Loooooong exposures (at night)

[macandal]

I have a simple question (I think). How does one guess the time to make a long exposure at night?

When I was starting in photography, I took a beginning photo class. My class went on a field trip one evening here in San Francisco to Sutro Baths. We were going to do long exposures. When we got there it was pitch black and you couldn't see anything. I was very surprised when I finished the exposure and I could see that my camera had captured something (this was done with a digital SLR)!

This is a shot I did with my digital camera (6 minutes, set to infinity):



360 sec ƒ/4 ISO 100 30mm
Canon EOS Rebel xTI, Sigma 30mm f1.4

(To see the full set of exposures, click here)

Anyway, when making a loooong exposure, under similar conditions to those in my trip to Sutro Baths (night, pitch black where you can't see what you're photographing, etc), how do you arrive at your camera settings (aperture, length of time, etc) to make an exposure?

Thanks.

[vinny]

I meter something with my spot meter. no guessing. or guess and double that.

[Merg Ross]

You could start here:

http://www.calculator.org/calculate-.../exposure.aspx

Be sure to allow for reciprocity.

[jp]

I don't really have a need/interest to photograph something with LF at night. DSLRs are so good at that right now. But that's my style and we're all different.

If I did, I'd take a flashlight and laser for focusing / composition. Use the DSLR for the metering, then add for reciprocity failure of the film. I'd probably err on the side of overexposure and use a pyro developer to maintain the highlights.

[macandal]

I meter something with my spot meter. no guessing. or guess and double that.

Sometimes you can't see anything Vinny; metering is not an option.

Thanks.

[macandal]

You could start here:

http://www.calculator.org/calculate-.../exposure.aspx

Be sure to allow for reciprocity.

Thanks Merg.

[macandal]

I don't really have a need/interest to photograph something with LF at night. DSLRs are so good at that right now. But that's my style and we're all different.

If I did, I'd take a flashlight and laser for focusing / composition. Use the DSLR for the metering, then add for reciprocity failure of the film. I'd probably err on the side of overexposure and use a pyro developer to maintain the highlights.

Agreed. My humble crop DSLR did indeed a great job at capturing what I couldn't see. However, when you're hooked on your 4x5, the way I am with mine, you want to do it with the clunker and not the DSLR. Thanks.

[Vaughn]

Some recommended times:

[vinny]

Sometimes you can't see anything Vinny; metering is not an option.

Thanks.

how are you composing/focusing if you can't see ANYTHING? or are you doing that during the day and coming back at night to shoot?

[macandal]

how are you composing/focusing if you can't see ANYTHING? or are you doing that during the day and coming back at night to shoot?

Vinny, if you saw the set I did at Sutro Baths (from my flickr set), most of those shots were done blindly, meaning that I couldn't see anything or I could barely make out what I was pointing the camera at (I'm pretty sure that was the case with the picture I attached in my original post). So much so that even if I could see something, focusing was not possible. That's why we were told to focus at infinity, open the aperture somewhat wide, and point the camera in the direction of something interesting (you would have to know where that "something interesting" was before hand to point it), and let your shutter go for X number of minutes (in the bulb setting).