This spreadsheet gives more than just depth of field figures but also
enables lenses on different format to be compared.
It is meant for use in the field on a palm-top Psion 5
but I have also transposed it to Lotus 123 and Excel
formats in case it is of use to anyone else. It is free!
It was started ages ago but some discussions on a photo newsgroup prompted me to
finish it.
It gives the following information.
a) Entering just two parameters, lens focal length and photo
format, gives:
 | 1) (Chart 1) Hyperfocal distance and
nearest focus chart for all normal f/ stops. This is the most useful for use in the
field and fits the Psion screen quite well.
|
| 2) (Chart 2) Depth of field table
for typical focus points and all normal f / stops. This is the usual table of depths
of field but is perhaps more useful in a studio.
|
| 3) Circle of confusion on which the above are based.
The circle of confusion (which is often a subject of confusion) is useful for
controlling the quality of the results.
|
b) Optionally, entering two more parameters, a selected
aperture and focus distance, gives:
| 4) Nearest and furthest focus distances based upon the
focus point and aperture entered, useful for closer focus ranges than up to infinity.
|
| 5) Field of view at focus point entered. This
enables you to compare the lenses of differing formats. e.g. by entering lens focal
length 80 mm and format 70 mm (Mamiya 7) I can see that this has a field of view at 10 m
which is the same as a 41
mm lens at 35 mm format. You can then compare the depths of field of each lens on
the different formats
|
I have used the most accurate formulae I have been able to find (more
accurate than some tables around, so they may differ)
Please be cautious - I am not a computer programmer and the formulae on
the spreadsheet are horrendously complicated - some of the formulae in the cells run onto
two lines! I may have made some errors although I can't find any. If you find
any please let me know.
I suggest that you leave the protection / locking ON as altering or
deleting a single cell could affect the whole spreadsheet. You only need to enter
data in two cells for most uses plus another two cells for the extra information.
Please let me know what you think of it and suggestions for improvements
are always welcome
Enjoy :-)
Brian E Eyley CompanyEmail
I am working on a revised and enhanced version that will be available
soon for a (very) small cost. Revisit here soon.
If a hover button does not appear here >
< you are probably using Netscape Navigator with Java disabled. Click here for more information and an alternative Table
of Contents.
Brian Eyley
3 The Potteries, Wickham Road, Fareham, Hampshire, UK PO16
7ET
Phone (+44) 01329 515122 fax 515133
CompanyEmail