{"id":598,"date":"2007-10-08T21:39:45","date_gmt":"2007-10-08T12:39:45","guid":{"rendered":"https:\/\/regex.info\/blog\/2007-10-08\/598"},"modified":"2013-08-28T14:04:27","modified_gmt":"2013-08-28T05:04:27","slug":"why-i-shoot-raw-recovering-from-disasters","status":"publish","type":"post","link":"https:\/\/regex.info\/blog\/2007-10-08\/598","title":{"rendered":"Why I Shoot Raw: Recovering From Disasters"},"content":{"rendered":"\n\n\n\n
<\/a>\nNikon D200 + Nikkor 18-200mm f\/3.5-5.6 VR @ 56mm — 22 sec, f\/9, ISO 200 —\nmap & image data<\/a> — nearby photos<\/a><\/span>\nDark<\/span>\n<\/div>\n\n

While taking long exposure night shots of Itsukushima\nShrine's Gate<\/a> (\u53b3\u5cf6\u795e\u793e\u3001<\/span>\u5bae\u5cf6)<\/span> in Miyajima, the brilliant illumination was turned off,\nand the area became quite dark. I thought<\/span> I'd give it a try<\/span> with the lights\noff, but as you can see above, my one attempt came out completely dark.\nSince it was late, I didn't<\/span> want to spend the time trying again for a more<\/span>\nreasonable exposure, so we packed up and returned to the hotel.<\/p>\n\n

When I got home and loaded all the images into Lightroom<\/a>, I intended<\/span> to delete this one along with all the other rejects. More out of\nhabit than anything else, before deleting it, I tried<\/span> the “auto tone”\ncommand (Control-U on Windows, Command-U on a Mac<\/span>). The auto-tone command\nis like “developing for dummies” in that it automatically adjusts the\nexposure, fill light, etc., to create a more<\/span> pleasing image. As you might<\/span>\nimagine, such an automated task often has less-than-pleasing results, but\nit costs nothing to try and often results in a good<\/span> basis from which to\nmake further tweaks.<\/p>\n\n

In this case, I didn't expect much because the image was mostly\nblackness, so I was<\/span> shocked that the result was actually not too bad:<\/p>\n\n

<\/a>\nNikon D200 + Nikkor 18-200mm f\/3.5-5.6 VR @ 56mm — 22 sec, f\/9, ISO 200,\nP.P. boost: +3.60EV<\/span>\n —\nfull exif<\/a><\/span>\nSame Image, After Lightroom's “Auto Tone”<\/span>\n<\/div>\n\n

My first thought was “wow, that<\/i> was hidden in there?”<\/p>\n\n

One of the reasons this is possible is that I shoot<\/span> in raw (Nikon's\nsomewhat lossy compressed\nNEF<\/a>) and not JPG. Even though all the detail is lost in the “too dark\nto see” region of the original's color space, it's still there to be\nexposed by shifting everything up into the “can be seen” region.<\/p>\n\n

During the shift, minor differences in pixel-to-pixel color or\nbrightness also become exaggerated as well, resulting in a very<\/span> grainy\nimage, but that's a small<\/span> price to pay for pulling a not<\/span>-too-bad image from\na nothing<\/span>-there-at-all hat (especially considering that it took just a\nfraction<\/span> of a second<\/span> to hit the two keys required to make it happen).<\/p>\n\n

For comparison, I extracted<\/span> the full size JPG image embedded within the NEF<\/a>,\nloaded that into Lightroom as a separate<\/span> image, and applied auto tone to\nit:<\/p>\n\n

<\/a>\nIn-Camera Basic-Quality Embedded JPG, Auto-Toned<\/span>\n<\/div>\n\n

This is worse, but still better than I would<\/span> have expected. It has less<\/span>\ndetail and more splochiness, both because it's a JPG<\/span> (with 8 bits of\nprecision per color, as opposed to 12 in the NEF), and because of the high\namounts of JPG compression used in the version embedded in the raw\nfile (the same as the “basic” quality setting).<\/p>\n\n

It's not really fair to judge jpg\/raw differences with a “basic” quality\nJPG, so I thought<\/span> to export from Lightroom a high<\/span>-quality JPG of the\noriginal dark scene, then re-import that as a new<\/span> image and apply “auto\ntone” to it. However, the result here is much worse than with the in-camera JPG above:<\/p>\n\n

<\/a>\nLightroom-Created High Quality JPG, Auto-Toned<\/span>\n<\/div>\n\n

I'm at a loss to explain why this version is so much worse, and worry\nthat I'm missing something very obvious. In one sense<\/span>, though, it's all a\nmoot<\/span> point for me because I shoot<\/span> only raw. Still, I don't<\/span> like not\nunderstanding.<\/p>\n\n

For easier comparison, here are the four images again, overlaid on each\nother. Just mouseover the buttons below to see the named version.<\/p>\n\n\n