Don_Campbell wrote:
Coyote_Cody wrote:
Don, thanks for the responses.
In the regard to "raw is raw', well obviously that may not be true if CHDK is 10 bit and Canon is 12 bit, Correct?
I said "raw is raw" with respect to noise in the raw image. Real raw files have no noise reduction applied. Most folks only view raw files after importing into an application that will apply some tweaking in making them visible. DPP opens the raw and automatically applies NR--at least in my hands on my machine in a VM of Windows.
I agree, I have LR4 & it seems all my raw files CHDK or Canon are noisier or at least different vs. my DSLR .cr2 raws in DPP for instance.
DPP does not process DNG's nor the other CHDK raw available. The simple reason I read is that the raw files on various P&S are all different sizes, 8mp vs 10mp vs 12mp vs this cam & that cam, and each new/diff P&S would have to have a customized bit readout (nibble/byte order, arrangement,etc - no generic solution) thus making a real '.cr2' file, DPP readable, too cumbersome lots of work. This is Canon's fault, no consistency, offsets for this & that change even for same cam but diff versions of f/w (f/w would not work for Canadian sx260 but worked for US version - diff versions- 100b vs 100c all because of adding french language supposedly)!
The issue of 10-bits vs 12-bits is a real issue if it's true and how do we find that out? I sure don't know. The 12-bits per channel statement I took as most authoritative is from a Canon PR. The 10-bits number is based on a statement in the CHDK forums by the CHDK authorities in 2008. Is it still that? Who knows?
The CHDK DNG is a dump of sensor data (found in the memory of the camera-part of porting issues) into a DNG formmated file structure (the other CHDK raw file is pure sensor data & generally not useful as you noted), nothing more or less?, thus the bit depth is whatever it is, provided by the sensor hardware/fw in camera, unless CHDK is processing the raw data with DNG software tools of some vintage age that can not do more than 10 bit in the file structure, throwing away the extra data, DNG certainly supports more.
"Pure sensor dump" is words without detail or the voice of authority. The only authoritative words I've found suggest that DNGs produced by CHDK are limited to 10 bits of color depth per color channel. Until we get something authoritative that is different about the SX50 it stands as a worry.
"Pure sensor dump" refers to the 'un formatted' raw you can get from CHDK (part of porting is finding the offset in memory of the sensor data, then determining how much data to read, how to read each 10 or 12 bit part, its order, etc, I believe/refer to this as the the non DNG raw data file offered by CHDK), it can be read by some software that knows how to interpret them, but I never saw it work correctly when trying several of the less popular/special s/w apps for this file type, thus I started using DNG raw only.
In case you don't know, If you get a 'chunk' of bits, it can be anything, so you must know what those bits are, 'their format'. You may need to read the bits in 8, or 10 or 12 bit chunks to get the byte or 10, 12 bits for the Red channel, the the green channel..... etc, or these 4 bits need to be the most significant bits of the 12 bit data for the Red channel, etc, you must flip them, so reading and formatting into DNG is not a 'blind' or auto process.
That is partly what CHDK sx50 porters are doing, and if they are getting successful raw photos from a sx50 then they have figured out how to read the sensor data correctly, but if they are chopping off 2 bits per channel because of DNG format limits, that will be VERY disappointing for all. I hope not.
The 'real' bit depth I believe is purely a function of the camera Hardware sensor D/A converter not s/w, although it may be f/w selectable (ie bit depth selectable depending on sensor hardware- have seen this) and if it is s/w then why not offer a bit depth of 16 or 24 or more for all cameras?
Whoa. It is the A/D converter that is at issue here. But it is also how that information gets mashed into a DNG format. How they do that may be by some convenient algorithm that they (CHDK developers) have no particular interest in changing for one camera or a few cameras.
You are absolutely correct, I meant A/D not D/A & true again about a special '12 bit' algorithm, but as mentioned above how do they know what bits to ignore, the sensor data is just a bunch of bits, so they would have to know which bits to ignore??
No it is a function of the D/A in camera, so why would CHDK reduce it somehow, I suspect the 10bit statement is from earlier years as P&S cams are/were 10bit depth, not 12, 14 or 16 bit. It lessens the file sizes & DSP processing the less the bit depth.
Sorry. You sidestep the idea that stuff in CHDK is in at least two parts: the algorithms and routines that work for all cameras; the special "glue" that links to those routines for a particular camera. I can easily see how they wouldn't create 12-bit per channel data handling software for one or a couple of cameras. I can also see that they might have worked out ways to let the camera do its own thing for raws and just kept CHDK's hands off. I don't know.
