Michael Reichmann's take on smaller full frame Sony FE mount lenses

Started Dec 18, 2013 | Discussions thread
Anders W Forum Pro • Posts: 21,468
Re: Totally different measure

Erik Magnuson wrote:

Anders W wrote:.

And why would selecting a measure on the ground that it is supposed to maximize the advantage of larger sensors be appropriate in the present context?

I thought the context was do larger sensors actually acheive the full theoretical advantage of size. Look at where I entered this thread.

Yes. That is the context. The extent to which larger sensors actually achieve the full theoretical advantage of their size depends on their efficiency. Efficiency is indexed by quantum efficiency as well as read noise. Consequently, you need measures of efficiency that, together, appropriately captures both aspects, like those I used.

If you are right about that, the implication is simply be that the efficiency advantage of smaller sensors is even greater for read noise than for photon noise

If it's not related to sensor size then it's merely a choice by the sensor designer -- not intrinsic to a smaller sensor but just an artifact of current implementations.

So what? As soon as we move from the theory to reality, we are dealing with current implementations rather than the intrinsic properties of size alone. The question is how the current implementations tend to fare with respect to efficiency. And the answer is that larger sensors tend to fare worse than smaller ones.

So are you saying that Canon shooters are just a bunch of wishful thinkers fervently trying to rationalize their poor purchase decisions?

Now why would I say that if I'm mostly a Canon shooter?

So what are you actually saying in this regard?

The scenario to which I referred you and others for a comparison of DR versus SNR-18% was the well-lit DPR studio scene,

It's about how you weight visual impressions of noise from that scene.

Certainly. And my point is that DR works better as a single measure of perceived IQ even for a fairly well-lit scene like this.

Furthermore, the presence of fine detail reduces the visibility of noise. This is true regardless of whether it is shadows, midtones, or highlights we are talking about.

This depends on the character of the noise vs detail. I.e chroma vs luma noise, banding patterns, etc.

No it doesn't. You see noise, no matter which form it takes, more clearly in smooth areas with little detail.

Consequently, it is sometimes a better idea to add more NR in the highlights rather than in the shadows. The image below is an example where I did exactly that. The sky, where there is hardly any detail to be preserved, was given more NR than the more detailed darker foreground

This is exactly my point. It's about where you have important detail.

No, it doesn't match any of the points you have previously made at all.

rather, my point is that if we insist on using one single number rather than multiple measures, then DR is preferable to SNR-18%,

For comparing light gathering capability? For comparing literal DxO measurements?

No. As already pointed out, for the purpose of gauging IQ as we visually perceive it (as far as noise is concerned).

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