AFOV calculator (1 Viewer)

I put together an Excel worksheet to calculate the apparent field of view using the triganomically correct formula. It allows you to enter the magnification and field of view as degrees, feet at 1000 yards, or meters at 1000 meters and then computes the AFOV and also converts the FOV to the other two units. If you save it to your desktop, you can easily check the AFOV of bins you’re looking at on the web without needing a scientific calculator.

I’m a complete novice at Excel, but it turned out to be surprisingly easy. I couldn’t see a way to attach the Excel file to this post, so I’ve included instructions on how to create it. If you prefer, you can email me and I’ll reply with my file attached. I created this in Excel 2007, but it should be the same in previous versions.

An Excel worksheet is a grid of white boxes called “cells”. Each cell is referred to by the column and row where it is located. So, cell B7 is column B and row 7. You can just type text or a number into a cell, but to assign a calculation to a cell, you click on the cell. The name of the cell appears in a box below the menus and you can then type the formula for the calculation into the box labeled “fx” which is also just below the menus. For all inputs, type them without the quotes and press the ENTER key when done. For the formulas, it should be easiest to copy and paste from this post to Excel.

Type “MAG” into cells A1, A5 and A9.
Type “FOV” into cells A2, A6 and A10.
Type “AFOV” into cells A3, A7 and A11.

Click on cell B3 and type the following into the “fx” box and then press ENTER:
=DEGREES(2*ATAN(B1*TAN(RADIANS(B2/2))))

Click on cell B7 and type the following into the “fx” box and then press ENTER:
=DEGREES(2*ATAN(B5*TAN(RADIANS(D6/2))))

Click on cell B11 and type the following into the “fx” box and then press ENTER:
=DEGREES(2*ATAN(B9*TAN(RADIANS(D10/2))))

Type “X” into cells C1, C5 and C9.
Type “deg” into cells C2, C3, C7 and C11.
Type “feet” into cell C6 and “meters” into cell C10.

Click on cell D2 and type the following into the “fx” box and then press ENTER:
=B2*52.5

Click on cell D6 and type the following into the “fx” box and then press ENTER:
=B6/52.5

Click on cell D10 and type the following into the “fx” box and then press ENTER:
=B10/17.5

Type “feet” into cell E2 and “deg” into cells E6 and E10.

Click on cell F2 and type the following into the “fx” box and then press ENTER:
=B2*17.5

Click on cell F6 and type the following into the “fx” box and then press ENTER:
=D6*17.5

Click on cell F10 and type the following into the “fx” box and then press ENTER:
=D10*52.5

Type “meters” into cells G2 and G6.
Type “feet” into cell G10.

That’s it! To test it; type “10” into B1 and “6” into B2. You should get 315 feet and 105 meters and an AFOV of 55.310607. Then type “10” into B5 and “315” into B6. You should get 6 degrees, 105 meters and the same AFOV. Then type “10” into B9 and “105” into B10 and you should get 6 degrees, 315 feet and the same AFOV.

Finally, select SAVE As from the File menu and save it to your desktop.

Or you could attach the XLS

Click "Go Advanced" at the bottom of a reply to get the full editor panel that has a paper clip toolbar item for adding attachments.

Hi,
there is a guy in a German optics forum who measured the AFOV of a number of binoculars. Those measured values include the effects of the various kinds of distortion of the optics, that cannot be easily calculated. Here is the list (SSW = apparent angle of the field of view):
http://www.juelich-bonn.com/jForum/read.php?9,202100,212609#msg-212609
Florian

Can't find "Go Advanced"

The only Add Attachments I can find won't allow the .xsl file type. It only accepts pictures and text files.

Found the Go Advanced

Still won't allow Excel file.

Well, that's a bit of an oversight. Obviously not set up for finance folks!

I started a thread here

http://www.birdforum.net/showthread.php?p=1447382

asking for XLS to be permitted in attachments. Please add your support.

You could put it on a free filehosting service (Rapidshare, Mediafire, etc, etc) or Googlepages if you have an account or even your own server to share it.

Kevin Purcell said:

Well, that's a bit of an oversight. Obviously not set up for finance folks!

I started a thread here

http://www.birdforum.net/showthread.php?p=1447382

asking for XLS to be permitted in attachments. Please add your support.

You could put it on a free filehosting service (Rapidshare, Mediafire, etc, etc) or Googlepages if you have an account or even your own server to share it.

Click to expand...

