I'm new to photography and recently bought a tripod which I took out with me last night to try out HDR-photography. The image was created in Photomatix with a single RAW through Tone Mapping. Although I think I've managed to get a fairly pleasing result after masking out the sky and more in Photoshop there's still too much noise. Please help me with techniques for reducing noise. I shot the image at 400 ISO - should that number have been even lower? Or would there be less noise if I had actually merged different images rather than using one RAW? Simply: how do I reduce noise in my HDR-photos?