[Digitalis]

I prefer weak AA filter (or no AA filter) with good sharpness + outstanding lenses than high ISO. D3s has 12 MP CMOS, M9 has 18 MP CCD.

I will admit that leica lenses are extremely good, but also consider the limitations of using a rangefinder.. They don't have any current production lenses over 135mm and they don't have any lenses that focus accurately at distances less than 1 m without the annoying limitations of a rangefinder system.

- For what they are rangefinders are extremely good, but within a narrow scope. at leas an SLR lets you see the focus errors coming. People complain that SLR cameras are unreliable and at the same time hand in their leica cameras for a service every year.

[ogl]

I will admit that leica lenses are extremely good, but also consider the limitations of using a rangefinder.. They don't have any current production lenses over 135mm and they don't have any lenses that focus accurately at distances less than 1 m without the annoying limitations of a rangefinder system.

- For what they are rangefinders are extremely good, but within a narrow scope. at leas an SLR lets you see the focus errors coming. People complain that SLR cameras are unreliable and at the same time hand in their leica cameras for a service every year.

As for me, I never used anything longer 135 mm in film era and now.:ugh:

[Class A]

First and most of all, colors are defined by the raw converter and can be adjusted to personal preferences, also in camera.

What about the choice of tristimulus basis, i.e., the peak responses of the R, G, B colour filters? Are they the same for each sensor? I doubt it.

If the colour basis differs between two sensors, you can tweak the conversion process for one to coincide with the other for one particular image, but not for all images.

[falconeye]

What about the choice of tristimulus basis

The human eye has its own tristimulus basis. A bad choice by a camera leads to a bad metamerism index.

[Unsinkable II]

The human eye has its own tristimulus basis. A bad choice by a camera leads to a bad metamerism index.

While you are the most informed contributor on any forum I visit, I must call you on this... bollox!

Daily vision gives the baseline, not the occasional (in comparison) viewing of light translated through a machine/computer.

Same with sound.

[falconeye]

While you are the most informed contributor on any forum I visit, I must call you on this... bollox!.

I may not be informed. But I am curious. So, please feed me so I can improve

Daily vision gives the baseline, not the occasional (in comparison) viewing of light translated through a machine/computer.

I must confess that I don't see where we disagree. I don't know for you, but my daily vision is done with my own eyes. And biological eyes do have photoreceptors with defined spectral response curves...

[RonHendriks1966]

Well I'm surprized that the CCD is that good in comparisson to the CMos sensor. On the other hand this valids the pictures I took with the 645D on iso1000 on PhotoKina, so maybe I already knew.

CMos is still better in DR.

[Eruditass]

Are there any articles on the D3X and how it apparently beats most of the MF sensors?

I know they don't test sharpness and resolution, but still.

[Class A]

A bad choice by a camera leads to a bad metamerism index.

If the metamerism index is defined that way -- assuming a standard human observer (surely individuals have differing colour perception) -- than that'll be fine.

I wasn't sure whether, e.g., DxOMark just measures RGB separation.

I could image that different sensors use different colour filters to achieve different image aesthetics. Surely a lot of things (colour separation, colour fidelity, sensitivity) must be balanced and there are more than just one "correct" solutions.

I might be wrong, though.

[RonHendriks1966]

When I look at this comparisson with the D3x and the 1Ds Mark III the 645D holds its ground good, it's just not a sportscamera we all know.
DxOMark - Compare sensors

[falconeye]

If the metamerism index is defined that way -- assuming a standard human observer (surely individuals have differing colour perception) -- than that'll be fine.

I wasn't sure whether, e.g., DxOMark just measures RGB separation.

I could image that different sensors use different colour filters to achieve different image aesthetics. Surely a lot of things (colour separation, colour fidelity, sensitivity) must be balanced and there are more than just one "correct" solutions.

I might be wrong, though.

Well, Unsinkable II thinks I know nothing about this, so take my response with a grain af salt

Neverthless, I'd say that the usage of different colour filters to achieve different image aesthetics is not an option. Humans perceive colors they way they do. Their perception was measured in field tests and turned into norm ISO 17321.

Actually, the studies for these norms were originally done to classify the naturality of light sources but serve well to test camera colors as well.

The test basically measures the deviation of a camera's RGB response from a standardized RGB response, for something like twenty or so color patches produced in a standardized process (not cheap to aquire). You see the patches in DxO's full color spectrum charts. The standardized RGB response is derived from a patch with known tristimulus values where a majority of humans say to see the same color.

In order to achieve a metamerism index of 100, the color filters would have to replicate the exact spectral response curve of the three types of human cones. This article contains interesting information about the spectral sensitivity of the eye and semiconductors:
http://www.astro.rug.nl/~sctrager/teaching/observing_techniques/Detectors1.pdf

It is known that Canon has a not very selective red channel (and DxO measurements confirm this, cf. the RGB calibration matrix coefficients). Therefore, the color noise is a bit amplified and color sensitivity is a bit reduced. However and surprsingly, the metamerism index for Canon cameras is not worse. The metamerism index doesn't change if you add one channel response curve to another if they originally didn't overlap.

[yusuf]

As per DXO, K-5 seems to have better DR and color depth. DxOMark - Compare sensors

Is that?

[rawr]

As per DXO, K-5 seems to have better DR and color depth. Is that?

Yes, marginally.

But don't forget the 40MP vs 16MP difference. 645D is medium format and K-5 is APS-C DSLR. They aren't direct competitors.

[falconeye]

the K-5 uses a back side illuminated CMOS sensor

Incorrect.

[Class A]

Incorrect.

To elaborate: Only the EXMOR-R technology implies back-illumination. The "standard" EXMOR technology does not.