Once the magic smoke comes out, things don't work any more.
John Kasunich
jmkasunich@fastmail.fm
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Thu, 26 Jul 2007
First day images from my new camera
The bird pictures I took on Friday got my photographic juices flowing. It's been several years since I last shot with an SLR, mostly because I'm too lazy and/or cheap to process film. I've been using point-and-shoot digitals since then, but I've wanted to get back into shooting with an SLR. I've been reading reviews for months, so I already was pretty sure what I wanted. I ordered a Pentax K10D and a Sigma 18-125mm zoom on Sunday, and they arrived today.
The obligatory pet picture:
(click to enlarge, 2.6MB jpg straight from camera)
The in-camera shake reduction works well... the image above was taken a focal length of 68mm. The rule of thumb would recommend 1/60 second as the slowest shutter speed, but the actual speed for that shot was 1/8 second.
Sitting in the kitchen I found a challenging target - the interior of the room is dimly lit by incandescents,
with bright overcast skies outside the window. I found it quite easy to have both blown out and totally black
pixels in the same shot. But some experimenting with metering off-target and then recomposing got acceptable
results.
(click to enlarge, 740K, cropped and saved at 85% quality with GIMP)
Outside it was a little brighter (but still overcast). Lots of flowers are blooming in the garden. I was
pleasantly surprised to find that the Sigma will focus at 16" from the film plane (it's specified for 1.64 feet,
which is about 20".) Not a true macro, but at about a 1:5 ratio, it's not bad.
(300K, cropped and saved at 85%)
The nerd in me wanted to know what the noise vs. motion blur tradeoff is as I raise ISO and speed up the shutter.
Back indoors, I took four shots of a painting on the wall about 25 feet away. Lens fixed at 125mm, f/5.6, changed
the ISO from 200 to 1600 and the shutter speed from 1/4 second to 1/30 second. Shake reduction on. Then I copied
a 300x300 pixel square from each shot, and pasted them into a 1200 pixel wide composite in GIMP. Click on the
image below to expand it to 1200 pixels wide (230K).
At 200 ISO and 1/4 second, I clearly had motion blur that the shake reduction simply couldn't handle. This is strictly tripod territory, but I was having too much fun playing with the new camera to dig out my tripod. At 400 ISO and 1/8 second there is still significant motion blur, but it's a little better than the first shot. A little noise, but the main problem with the image is definitely blur, not noise.
At 800 ISO and 1/15 second, the image is much sharper. I don't know if the remaining blur is from motion, lens limitations, JPEG lossiness, or the in-camera RAW to JPEG conversion and filtering. Noise is definitely starting to show up though. And finally at 1600 ISO and 1/30 second, there is no obvious change in sharpness, but noise is much worse.
If I had to pick one of the pictures, it would probably the the 800 ISO one. The "right" way to get the shot in that light is with a tripod and a much longer exposure, but it sure is nice to know that I can get reasonable images shooting handheld in what would normally be considered unreasonably dim light.
(posted: 26 Jul 2007 01:03) (permalink)