Right, I have done this test (http://www.calcot.plus.com/RAWTest/)
I found no obvious difference between the original RAW and JPG images, so for the rest of the test I used a jpg created from the RAW file with no adjustments whatsoever, so that I know the two methods have exactly the same start point in terms of exposure etc. normal.jpg is the original, straight from the camera exposure (apart from a resize for the web). Normalexp.jpg is a crop of that image which I will use to analyse the differences. RAWminus1exp.jpg is a crop of a jpg created from the RAW file with -1 exposure plus come extra sharpening and contrast all done in the RAW software RAWminus2exp.jpg shows that even reducing the exposure further in the RAW software, yet more detail can be extracted from the blown highlights. Jpgminus1exp.jpg is the straight jpg edited in paint shop pro to -40% brightness and +10% contrast to give a similar exposure that the RAW-1 gave. Adjusted RAW/JPG are the resised full images. The adjustment to the exposure in RAW has brought back all of the lost highlight detail. None of this was recoverable from the jpg. The exposure adjustment to the jpg has resulted in far more of the mid-tones being lost into shadow too. Maybe better PS skills would avoid that to some degree, but the image would almost certainly be degraded compared to the RAW adjustments. Seeing the full size files, this is clear cut for me. Jpg is not a problem from a compression point of view, but creating the jpgs from the camera is throwing away some of the information from the image capture which can never be recovered. If you have any small exposure error then RAW will probablybe able to correct that for you, but jpg will not. > -----Original Message----- > From: Rob Brigham > Sent: 14 October 2003 10:29 > To: [EMAIL PROTECTED] > Subject: RE: *istD vs. Digital Rebel > > > I am 100% certain that both will be fine. Will do it later > today to satisfy your wishes, if someone else doesn't do it first. > > What I am more interested in is: > > 1 Take a slightly under/over-exposed RAW shot, set the WB how > you want it on the PC, increase sharpening, and alter the > exposure slightly. > > 2 Convert this to JPG. > > 3 Take a slightly under/over-exposed Best JPG using a preset > WB, apply USM, adjust the brightness, and (if necessary) the > colour to match your ideal. > > 4 NOW compare the two. > > I reckon the adjusted RAW image will have lost less detail > due to the exposure problem, sharpening will have degraded > the image less at 100% viewing and colour adjustment will > have been easier. I would be very surprised if at least one > of these isnt correct. > > I will also be doing this test when I get a chance, and will > happily admit if I am wrong. > > The differences may still be negligible, but I can be really > picky about things like that at times. I wont care in most > situations, but if I have an image I feel passionate about it > will matter to me. > > I'll let y'all know how the test goes. > > > -----Original Message----- > > From: Cotty [mailto:[EMAIL PROTECTED] > > Sent: 14 October 2003 10:20 > > To: pentax list > > Subject: Re: *istD vs. Digital Rebel > > > > > > On 13/10/03, [EMAIL PROTECTED] disgorged: > > > > >One of the things Cotty has found, though > > >I can't actually verify it with my own little eyes, is > that the fine > > >JPEG save is pretty much indistinguishable from RAW. > > > > Seriously, I would be very interested to hear from any *ist D user: > > > > please take this test!! > > > > 1. Take a RAW shot of a nice landscape. > > > > 2. Now switch to large/fine jpeg mode and take another shot of same. > > > > 3. Extract RAW shot later on computer, have it open in one > > window in Photoshop. > > > > 4. Open the jpeg shot of same in another window in Photoshop. > > > > 5. Zoom in on both equally so you're looking at the same > > group of pixels in each shot - compare. > > > > > > > > Cheers, > > Cotty > > > > > > ___/\__ > > || (O) | People, Places, Pastiche > > ||=====| www.macads.co.uk/snaps > > _____________________________ > > Free UK Mac Ads www.macads.co.uk > > > > > >
