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1. ## f-stop printing calculations

What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

For example
If the base time is 8 sec:
+1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

Todd

2. Originally Posted by Todd Barlow
What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

For example
If the base time is 8 sec:
+1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

Todd
------------------------------------------------------------

This should give you a good starting point.

3. Todd,

I made up my own tables in a spreadsheet. If you can handle openoffice or Excel spreadsheets, the attached .zip file has both formats (done in openoffice) that produce an f-stop printing table. You can look at the formulae used in the spreadsheet to get an idea of how it works.

I just taught two 6th graders the basics of B&W, and since they'd just learned the basics of geometric progressions with camera stops and shutter speeds, f-stop printing seemed very natural and logical to them. I now use an RH Designs timer rather than these charts.

Lee

4. Thanks Lee, that is great. Helps us what got problems with cypherin.

5. RH Designs Stopclock timer will do this for you and is much more accurate but the trade off is it is more expensive.

lee\c

6. Originally Posted by Todd Barlow
What is the formula that is used to calculate the times shown in the various f-stop printing sheets?

For example
If the base time is 8 sec:
+1 stop = 16 sec how do you arrive at +1/2 stop = 11.3 sec?

Todd
Simple

it would be T x 2^+f
(^ means to the power)
it would be
8 x 2^ +1 = 16
8 x 2^+0.5 = 11.31

M.

7. For those without a spreadsheet program, an f-stop timing table for printing is at: http://www.largeformatphotography.in...pTimingAdv.pdf
This is a .pdf file of a page from Way Beyond Monochrome.

I didn't mention it in my earlier post, but openoffice is free and very capable, and available for Windows, linux, solaris, BSD, and Mac OS-X. See openoffice.org

Lee

8. Yes I saw the .odt in your zip-file

9. Todd:

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