Crop factors caused by different sizes of sensors in different cameras still confuses a lot of people. Mostly because there’s so much bad information out there and a lot of the explanations about how sensor size affects your image either try to simplify things too much or they get overly confusing, making the situation worse.
Well, filmmaker Daniel Scott Murphy is trying to help you understand them with his new crop factor calculator. There are a few of these out there already, but this one actually offers a visual indication of the crop, simulating the results with a real image. It can even take speed booster lens adapters into account.
Compared to the other crop factor calculators out there, this one’s extremely useful, as it immediately lets you see the effect it will have on your image at various focal lengths using different sensor formats. But it does also show the crop factor and effective equivalents below the image, too – and you can check his maths on this spreadsheet.
At the moment, the calculator covers lenses designed for full-frame and Super 35mm. The destination sensors include many of the current popular ones including Canon APS-C, Sony APS-C, Canon EOS R 4K, the Pocket 4K, the Panasonic GH5, etc. in various focal lengths from ultra-wide 12mm to a somewhat long 200mm.
While the calculator is currently aimed more towards filmmakers, hopefully, he’ll expand it in the future with more focal length options, as well as sensor sizes. Nikon and Fuji APS-C, for example, are both slightly different sizes to both each other as well as Canon and Sony APS-C. Some of Panasonic’s cameras also have a little extra crop factor to deal with when shooting in 4K.
It would also be nice if it could be used in reverse. If I’m using a 12mm lens on a Pocket 4K, for example, what focal length would I need to put on a Super 35 or full-frame camera to get the same field of view? It’s easy enough to figure out yourself, but for the uninitiated, the visual reference this calculator offers can be extremely handy.
Daniel does have a “Buy me a beer” button on the crop factor calculator website for those who like and use it. So, I suppose if people buy him enough beers, he’ll be motivated to keep working on it. Assuming he’s still sober enough.