Reading resolution charts comparing MFT lenses to FX lenses

Started Mar 29, 2013 | Questions thread
Anders W Forum Pro • Posts: 21,466
Re: Speaking of Flat Earth believers ...

Daniel Lauring wrote:

Anders W wrote:

2. With respect to light accumulation (and thus photon noise), DoF, and diffraction, however, f-stops have to be divided by the square root of the sensor area in order to be equivalent. For example, if x is the f-stop on FF and y the equivalent f-stop on MFT, then

y = x / 2

since the FF sensor area is approximately four times the sensor area of MFT, and the square root of four is two. For example, if x is 8 then y is 4 so that f/8 on FF is equivalent to f/4 on MFT.

This is the toughest concept for people to grasp.  Based on this, a FF sensor can do everything a smaller sensor can do, as far as getting shallow DOF, you just need to stop down.  However, the inverse is not true because of the limits of the lens hardware.


Having said that, many FF advocates also fail to understand that more DOF is very often a good thing.  Lighter weight in many cases certainly is.

At least some FF advocates fail to understand these things yes. But Great Bustard certainly isn't one of them.

Finally, diffraction limits are not hard points.  They are just another point in the resolution chain that includes DOF, camera shake, focus accuracy, ISO noise...etc. etc.  Sometimes you trade one off for another.  For example macro shooters regularly trade off diffraction for DOF, often shooting up at F22.

Sure. The point here is that all formats are equally heavily affected by diffraction at the same DoF (but different f-stops). In that sense, the smaller sensor doesn't buy you any DoF advantage (as is sometimes thought).

The primary advantage of the smaller sensor is that it translates into less bulk and lower weight, not least when it comes to the lenses, provided that you can live with the fact that the lenses are not equivalent to FF lenses with the same max aperture (f-stop). And that advantage can, if you want, be converted into greater versatility, and in the end better IQ, simply because you are able to have more equipment (e.g., lenses) with you within the same bulk/weight restrictions. This is one of the most important reasons why I am using an MFT rather than an FF system.

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