Eight Bits?

[rsl]

Dave, Artichoke, Jaap, Thanks for your responses. Dave and Artichoke, thanks especially for the extended explanation of what Leica's doing with the file. I gather what you wrote is more or less a summation of what Leica has posted somewhere. If that's what they're doing, it may help to explain some of the glitches that have occurred. It's pretty obvious that the algorithms for the kind of .DNG they're building must be very complex. Seems to me it would be pretty easy for a single jump error to put the camera into an endless loop and hang it up while it's trying to process a file. Jaap, thanks again for the offer. Let me know if you're able to get a .DNG up where I can download it.

 

[willie_901]

Creating 8 bit files for printing makes sense. If you're printing to an inkjet the driver is going to convert the file to 8 bit anyway.

But with respect to your second comment, are you talking about 8 bit .JPEG or 8 bit .DNG? The statement has an ominous sound.

I was referring to 8 bit DNGs.

JPEGs always mean there is a loss of information which is justified by an increase in convenience. The impact of the information loss can be trivial (e.g. web page display, low resolution printing, or an image with very little information to begin with).

 

[rsl]

I was referring to 8 bit DNGs.

JPEGs always mean there is a loss of information which is justified by an increase in convenience. The impact of the information loss can be trivial (e.g. web page display, low resolution printing, or an image with very little information to begin with).

Willie, Thanks. Yes, I know what happens with jpegs, which is why I haven't shot one for several years. Practically anything I keep around and count as good gets printed at about 11 x 14 for display and sale in a gallery, so I can't afford the losses jpegs give me. On the other hand, I've got some very good shots from long enough ago that raw wasn't available. I have to keep prints from those well below 8 x 10.

 

[rsl]

Russel. I'll work on it this weekend.

Jaap.

Got all three. Thanks so much. They were exactly what I was looking for and I'm suitably impressed. The backlit snow scene at ISO 320 and 1/8000th, especially was impressive. I was able to take it into CS2 and improve the details in the lows without seeing a noticeable amount of noise. Fine shot from an asthetic standpoint too. The little church at ISO 160 and 1/200th was great. Lots of post-processing latitude even in the highs. Absolutely no noticeable noise. I was able to do a lot of high-frequency sharpening without any problem. The pieta at ISO 320 and 1/20 was a bit noisy, but that was because of the low shutter speed. Still, a fine shot and easy to work with.

Earlier I took Dave's advice and downloaded the two .DNGs from Leica's home site. At the risk of being cast into outer darkness I have to say that if my D2X had produced raws like those I'd immediately have started test shots to make sure there wasn't something wrong with the camera. It's hard for me to believe Leica would put anything that bad up as an example of the M8's abilities. What on earth were they smoking?

Again, thanks.

Regards,

 

[jaapv]

Thanks for the kind words, Russel. Happy to oblige. Obviously you are a (former) pro with (maybe) different standards from my amateur ones, but I only can say there is no way I could wish for better quality files than these for my purposes. I don't know what Leica is doing to promote these camera's. When I see some of the work on LUF for instance, they have the best publicity for this camera right under their corporate nose....I'll send you another high-contrast one from that church and see what you make of it, as the Pieta one was more for the colour rendering.

 

[Gabriel M.A.]

Isn't this, like, omg, you know, very old news?

 

[jaapv]

Nah-just a private conversation which, I admit, should better have been done by PM's.

 

[rsl]

Jaap, No I did some pro work back in the late sixties and early seventies but I found I disliked making the kind of photographs someone else wanted instead of the kind I wanted. On the other hand, I've been a devoted amateur in the original meaning of that word since I was twelve, and that was a long time ago. Nowadays I have prints in several local galleries and sell reasonably well, though if I had to depend on my sales for a living I'd soon starve. Since I'm also a retired US Air Force officer and still a software developer with a few local clients and a fair amount of shareware out there I won't starve even if I don't sell.

I'm inclined to agree with you about the overall quality of M8 .DNG files. I hunted around on the web and found a few more downloadable Leica .DNGs. Same high quality, though they weren't as good test shots as the ones you sent me. I was specifically looking for backlighted captures. I only use flash if I'm doing a wedding or something like that, and then only on a D2X with iTTL capability. I use a rangefinder exclusively for street work and don't even own a flash for that. So, since digital has somewhat limited latitude I sometimes end up with captures that need some enhancement in the shadows. That's the acid test -- to be able to bring up the lows without introducing noise -- especially color noise. The files you uploaded proved to me that the compression algorithms Leica's using don't degrade the capture. The lows are solid and even the highs, where they evidently are tnrowing away some data, are very satisfactory.

 

[rsl]

Isn't this, like, omg, you know, very old news?

Gebriel, If you think this is "like, very old news" check out the comments on B&H's Leica M8 page. I'm not the only one put off by the idea of stunting a high color-depth capture by converting even part of it to 8 bits. It's one thing to read about how wonderful Leica's approach to this is and another to accept that at face value. Jaap sent me some backlighted .DNGs that proved the point. Seems to me that since even Leica admits that their compression algorithms reduce the potential quality of their .DNG files, they ought to put up some good .DNGs to demonstrate that what's left is truly acceptable. They're not doing that and they're asking all of us to plunk down five grand on faith. Considering the other problems the camera's had, that's pretty hard to do. The files Jaap sent me and that I worked with blew away any lingering doubts in my mind.

Jaap, I don't agree we should have done this exchange by PMs. I was a real skeptic. Now I can vouch for those files. I've read a lot of stuff on here about how great the M8 files are, but they seem mostly to be from people shooting .jpegs. Anyone out there not satisfied with jpeg quality is going to want to know what Leica's .DNGs are like.

 

[Steve L]

What I don't get is why Leica's approach is "better" than just using lossless compression on the high resolution file, like Canon does - the result seems to provide files of similar size for similat numbers of megapixels, but Canon's approach loses no information, while Leica's does.

There seems to be a philosophical approach where some manufacturers compress and some don't - but Leica's decision not to simply losslessly compress, but instead to throw away highlight/midtone info, seems strange...at least without seeing comparison files.

 

[jaapv]

What I don't get is why Leica's approach is "better" than just using lossless compression on the high resolution file, like Canon does - the result seems to provide files of similar size for similat numbers of megapixels, but Canon's approach loses no information, while Leica's does.

There seems to be a philosophical approach where some manufacturers compress and some don't - but Leica's decision not to simply losslessly compress, but instead to throw away highlight/midtone info, seems strange...at least without seeing comparison files.

I really do not care that much about the approach. The results interest me - and they are as good as it gets.

 

[Artichoke]

you must consider

you must consider

What I don't get is why Leica's approach is "better" than just using lossless compression on the high resolution file, like Canon does - the result seems to provide files of similar size for similat numbers of megapixels, but Canon's approach loses no information, while Leica's does.

There seems to be a philosophical approach where some manufacturers compress and some don't - but Leica's decision not to simply losslessly compress, but instead to throw away highlight/midtone info, seems strange...at least without seeing comparison files.

that Canon is taking data off the sensor with a 12 bit ADC
Leica is using a 14 (or 16) bit ADC which generates a much bigger RAW file if uncompressed
I think they made an excellent decision & the quality of the DNG produced by the M8 is outstanding & I appreciate that it writes at 10 MB and not 25 MB like my S3's RAW files (which also uses a 14 bit ADC)