PEF vs DNG

[Trub]

I've been capturing in DNG but I was wondering if there was any difference visually between the two.

[daacon]

http://www.pentaxforums.com/forums/i...0-dng-pef.html

[Trub]

I was searching PEF vs DNG and nothing came up.

[Photo Tramp]

There is no difference in the image by what you see the only difference is in the file size. But the PEF file would be considered a true RAW file.

[photog]

Originally Posted by Photo Tramp

There is no difference in the image by what you see the only difference is in the file size. But the PEF file would be considered a true RAW file.

I agree with your principal point. There IS no essential difference between the images produced by the two. However there is an important practical advantage to be gained by using the PEF.
PEF is a non-lossy compressed format whereas DNG as saved in the Pentax SLR (unlike the compressed format that DNG converter produces) is Non-compressed. My 4GB card will hold 239 DNG but approximately 350 PEF. Approximately because the degree of compression depende on the subject matter.

When DNG converter copies to my picture folder the compressed file is identical in size to the PEF. Obviously they use the same compression algorithm.

However, as regards the statement that DNG is not a RAW file: It is simply a data file as is PEF, NEF CR1 and so on. Therefore, it is reasonable to consider it a RAW file.

Do not let this distract you from the marvelous picture making ability of our Pentax system. Keep on SHOOTING! Forget about trucking...

[GaryML]

Originally Posted by photog

I agree with your principal point. There IS no essential difference between the images produced by the two. However there is an important practical advantage to be gained by using the PEF.
PEF is a non-lossy compressed format whereas DNG as saved in the Pentax SLR (unlike the compressed format that DNG converter produces) is Non-compressed. My 4GB card will hold 239 DNG but approximately 350 PEF. Approximately because the degree of compression depende on the subject matter.

When DNG converter copies to my picture folder the compressed file is identical in size to the PEF. Obviously they use the same compression algorithm.

However, as regards the statement that DNG is not a RAW file: It is simply a data file as is PEF, NEF CR1 and so on. Therefore, it is reasonable to consider it a RAW file.

Do not let this distract you from the marvelous picture making ability of our Pentax system. Keep on SHOOTING! Forget about trucking...

For me, the main advantage of DNG is that recovery utilities for SD cards support the DNG format, but not PEF. So in the (unlikely) event that your SD card becomes corrupted, you have a chance of recovering the DNG files with a recovery utility, but almost no chance of recovering lost PEF files.

[GaryML]

Originally Posted by photog

When DNG converter copies to my picture folder the compressed file is identical in size to the PEF. Obviously they use the same compression algorithm.

I'm not sure what DNG converter you are using, but I don't get the same results that you do. I performed the following test:

I took the identical image in both .PEF and .DNG format. The camera was on a tripod and the exposure settings were identical. All I did was change the menu setting for RAW from PEF to DNG. Here are the file sizes:

PEF:
13,582 kB

In camera DNG:
16,674 kB

Pentax Browser DNG conversion:
21,687 kB

Adobe RAW converter DNG (Lightroom):
10,747 kB

Note that the Adobe-generated DNG file cannot be read by the Pentax Photo Browser or Pentax Photo Lab. The Adobe RAW converter (Lightroom) has no problem with the Pentax DNG files either directly from the camera or from the Pentax Browser DNG converter. However, Lightroom can't read the .tiff files from Pentax Photo Lab.

[LV Dan]

From my understanding of the file structure, both the PEF and the DNG are pure raw pixel data so the quality should be exactly the same with only the wrapper having different data. However, older DNG files could have munipulation for color balance. The newer versions of DNG can now have both the adjusted data and the raw pixel data in the same file, making the DNG file larger. The benefit of this is that you can always revert back to the original raw data but also view the file with optimization. This is according to the Adobe DNG conversion FAQ.