[Jack Glisson]

I recently purchased a K10D, I already own an ist-d, I normally shoot in RAW format, I have noticed that the PEF files are smaller on the K10D than the 6 mp ist-d, I took controlled test shots and here are the resulting file sizes before any manipulation:
K10D
PEF - 10,997,640
DNG - 16,926,990

ist-d
PEF - 13,614,389

Seems like the 10 mp camera should provide much larger files than the old ist-d?? I made sure lighting, subject, shutter speed, aperature, and sensitivity matched on both cameras and used the same lens as well.
ANY IDEAS? Have I just overlooked something?

[Jun Park]

I noticed the K10D PEFs are anywhere from 9 MB to 14MB depending on the scene while the DNGs are consistently around 16.6 MB. I also noticed the K10D will shoot 12 consecutive shots in DNG (using the ATP 150x Promax cards) while it will only shoot 9 consecutive shots in PEF.

[Jack Glisson]

Thanks for the input - you may be right although it seems that compression goes against why we shoot raw. Also I had emailed Pentax and their brief reply was that the raw file should not be smaller with the K10D than with the ist-d. They also mentioned resolution though and as far as I know there is no way to change resolution in raw format. I have sent a more detailed question with specifics but will have to wait until after Hollidays to get the answer I am sure. At least I know someone else is getting the same results so maybe there is othing wrong with my new equipment - It seems like an awsome camera!!

[jfdavis58]

I can think of a whole bunch of lossless compressions schemes that might be used; simply packing 4 sensor values (12 bits each) into 6 bytes (vs 8) comes immediately to mind-making the expected uncompressed file size for RAW near 15MB.

I've got 2500 or so PEFs and another 4500 DNGs from the K10 to date. 9-16MB seems the typical range of PEF sizes; the DNGs are tightly grouped at 16.3-16.5MB.

[Ivan Glisin]

I have noticed that the PEF files are smaller on the K10D than the 6 mp ist-d [...] ANY IDEAS? Have I just overlooked something?

Here is what is going on:

K10D PEF: lossless data compression used -- approx 10M files
K10D DNG: no compression -- approx 16M files
*istD PEF: no compression -- approx 13M files
*istDS PEF: simple compression used (bit stripping) -- approx 10M

So everything is just fine.

Note though that Pentax initially announced PEF and DNG size to be the same on K10D, but PEF ended up being actually compressed. I think implementing compression was a low priority task but somehow managed to get completed for PEF but not for DNG. I am expecting DNG compression with the first firmware upgrade.

[dave kitson]

I recently purchased a K10D, I already own an ist-d, I normally shoot in RAW format, I have noticed that the PEF files are smaller on the K10D than the 6 mp ist-d, I took controlled test shots and here are the resulting file sizes before any manipulation:
K10D
PEF - 10,997,640
DNG - 16,926,990

ist-d
PEF - 13,614,389

Seems like the 10 mp camera should provide much larger files than the old ist-d?? I made sure lighting, subject, shutter speed, aperature, and sensitivity matched on both cameras and used the same lens as well.
ANY IDEAS? Have I just overlooked something?

The sizes that you are getting are OK. On the K10D the DNGs are not compressed but the PEFs are and will vary a bit in size depending on the image. PEFs on the *istD are uncompressed and inefficiently packed (uses 16bits of filespace to store 12 bits of data) so the files are proportionately much larger.

PEF compression is lossless on the K10D and you do not lose image quality.

dave

[dave kitson]

Here is what is going on:

K10D PEF: lossless data compression used -- approx 10M files
K10D DNG: no compression -- approx 16M files
*istD PEF: no compression -- approx 13M files
*istDS PEF: simple compression used (bit stripping) -- approx 10M

So everything is just fine.

Note though that Pentax initially announced PEF and DNG size to be the same on K10D, but PEF ended up being actually compressed. I think implementing compression was a low priority task but somehow managed to get completed for PEF but not for DNG. I am expecting DNG compression with the first firmware upgrade.

We must have been typing at the same time... hence my virtually duplicate reply..

dave

[Jack Glisson]

Hello, thanks to the contributers and their input - I understand what is going on a little better now. One of the things that threw me off was a reply from Pentax that said "the file size should not be smaller than from a ist d" maybe I will get a different tech next time or either be able to explain the problem better - thanks again!