Archived posting to the Leica Users Group, 2005/06/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks for the info. It all makes pretty good sense. Frank On Jun 7, 2005, at 2:31 PM, R. Clayton McKee wrote: > On 7 Jun 2005 at 12:35, Frank F. Farmer wrote: > >> 1) Cameras like the M4-P have hot shoes, but no batteries to speak of. >> How does such a camera trigger the electrical contact on the hot >> shoe? >> >> 2) Why was this changed on the M6TTL? Does it have to do with the TTL >> flash meter? >> >> 3) Will a "classic" M6 w/out a battery trigger a flash in its hot >> shoe? > > > For a nondedicated, single-pole flash unit like a 283, all the camera > has to do to fire the flash is close the circuit between the two > contacts on the shoe. It's a timing issue, no more. That's easy to > do with a mechanical switch. (4Ps and before had multiple pc sockets > because the timing lag for a bulb flash is different from that for > electronic flash. By the time the 6 was coming out, bulb flash was > mostly extinct so there was no need for the M sync. A handful of the > very last 4P run had m6 top plates and rangefinders, and theydidn't > have the M-sync either. 85 or 86 production here.) > > When you go into TTL or even AE flash, you've got electronic control > data being passed back and forth between the processors. That's a > whole other set of issues... I'm guessing even the main circuit on > the M6TTL is electronically operated, just for the sake of design > simplicity. > > The classic M6 has a single-contact hotshoe, as I recall; I'd bet > lots of your money that it's mechanically triggered as well. I don't > have any convenient way to test that, though... both my bodies are > 4P's. > > > -- > > > R. Clayton McKee www.rcmckee.com > Photojournalist rcmckee@rcmckee.com > P O Box 571900 voice/fax 713/783-3502 > Houston, TX 77257-1900 dig pager 281/510-3588 > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >