MOON

Comments

• bruto

  December 2017

  I can't give you much on stars, except a couple of basic ideas.
  
  First, make sure you focus correctly. Most modern AF zooms will manually focus past infinity if you just do it blind, so make sure you really look. If you can't see well enough, focus on the most distant clear object or light you can find. You're better off focusing a bit close than a bit too long.
  
  Needless to say auto exposure won't satisfy here, because it will try to make the sky too bright. You'll have to experiment or do more research to find the best manual settings. Watch out for high ISO which will look very noisy in the dark. Longer exposures also will heat up the sensor a little and make for even more noise.
  
  You'll gain some by using long exposure noise reduction, but be aware that this works by taking a second image with the shutter closed (it is a picture of the sensor noise itself, which is then subtracted from the image). If you use this with a 20 second exposure, it will stall the camera for another 20 seconds. So be patient.
  
  Some astro photographers take multiple shorter exposures and combine them in postprocessing to reduce noise, but that's something I can't help with, as you'd need the right software.
  
  If you expose too long, the stars will move and make a star trail. That can be nice if you want it, annoying if you don't. There is something called the "500 rule," a rough guideline, which says your max. exposure time should be 500 over the focal length (in 35 mm equivalent, so it's actually 1.5 the focal length here). So, for example, if you were using a 35 mm. lens, your maximum to avoid smearing stars would be 500/50 seconds. That's' only 10 seconds, not ideal. Unless your lens is fast, you're going to have a struggle avoiding elongated stars, but how important that is depends a little on what your subject is, and how big you print.
  
  For the moon, remember that the moon itself is surprisingly bright. In a general sky shot, if you're getting good stars you'll probably blow out the moon. If your object is the moon, spot meter it if possible, and check your histogram after a shot to make sure you're not blowing out highlights.