Originally posted by watchingskyfallatm 25mm f1.4
Mount this lens. Select M mode on camera and place camera on tripod. Choose F to 1.4 if you want the balls to be round, choose f2 if you want to give them a shape. The shape depends on number of aperture blades and how they come together. Most new Pentax lenses have rounded aperture blades, so a bigger f number will still be round, just smaller. Older lenses usually have straight blades, turning the round balls into hexagons and similar shapes.
Now select MF and focus relatively near the minimum focus distance. Aim camera at lights, like christmas lights or many small candles.Turn off all or most other lights.
For the final touch, use shutter speed and ISO (ISO should be lowest number, or near that) to make the photo brighter or darker. If you use an automatic mode like Av, press the EV +/- button (exposure value compensation) to make the photo darker or brighter. You probably want to make it "darker".
If you shoot raw, you can make the photo look great in photoshop, aperture, gimp, faststone, raw therapee.. if you shoot jpeg, choose a jpeg mode that has big contrast and saturated colours.
Simply put, what you need is low f-number and misfocused image (usually focused "too close"), while keeping the point light sources relatively close as well. Play with these distances to get a sweet spot. You can try other things like in-camera HDR or one of the jpeg modes that mimics film style.