Milky Way Exposure

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Today’s Question: Could you expand on how you exposed for your Milky Way photo on page 48 of the November 2014 issue of Pixology magazine?

Tim’s Quick Answer: The photo referred to in today’s question features a rock formation near Castle Valley, Utah, with the Milky Way in the night sky. The image was captured with a 24mm lens focal length at an aperture of f/4 and a shutter speed of 15 seconds at 6400 ISO.

More Detail: You can view the photo referred to in today’s question on my 500px page here:

https://500px.com/photo/91347311/milky-way-from-near-castle-valley-utah-by-tim-grey

The first key to capturing a photo of the Milky Way is to determine the time that the Milky Way will be visible in your area, and to make sure that this time will be at night with a clear sky. It is also helpful if the appearance of the Milky Way will coincide with a time of night when the moon is not going to be above the horizon, or when there is a new moon, so that the light from the moon doesn’t interfere with your exposure. It is also important to be as far away from bright lights (such as towns and cities) so the overall sky will be as dark as possible.

I then typically aim for a 15-second exposure, in large part to minimize the appearance of any star movement. The actual limit of your exposure duration is determined by the focal length of the lens, and you can employ a longer exposure if you are using a lens with a shorter focal length.

One of the most challenging this to achieve with a night shot such as this is accurate focus. In theory you just want to set the lens to focus at infinity, but in my experience this often does not produce the best results. I prefer to use the live view display on the camera, zoomed in on some stars, so that I can use that as the basis of establishing a manual focus adjustment. Of course, even with exposure simulation in the live view display it can be very difficult to see the stars and achieve optimal focus.

Naturally you’ll need to employ a tripod, and I also recommend using a cable release to ensure you don’t impart movement to the camera when triggering the exposure and to make it a little easier to work.

A good foreground element silhouetted against the sky can also add a degree of interest to a photo that includes the Milky Way. Most important, you should have some fun and enjoy your time out among a darkened landscape when photographing the night sky.