Long exposure device for Bulb setting?

[Pyrogallol]

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Just count the seconds yourself, no need to be too accurate.

[ianman]

4 minutes ago, OThomas said:

There is it’s called a calculator 😉

Cheeky b.... 

You found what I meant, as sort of Massive Dev Chart for reciprocity.

[Pyrogallol]

Here’s an example from a week or so ago.

M2 with 50mm Summicron, about 8-10 seconds at f11 on tripod, Ilford Pan F in Perceptol, copy of a darkroom print. I know my counted seconds are a bit long but the negatives came out ok. On a longer exposure a little extra exposure won’t do any harm.

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[250swb]

If for example you have a meter reading of 2 seconds with FP4 (all films have their own reciprocity curve but there is a general fudge zone within the one to four second range, you just double it) press your cable release and count slowly one elephant, two elephant, three elephant, four elephant, and you will be ok, you have just taken into account reciprocity. Some people use Mississippi instead of elephant, it depends how you were taught or what you prefer. Reciprocity increases as the exposure get longer, so for a ten second reading you may need an exposure of thirty seconds, depending on the film.

[adan]

10 hours ago, rjsphd said:

Did anyone ever make a mechanical timer to use with the Bulb setting to get accurate long exposures?

I think it is a certainty that someone, somewhere, over the past 150 years, came up with such a device. More than once.

Not what you want, but there were certainly a lot of accessory mechanical time-delay devices ("self-timers") made, with or without a cable, for cameras that didn't have their own built-in self-timer for self-portraits. Not a big leap at all to rearrange the connection to the camera, and the clockwork, so that it times the shutter-open time, instead of the seconds-to-get-in-front-of-the-camera time.

Leitz HEBOO

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In their heyday, the "magic shops" of the major photo magazines (LIFE, LOOK, Picture Post, Nat. Geo.,etc.) no doubt built one-offs or handfuls of such mechanical long-exposure timers in-house for their staff photographers. And no doubt many hobbyists with a mechanical bent made their own also.

And I expect someone at least tried to market commercial versions.

(See Gjon Mili, a genius of tech wizardry photos for LIFE in the mid-century - lots of flash innovations, but also lots of time exposures: https://www.icp.org/browse/archive/constituents/gjon-mili?all/all/all/all/0 )

The only question is whether they still exist, and whether they can be tracked down in the bowels of older camera stores or antique/thrift shops.

I'll bet MIT's library may have bound hard copies of old photo magazines from the 1930s-1970s, that may have adverts for such things (my old state university in Illinois still does. ) Those might show what existed, and give you some specific names or brands to seek out.