how to compare camera to mobile phone?

Started 1 month ago | Discussions thread
Michael Fryd
Michael Fryd Forum Pro • Posts: 10,884
Re: how to compare camera to mobile phone?

SergeyAU wrote:

there was a discussion before about why phones seem to take better pictures these days. I am just trying to work out a simple formula to convert settings that my s9 has taken pictures with to settings on my Canon M100

S9 crop factor is 6.1 (1/2.55" sensor)

M100 crop factor is 1.6

Is there a simple calculator somewhere to convert aperture, shutter, ISO from one size sensor to another?

If phone used f1.7, 1/125, ISO 1200, what should I set my camera to for a similar looking picture?

The short answer is that you multiple by the focal length and the f/stop by the ratio of the two crop factors. In your case you multiply by 6.1/1.6 or 3.8

As you are using a different f/stop, you will need to use a different ISO setting.  Set your mirrorless to Auto-ISO.


The general rule is that you get the same depth of field and same shot noise (the noise inherent in the light itself) when the angle of view, aperture diameter and shutter speed are the same.

Aperture diameter is the actual focal length divided by the f/stop. For instance, a 100mm lens at f/4 has an aperture diameter of 100mm/4, or 25mm.

The formula for finding the matching focal length on your mirrorless camera is

Smart-phone-focal-length * Smart-phone-crop-factor / mirrorless-crop-factor

Suppose your mirrorless had a 1.6X crop factor, and your smart phone had a 6.1X crop factor and an actual 4.6mm f/1.7 lens.

You would need a 17.5mm lens on your mirrorless: 4.6mm * (6.1/1.6)

In order to match the depth of field you also multiply the f/stop by the ratio of the two crop factors.

1.7 * (6.1/1.6) is 6.5

Therefore the 17.5mm lens on your crop body would need to be at f/6.5

Keep in mind that this formula matches only depth of field, angle of view, and shot noise.  It does not compensate for different processing, or different sensor efficiencies.

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