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Re: [OM] dumb question

Subject: Re: [OM] dumb question
From: Moose <olymoose@xxxxxxxxx>
Date: Thu, 05 Mar 2015 16:28:45 -0800
On 3/5/2015 3:20 PM, Bob Benson wrote:
Something I just haven't quite understood .

Why would a D4 or D4S (16.4 meg) image be different/better than an M1 (16
meg) image?

Fuji X-M1? Oly E-M1? Doesn't really matter, as they will be very similar right 
down to the pixel level.

That is,  what quality factors are enhanced by a physically
larger sensor but with the same pixel count?

The most important factors should be* Dynamic Range and high ISO noise.

Each individual sensing unit, called a sensel, is larger on the FF sensor. It can generally react to a lower photon density than a smaller sensel because of its larger surface area gathering light for the single semiconductor junction. It also should have a bigger 'bucket', able to 'hold' more total light than the smaller one.

The top end of DR is defined by the point at which the sensel becomes full. The bottom end is more loosely defined as the point where noise overwhelms signal. A larger sensel will generally improve both ends, for the reasons above.

Just the same factors generally allow larger sensels to have lower noise at 
higher ISOs.

All those "should"s and "generally"s are because designers may choose to optimize different factors in different sensor systems.

I have personally encountered some years ago a situation where the APS-C sized portion of a FF sensor actually resolved slightly more fine detail than an APS-C sensor with more pixels than the equal area on the larger sensor. So there are other factors at work, AA filters, inter sensel leakage, and I don't know what else.

And sensor technology continues to improve, so age of the design is a factor as 
well.

I guess I understand the DOF aspect, but what else would be in play?

What Size Moose

* I say 'should' because I have no personal knowledge about any of these 
cameras but the E-M1.

--
What if the Hokey Pokey *IS* what it's all about?
--
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