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Photo Forum / Digital Photography / DSLR Cameras / July 2006Sony's new DSLR RAW files small
>From dpreview: · RAW (12-bit,.ARW format, approx. 9.1 MB per image) Files (RAW) from a 5 meg camera are usually 10 MB, from something like the Nikon D200 they are HUGE. Sony is a 10Meg camera as well. > >From dpreview: > · RAW (12-bit,.ARW format, approx. 9.1 MB per image) > > Files (RAW) from a 5 meg camera are usually 10 MB, from something like > the Nikon > D200 they are HUGE. Sony is a 10Meg camera as well. Obviously the files are compressed, the noncompressed files in the D200 are 15+mb, compressed they vary between 7 and 11mb (my experience). Either Sony is not including some info in the files or they are compressing them. Tom Compression which leads to loss of information....in most cases you wont see it, when you do, there is nothing you can do about it. On my D2X I have it set for uncompressed RAW files, you have the option to compress and lose information but save file space, or leave uncompressed. When information is lost its usually in the highlights. JR > >From dpreview: > · RAW (12-bit,.ARW format, approx. 9.1 MB per image) > > Files (RAW) from a 5 meg camera are usually 10 MB, from something like > the Nikon > D200 they are HUGE. Sony is a 10Meg camera as well. > Compression which leads to loss of information....in most cases you wont > see it, when you do, there is nothing you can do about it. On my D2X I > have it set for uncompressed RAW files, you have the option to compress > and lose information but save file space, or leave uncompressed. When > information is lost its usually in the highlights. Are you sure that they don't apply some form of lossless compression? What would be the point of lossy RAW file? Wouldn't that kind of defeat the purpose? >>Compression which leads to loss of information....in most cases you wont >>see it, when you do, there is nothing you can do about it. On my D2X I [quoted text clipped - 5 lines] > What would be the point of lossy RAW file? Wouldn't that kind of defeat > the purpose? Sounds good for those who don't know how to extract the information and just use a basic conversion program like Irfanview. >> Compression which leads to loss of information....in most cases you wont >> see it, when you do, there is nothing you can do about it. On my D2X I [quoted text clipped - 5 lines] > What would be the point of lossy RAW file? Wouldn't that kind of defeat > the purpose? For reason or reasons unknown Nikon chose to implement a lossy compression algorithm on the D2X. Not one of their better decisions IMO but perhaps they couldn't figure out how to implement a lossless one that achieved a high enough compression level to be worthwhile.  Signature--John to email, dial "usenet" and validate (was jclarke at eye bee em dot net) > >> Compression which leads to loss of information....in most cases you wont > >> see it, when you do, there is nothing you can do about it. On my D2X I [quoted text clipped - 10 lines] > they couldn't figure out how to implement a lossless one that achieved a > high enough compression level to be worthwhile. Just turn it off and forget about it......CF cards are CHEAP now.....I can get a 4gb microdrive for $69...why worry about compression....And for 99% of the shots, you dont notice the compression...I didnt in my tests, but why risk it.... JR >> Compression which leads to loss of information....in most cases you wont >> see it, when you do, there is nothing you can do about it. On my D2X I [quoted text clipped - 5 lines] >What would be the point of lossy RAW file? Wouldn't that kind of defeat >the purpose? To some degree; having posterized highlights as in the compressed NEFs probably reduces the advantage of exposing to the right a little, and creates a little more noise when you boost the saturation of contrast of the highlights, but the shadows are still untouched (up to about RAW level 163, IIRC). 163 would typically be the "middle grey" value of the red channel, and a stop below it in the green channel. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >Compression which leads to loss of information....in most cases you wont >see it, when you do, there is nothing you can do about it. On my D2X I >have it set for uncompressed RAW files, you have the option to compress >and lose information but save file space, or leave uncompressed. When >information is lost its usually in the highlights. That's the Nikon way, but for most other compressed RAW formats, there is no loss; it is like a .zip file. I imagine that RAW data would compress well with separate bitplanes with run-length encoding for the 8 most significant bitplanes, and then 4-bit nibbles uncompressed for the least significant bits. That would take longer to write and read, though, without special-purpose CPUs. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< Sony has no real experience with compressed raw files in their high end EVF cameras. Also they have no experience with tuning exposure to maximize pictorial information captured in the raw format as, for example, Nikon does with its dSLRs. It will be interesting to see what Sony has done with the base Minolta design when these cameras are finally available in the real world. If I had a collection of Minolta auto-focus lenses I would have one of these Alpha cameras already on order. bmoag (aetoo@hotmail.com) wrote in rec.photo.digital.slr-systems: > It will be interesting to see what Sony has done with the > base Minolta design when these cameras are finally available in the real > world. If I had a collection of Minolta auto-focus lenses I would have one > of these Alpha cameras already on order. The Alpha is essentially an upgrade of the Minolta 5D. I'll wait for the Sony upgrade to the 7D. I'll take the ease of use of