OK -- made a test of Import in 3.3, in Lion with images on a CF card from my D800. Checked Preview Preferences before hand, and found Half-size selected, which for the moment I left unchanged. After Import, I did a Show Package, found the Previews folder, and within the latest folder, where I could see all the jpegs for the previews. Opening one, I found it to have full size pixel dimensions of 7360 x 4912 (but with high compression of course), which I took to confirm it was from the camera. Once I had selected that photo in Aperture to view, I checked the preview again -- now its dimensions had gone to half those above, but with a lower compression, indicating it was now a Preview that Aperture had generated.
This would appear to prove that the camera generated Preview is kept until any image has been selected in Aperture to view.
Btw, used Graphic Converter to open preview jpegs from the Package.
Possibly meant sarcastic, but jpg is a way better to shoot than raw. jpg looks the same across all software, whereas raw differs quite a bit from software created by different manufacturers. You think Aperture has the best raw convertors? Of course not. How can they create the best; it's a software company who has no knowledge on optics, leave that to the camera manufacturers. Problem is, they don't have any knowledge on creating software as optics is their business. That is the reason their software isn't as polished as, say Apples' Aperture. They get the raw right, Apple gets the software refinement right.
Shoot jpg; it'll be here in 100 years time. raw won't. The format may, but there's no standard. jpg is here to stay.
You sound like Ken Rockwell, who we are to believe, gets every shot perfectly, and never needs to editand uses only Basic JPEG sizes for all his work!
I shoot more times than not in very imperfect, available light situations, and I have never found a JPEG that I could as effectively adjust as can be done with RAW. When I have shot in pairs, the RAW in Aperture looks as good or better than the JPEG from the camera, before any editing.
I could allow my cameras to give me TIFFs, but they don't adjust as flexibily, either.
jpeg is o.k. if you can get the image right when shooting and do not need any editing afterwards, or are happy to leave all postprocessing to your camera. But jpeg is not a lossless format. If you want to be able to do image processing afterwards - white balance - straighten the horizon - retouch - selective color correction - then you will be much better of with a lossless image format. Raw or tiff.
jpg looks the same across all software, whereas raw differs quite a bit from software created by different manufacturers.
I consider that feature of raw - not a bug. Which raw converter you choose is your first decision on how to develop your image - a matter of taste.
jpeg for snapshots - a lossless format for images that need to be developed and turned into a piece of art - or for scientific data and documentations - my most frequent use of pictures.
Phil, just for starters: JPG is 8-bit. And compressed. And was developed to maximize compression so images could be more easily used on the WWW. (RAW is not even an image file format (it describes a family of proprietary sensor data formats).) JPG is the fast-food of image file formats.
"Better" cannot be decided without specifying "for what". JPG is better for images that will be used on Web pages.
For almost all other uses -- and especially for any use where color depth and/or dynamic range are important -- RAW is not only vastly superior, it is almost incomparably so.
For an excellent primer on RAW, I suggest this Adobe whitepaper. It includes a helpful section on the difference between RAW and JPG.
Message was edited by: Kirby Krieger -- errors in the first paragraph.
Wow, fantastic responses - thanks guys. I seriously need to reconsider, it seems. Yep, Ken Rockell on his dislike for raw, I read it, understand his view and indeed agree. For the reasons he states, I think it is well founded.
But to recoup some of your views:
TIFF's are less flexible - got it, so raw, or perhaps DNG is 'better' than JPG.
Ernie, Ken indeed uses JPG for most, but not all work. He also uses raw. But yes, he does print a 3 foot JPG (Basic!) and tells us there's no need for the Medium or Fine setting. So I tried, and agree. Not a cheap try, as the print was over $ 100
Personally I don't want to adjust an image after I took it. I'd be so much happier if I have learned to take the picture as I want it to look and with JPG, I can still adjust the horizon (which for some reason I often need to set straight). But with JPG I can also adjust a single color, vibrancy, exposure - the lot.
I really need to take a look at raw again. Not that I want to adjust my photos, but because of your responses, for which I thank you.