Contains adsIn-app purchases
59 reviews
Content rating
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About this app

mmCalc is a super simple photography focal length calculator. Simply input your focal length, sensor size, and max aperture and we'll give you what the 35mm equivalent is of that configuration. If the simple calculator doesn't suit your needs, we also offer calculators for crop factor based on sensor size and completely custom lens + sensor crop factor calculations.

mmCalc also provides calculations for medium format and large format sensor sizes.
Updated on
Jun 14, 2018

Data safety

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59 reviews
Jake E Hobbs
November 9, 2021
Doesn't work without net connection which makes the app redundant. Especially when I paid for pro and still get shown ads when I do use the app on an Internet enabled device. Trying to log a support ticket via the app leaves my device hanging. Very poor.
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A Google user
January 4, 2019
On this app, I could only key in the focal length. Tapping on 'Sensor' and 'Aperture' just shows a blank pop-up, hence rendering the app rather useless.
4 people found this review helpful
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Joe Scotto
January 9, 2019
Hello, the hosting company that mmCalc uses encountered a massive outage on January 3rd to 5th 2019. We have since moved away from this host due to their error. Please try the app again, you should no longer have an issue.
Simon Grady
June 22, 2021
Can't give a good rating because crop factor does not affect fstop. Happy to change my review if/when this is corrected. Focal ratio is a relationship of physical parameters, which are not altered by crop factor. In other words, the actual physical focal length is the same in a crop sensor camera, the angle of view is narrower AS IF the focal length was longer. Of course - it is not physically longer, so the f ratio remains the same. Let's nip this unscientific myth in the bud eh?
1 person found this review helpful
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Joe Scotto
November 8, 2021
Hello, Crop factor actually does impact the perceived f-stop. The lens regardless will always let in the same amount of light but the actual depth of field will overall be less as you will have to reposition your shot due to the crop. This is explained in the app when you run a calculation.

What's new

Fixed a bug where clicking "Show Lens Modifiers" would instantly open the teleconverter input.