PEF or DNG??

Really, as the title says, I'm not too sure what's the difference between the two quality wise, but I tend to shoot in DNG as it's directly compatible with lightroom.
Are there advantages if I shoot in the other formats?
Thanks for reading (or answering) another silly question of mine!

No such thing.

Cannot see any difference between PEG and DNG, other than DNG has by default more support.

Davex.

Now the DNGs are a similar size to PEFs then there is little difference. I am using PEF simply because it took a while for Adobe to support K5 PEFs.
Theoretically the DNGs will be readable in years to come whereas the PEFs may not be.

PEF's on the DS/K10D/K20D. DNG's on the K-5. Only because I need to upgrade Photoshop CS4 to read them.
However, the reality now is, there is very little difference between them, well at least for me

There was an interesting throw-away comment in AP's review of the K-5, where it was suggested that PEF did give superior results although the convenience of DNG outweighed that.

Thanks John, missed that bit.
However, what I have got so far with DNG seem fine. (albeit only 70 shots so far.)
However, I will upgrade CS4 at some point.

Interesting John.
I shall have to give it a try. Of course I will be using PSE9 not CS whatever but that shouldn't make too much of a difference.

So far the DNGs have actually needed very little work on them.

Was there any rationale or evidence given for this?

I do know that on my K20D a PEG file is almost half the size of a DNG file. So either one has redundent bytes or one is compressed.

No, hence the phrase "throw away comment" - it was just written as though assumed, obvious and already proven....

If I recall something I read recently, doesn't PEF make use of a different profile by default than DNG? One may look better than another, especially in ACR where the K5 is now explicitly supported.

emmm, ok so I'm slightly confused though guys are explaining things..
DNG works directly with PS/LR, but what about PEF? can I still shoot in PEF and import it directly into LR? I've got LR 3 64bit, and am I correct that there aren't any lens profiles for pentax lenses? (as all my photos come out saying the lens used is unknown :S)

Yes, LR3 (which basically uses Adobe Camera Raw) now supports the K5. So you may now use DNG or PEF.
I'm just in the habit of using DNG so that I do not have to wait for software updates.

As far as I know there is no significant quality difference when using DNG or PEF (I still have yet to read on the exact format and how DNG can be data-identical to PEF without some sort of conversion or loss of brand/model specific information)... but either way, the result is what it is. At ;east identical enough that it doesn't matter for most people -- professional or otherwise.

The latest update for LR3 includes Pentax camera lens profiles. Quite a few actually.

Yes there are a number of Pentax lens profiles in LR3. They first added the 645 lenses, but the latest LR3 version comes with DSLR lenses now, although the range needs to be expanded. I think the Limiteds and DA* 's have been done.

I normally shoot in RAW, but I just shot a couple of PEFs on my K20Dand they did indeed import into LR3.

Dunno if K-5 PEF will import. I guess you should try it.

I'm wondering about shooting PEF instead of RAW now. Not for any other reason other than they are 13MB instead of 24MB. Quite a disc saving!!

hhh that's good to know!

Good point. IS there the huge filesize difference between PEF and DNG on files from the K-5 as well?

For two examples,
PEF: 30.1MB, DNG: 31.8MB
PEF: 25.5MB, DNG: 25.7MB

I thought at some point the DNG was not compressed where the PEF was, but as of the K7 I believe both are compressed.
Although it appears PEF might compress slightly better??

These were hand-held shots, so slight changes in composition may affect compression.
Probably best to do with consistent environment and tripod.

Either way, DNG has worked well for me and I don't have to worry too much about the future of finding a reader for it... if all goes well. i.e. How long do you think the *istD PEF format will continue to be supported? (of course disk space is cheap, no reason to remove the support libraries from major applications, I suppose.. )

Not sure the 1-4% savings is worth the hassle for me in the long run.