exposure question

[spiffybeth]

tonight ill be shooting in a very low light environment (a bar). last time i shot it, i was shooting digital so i could adjust my settings as i saw fit, but this time id like to shoot film.

the settings i had it on was iso 1600, f/3.5-5.6 18-55mm (kit lens) and i set the shutter for 1/30.

this time, im going to be using film. iso 400 and a 50mm f/1.7. what should my shutter be to keep that same exposure?

what about if i shot at f/2.8?

 

[Battou]

that ain't gonna cut it I don't think.

My self I would be using 800 and 1.4 (in your case 1.7) and keeping the shutter as fast as possible.


But not knowing the exact light situation I can't be sure if that is too much or too little....this is one of those things one has to be there and read them selves to give the best advice.

 

[spiffybeth]

ok, lets say i had iso800 and the lighting was the same as the first scenario. what then?

 

[Battou]

ok, lets say i had iso800 and the lighting was the same as the first scenario. what then?

You'll have to jog my memory

 

[spiffybeth]

see the first post.

there must be an equation i can solve to find the answer, right????????

 

[Battou]

I am horrible with equations, I was hoping for a link to the afore mentioned outing so I could see it.

 

[Steph]

What aperture did you use when you shot the scene with your digital camera?

 

[KevinDks]

Well, f/2.8 is two thirds of a stop faster than f/3.5, so if 1/30th at f/3.5 was OK at ISO 1600 then f/2.8 at 1/30th will be a third of a stop under that exposure at ISO 800. With negative film that shouldn't be a problem, but I think I'd make sure I had a mixture of shots that included some with a bit more exposure as well.

 

[spiffybeth]

What aperture did you use when you shot the scene with your digital camera?

f/3.5 and f/5.6

 

[spiffybeth]

Well, f/2.8 is two thirds of a stop faster than f/3.5, so if 1/30th at f/3.5 was OK at ISO 1600 then f/2.8 at 1/30th will be a third of a stop under that exposure at ISO 800. With negative film that shouldn't be a problem, but I think I'd make sure I had a mixture of shots that included some with a bit more exposure as well.

and if i went with f/1.7, at 1/30, that should be ok?

 

[KevinDks]

f/1.7 is another stop and a half faster than f/2.8 and so, let's see if I can keep track here, err - about two thirds of a stop to a stop more exposure than you had with your digital at f/3.5 and 1/30th I think. Bracket between those kinds of settings and the latitude in negative film will take care of the rest.

This wiki page has useful tables which set out the f/ number sequence in half and third stops

This web page has a chart that gives you a rule of thumb exposure guide for all kinds of situations, and equivalent exposures.

Kevin

 

[spiffybeth]

thank you very much, kevin!!!!!

 

[christopher walrath]

You have to keep your shutter speed at 1/60 or more, so ISO400 at 1/60 would be f/1.4 to f/2 at your orig dig aperture range.

ISO 1600 to ISO 400 is a 2 stop drop in exposure. 50mm lens in a darkroom should be set at no less than 1/60, not to mention this is a good flash sync speed. 1/30 to 1/60 is a one stop drop in exposure. That gives us three stops total drop in exposure. To maintain reciprocity we must then increase three stops on the aperture. f/3.5 to 2.4 to f/1.6 to f/1.1. On second though, get ISO 800 and shoot from f/1.7 to f/2.8. 'Cause that f/1.1 is not attainable and you would have to drop your shutter speed way too low to hope of a sharp image. Get faster film. It's gonna be a little grainy, but you gotta work with the light.

 

[spiffybeth]

thanks, chris!