I have just tried stacking star field pictures for the first time, and I have to say I am sold! I have been struggling to get good star trails. Long exposures are fraught with pitfalls on digital cameras, from sensor artifacts to sensor overheating to passing cars blowing out the lights. Taking a series of shorter shots and stacking them in software really gives a much better result avoiding those pitfalls. Even if a passing car blows out some shots, you have whatever was taken before and after to work with to recover something worthwhile. I’m really excited about what I got here with one set of ten shots of 1 minute duration. I used the freeware StarStax for the stacking. It was quick, easy, and gave a great result right out of the box. I am also fascinated by the colors of the stars that come through. I have amped them up with a saturation boost in Aperture, but the colors are real. Such diversity! The camera was a Nikkor 18-55mm AF-S VR set on 55mm. I prefocused on infinity using a distant bright light. By turning off the auto-focus on camera, but turning the autofocus back on on the lens itself, I am able to lock the manual focus in position. The manual focus is very loose on this lens and will not hold well without locking it in this way. It also will focus a bit past infinity so just going by feel won’t work. Camera was a Nikon D90. I used a third-party intervalometer that works marvelously well.