Nikon D200 + Nikkor 18-200mm f/3.5-5.6 VR @ 56mm — 22 sec, f/9, ISO 200 — map & image data — nearby photos
While taking long exposure night shots of Itsukushima Shrine's Gate (厳島神社、宮島) in Miyajima, the brilliant illumination was turned off, and the area became quite dark. I thought I'd give it a try with the lights off, but as you can see above, my one attempt came out completely dark. Since it was late, I didn't want to spend the time trying again for a more reasonable exposure, so we packed up and returned to the hotel.
When I got home and loaded all the images into Lightroom, I intended to delete this one along with all the other rejects. More out of habit than anything else, before deleting it, I tried the “auto tone” command (Control-U on Windows, Command-U on a Mac). The auto-tone command is like “developing for dummies” in that it automatically adjusts the exposure, fill light, etc., to create a more pleasing image. As you might imagine, such an automated task often has less-than-pleasing results, but it costs nothing to try and often results in a good basis from which to make further tweaks.
In this case, I didn't expect much because the image was mostly blackness, so I was shocked that the result was actually not too bad:
Nikon D200 + Nikkor 18-200mm f/3.5-5.6 VR @ 56mm — 22 sec, f/9, ISO 200, P.P. boost: +3.60EV — full exif
My first thought was “wow, that was hidden in there?”
One of the reasons this is possible is that I shoot in raw (Nikon's somewhat lossy compressed NEF) and not JPG. Even though all the detail is lost in the “too dark to see” region of the original's color space, it's still there to be exposed by shifting everything up into the “can be seen” region.
During the shift, minor differences in pixel-to-pixel color or brightness also become exaggerated as well, resulting in a very grainy image, but that's a small price to pay for pulling a not-too-bad image from a nothing-there-at-all hat (especially considering that it took just a fraction of a second to hit the two keys required to make it happen).
For comparison, I extracted the full size JPG image embedded within the NEF, loaded that into Lightroom as a separate image, and applied auto tone to it:
This is worse, but still better than I would have expected. It has less detail and more splochiness, both because it's a JPG (with 8 bits of precision per color, as opposed to 12 in the NEF), and because of the high amounts of JPG compression used in the version embedded in the raw file (the same as the “basic” quality setting).
It's not really fair to judge jpg/raw differences with a “basic” quality JPG, so I thought to export from Lightroom a high-quality JPG of the original dark scene, then re-import that as a new image and apply “auto tone” to it. However, the result here is much worse than with the in-camera JPG above:
I'm at a loss to explain why this version is so much worse, and worry that I'm missing something very obvious. In one sense, though, it's all a moot point for me because I shoot only raw. Still, I don't like not understanding.
For easier comparison, here are the four images again, overlaid on each other. Just mouseover the buttons below to see the named version.
Remember, the auto-tone versions have had only the automatic “auto tone” command applied to them, with no human artistic or technical skill applied.