Convert-Me.Com - online units conversion
Instant conversion pages: weight, length, volume, weight to volume, area, cooking, pressure, more...
EV (Exposure Value) to LUX
Forum rules
Dear convert-me.com forum visitors,
Our forum has been available for many years. In September 2014 we decided to switch it to read-only mode. Month after month we saw less posts with questions and answers from real people and more spam posts. We were spending more and more resources cleaning the spam until there were less them 1 legitimate message per 100 spam posts. Then we decided it's time to stop.
All the posts in the forum will be available and searchable. We understand there are a lot of useful information and we aren't going to remove anything. As for the new questions, you can always ask them on convert-me.com FaceBook page
Thank you for being with us and sorry for any inconveniences this could caused.
Dear convert-me.com forum visitors,
Our forum has been available for many years. In September 2014 we decided to switch it to read-only mode. Month after month we saw less posts with questions and answers from real people and more spam posts. We were spending more and more resources cleaning the spam until there were less them 1 legitimate message per 100 spam posts. Then we decided it's time to stop.
All the posts in the forum will be available and searchable. We understand there are a lot of useful information and we aren't going to remove anything. As for the new questions, you can always ask them on convert-me.com FaceBook page
Thank you for being with us and sorry for any inconveniences this could caused.
2 posts
• Page 1 of 1
- bngoofy
Re: EV (Exposure Value) to LUX
by Knight » Fri Jan 30, 2004 3:06 am
bngoofy wrote:EV (Exposure Value) to LUX
Any idea how to do this?
The definition of EV=0 is an exposure of 1 second at f/1 using ISO 100 film, or any equivalent thereof (2 seconds f/1.4, 4 seconds f/2.0 etc)
The technical definition of Ev is 2Ev = LS/C.
Where:
• Ev = the exposure value
• L = field luminance
• C = Exposure Constant - If you use candelas/ft2, it is 1.3. If you are using LUX (candelas/m2), it is 12.5.
• S = film speed following the ISO standard
Now, as far as where I think you're trying to go with this... Consider that 2ev = A2/T
where:
• A = the f-stop number of the aperture
• T = shutter time in seconds
Combining these two; EV = log2(A2/T) = log2(LS/C) - This is perhaps the most vital formula there is for understandiing the basics of the mathematics behind photography.
I hope this helps!
- Knight
- Expert
- Posts: 309
- Joined: Tue Jan 13, 2004 9:43 pm
- Location: Los Alamos, NM
More info
2 posts
• Page 1 of 1