Accurate Timing of Long Exposures

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When shooting in low light conditions with slow film at small apertures, exposure times can easily exceed one second in many cases. Does anyone know of an effective method for accurately timing exposures that exceed one second? I am using Copal #0 and #1 shutters with a cable release. I have tried counting "one-thousand and one, one thousand and two..., etc) in my head while the shutter was open, which is not a very consistant methodology, as an error of 1/4 second on a two second exposure is significant. I've also tried cocking and firing the shutter twice at one second exposures each, but that introduces the possibility of moving the camera between exposures. Any ideas?

-- Richard Weber (rweber37@home.com), March 17, 2001

Answers

I just time my long exposures with my wristwatch, a Timex of the digital variety. With shorter exposures, I'll just watch the seconds count off until the proper exposure has been reached and hit the shutter release a 2nd time (shutter speed set on T). For long exposures, generally anything exceeding 30 seconds or so, I'll just use the stopwatch function on my watch so I don't have to remember when I started counting. In low light when it's hard to see the face of the watch, just hit the little Indiglo button. I'm sure there are other ways of timing long exposures, but this has worked well for me as long as I've been doing photography.

-- David Munson (orthoptera@juno.com), March 17, 2001.

Richard, you might try counting elephants. "One elephant, two elephants, three elephants," etc. If you are shooting neg film and are worried about inconsistencies, just make sure your error is on the overexposure side. A 1/4 second error on the overexposure side of 2 secs is negligible. Like has already been mentioned, a wrist watch is a good tool to use especially if yours has a timer that beeps. Some meters have a timing device function. My Sekonic 518 does. If exposures get really long, exposure accuracies become less important. If an exposure is, say, several minutes long, a 15 second error won't be all that bad. When I am working in the studio, I often have to make exposures of 15 to 30 minutes. I always bracket by making two exposures, one is twice the time of the other. With exposures that long, it can be difficult to tell the difference between the 15 minute neg and the 30 min neg.

-- Ken Burns (kenburns@twave.net), March 17, 2001.

Try using a metronome (an electronic one that doesn't have to rest on a level surface). Set it to 120 and subdivide each beat into two or four. Figure out how many half seconds the exposure should be, and once you've got the rhythm, press the release. Musicians do this all the time and manage to be quite precise (on the order of thousandths of a second).

-- David Goldfarb (dgoldfarb@barnard.edu), March 17, 2001.

When I shooting chromes in the last studio I worked for, exposures run 30 seconds plus on a regular basis. We used quartz digital and mechanical stop watches purchased at the local hardware store, etc.

-- Sean yates (yatescats@yahoo.com), March 17, 2001.

I suppose I should have also mentioned in my original posting that I am shooting large format landscapes, so metronomes and the like are a little impractical. The timing issue is generally most critical with exposures between 2-5 seconds, where the "human factor" of inaccuracy is most significant. I suppose without having some widget that would depress the cable release for a pre-set time (yippee! another widget to drag along with me!), the "human factor" will be unavoidable.

-- Richard Weber (rweber37@home.com), March 17, 2001.


Richard,

Prontor makes an interesting gizzmo which has a timer (2-32 sec) attached to a cable release. Linhof sells it for about $625, but you can find a used one for about $25. It should help you with your long timing exposure. Cheers,

-- Geoffrey Chen (db45tek@aol.com), March 17, 2001.


Hi Richard, if you are shooting B&W I don't think it has to be all that accurate. In the past shooting at night and at dusk or dawn, If I metered a couple of secs, I'd think, OK somewhere between 2 and 4 sec, maybe shoot one around 2 1/2 to 3 1/2. It might be more critical the amount you cut back on your development so you don't block out details. Seems in the 2-5 bracket half sec more or less didn't seem to me to make much difference, but then again maybe I'm wrong. I don't think I'd opt for the two exposure method, I'd be worried about something moving. Best, David

-- david clark (doclark@yorku.ca), March 17, 2001.

