Sunday, October 5, 2008

G9: Large, comparative samples

There are many and fierce debates about the relative merits and faults of cameras and processing. Although the debate rages on, I've almost given up because the basis of the debates is so subjective. On the other hand, there is a real difficulty in making comparisons. What is the final output of the "photograph"? A snapshot sized print? An enlargement -- 8x10? Larger? Will the photo only be seen from a computer screen? How large is that screen? Is the screen calibrated for proper color, brightness and contrast? No wonder so many people have such diverging views -- not to mention justification of their expense in obtaining that camera!

For the G9 and many other small sensor digicams, one of the major issues is noise at high ISO. The G9 applies its own noise reduction algorithm to its in-camera JPEG but other noise reduction software is readily available. In particular, some G9'ers, myself included, usually shoot in raw mode and apply noise reduction afterward. Which method is best? Does it matter? Can a G9 high ISO be saved?

To systematically investigate the various high ISO and processing options, I thought to post some full size images for comparison. These will be posted on a special SmugMug gallery. The first set of images is a simple set of shots at the sky. These images were taken at ISO 100, 400 and 800. The G9 was set for raw+jpeg so the images are in pairs. When the G9 is set for raw+jpeg, the jpeg is full size but a little more compression is used. I know this confuses the issue somewhat but I made additional comparisons (unposted) and the differences between the G9 "fine" and "superfine" images are small. As it is, this set of comparisons includes eight images and there's no real point to adding more.

My intent was to simply point the G9 at the sky and fire away on Av mode. Then I decided to throw in exposure bracketing so I added a polarizing filter to keep exposures within range. Even so, the G9 neutral density filter was necessary for the ISO 400 and 800 shots. So the first two shots (ISO 100) are without the ND filter, the ISO 400 and 800 are with the ND filter. All of these shots are slightly underexposed.

The exposure was increased by +2/3 stop for a final set of shots. Of course, I forgot to remove the ND filter for these so the exposure is much longer than expected.

The in-camera jpegs were all done at "normal" settings. The raw files were converted in ACR and followed with noise reduction using Noiseware. Noiseware was used at its default settings. The raw files were all done semi-automatically using the ACR auto toning (exposure) and a Photoshop Action.

In comparing these samples, the general idea is not so much which exposure, contrast, saturation, etc is preferable to you personally as it is to see that there are, or can be, differences. Don't even bother to tell me that you can process the in-camera jpeg to have the same saturation and contrast as the processed raw image. Also, don't bother to tell me that the in-camera settings can be adjusted for more or less saturation, sharpness and contrast. But do notice that the first three conversions from raw have quite different look from the first three jpegs. This difference is largely due to the initial underexposure. These are comparisons of the in-camera auto processing of underexposure to the ACR auto processing of underexposure.

In the last two images, the G9 exposure setting was 'corrected' by adding 2/3 stop compensation. The in-camera jpeg and the auto process raw are much more similar.

Examine the files, pixel peek, print your own, order from SmugMug -- whatever you prefer. There's something or other to be learned here and it is different for all of us.

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