Accurate Timing of Long Exposures

[Rob Tucher]

YEARS ago Popular Photography had an article on how to make a tiny electronic metronome. It is a list of parts put together in a certain configuration inside a tiny parts box that Radio Shack sells (1/2"x3"x1-1/2") with an earplug plugged in. I made one. I put the device in my shirt pocket or elsewhere, the plug in my ear, and turn it on. It clicks every 1 second. I started and stopped exposures on the count and it was very accurate. Unfortunately it got smashed and I don't have the article anymore. But something like this might be available, or you might find the article in an archive.

[chris jordan]

i've been doing exclusively night photography for years, frequently exposing in the 2-3 hour range, and never shorter than about 4 minutes. i had my view camera for something like 3 years before i finally used one of the shutter speeds on my shutter! unfortuantely i frequently forget to bring a watch with me, and consequently end up making wild guesses on exposures. once i had an exposure that required 18 minutes (including reciprocity failure) and i had forgotten my watch so i just stood there and counted "one thousand one, one thousand two..." for 18 minutes. just to be sure, i bracketed one at 40 minutes, which i didn't count-- just hung out for about 40 minutes and clicked the shutter closed. and i gotback two transparencies, both spot-on, that look like they're exposed about 1/4 of a stop apart! ~cj

[Sean Billy Bob Boy yates]

Anybody know how fast the sun moves? I'm assuming there's someway to gigure out how much time has passed by the change in shadows, but of course that'd be a function of time of year, lattitude, etc. and of course you couldn't do it on a cloudy day or in Greenland in winter,etc.............

[Yong-ran Zhu]

I have bought a Prontor cable release made in Germany (Schneider Optics) from Jeff at Badger Graphics (Tel. 920-766-9332). It is a great tool for precise long exposure. It is expensive. However, if you will use long exposure a lot for your photography, you will be very happy to have it.

[Struan Gray]

Dan, you're making things too compicated. Why do you think the VCR manufacturers put that blinking "12:00" on the front, if not for the use of large format photographers? You can save yourself a lot of weight by discarding the tape and just counting blinks.

If you're hiking a long way from the road you can even dispense with the power supply. Simply throw the VCR into the air so that it rises four feet above the point you release it. Catch it again at the same point on the way down and exactly one second will have passed - repeat as needed. Senior photographers who lack the stamina or dexterity for this technique can always tie a one meter length of string to the VCR and use it as a pendulum bob, but local gravitational anomalies can make this less accurate.

[Robert Opheim]

I have used my watch - but after several minutes - sometimes I forget where I started from (it comes with time) So I replaced it with a stop watch. One more thing not to go wrong. Often exposures are several seconds to twenty minutes or more. The stop watch is small -

[Doremus Scudder]

Good grief, Charlie Brown!

Long exposures are easy! Any Sousa march runs along at 120 beats per second. So do a lot of pop songs. Find one you like, play it in your head and count, "one anna two anna three..." You'll be within a small percentage every time.

I just counted off 5 minutes (300 seconds) for the fun of it and was only 3 seconds off at the end.

You don't need watches, metronomes, apps or the like; use your head.

Best,

Doremus

[Cletus]

Seems like the more pertinent issue here is reciprocity characteristic of your particular film, rather than how consistently you say elephant, Anna, one-thousand, etc.. I'd have to check my little reciprocity calculator for HP5, but it's pretty easy to get exposure recommendations well into the minutes - and longer - when shooting with smallish apertures in low light or at night.

Anymore now I just guess (estimate) exposure times over about 5 seconds or so and use my wristwatch for timing. A little experience goes a long way and I pretty much always get usable negatives these days. I.e. Meter gives an EV of 3 or 4 or something, which is...let's say 16 secs @ F22. I'll open the shutter for about 2 to 4 minutes under these circumstances (or refer to my HP5 reciprocity calculator on my iPhone) but I rarely get an unusable negative. Close enough is usually close enough for long exposures, with my film anyway.

[Jody_S]

Some excellent suggestions earlier in this thread, I may have to try some of them. I particularly like the idea of bringing a portable power pack, VCR, and tv into the field. I wouldn't necessarily use the Rodney King tape, I think counting murders in a Tarrantino movie could do as well for longish exposures.

[David Lobato]

Earlier this year I did an 8x10 project that started before dawn. I used my iPhone timer, worked perfectly, and it's lit up too. I wedged it under the bellows for hands free operation. You can choose between stop watch or timer modes.