the 7D over a few more pixels any day. SignatureJeff Rife | "Hey, Brain, what do you wanna do tonight?" | | "The same thing we do every night, Pinky... | try to take over the world." Hi, > The Alpha is essentially an upgrade of the Minolta 5D. I'll wait for the > Sony upgrade to the 7D. I'll take the ease of use of the 7D over a few > more pixels any day. +1 - I was disappointed by this too : the body clearly shows 5D filiation by the lack of rear wheel, and other buttons for direct access to functions, which is /the/ reason why I like my 7D. Regards, SignatureStéphane > world. If I had a collection of Minolta auto-focus lenses I would have one > of these Alpha cameras already on order. I have over $10,000 in 6 Minolta lenses (+2 TC's). I'm in no hurry to buy the A100. It is really a glorified P&S. Sony will have to do MUCH better than the A100 to convince me that they're in the DSLR business. Cheers, Alan Signature-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm -- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm -- [SI] gallery & rulz: http://www.pbase.com/shootin -- e-meil: Remove FreeLunch. Alan Browne (alan.browne@FreeLunchVideotron.ca) wrote in rec.photo.digital.slr-systems: > > world. If I had a collection of Minolta auto-focus lenses I would have one > > of these Alpha cameras already on order. > > I have over $10,000 in 6 Minolta lenses (+2 TC's). Yow. I take it you have a lot of big glass. > I'm in no hurry to > buy the A100. It is really a glorified P&S. Sony will have to do MUCH > better than the A100 to convince me that they're in the DSLR business. I've probably only got $3,000 or so in 7 lenses but I'm still with you on this. Give me a 7D body/control layout with at least some of the good features of the A100 (pixel count, dust shaker, etc.) and I might be tempted, but anything else is just as you say: a glorified P&S. SignatureJeff Rife | "Wheel of morality, | Turn, turn, turn. | Tell us the lesson | That we should learn" | -- Yakko, "Animaniacs" > Alan Browne (alan.browne@FreeLunchVideotron.ca) wrote in > rec.photo.digital.slr-systems: [quoted text clipped - 14 lines] > good features of the A100 (pixel count, dust shaker, etc.) and I might > be tempted, but anything else is just as you say: a glorified P&S. First time out they are probably testing the water. Whether you get your pro spec one will be determined on how well this one sells. >From dpreview: · RAW (12-bit,.ARW format, approx. 9.1 MB per image) Files (RAW) from a 5 meg camera are usually 10 MB, from something like the Nikon D200 they are HUGE. Sony is a 10Meg camera as well. You are assuming that the format is 3 bytes per pixel (although 12 bits suggests that the colour depth is a measly 4 bits each!). There is nothing in the rules to say that they can't use simple space saving techniques (like run length encoding) or more sophisticated lossless compression (like zip or lharc). Even MS Windows XP will compress your raw files without loss (but only on an NTFS drive). OTOH if they apply Jpeg in any but its trivial configurations there will be data loss and (at higher compression) artefacts in the image. > You are assuming that the format is 3 bytes per pixel this is invalid assumption. Each pixel in RAW file holds just one channel information in 12bits, so the "natural uncompressed" size of 10Mpx, 12bit RAW file is 10e6 * 12 / 8 = 15MB, plus metadata overhead . This is certainly true for D200 - uncompressed RAW size is 15.8MB. Given that Sony's RAW 10Mpx image is just 9.1MB, the file is obviously compressed, but there is nothing (yet) to suggest that the compression is not lossless. B. >You are assuming that the format is 3 bytes per pixel (although 12 bits >suggests that the colour depth is a measly 4 bits each!). It suggests no such thing. It suggests that the red resolution is 50%, the blue resolution is 50%, and the green resolution is 71%. Signature<>>< ><<> ><<> <>>< ><<> <>>< <>>< ><<> John P Sheehy <JPS@no.komm> ><<> <>>< <>>< ><<> <>>< ><<> ><<> <>>< >>From dpreview: > · RAW (12-bit,.ARW format, approx. 9.1 MB per image) > > Files (RAW) from a 5 meg camera are usually 10 MB, from something like > the Nikon > D200 they are HUGE. Sony is a 10Meg camera as well. The RAWs from a KM 7D are roughly 8 megs at 6.1 mp and as far as I know they aren't compressed. Kevin Agard (kevin..spamx.agard@verizon.net) wrote in rec.photo.digital.slr-systems: > > · RAW (12-bit,.ARW format, approx. 9.1 MB per image) > > [quoted text clipped - 4 lines] > The RAWs from a KM 7D are roughly 8 megs at 6.1 mp and as far as I know > they aren't compressed. The Alpha has a new image processor chip inside (the "Bionz"...whatever that means). Maybe among the things it can do is fast lossless compression of RAW files. SignatureJeff Rife | "Isn't that just great? I can't find a real | relationship...I'm incapable of meaningless | sex...what does that leave me? Oh, my | God...I'm gonna have to learn computers." | -- Jon Cryer, "Partners" > The Alpha has a new image processor chip inside (the "Bionz"...whatever > that means). Maybe among the things it can do is fast lossless > compression of RAW files. The Sony A100 takes the R, GR, B, GB data and arranges it in blocks instead of lines like RGRGRGRGRGRG GBGBGBGBGBG The file apparently looks like: RRRRRRRRRRRRRRRRR GGGGGGGGGGGGGGGGG BBBBBBBBBBBBBBBBB GGGGGGGGGGGGGGGGG This has allowed Sony to apply a lossless compression very efficiently, but my contacts working on raw files comment that this format is very prone to data corruption. Each RGRGRGRG etc line has to be read from the data blocks in a simple pattern, fast enough to do, but not sequential. Corruption of any part of the raw file makes the picture very hard indeed to recover. But it does make for a small raw file without loss. David |
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