Looking for suggestions for exact timing in bulb mode

Discussion in 'Medium Format' started by graham_martin|2, Dec 20, 2009.

  1. I like to take night shots of city lights, outdoor Christmas lights etc in which an exposure of 3 or 4 seconds (or longer) is called for. Other than the tried and true, but not 100% accurate, "one one thousand, two one thousand..." etc. what other methods do you use to get an exposure for the exact amount of time you want? Needless to say, I use a cable release to trigger the shutter. I am wondering if there are mechanical cable releases that have a timer on them?
    Thanks
     
  2. The timer on my iPhone. I am sure most cell phones have one. If there is a mechanical release with a timer, I could use that for sure. I take a lot of night shots myself.
     
  3. Counting will be accurate enough, but i use the timer in my exposure meters, or a (cheap plastic quartz) handheld stopwatch. They all give beeps at both start and stop of the timed sequence.
     
  4. I use an old clockwork alarm clock which is still small enough to carry around and which tick-tocks audibly loud. Tak
     
  5. how about a wristwatch ? Seriously. how 'accurate' is your exposure in the first place? If your exposure is 3 seconds, then being off by 1 second in 3 is 1/3 stop over/under exposed; not that much.
     
  6. I am a large format photographer who routinely shoots 2 second to 15 second exposure and have always used a digital watch with no problems. Remember that as your exposures get longer, the need for exact exposure times (within small fractions of a second) decreases. Randy
     
  7. No reason to be 100% exact on these long exposures - you won't see a difference. The only wrist watch I own does everything for me - it's a cheap Timex and it works like a charm.
     
  8. If you are off in your timing a 4 sec shot by 1 sec (pretty sloppy counting 21 .. 22 .. 23 ... 24 in my book), then your exposure will be off by 1/4 of a stop. Now even modern cameras get only about 1/3 of a stop correct exposure and shutters/ aperture settings etc are never that accurate anyway ..... Thus you will see no difference on the film, or hardly any. Besides the Schwarzschild effect (long exposures) is also only so-so accurately predicted on the film data sheet.
    So: do not worry is my advice. Too small of an error to try to fix. Irrelevant.
     
  9. Hadn't expected so many good suggestions so quickly. My exposure meter doesn't have a timer, but I do have a Nikon MC-36 shutter release cable with a countdown timer that beeps. I could probably use that. I also see the point that for a 30 second exposure that being off by a second or two really isn't going to make that much difference.
     
  10. When you expose a should-be exposure of 4 seconds 1 second too short, the difference is not 1/4 stop, but 0.4 stops and a bit.
    Expose that same 4 second exposure 1 second too long, and the difference in stops is 0.3.
    Similarly, being off by 1 second on a should-be exposure of 3 seconds constitutes a difference, not of 1/3 stop, but of about 0.4 stops (if too long) and almost 0.6 stops (when too short).
    Quite a bit!

    But the effect named after mr Schwarzschild will indeed cover a lot (or rather, make matters worse when you err on the short side, make things better when you err on the long side).
     
  11. There are cable releases with timers, although I doubt that they're still being made. I bought a Prontor one several years ago on eBay. It works fine, but I use one "one thousand, two one thousand, two one thousand...." more often.
     
  12. How to time a bulb exposure?
    Mostly, I just count. 60 bps is a good "Bach - Allegro" tempo for one who has tapped a foot in many concerts, and the traditional "thousand one, thousand two..." method can be good enough. As "Q" points out, good enough is often more than good enough. Being off 1 second out of 5 is not photographically significant. As a practical matter, most time exposures are going to fall in the 2-15 second range.
    For fussy exposures like landscapes and interiors, I sometimes rely on my non-digital wrist watch and target a range of not less than 5 seconds. I hadn't though of using a cell phone, but that takes two hands while you burrow through the menus, and loses its place when you close the cover (or whatever). If it's too dark to see your watch, the exposure time doesn't matter - you're looking for star trails or keeping the background from getting too light.
     
  13. Standard march tempo is 120 beats per minute. Just whistle a Souza march and your left foot will hit the ground every second. Unless you're marching out of step of course!
    Joe D.
     
  14. I always carry a hand-held stopwatch with large numbers in my camera bag. I also carry a piece of 5 x 7 mat board that has been sprayed flat black. I place the mat board in front of the lens, trip the shutter (using a locking cable release to keep the shutter open) and then simultaneously remove the card from in front of the lens and start the stopwatch. By tripping the shutter first with the lens still covered, you eliminate the possibility of camera shake due to mirror slap. When the time has elapsed, I once again place the mat board in front of the lens and release the cable release.
     
  15. Wristwatch, very practical device.
     
  16. An analog watch (believe it or not, many kids can read REAL clocks anymore) and a quick hands and fingers should do it.
     
  17. The other solution would be to take the camera out of bulb mode, place it on manual and just set a three or four second exposure. Even my simple compact digital camera can do that.
     
  18. Yes Bruce, your digiwizz camera can do that, but not a Hasselblad. (Medium format forum!)
    Yes, I always try to err on the long side with long exposures, never even think of cutting a bulb exposure short. So that is why I thought of 1 sec off = a fraction of a stop long = insignificant re reciprocity failure. And unfortunately clocks/watches/ ... by themselves do not work too well when it is dark enough to need multisecond exposures. And then only the numbers count in my head works.
    I have never witnessed a failure of proper exposure due to loosing count ... And I do take my brain with me when I photograph: So I have no need for another gadget at all, other than tripod and light meter.
     
  19. Sorry, didn't notice the forum. Looks like it's back to one Mississippi, two Mississippi, three Mississippi....
     

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