Ulophot
7-Jul-2019, 07:17
I ended up creating a simple Excel calculator yesterday, for bellows extension exposure compensation with my forthcoming additional focal length. Before you reply, "But there are 39 gazillion phone apps already," please understand that I do not use a smartphone and like it that way. Thank you. If similar Excel sheets are already available, at least I have had the satisfaction of solving a problem myself.
The calculator is simple, because my Excel and math skills are elementary. One simply enters the focal length; calculations for extension and exposure factor are automatically calculated for a supplied range of distances (which, of course, can be changed for different lenses or preferred distances). It's fine for the work I do.
However, although I created a column for exposure factor, I don't know how to create a formula for a final column rendering that increase in f/ stops based on that factor, which would be formatted as a fraction (that, I can do.)
For example, with a 5.31-inch (135mm) lens entered in one cell, the following calculations are done, but I had to enter values in the last column manually.
Distance, feet Bellows extension Exposure factor Exposure increase in stops
0.84* 11.24 " 4.47 2 1/2
1 9.54 " 3.22 1 1/2
1.5 7.54 " 2.01 1
* Excel sheet has an inches column as well
Can someone provide me an Excel formula for the "Exposure increase in stops" column?
I don't know if anyone else would find this handy. I have written our site owner to ask if he would be interested in posting a link on the home page, once I finish it. Otherwise, since I don't have a website, I may post the file to a Dropbox link for anyone who happens to see it or would like to host it on his or hers.
The calculator is simple, because my Excel and math skills are elementary. One simply enters the focal length; calculations for extension and exposure factor are automatically calculated for a supplied range of distances (which, of course, can be changed for different lenses or preferred distances). It's fine for the work I do.
However, although I created a column for exposure factor, I don't know how to create a formula for a final column rendering that increase in f/ stops based on that factor, which would be formatted as a fraction (that, I can do.)
For example, with a 5.31-inch (135mm) lens entered in one cell, the following calculations are done, but I had to enter values in the last column manually.
Distance, feet Bellows extension Exposure factor Exposure increase in stops
0.84* 11.24 " 4.47 2 1/2
1 9.54 " 3.22 1 1/2
1.5 7.54 " 2.01 1
* Excel sheet has an inches column as well
Can someone provide me an Excel formula for the "Exposure increase in stops" column?
I don't know if anyone else would find this handy. I have written our site owner to ask if he would be interested in posting a link on the home page, once I finish it. Otherwise, since I don't have a website, I may post the file to a Dropbox link for anyone who happens to see it or would like to host it on his or hers.