Today's modern, fully automated cameras make taking great vacation photos a breeze. However, many are not suitable for astrophotography. A basic 35-mm SLR camera with full manual operation is much better for this kind of work. There are several features you need. The camera should have a non-battery B (bulb) setting. This feature allows you to take long exposures without draining the camera battery. Some camera shutters require battery power to open and close. Some use battery power to hold the shutter open. A series of 15-minute astrophotos on a cold winter night will quickly drain the battery and leave the camera dead on the tripod. The non-battery B (bulb) setting is an essential feature of an astrophotography camera.
The camera should also have a feature called mirror lockup. A typical 35-mm camera uses an internal mirror to redirect light to the viewfinder. This allows you to see the image and set focus before taking an exposure. When the shutter is tripped, the mirror slaps up out of the light path. The image in the viewfinder goes dark because all the light is passing through the lens to the film. This mirror slap introduces a small amount of vibration. Since most daylight photos last a small fraction of a second, the vibration is not recorded. However, the longer exposures used to photograph the night sky will record any vibration caused by mirror slap. Images will look fuzzy and unfocused. Mirror lockup allows you to position the mirror out of the light path before the exposure is taken. This is another essential feature of a good astrophoto rig.
Also, look for a camera that accepts a variety of focusing screens. Most standard issue focusing screens work well for bright objects but do not allow you to achieve critical focus on the stars. A simple, clear, matte focusing screen is often the best choice. This feature is valuable but non-essential. Since all objects in the night sky are for all practical purposes infinitely far away, you can set the focus of your camera to infinity and get good results.
These are the main features that make for a good astrophotography rig. To summarize, you should look for a camera with the following:
I mentioned earlier that many newer cameras are so automated that they don't make good astrophotography rigs. An older, used camera can be the perfect choice for the beginning astrophotographer. Here's a list of older cameras that have all the desired features:
With the exception of the Nikon, these aren't necessarily top of the line cameras. However, they are affordable and offer the features you will need to take good astrophotos.
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Revised: February 11, 2002 [WDF]