Radio shack makes a small (2in x 2in) countdown timer for about $15 that is very accurate (quartz timer). I use one and set it to 2-?? seconds and hit the start at the same time I open the shutter. It beeps when it hits zero and I close the shutter immediately. If it is light enough to see the face of the LCD, I can be "prepared" when zero is near. If it is so dark that I can't see the LCD, the expopsure times are usually >30 seconds and it doesn't matter if I'm a 1/2 second slow on the close, anyway. It has a little clamp that allows me to clamp it to my shirt or jacket. Especially useful for long (>10 second) exposures but still useful for 2-10 second ones.

-- Steve Baggett (sbaggett@midsouth.rr.com), March 17, 2001.

I shoot large format landscapes and don't find a metronome impractical. Have you seen a modern quartz metronome lately? They are quite small and compact. Not one of those big Seth Thomas spring-wound metronomes (the kind Ansel used in the darkroom to time dodging and burning exposures, incidentally) with the baton waving back and forth or the old Franz electric with the faceted light on top that you need to plug in. You can find an accurate, sufficiently loud, battery operated metronome that weighs about an ounce or two and fits in your shirt pocket for less than $30.

-- David Goldfarb (dgoldfarb@barnard.edu), March 17, 2001.

Sheesh, it aint rocket science, its amazing how complicated some people can make it. Just do what Steve there sez, get an el cheapo timer and wing it. I use a stopwatch that I stole from my psychotic high school football coach after he tackled me and a friend from behind in the hallway because we were making fun of him.

Ooops, guess that cats out of the bag 23 years later. But its taken a lickin and keeps on tickin.

-- Wayne (wsteffen@skypoint.com), March 18, 2001.



With a Calumet electronic shutter tester I find that all my large format shutters are rarely closer than 1/6 stop to the indicated shutter speed (and these are all on new and well looked after lenses).

According to Calumet this means that at an indicated speed of 1 second the actual shutter speed can range from 0.89-1.12 seconds. This is about a 12% error.

Iíve also tested how accurate the shutter speed is on the B setting using my wristwatch second hand as the timer at 2, 4 and 8 seconds. I found that there was always less than a 10% error. I was never even close to a 1/4 second error on a 2 second exposure timed with my wristwatch. I doubt if thereís any point in being more accurate.

-- Philip Y. Graham (PYG@plastsurg.com), March 18, 2001.


The electronic metronome is a great idea. The one I use in the darkroom for test strips,dodging/burning is a little larger than a watch and costs about 20 $US. It makes a very distinct beep. George

-- George Nedleman (gnln@thegrid.net), March 18, 2001.

i like the old eugene smith exposure method - you lick your finger and hold it up in the air to see which way the exposure is coming from, and then you expose the film untils it feels right. i have always been paranoid about reciprocity failure (after being reminded of it 50,000 times by my mentor long ago), and have consequently always given wildly too long exposures in compensation. i have never managed to overexpose a negative that way. i shoot lots of interiors of old unlit warehouses and commercial bldgs, inside hwy tunnels, powerhouses, etc. if my meter says 4 secs, i will do one at 8secs and one at 16 secs - i can usually hardly tell the difference between the negs, and either neg will be quite printabble. when my meter says 1 minute, i just open the shutter and wander around for a while. my experience has shown that this method works flawlessly. obviously there is a lot of latitude in exposures of this length.

-- jnorman (jnorman@teleport.com), March 18, 2001.

Hi Richard

I learned in the swiss army ( the only thing I learned ) count seconds like thies: Twenty-one,twenty-two,twenty-tree etc. You can drill it with a watch in the beginning to get the feeling how fast to count! Otherwise I`m thinking much similar to jnorman`s posting!

-- Armin Seeholzer (armin.seeholzer@smile.ch), March 18, 2001.


