Lens Calculator
This calculator is intended to help you work out the settings for your camera/lens. Some software requires you to specify the field of view of your lens rather than its focal length, and if you don't know what that is, this calculator may help you work it out. For instructions see lower down the page.
| Lens focal length: | (mm) fisheye | |
| Film format: | ||
| x (mm) | ||
| Field of view: | x (degrees) | |
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About the film scans (if any) |
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| Scan resolution: | (ppi) | |
| Scan size: | x | |
| Scan accuracy: | % | |
| Scan field of view: | x (degrees) | |
| 'Effective focal length': | x (mm) | |
Instructions
- enter the focal length of the lens (or an approximation)
- select the film type, or enter in the physical size of the film or CCD
- select portrait or landscape as appropriate
- click 'Lens Calc' to get the calculator to work out the field of view
if you digitised your pictures from film or from prints of the full frame:
- enter in either:
- the resolution you scanned at and the size of the scan in pixels
- the physical area of the film scanned (note: not the physical size of the print, if scanned from a print)
- click 'Scan Calc' to get the calculator to work out the accuracy of the scan, the field of view and the resulting focal length of the scan (normally slightly longer than that of the lens)
The scan calculator allows you to work out what the theoretical focal length is of the scan, given you have cropped the image captured by the lens and have therefore a slightly smaller field of view than the lens. This is explained in my discussion of digitising