Increase shutter spead and fstop

Noel Evans

Noel Evans

Mod V3 New and Improved
Staff member
Does anyone have a general guide as to the light loss and comparative f stop to keep image the same.

For example Im shooting a low action portion of a scene and for arguments sake my settings are:

Shutter speed 1/48th and fstop 6.8

Now I want to move to a slightly higher action component of the scene so I want to increase my shutter speed to 1/120th - so to keep my image the same whats my new fstop?

Im looking for a general guide I can draw up print out and tape to the inside of my pelican for reference. I realise it might not bee exact but as I said for reference purpose.

Any help appreciated.
 
Well, just keep in mind that doubling the shutter speed denominator (i.e., going from 1/50 to 1/100) cuts the amount of light in half. Halving the denominator (i.e., going from 1/48 to 1/24) doubles the amount of light.

And, with the iris, stopping down one f-stop (i.e., from 2.0 to 2.8) cuts the light in half, and opening up one f-stop (i.e., from f/11 to f/8) doubles the amount of light.

So 1/48 at 5.6 would deliver the same exposure as 1/96 at f/4, and the same exposure as 1/24 at f/8.0.
 
Thanks Barry........lol I was waiting for you to answer. Based on those numbers I will draw up my chart. This would work for any cam so its very useful in the field. Cant believe no one has done it before? Maybe they have?

Anyway Barry you are absolutely No.1 in my book! But thanks to horse, terry lasiter, john hudson, JDS, dan, isaac brody and a few others I know how important the tech aspects are and thats one thing my personality type does not like... but I am working on things like this to keep me in line. Will post the chart when I have it done for others who maybe like me can always see the big picture but cbf with small detail. The problem is you need to do both.....

EDIT: also need to say thanks to the FCP forum members who have helped me so much this past few months since the changeover..... (cpt mensch comes to mind)...... I worked on premiere for a long time but I cant believe what I can do now. For those who have wondered about FCP when you put in the effort this thing JUST PLAIN WORKS. hehe

I am not a fanboi of any os, in fact mac annoys me considerably... but FC Studio a dream.

And so ends my sentiimental post :P
 
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