I'll also cast my vote for the metronome. About a year ago I tested myself with the calumet shutter timer, and compared the metronome vs. a stopwatch. I was more accurate and consistent with the metronome. I expect you anticipate better because you get a rhythm going before you trip the shutter. Besides it's fun to play with! A number of the portable electronic units have an earphone jack in case you want your timing to be private. For longer exposures I'll set mine at 30 beats/minute so you get a bleep every two seconds which makes counting easier. Of course for exposures over 10 seconds the error difference between the two isn't that significant.

-- Larry Huppert (Larry.HuppertNOSPAM@mail.com), March 18, 2001.


"...I tested myself with the calumet shutter timer..."

I wouldn't say that too loudly. We look strange enough as it is hauling around these big cameras standing under the darkcloth and all.

-- David Goldfarb (dgoldfarb@barnard.edu), March 18, 2001.


I too use a metronome but set it so that it beeps once per second. The kind of metronome I'm using (and I suspect others also are using) is not the traditional old large woode thing that you used to see sitting atop pianos. The one I use is digital, about a half inch or less wide, and smaller than a pack of cigarettes. It easily fits in your shirt pocket, can't weight more than a few ounces, and cost about $10 at a music instrument store. I don't like to wear my watch when photographing in many areas because of the theft problems - I figure they might get my camera gear but at least they won't get my watch if I leave it at home.

-- Brian Ellis (bellis60@earthlink.net), March 18, 2001.

Take a small lead fishing sinker, paint it white (for visibility) and tie a string to it. At a distance of one meter from the sinker, mark the string with some tape or dye. Tie the string around any available tree branch leaving one meter between the sinker and the cinch point and give it a swing. Start your count from the top of the swing and note each time the sinker reaches that exact point in it's arc. Voila! You've made a second timer that will fit in your camera bag or pocket and needs no batteries, AND is ACCURATE!

-- Robert A. Zeichner (info@razeichner.com), March 19, 2001.

If your in doubt why not just shoot several sheets?!... or shooting at less of an apeture so you can get the second exposure...

-- Scott Walton (f64sw@hotmail.com), March 19, 2001.

I too shoot landscapes in the wilderness. For most of my low light shots I am dealing with tens of seconds to minutes. My digital wrist watch is as accurate as needs be (plus the alarm is crucial to wake me up in my tent at 4:30am!). The hard part is correcting the final exposure time on the fly when the light is increasing at a stop per minute. Fortunately, plus or minus ten seconds makes no practical difference.

For shorter exposures, 2-5 secs say, an analog watch with sweep second hand is indispensible. I can usually avoid this touchy range, however, by stopping down or opening up an extra stop.

-- Richard Ross (ross@hrl.com), March 19, 2001.


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.

-- Rob Tucher (rtphotodoc@hotmail.com), March 19, 2001.

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

-- chris jordan (cjordan@yarmuth.com), March 19, 2001.

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.............

-- Sol (yatescats@yahoo.com), March 19, 2001.

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.

-- Yong-ran Zhu (yzhu@mcw.edu), March 19, 2001.

Boy, I have tried all the methods mentioned above and all in the answers before this. After all that, and after exhausting all the funding possible in seventeen Federal Grants on how to tell time accurately for long exposures(some Postal & some Pentagon grants), I have come up with a foolproof way to do it. I carry a VCR and portable power pack with me any time I think I may have a long exposure to deal with. I then put in a tape of Rodney King getting the tar beaten out of him. At 3 baton beats per second, I am pretty good at timing the exposures. At least up to the 54 beat mark. I will apply for a couple of law enforcement agency grants of at least $50,000 each to see if I can figure out a way to play the tape more than once without rewinding so I can count even longer.

If that doesn't work, and since I live in Utah, I can just use the old Mormon method of counting... one'Polygamy, two'Polygamy, etc. It should work fine at least until I get to 55, the number of wives ol Brigham Young had. I guess then I could count the number of Polygs living here in the State now, that will get me to at least 80,000 by news reports. That would be a long exposure.

All these should be cheaper than buying a watch and a lot more fun too.

-- Dan Smith (shooter@brigham.net), March 19, 2001.


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.

-- Struan Gray (struan.gray@sljus.lu.se), March 20, 2001.


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