Oly720man From United Kingdom, joined May 2004, 7113 posts, RR: 10
Reply 1, posted (6 years 10 months 2 weeks 1 day 22 hours ago) and read 2500 times:
It's most obvious in the brighter part of the photo on the left edge, 1st photo, and along the top, 2nd photo. Basically the graininess and it's due to how the CCD sensor reacts to low light levels. Because you need a certain amount of light to "trigger" a pixel, you can end up with a random pattern of noise when there is little light.
You __might__ be able to clean it up a bit with something like neatimage.
Soon7x7 From , joined Dec 1969, posts, RR:
Reply 3, posted (6 years 10 months 2 weeks 1 day 20 hours ago) and read 2465 times:
Next time if your camera has a long exposure noise reduction setting, engage that, as noise seems to occur mostly in the dark fields. It is sometimes , I believe confused with grain...but I'm led to believe that noise is actually gaps in the exposure if you greatly magnify the image...I'm not 100% sure of this but that is what I've been told. I'm sure I'll be corrected on this.
JohnJ From United States of America, joined Jun 2000, 1725 posts, RR: 2
Reply 4, posted (6 years 10 months 2 weeks 1 day 17 hours ago) and read 2444 times:
Even for night shots, if you're using a tripod use the lowest ISO setting your camera supports. This will require a longer exposure time, but for stationary subjects like yours with the support of a tripod, this shouldn't be a hindrance and the lower ISO will reduce the grain and noise.