As above, the sensor data is just memory in ram, they must discover the offset to its beginning and its size and then must read it bit for bit, nibble by nibble and interpret it correctly to get all the GRBG at whatever bit depth correctly, no half way here, it must be correct of it is WRONG, so if they can 'interpret' it correctly, then stuffing it into DNG would be the relative easy part IF DNG is an open standard as implied, then they just indicate in the file it is 12 bits not 10, or is it just a stupid file header value, hope not.
What would be nice is if they left the 12-bit per channel paths in the software and let the camera produce its own raws and allowed it to do that for a wider range of camera shooting modes than is allowed in the stock camera. I have no idea if that's what will be done or has been done with other cameras.
The camera does produce it raws, Canon (as others said) does NOT apply their fancy/special algorithms to raw .cr2 output whereas they do to jpg outputs.
I suspect it is simply Canon has not broken up their 'special software stuff' away from their jpg processing algorithms. Likely it would need a major re-write of their 'Power shot' algorithms/code segments and they were not willing to do it. Maybe next generation?
Does the S95/100/110 get those special processing for their raws (jpeg+raws)?? If so then why not sx50, if not a re-write is in order!!
It might be DSP speed for jpg-raws (extra work for 2 file ouputs) but it would NOT be DSP speed for processsing ONLY raws with these specials.
As mentioned elsewhere, CHDK usually does not put the same limits on things that Canon does, but I have seen issues of Auto mode vs Program mode and ported things NOT working in both modes, we will see!
As to the 'lens distortion', IF you do not see lens distortion via Canon raw files, then SURELY Canon is processing the raw file either in-camera or RawT. is auto-magically before you see it, because it is there.
I don't "see" the raw file in raw format. The only way I "see" a raw file is as imported and preliminarily processed by a converter software package. I don't know what level of geometric processing has happened where in the chain of data movement.
LR4 shows the CHDK DNGs unaltered UNLESS it is one of their 'recognized' cam/lens. Since NO P&S Canon other than a handful (S95/S100...) are 'thought' to have or need raw processing, then it never recognizes them and thus it NEVER applies any processing at all, as it does not have data to do such.
I have added lens correction file for my 300hs in LR4 but I must initially manually enable it in the 'lens correction' section of LR4, whereas for my DSLRs it recognizes most of my lens and you can choose to use it or not, but it does pre-process the photo to a degree, it has pre-set values, a best guess, but can be canceled and overridden.
Once you add a lens correction file for a cam/lens, it will use it automatically but you can disable or manipulate if wanted, also you can 'create' a generic raw setting of all settings and then LR4 will 'auto' apply them, good and bad IMO.
Lens distortion in the sx50 should be seen in Canon raw (I certainly see it in DPP with my DSLR's & Canon lens) & certainly will be seen in CHDK DNG files, thus the questions of the 'barrel' being seen in widest angle shots.
I can't say that I remember if any 4.3mm wide angle images were among those I've looked at in DPP. I've used DPP almost not at all. I've used RT almost entirely as a converter of DNGs to standard color images. The Adobe DNG Converter program certainly produces corrections for lens distortions. You may be right that DPP would show that lens distortion for a photo taken at a 4.3 mm focal length.
Not DPP but LR4, DPP does not process DNGs, only .CRW & .CR2 raws and maybe TIFFs, as well as jpgs.
I think the sx50 has more than raws as a benefit over the sx40 but still not sure worth $160 or more, I will test/play with one next week.
You'll have to look deeply into the various strengths it has. I would never (and didn't) buy an SX40 to replace my SX20. I did buy an SX50 to replace it and did so only after reading user's reactions, reading reviews and seeing photos that the camera produced. I knew that the EVF was woeful (way worse than the SX20's) but that users were having a lot of fun and taking nice photos. When the camera went on sale in my town I bought it. I have been very happy with image quality for a small sensor camera. I accept the woeful EVF which I knew it had.
To me, the photos from sx50 look the same as sx40 which look the same as my 300hs, they all use the same basic (GOOD) sensor, the CMOS BSI 12.1mp (thank Canon for no 16mp sensor crap), my DIGIC 4 processor in 300hs is as fast as DIGIC 4/5 in sx40 or faster than DIGIC 5 in sx260hs and does many of the same special modes as fast.
So it is NOT really the jpg quality, they are the same to me (I tested sx40 even using CHDK last year), but the lens, the 2 buttons on front for framing, etc, the EVF is worthless to me (same as sx40) so I am thinking of the overall package is it worth the extra $$, ??
Thanks for all the input!! I do look forward to playing with the sx50 next week!
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