter timing to the peak >>> output >>> of flashbulbs. "F" bulbs peak 5 milliseconds after ignition, while >>> "M" >>> bulbs peak at 20 milliseconds. Each is of a relatively short >>> duration, >>> but not as short as electronic flash. "FP" (focal plane)bulbs are a >>> horse of another color as they peak after about 5ms, but have a long >>> duration so a focal plane shutter can be used at higher speeds. >> I don't think it can be "peak", as that point will vary from bulb to >> bulb. It's start - the bulbs need more time to get lit and start >> outputting light, so they have more lead time. Electronic flash fires >> much quicker and can be started once the shutter is open. >> > > Paul is correct on this one. > > William Robb > > > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
