Exposure metering

Light, film, exposure..
Andrew Nichols
Posts: 181
Joined: 11 Dec 2012, 17:19

Re: Exposure metering

Postby Andrew Nichols » 10 Jun 2013, 22:19

I'm still learning... I think.

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Waltzing Paul
Posts: 49
Joined: 16 May 2013, 21:11
Location: Brisbane, Qld

Re: Exposure metering

Postby Waltzing Paul » 11 Jun 2013, 15:22

Just been reading my LF Technique book and come across 'the bellows factor' which needs to be calculated after taking a light reading.
No one has mentioned that.
Let's hear something about that.
Paul

The pictures you want tomorrow, you have to take today". - Anonymous - Kodak advertisement

Walter Glover
Posts: 928
Joined: 31 Jul 2012, 22:31
Location: Canterbury, NSW

Re: Exposure metering

Postby Walter Glover » 11 Jun 2013, 15:48

Paul,

you might find it is fairly commonplace for folk on forums to answer the question asked - particularly to a newbie - and not to broaden the topic.

If you have a spreadsheet app on your iPhone I can send you a sheet that calculates it.
Walter Glover

"Photography was not a bastard left by science on the doorstep of art, but a legitimate child of the Western pictorial tradition." —Robert Galassi

Lachlan717
Posts: 494
Joined: 03 Aug 2012, 16:49

Re: Exposure metering

Postby Lachlan717 » 11 Jun 2013, 17:27

Waltzing Paul wrote:Just been reading my LF Technique book and come across 'the bellows factor' which needs to be calculated after taking a light reading.
No one has mentioned that.
Let's hear something about that.


Paul,

Bellows factor is based on the inverse square law of light.

Have a look here for its explanation: http://www.youtube.com/watch?v=IYMKERZ4sZo

Light's intensity drops as you move the subject from the source. In our (simplified) terms, that refers to the film being moved further from the subject due to lengthening the bellows' draw. Thus, it dims the light hitting the film.

If you know this, then you can add additional exposure based on how far the film's moved back/how much bellow draw you have.

Plenty out there on it. As I shoot mainly landscapes, it doesn't really affect me.

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Waltzing Paul
Posts: 49
Joined: 16 May 2013, 21:11
Location: Brisbane, Qld

Re: Exposure metering

Postby Waltzing Paul » 11 Jun 2013, 22:22

Walter, sorry I don't have an iPhone.
I do have the instructions though in the book I have.
Just another thing to factor in when I get going.

Lachlan, just watched the youtube link you posted.
Thanks, that explains it very well.
As my interest is mostly going to be landscapes I shouldn't have too much to worry about.
Although I did have a practice this afternoon at shooting one of my orchid flowers up real close using a 90mm lens.
Very impressed to get it to fill the 4x5 frame.
Paul

The pictures you want tomorrow, you have to take today". - Anonymous - Kodak advertisement


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