Advantages of Foveon sensor Locked

Started Jun 23, 2013 | Discussions thread
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bobn2
Forum ProPosts: 32,299
Re: Advantages of Foveon sensor
In reply to Lin Evans, Jun 23, 2013

Lin Evans wrote:

Bobn2 wrote:

Lin Evans wrote:

Bobn2 wrote:

Lin Evans wrote:

Hi Mike,

The issue with color "accuracy," as you say, is primarily one of post capture processing, however, no amount of post processing can retrieve subtle variations of hue which were not captured in the first place.

No Bob,

This is exactly the problem with the CFA sensor. If subtle variations of color are not captured - and they are often not captured with CFA sensors, then they can't be reproduced in the finished image or print.

The facts are the facts. Your subjective preference is your preference. There is nothing wrong at all with you preferring the Foveon's colour response, but it is simply not as accurate as the organic colour filter. You should be able to express your preference without needing to bend fact to make your preference somehow 'factual'.\

No Bob,

What you present as "facts" are not facts at all. They are "your" suppositions based on what you have read. When theory and practice collide and practical experience doesn't match theory, then practical experience trumps theory. This is true in science or in the real world.

It depends on the 'practical experience'. The 'practical experience' of the people who tell you that a copper bracelet reduces rheumatism, or the 'practical experience' of people who tell you that they were abducted by aliens, etc. In short, old wives tales don't equal 'practical experience'. What equals practical experience is properly conducted and rigorous experiments. And, surprise surprise those back up the theory. The CIE colour vision model is not a new thing, it has been the basis of colour reproduction technology since the 1930's. This stuff is pretty well understood, and what is clear is unless the filters match the correct three stimuli frequency response, you will get metamerism (incorrect colours).

Your 'practical experience' simply says that you prefer the colour rendering of your Sigma to the 'correct' rendering - as I said, that is your privilege, but don't pretend that your preference is a universal truth that everyone else must accept.

No Bob, What you have done is present what you "think" is actuality. It's not me who is creating a fantasy. I "know" what I get from my very large collection of both Sigma and pro-level CFA cameras. You present yourself as an "expert" on Foveon sensors, yet you have yet to demonstrate that you know anything at all about them except what you have read which fits your own quite obvious bias. You are sounding very much like a Joe W. "mini-me" here.

Joe Wisniewski, a man who has actually designed Foveon sensors into equipment. Someone who actually knows how colour reproduction works. So, if I sound like him, it's not a surprise. He's right and I am too.

I have told you that CFA sensors have very poor color resolution.

You have then told me an untruth.

It has been demonstrated "scientifically" by color resolution chart photography multiple times and right here on dPReview.

I have never seen such a scientific demonstration. Maybe you could reference once such.

If the sensor can't "resolve" the colors, all the "organic" filtering it the world can't produce the colors.

Totally meaningless. The colour filters provide the colour separation between the three colour channels. They do it more effectively than do the silicon filters of the Foveon sensor, they have a sharper cutoff which more closely approximates the required RGB primaries.

Interpolating colors simply is not as accurate as primary detection of colors.

Again meaningless. Sampling RGB values at every pixel position does not by itself produce more accurate colour, especially if the filters are a poor approximation to the standard primaries. All it means is that there are more bad primaries. In any case, when you display as a JPEG those chroma channels are going to be decimated in any case, throwing away any extra colour information you think you might have (one reason why the comparisons done here using JPEG images are meaningless).

In any case, the colours produced from a Foveon raw are far more highly 'interpolated' in the colour space than they are from a Bayer camera. Those require simple linear weighting to produce the standard primaries, while Foveon's require complicated non-linear maths to get a reasonable result.

Now you keep right on arguing and presenting your irrelevant "data" and you go right on believing what you wish to believe. But "please" stop trying to tell people who actually "use" this technology that they are blind and incompetent.

I cannot stop because I never started. I haven't told anyone who actually uses this technology that they are blind and incompetent, and it is dishonest of you to suggest that I have.

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Bob

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