I looked at the shutters on the Packard site and am either partially confused or thoroughly not entirely sure about how they work. It SEEMS that one can get either B or T type timed (#5) or that plus instantaneous (1/125 s) exposure (#6) but not the usual Copal type speed variety? Nice that they go up to 8" indiameter - I guess one could machine adapters to fit most barrel lenses? What is the Syncro shutter?
Thanks for any help!
When I was 16 I thought my father the stupidest man in the world; when I reached 21, I was astounded by how much he had learned in just 5 years!
-appropriated from Mark Twain
The "Synchro" is a trigger switch to fire electronic flash when the shutter opens.
Richard, I believe that the instantaneous speed on the Packard is 1/25 second. These are really great shutters once you get the hang of them; especially so if you have a collection of barrel lenses!
Another option, if you can find one, is the Luc shutter, although smaller than the Packards. I used a Packard on my 8x10 Agfa/Ansco 8x10 with good results.
Richard, a page here on my site may answer some of your questions about Packard shutters. I do the bulk of my whatever-it-is with Packards.
The speed of the Packard at "Instantaneous" depends on the shutter size, the bigger the slower, as well as condition factors.
Originally Posted by Ernest Purdum
Which brings up a question I asked before, but never got a responce on. And that is, with the shutters such as the Packard or more particularily, the sinar, used as a shutter only,no f stop management, how can the rated speed be the same for lenses of varying back lens diameter.
If you have a 4 inch Packard hole mounted behind the lens, as an example, and use varying lenses with it, say, for example a lens with a 4 inch rear diameter and a lens with a 2 inch rear diameter, can the same speed pass the same amount of light for both lenses.
Won't the larger lens be at wideopen shutter for a briefer period of time?
Won't the smaller lens be open functionally for a longer period of time than if a 2 inch shutter was used?
Regards
Bill
"Won't the larger lens be at wideopen shutter for a briefer period of time?
Won't the smaller lens be open functionally for a longer period of time than if a 2 inch shutter was used?"
Yes and yes, BUT the timing difference should not equal 1/3 stop of exposure. In practice it's really not a bother.
[QUOTE=cowanw;646407 Won't the smaller lens be open functionally for a longer period of time than if a 2 inch shutter was used?
Regards
Bill[/QUOTE]
That's very true and the same is true when you change aperture settings of an interlens shutter like a Copal. As Paul indicated, it's one of the several rather small inaccuracies we mostly just live with.
Last edited by Ernest Purdum; 8-Nov-2010 at 18:04. Reason: I don't know how to properly select a quote.
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