Orquid "Phoenix"

Orquid "Phoenix"

by ceinmart

submit your photo


Hall of Fame
View past winners from this year

Please participate in Meta
and help us grow.

Take the 2-minute tour ×
Photography Stack Exchange is a question and answer site for professional, enthusiast and amateur photographers. It's 100% free, no registration required.

I meter a surface at ASA 100 and get F4 at 1/15 second. What is the illumination coming off that surface in Cd/square foot ?

share|improve this question
1  
Probably best asking this on physics.stackexchange –  MikeW May 26 '13 at 0:00
    
Maybe How to calculate Lux from EV? –  mattdm May 26 '13 at 4:43
    
I think the linked question contains the information you're looking for. –  John Cavan May 27 '13 at 0:44
add comment

marked as duplicate by Itai, AJ Henderson, dpollitt, mattdm, John Cavan May 27 '13 at 0:43

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

1 Answer

This Kodak reference for estimating luminance and illuminance may help.

Your metering at ISO 100, 1/15th and f/4 would be equivalent to ISO 400, 1/30th and f/5.6 if I've done the math correctly. So use their value for f/5.6 which is 2.67 Cd/ft2

share|improve this answer
add comment

Not the answer you're looking for? Browse other questions tagged or ask your own question.