70D Dynamic Range is actually great, despite what DXOMark says

Started Jan 21, 2014 | Discussions thread
TTMartin Veteran Member • Posts: 7,304
Re: 70D Dynamic Range is actually great, despite what DXOMark says

janfi67 wrote:

Oh yes, please... prove me that my lovely Canon camera is better than DxO and other say. Explain me why they are all wrong and why the DR is far better than 11EV. I can't wait to know.

Yes, keep believing that the Canon 6D, 1DX and every other Canon dSLR using the CR2 file format including the original 2003 APS C Digital Rebel have basically the same per pixel DR, because DxOMark says so, despite substantial evidence to the contrary.

Hummm... Like all photographers, I can only use the RAW files, not the sensor output. So I only care about what the RAW file contains and what I can do with it.

Then you should care that Canon Digital Photo Professional (DPP) does a better job at decoding the RAW file, and not what testing sites using a 3rd party RAW converter say.

Do you think Canon doesn't apply some kind of noise reduction prior the RAW file being written? Never heard of CDS? It's embedded in the sensor itself (including the Canon ones) and it's a noise cancellation system.

If all manufactures apply some noise reduction prior to the RAW file being written then what exactly is DxOMark testing? Certainly not the sensor performance like they claim.

You seems misinformed. Take a look at public domain RAW converters sources and documentation. After reverse engineering they use data provided by the masked portions of the edge of the sensor to reduce the noise.

When I looked at DCRAW, it did not. If I am wrong please post the portion of code that uses it.

And how can you tell than products like DxO or ACR don't use them?

Because their conversions contain more noise than those converted with Canon DPP.

Are you aware of all the details about CR2 format Canon discloses only under NDA?

Are you? Can you name someone other than a Canon employee who is? And anyone working on reverse engineering the CR2 file would be in violation of their NDA, so any implication that you or anyone else has more knowledge about what Canon actually does in the CR2 file is just a red herring.

This is one of the funniest part of your post, and once again, you're wrong.

Do you realize what does recording RAW data in sYCC mean? I don't think so, despite the picture you post.

An sYCC encoded image is obtained AFTER DEMOSAICING the CFA RGB data. It's not a RAW format.

This is where your thinking falls apart. You assume because the original Canon CRW format and Nikon NEF used a certain format to encode their RAW data that Canon had to be constrained by that when they developed the CR2 format. A RAW format is what the manufacturer wants to use to maintain all the data from the sensor. Sorry, the manufacturer does not have to be constrained by your definition of how sensor data is maintained in the RAW file.

Switch a Nikon D300 to 14 bit NEF and it slows to 3 fps, the Nikon D7100 isn't much better. So you don't think it's possible that when Canon developed the CR2 file format that they recognized that in order to move 14 bit RAW data more quickly that they had to find a different way to encode it?

For your information, Canon sRAW formats use YCC encoding, but they aren't RAW format per se, and they are not used by DxO to perform their tests. It's a kind of lossless jpeg, but using 15 bits data for the 3 components, Y, Cr and Cb, not 8 bits like traditional jpeg.

sRAW is not a RAW format because you say so? Canon says it is a RAW format. Again a RAW format is whatever format the manufacturer wants to use to maintain all the necessary data from the sensor.

It seems you have no idea of what the CR2 format is, and how it differs for 6D compared to previous Canon cameras. There are many differences that can explain a RAW converter that doesn't know the 6D exists fails to convert a 6D image.

For example, since Canon 50D and digic IV, CFA RAW data are encoded in 4 components into the CR2 files. The 6D (and the 1Dx) use only 2 components. Tricky for a RAW converter, isn't it? This has nothing to do with sYCC.

No, it is an example of how the CR2 format hasn't been reverse engineered. Each camera that comes out, 3rd party RAW converters have to go in and look for what data that they can find that matches their concept of what RAW data should look like. And then force that round data into a square hole.

Once again, you don't understand what you're talking about. HSL is used in Canon picture style editor. It has nothing to do with demosaicing.

Any time you demosaic it has to be done into a color space. And this is just another clue that Canon isn't simply using RGB to encode the data in the CR2 file. 3rd party RAW converters demosaic using the assumption that the data is in an HSB color space like the CRW and NEF formats use. It's clear from the Canon Picture Styles that Canon is using the HSL color space in camera (Picture Styles affect in camera JPG processing). Canon writing the RAW data into the HSL color space would explain why Canon is so much more efficient in moving RAW data.

I'm really disappointed. I expected strong evidences, solid technical arguments. But no, it was only blabla and technical words ans concepts not understood by a Canon fanboy.

Ditto, except what you be called a DxOMark fanboy?

By the way. I'm very happy with my Canon cameras even if they have less DR than other brands.

Maybe that's because they really don't.

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