Too many Megapixels?

[Phil1974]

I always thought that the big advantage of full-frame sensors was the larger surface area allowing for bigger photosites (?) which meant improved light gathering and less noise. With today's cameras offering up to 50 megapixels (Canon 5dsr) is there a point when there are too many photosites crammed on to the sensor, meaning they are being made smaller and therefore no better than their APS-C siblings?

 

[Kodiak Qc]

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It is not only about the MPs in themselves, Phil, cause if it was, I
would vote for you and give you right. MPs alone are a nonsense!

A higher count of MPs means a lot more developments under the
hood: faster processors, greater buffers, and software performance
do complete the higher pixel count in the recording of data and give
it its sense. These improvements translate in higher native ISO, equal
or better low light performance, cool noise reducing processes, faster
data transfer, etc.

I now have four cameras with 12. 24 and 2 with 36MPs and they all
have the role in my (our) production: sometimes as main shooting
tool and other time as BU bodies.

When is enough? Enough is defined by your end use of the captures.

 

[Sejanus Aelianus]

is there a point when there are too many photosites crammed on to the sensor, meaning they are being made smaller and therefore no better than their APS-C siblings?

The laws of physics would appear to say "yes". This chap has a very clear explanation of the basics: http://www.clarkvision.com/articles/does.pixel.size.matter/

On the other hand, as technology develops, that which is impossible today becomes possible tomorrow and commonplace the day after.

 

[woof woof]

I think that if higher MP counts are accompanied by electronics designed to get the best out of them the possible downsides of the higher MP count can be mitigated. For example on chip analogue to digital conversion, back lighting etc... these things help. Another thing which could help is downsizing the final image to your required size and that's an option which may become more realistic with higher MP count and larger chipped cameras.

My 24mp Sony A7 thrashes my 12mp Canon 5D

 

[Nawty]

FF is 'better' as it requires less magnification for any particular image, simple as that really.

 

[snerkler]

FF will still be. We know that the 5DS/R doesn't have the best sensor performance, but it still has significantly better noise handling than the 7D2. Neither can compare to the mighty impressive A7R2 in this area though, the Sony with it's 42mp has better noise handling than FF cameras with much less MP, even better than cameras like the D750.

http://www.dxomark.com/Cameras/Comp...R-versus-Canon-EOS-7D-Mark-II___1035_1009_977

And even the DF which is 'only' 16mp
http://www.dxomark.com/Cameras/Comp...sus-Nikon-D750-versus-Nikon-Df___1035_975_925

 

[sk66]

I always thought that the big advantage of full-frame sensors was the larger surface area allowing for bigger photosites (?) which meant improved light gathering and less noise.

The benefit here is the larger sensor area... the size/number of the pixels is irrelevant (what Ned referred to).

With today's cameras offering up to 50 megapixels (Canon 5dsr) is there a point when there are too many photosites crammed on to the sensor, meaning they are being made smaller and therefore no better than their APS-C siblings?

There are many different benefits to a higher pixel density (greater MP), most of which come from "oversampling." When you have more sample points (pixels) you get more accurate information (i.e. color). It may be "less" information (light) per sample, but the information gets combined for a result of "same total w/ greater accuracy" as another sensor of the same size. This is also one way of eliminating/preventing moire, and has allowed for the elimination of AA filters for cameras with very high pixel densities.

The increase of MP's has largely resulted in sensors with resolution capabilities that most (no?) lens can match. And even if the lens could, the situation/photographic requirements usually won't allow for it. The small pixels are typically operating with some level of diffraction limiting and this also eliminates the need for an AA filter.
But even with these limitations, the higher sensor resolution (almost) always generates an increase in recorded resolution. It's typically *much* less than one might think... i.e. a 24MP sensor may only record 1MP more than a 10MP sensor with a given lens/settings.

The only question is, do you actually need these "improvements," and are they worth the "penalties?"