40D RAW Artifacts

[rfcbeach]

<p>Hey, guys. Well, I'm new here, and this seemed like the best place to ask a question of this sort. I purchased an $850 refurbished Canon EOS 40D EF 28-135mm lens kit from Adorama on December 22nd for Christmas, and on all of my RAW images, they are showing JPEG-like compression artifacts. Me being the obsessive person, I immediately saw this as a defect in a refurbished camera and have contemplated the possibility of dragging my ass over to Adorama in Manhattan, returning the camera and spending the extra $100 or so for a brand new one with the EF 17-85mm lens kit instead so I can get wide-angle coverage.<br>

<br />The thing that irked me though about the RAW images is that they are showing the JPEG artifacts way more than even the out-of-camera JPEG images! It's just got a lot of square artifacts that are mushing up the colors and blotching out fine details and its annoying me. If you guys have any suggestions as to how to fix this, if it's just a bad copy, or if I'll have to live with it. Thanks a lot!<br>

<br />- Robert</p>

[bryantan]

<p>What RAW converter are you using? Some samples?</p>

[robertjewett]

<p>Let's see what you are talking about.</p>

[bobatkins]

<p>You can't view a RAW file, you can only view a RAW file which has been converted (demosaiced). How are you doing the conversion?</p>

<p>I suspect it's not a camera problem.</p>

[myrjola]

<p>Just checking; are you talking about viewing the RAWs on the camera LCD or on a monitor after transferring them out of the camera? I'm asking this because the in-camera preview uses a smaller thumbnail image embedded into the RAW file and as a result will look quite blocky when zoomed in.</p>

[brad_smith8]

<p>Are you possibly shooting sRAW (small RAW), and blowing them up past their normal size?</p>

[rfcbeach]

<p>Well, I only really noticed them on the camera screen, it's possible that I'm just a complete moron. I only got my first dSLR on Christmas so it's entirely possible that I'm just a nitpicking idiot. I was just concerned, but now that I've seen the comments, they really don't show up on the full-size images on the computer. I was just confused. Also, just to clear things up, I've been using Adobe Photoshop Lightroom 2.2 to do my RAW conversions. I always shoot in RAW, I never really saw the point of sRAW. Thanks for clearing this up, guys. I really appreciate it!</p>

[chris_dahler]

<p>I wouldn't say you are an idiot; any question by anybody will seem naive to a sufficiently experienced person. Your camera does have to convert that RAW image to display it on your camera screen. If you think about it, you took a picture that is 3888 x 2592 = 10,077,696 pixels. Your camera's viewing screen is only 230,000 pixels, so you know a whole <i>ton</i> of compression/information loss is going on there to display that image on that tiny screen. It's no wonder you see compression artifacts!</p>

<p>This also illustrates how useless the whole megapixel war is for people who primarily display images on their computer screen. I have a 24" iMac with 1920x1200 = 2,304,000 pixels. Your camera takes an image that is a little under <i>5 times</i> that size! Granted that the extra pixels serve to smooth and blend the image, capture deeper color information, etc., but still, that's a lot of overkill for a picture on a 24" screen.</p>

[martyn1]

<p>Robert,<br>

Your camera displays an embedded JPEG image that resides inside the RAW file, kinda like a thumbnail. the screens on the 40D are awful too.</p>

<p>If you cant see them on the monitor or in print don't worry about it.</p>