Gianfranco Irlanda wrote:
This weekend I went on a trip to the Mississippi River to do some eagle watching and took my *istD along. The way the trip was planned, with a visit to the Quad Cities' Eagle Days coming first, followed by lunch and a visit to the local tourist visitors' center, we didn't actually get out to do any eagle watching until late in the afternoon on an overcast day. I still got what I hoped were a few good shots of bald eagles, but when I got home and looked at them on the computer screen, they were all noisy and striped and somewhat underexposed.Hi everybody,
I guess the wise people of the *istderhood can enlighten me
about an issue regarding the low light behaviour of the D.
When shooting at 1600 (with noise reduction turned off) every
now and then the pictures show a cartain amount of "striping",
visible in the dark (or evenly lit) areas. There is no real
pattern, just a certain amount of stripes (lighter and darker
alternating) on a single shot, sometimes on two/three
consecutive ones. This seems to happen at every speed 8ranging
from 1/30 to 1/6) with no significant difference.
Looking at Luigi's concert pictures (http://www.livejournal.com/users/ouij/) it seems, to me at
least, to be an issue present in his DS too (I may be perfectly
wrong, though...)
Would you *istD users care to experiment a bit and let me know
before I ask Tecno2000, the official assistance in Italy, to
check my camera?
Thanks in advance.
Ciao,
Gianfranco
PS: I'll show you in 1/2 hour what you should (or should not...) see, I have to dig out the right files.
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The batteries were fresh, and I didn't really do any consecutive shots that would indicate an I/O problem with the CF card or any of the other problems mentioned on this list as possibilities. My best guess is that it is some kind of metering problem. The combination of low light, a really slow lens, and stop-down metering seems to be the culprit in my situation. The bad pics were all shot at ISO 3200 using a Sigma 70-300 zoom, a Vivitar MF 2X teleconvertor, and the green button. I'm guessing the largest aperture on this setup is F11, which is why I went with the 3200 setting. I suppose I should have expected trouble with this poor man's setup.
Tonight I did a quick test of this same rig, just pointing it at a green lighted power button in a relatively dark room. I got noise and striping at every ISO setting from 200-3200 using the stop-down metering from the green button. I then did another series at 3200 starting with the meter's recommended shutter speed and then increasing the exposure time. As the exposure time increased, first the stripes went away, and then the noise went away (and the exposure improved). If someone else could do a similar experiment to see if this can be duplicated, I'd appreciate it. Meanwhile, since I can't afford a real telephoto lens, I'll have to keep my eye on the weather and see if I can get back out to see the eagles on a sunny weekend before they head back up north in the spring.
Glenn