I believe the reason the forum does not allow xls format is because it may contains macros, some of which may be malicious.

Yet curiously they allow .doc files which are macro capable. And doesn't Excel give you an option to open a file without executing the macros?

So that doesn't seem like a consistent argument.

I guess you could try uploading it as comma delimited text ...

A third party file sharing site is perhaps the only option then.

Program Upload

I found this upload problem interesting and had a couple of hours this morning to play around with the AFOV problem. I find Excel a little cumbersome so I put together a simple program to try to upload.

I have uploaded dot xls before and tried a simple one again (attached). I think there is a 1.9 mb. limit on file size.

I could not upload the dot exe file so I renamed it to dot txt. Those who want to download and try need to rename it back to AFOV.exe when saving.

This was fast and has not been proofed. If (when) you find bugs, email or PM me and I will try to fix them.

Have a good day, all.
Ron

The XLS works fine, Ron!

Not running Windows so I can't check the EXE. The problem with naming and renaming an EXE to txt is they may or may not preserve all of the bits (depending on the MIME type they use). If you used a binary filetype that would be certain to work (.doc, .pdf, .xls and so on) so long at it fits the size requirements.

And if people do use .xls it's a good idea to make sure its not using an exotic (new!) Microsoft file format. Lowest common denominator works best especially for those that don't use Microsoft products.

Kevin Purcell said:

The problem with naming and renaming an EXE to txt is they may or may not preserve all of the bits (depending on the MIME type they use). If you used a binary filetype that would be certain to work (.doc, .pdf, .xls and so on) so long at it fits the size requirements.

Click to expand...

Thanks Kevin, I did not take time to look at the file types this morning and just chose one that I knew would be accepted. I renamed the file to dot PDF and added it above. I did download and rename the txt file and it appeared to load and run, though I did no checking. Did no beta testing, so may be full of undocumented features (bugs).

Have a good day.
Ron

Ron,

I was able to download your .xls file but neither of the other two on my Mac system. Adobe Reader 9.0.0 doesn't recognize the .pdf file. Neither MS Word nor NeoOffice recognizes the .txt file.

Keep trying.
Ed

Ed: you are missing the point of our previous discussion.

The "pdf" and the "txt" files are both Windows EXE renamed to PDF or a txt file. Neither will make sense to a PDF reader or a text editor. To use them change the suffix to EXE then run them on a Window machine.

So unless you have an Intel Mac and Bootcamp or an emulator (VMware Fusion, VirtualBox or similar that boots Windows) you aren't going to be able to make use of thoses attachments.

Kevin, I meant to tell you, but had a crowd and trying to get out of the office. First tried to rename to a jpg but BF gave an invalid file type error so I went straight to txt to avoid any header read problems.

Ed this will not run on your Mac.

Best
Ron

Excel 2003 and 2007 files

I downloaded Surveyor's AFOV.txt file and renamed it to AFOV.exe. It runs.

I attached my AFOV.xls (Excel 2003 and earlier) file as AFOV_xls.txt and my AFOV.xlsx (Excel 2007) file as AFOV_xlsx.txt.

BinoBoy,

I downloaded the xls file and ran it. Works fine. You should be able to upload either the xls or xlsx directly up to 1.93 mb. I was going to delete two of my attachments to free up space but can not edit anylonger. If you can not upload directly, let me know and I will try. You may want to try to replace the two txt files with the regular binary files.

Best
Ron

BinoBoy,

I converted your AFOV_xls.txt file to AFOV.xls (by changing the title only). It launched Excel 2004 on my Mac as well as NeoOffice (calc).

The AFOV_xlsx.txt file was converted to AFOV2.xls but Excel 2004 rejected it as did NeoOffice.

The Excel 2003 format looks like the way to go.

I don't know why you can't post it as an .xls file directly, since Ron posted TNList(1).xls in post #9 and it also worked very well.

Please spare the .exe files since we Mac guys haven't used them since the Dreaded Old System (DOS) days.

Ed

PS, Just to test it out, I've attached your file converted to .xls. I can download and run it, —*and probably you can too. :t:

Seems to work now.

When I tried originally, it gave me an error message. Now it is taking it. Maybe they changed something to allow it.

Sneaky guys! They're gonna blame you for sure, BinoBoy, 'cause is says valid file extensions include ... xls xlsx." But, I'm on your side. B

Hey, they fixed it

http://www.birdforum.net/showpost.php?p=1448820&postcount=3

How about that!