Using a light meter on the ground glassgreenspun.com : LUSENET : Large format photography : One Thread
I have a minolta Autometer III and the booster II. It shows how to calibrate the meter to use it on the ground glass of a large format camera.
Does anyone do this? I seemed to be able to calibrate mine. 2.4 compensation.
Or is this a waste of time?
-- Pete (email@example.com), June 05, 2001
In the studio it works good but it just seems easier to to meter regularly either in the studio or on locations.
-- Scott Walton (firstname.lastname@example.org), June 05, 2001.
I was thinking of using this for extended bellows..
For some macro work....
-- Pete (email@example.com), June 05, 2001.
Indoors for macro work it's ideal. Outdoors, particularly with the wind blowing, it's generally easier to use a spot meter.
-- David Goldfarb (firstname.lastname@example.org), June 05, 2001.
I often used it for indoor macro work some years ago. I also used it outdoors, particularly with a polarizing filter, but today I prefer either the Sinar booster if I really need it or spot metering. The main reason is that using the booster is very unpractical: one must be very careful to correctly place the booster on the GG and perfectly shield it from the light in the same time, which is not an easy thing. this said, I obtained excellent results with that technique. Exact amount of compensation depends on the ground glass you have and other factors, like lense's light fall-off. It is therefore not possible to say whether 2.4 is correct or not. Be sure that you aim your camera at an even and evenly illuminated surface, like a white wall. The light must not be changing either. Palce the sensor really perpendicularly to the GG and shield it as well as you can. You can make a drawing of your GG and if it has a grid, you can write down a compensation factor for each square (probably between +/- 0.1 and 0.3 f-stop)if you are patient enough. Do not forget to put all camera movements to zero before calibrating. Try with several lenses to verify constancy of your measurements.
-- Emil Salek (email@example.com), June 05, 2001.