Long Exposure on LF Lens

[mervynyan]

Hi all,

It is my first post here. I am ready to buy a 4x5 LF camera. I have been 35mm film shooter for a long time. However, these is just one thing I want to understand before I go shopping.

How do you achieve exact timing of exposure longer than 1 sec. My SLR certainly can time this, as well as I can get a meter reading. If I want to shoot at f32 for 8 seconds, what accessory do I need? I cat read the watch, but it is too difficult.

Thanks for your help.


Cheers,
Mervyn

[cotdt]

you can count the time... one one-thousand, two one-thousand, ... etc.

[steve simmons]

Before you buy any equipment may I suggest some reading

The Free Articles section of the View Camera web site

www.viewcamera.com

one of these books

Using the View Camera that i wrote
User's Guide to the View Camera by Jim Stone
Large Format Nature Photography by Jack Dykinga

Film exposed, or needing to be exposed for more than one second may suffer from reciprocity failure which is essentially a decrease in film speed. Depending on the film, but if the meter calls for an 8 second exposure you may need to go longer, possibly up to 40 seconds. In this type of situation if you miss by one or two seconds it won't matter at all. You should pick just one film and use it for at least a year to figure out how it works. Don't join the film of the month club. Info on RF for just about any film is available from here, one of the books, or the mfg's web site.

steve simmons
publisher, view camera magazine

[Mark_S]

As steve mentioned, long exposures tend to run into reciprocity issues, so you need to figure that out.

That said, don't worry too much about getting 100% accurate exposure times. Remember we measure exposure in stops, and to get an appreciable error on a 5 second exposure, you have to be off by a lot. More important than absolute accurate timing is being able to accurately reproduce what you are doing next time. For me, I use the shutter to time exposures up to 1s, from 1s to a couple of minutes I use my pulse to count exposures, and for longer than a couple of minutes I try and figure something else out (I don't wear a wristwatch, but you can usually find someone with a watch, or a clock etc)

[rwyoung]

For longer exposures, a watch or timer or your pulse (if you pre-calibrate). I've been seeing variations on little minute and second timers at dollar stores and they look very promising for long exposure pinhole (and lenses, I like playing with ortho film) stuff...

Anyway, Steve's standard reply above is pretty good. And his book ain't half bad either...

[mervynyan]

Thanks Steve, I indeed read thoses booked you named, I also undetstood reciprocity failure etc from my 35mm film.

I guess my question was related to a more partical operaiton in the field. After I am done with all the calculations, I can count or look at a watch for tens of seconds, but not in tens of minutes or few hours. Nor do I want to stay up all night to photography star trails.

Normally I just bracketed 3-5 stops and go home. Since bracketing isn't easy on LF, that presents a dilemma. It is to heavy to carry some many gears-

Cheers,
Mervyn

[Brian Ellis]

If you're making an exposure in the tens of minutes or for hours there isn't much you can do except to set the shutter so that it locks open (the "T" or "B" setting, I can never remember which is which), note the time, and go on about whatever else you planned to do, then come back when the time is about up. I don't do that type of photography, perhaps there are better solutions than I'm aware of. But as I'm sure you know, when you get into hours of exposure reciprocity failure is so severe that it's almost impossible to overexpose so when you return isn't very critical.

[lenser]

If you are really wanting accurate times for excessively long exposures, you might want to look into a digital cooking thermometer. I've got a Timex cooking thermo timer with a removable probe. I can set it for up to 23 hours 59 minutes and the alarm would wake the dead for several counties around. It's about the dimensions of a very flat cigarette pack and weighs only a few ounces. I haven't had to change the AAA battery in three years of steady use and it gets thrown in a drawer without cushioning when I'm done with it. Seems to be abuse friendly. I can't find the instruction sheet to see if it has a lighted display, but surely someone makes this kind of unit with a lighted crystal or some other type of ilumination.

Good Luck.

Tim

[Scott Knowles]

I use a 1950's military stopwatch marked in .2 second increments which I had refurbished and checked. Since I often carry a pocket watch, adding a similar style stopwatch wasn't much of a stretch. I would guess once you get past about 10 second, accurarcy is relative.

[Dave Moeller]

You can pick up electronic kitchen timers for a few bucks. You just enter the time that you want, start the exposure and start the timer. The timer counts down so you can check it if you're curious, and it begins beeping when it reaches zero. Simple, cheap, small, and effective. I use one in the darkroom for timing development as well as in the field for long exposures. (Heck, when I was in physical therapy, my therapist used one to time me on the stationary bike.) It's the most bullet-proof solution I've found for timing things longer than a few seconds.