I'm getting up to speed with my new Nikon D-800 - and finally got a version of Camera Raw that can open the images.
I did a quick test with 2 file sizes for the D-800 NEF files.
Uncompressed is about a 79 MB image size ---
and "LossLess" compression creates an image file about 48 MB.
My first quick look shows more noise in the "lossless" compressed image when opened in Photoshop CS6.
There may just be no "free lunch" here --- more data in a bigger file size.
It will take some big cards to handle a full day of shooting with 80MB images ...
Anyone else do this test yet? I need some time with my tripod to repeat it carefully.
#1. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 0Tue 08-May-12 01:21 PM
>Anyone else do this test yet? I need some time with my tripod
>to repeat it carefully.
I put the D800 on a tripod in the studio and shot some test cards with an 85mm f/1.4 Nikon lens - at f/5.6 - 1/125s - at ISO 6400.
The NEF uncompressed file was 77MB - and a second shot with LossLess compression was 54MB.
I opened both with the beta of Camera Raw 7.0 and the new Photoshop CS6. I did not use any sharpening or noise reduction. I boosted the images to 100% on the screen - and took a screen shot of the images side-by-side.
There are no readily-seen differences between the two images - 77MB on the left and 54MB on the right.
I think that I can save some space on my CF cards and that I can shoot LossLess NEFs with confidence.
And - my D800 is a fantastic camera - with no focus problems.
Attachment#1 (jpg file)
#2. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 1MotoMannequin Registered since 11th Jan 2006Tue 08-May-12 07:58 PM
Perhaps I've misread but I find your two posts seem to contradict each other. The first says you see a difference and the 2nd says you do not.
PSA: Uncompressed NEF is for those of the mindsent who would try to comare image quality of 2 different brand CF cards (yes these people exist). There actually is a free lunch with lossless compression - the result is exactly the same data as the uncompressed file, just as when you ZIP then unZIP a file, the unzipped one is the same as the original. Therefore, always take advantage of lossless compression.
Lossless compression takes advantage of repeating patterns in data. The simplest and most easy to understand is run-length encoding (RLE). Imagine I'm trying to compress a B&W image, using "B" for a black pixel and "W" for a white pixel. I have a row that looks like this:
I could encode this data like this:
...meaning 12 Ws, followed by 1 B, followed by 12 Ws, etc. This compressed 67 bytes down to 18 without any loss of data. I can fully recover the original string from the data in the compressed string.
Of course, some data doesnt' compress down so well. The string:
Which is the same length of the original. Data compression algorithms talk about the amount of "entropy" in the data which involves the amount of repeating patterns and how far the data can be compressed. When you try to zip a jpeg you will find it doesn't compress much at all. Even though jpeg runs a different compression algorithm than zip, once the data is compressed is has very low entropy, and zip can't find much to compress. What ZIP does is greatly more clever and complicated than RLE, but you get the idea.
Lossless means you can 100% recover the original data. The only theoretical downside would be additional processing time to do the compression, but it turns out that writing the bytes to flash takes longer than compressing them, so you have a net gain in processing time when using losless.
I guess the other possible downside is that a single byte corrupted in a compressed file might render the entire file unusable, while a corrupted byte in an uncompressed file might only corrupt one pixel. In pracitce, this is a vanishingly rare issue, and one I'm personally not concerned about.
Larry - a Bay Area Nikonian
My Nikonians gallery
#3. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 2Tue 08-May-12 08:50 PM
> Perhaps I've misread but I find your two posts seem to contradict each other...
My first "test" was a hand-held shot out my back door. You can ignore the results.
As I indicated, I did the second test under studio conditions - on a tripod - and I could see no differences between the uncompressed NEF and the LossLess compressed file.
That was good news to me as I can get more images onto a CF card after compression.
#4. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 0
I know another person did a test with 2 shots and then in CS5 using difference in layers found nothing and there should not be. That is what Lossless means.
For people that have a hard time understanding that... think of zip (or rar or any other compression scheme) on a computer. You put a bunch of files in a single zip file and when you unzip them they are 100% back to what they were to begin with. I cannot understand why they even offer an uncompressed version. Why would anyone need a 79 meg file instead of a 40 something... No benefit I can see.
Visit my Nikonians gallery.
#6. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 5RodW Registered since 25th Mar 2012Sun 13-May-12 08:28 AM
>Just curious, when does the 'un-compress' happen?
Just a guess, but with the speed of current CPU's, there will be heaps of unused clock cycles while reading the files from the HDD (which is a lot slower) so there is time to uncompress on the fly as you read the data into the program that opened it without holding you up at all. That's the beauty of multi tasking CPU's and operating systems.
Windows has supported compressed files at the OS level since Win NT was released way back in the early '90s and they never seem to slow the OS down.
Brisbane, QLD, Australia
#7. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 6
#8. "RE: NEF vs. LossLess NEF D-800" | In response to Reply # 7JosephK Nikonian since 17th Apr 2006Sun 13-May-12 02:13 PM
The uncompress happens every time the file is opened. Thus, it is a little slower to open. Whether or not you will notice the speed difference is open for debate. My guess is that you will see a speed increase on the compressed file since you are reading a lot less data off the disk.
Seattle, WA, USA
D700, D200, D70S, 24-70mm f/2.8, VR 70-200mm f/2.8 II, 50mm f/1.4 D,
17-55mm f/2.8 DX, 70-300mm f/4.5-5.6 VR, 18-70mm f/3.5-4.5 DX