Spring 2012

Spring 2012
by ani

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Have there been any change in Canon's RAW (CR2) format in the Canon EOS 70D camera, comparing to older models like the EOS 60D?

I could not open the 70D RAW files in Photoshop on a friend's computer, while 60D RAW images are opened without a problem.

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up vote 10 down vote accepted

In general, RAW file converters, including Photoshop, will only open RAW files from camera models they know about. There's nothing special about the 60D to 70D transition here; you don't say which version of Photoshop (to be specific, raw files support depends on Adobe Camera RAW plugin which is updateable either with Adobe's update tool or through installer) your friend has, but presumably it's not the latest, which does support the 70D.

However, that only answers half the question: why do the RAW converter manufacturers do this? The answer to that is because while the data contained in the RAW file doesn't vary much - at a coarse level, it just contains a sequence of values read by every photosite on the sensor - how to interpret those values can vary significantly between two camera models from the same manufacturer. This may be more true than most for the 60D and the 70D due to the 70D's significantly different "Dual Pixel AF" sensor structure, but it applies to any new camera.

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Yes. Every camera with a proprietary raw format – any raw file that doesn't have a .dng extension – will need to be supported separately by each raw converter, even when it has the same file extension as other cameras that are already supported.

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Even RAW convertors that can handle DNG files need to be updated to accommodate new models. – Michael Clark Dec 25 '13 at 23:59
True, as the camera's profile still needs to be established, even if the file itself may still be able to be read. I use a Ricoh GR, which records DNG, and Lightroom 4 can open its files even though it lacks the colour profile and lens data that's included in LR5. Conversely, DxO Optics lost its ability to read those same DNG files after a firmware update changed the manufacturer name. So clearly there's no such thing as a universally readable raw file. – mpr Dec 26 '13 at 0:12
It is even worse than that. If you use Adobe's DNG convertor to convert RAW files from a newer camera to be DNG files compatible with an older version of ACR/PS/LR then demosaicing may not produce accurate colors if the exact colors of the Bayer filter are slightly different in the newer model. This can usually be corrected through WB fine tuning. But some newer models have even changed the sequence of the R-G-B masks in which case really weird colors can result. – Michael Clark Dec 26 '13 at 0:20
Right. Universal DNG is a myth or an approximation at best. Several cameras have required even revisions to the file-format itself and its header contain flags to flag Fuji sensor particularly for example which have had offset pixels, hexagonal pixels, photosites of different sizes and, of course, a completely different color-filter array now. – Itai Dec 26 '13 at 5:29

I had the same issue, and looked up which versions of Lightroom, Camera-Raw, PS were required. In my case updating Camera-Raw plugin allowed my version of PS to read them, but I could not do so with Lightroom. So, I went with Adobe's free DNG converter.

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Part of the problem here is that Canon is not consistent, and does not follow normal conventions, in their file name suffixes.

The original Canon RAW file was .CRW (Canon Raw). This was changed to .CR2 (Canon Raw Version 2). Then the trouble starts. The CR2 format has been changed. You'd expect therefore to see a new suffix each time the file format changed (e.g. CR3, CR4, ...) but unfortunately Canon kept the CR2 suffix. So now Canon RAW files with a .CR2 suffix can have different formats. Hence image processing software can successfully process some files but not others.

Regarding keeping up-to-date with file formats, Adobe does not seem great. Often you have to "update" LightRoom/Photoshop/ACR to handle the new formats. That in turn can force you to install a later version of your operating system which in turn might need a new computer! [You could imagine that everyone involved in Hi-Tech industry is in a conspiracy to force us to spend small fortunes in this way].

I have found that Iridient is much better at handling the most recent RAW files, and also tends to run on older versions of Operating Systems than Adobe tools. For example there is a version of Iridient that runs on OS X 10.6.8 (Snow Leopard) whereas most other recent software demands OS X 10.6.8 or later, and many Mac users see anything after Snow Leopard as a downgrade!

The important point is that at the time of writing (mid-2016) Iridient copes with all versions of .CR2 up to the latest in the G1x mark ii. I believe the differences are due to the G1x ii's ability to create images in a variety of aspect ratios.

Users of Sigma's cameras might like to know that Iridient is also one of the few developers that can process X3F files ... the RAW files from Foveon's Merrill chip (I cannot say whether it handles the Quattro formats). It is more stable, faster and generally nicer to use than Sigma's own SPP software and, in my opinion, it also makes a better job of them, especially in avoiding blown-out highlights. Adobe did process X3F files from the earliest Foveon chips, as in the original DP1 and DP2 cameras, but have never added support for the DP1/2/3 Merrills, the SD1 Merrill, or the Quattro cameras, and probably never will.

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The data in a RAW file is different for every model of camera. The basic structure is often the same, but differences in the sensor and how the sensor data is processed by each model of camera means that the RAW files need to be processed differently. If the software is not up to date enough to understand how to process the RAW data for that particular camera model, then it can't figure it out. You can try forcing a model with a similar sensor, but it may get weird results depending on how the sensor data is supposed to be processed (mathematically).

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