As simple as it may seem, taking photos of the moon can be challenging. If your full moon images look like a glowing white dinner plate in the sky, you are not alone. Let's find out why that is, and then work to fix it.
The moon is not a completely featureless orb and to capture some of those formations requires an understanding of how your camera sensor determines exposure. Your camera contains a built-in light meter that reads the entire scene in the frame and averages the lights and the darks to arrive at, what it thinks, is the proper exposure. This averages out to be 18% grey. This works well for most scenes especially when photographing things in the mid-tone area - trees, grass, blue sky, etc. or when the scene is uniformly lit.
If you are out during the next full moon and want to capture it with no other points of interest in the frame, the exposure issue is relatively easy to solve. Here are two methods to experiment with.
- Use spot metering. Instead of trying to determine the proper exposure for the entire scene, when you switch to spot metering the camera determines exposure based on the light in one spot, usually the centre of the frame. If you place the moon in the centre of your frame you should get a much more accurate reading.
- Use exposure compensation. First, let's have a closer look at the camera settings I used for the first shot in this post.
Camera: Olympus OMD - E-M1
Lens: Olympus 75-300mm f/4.8-6.7 II
Shooting Mode: Aperture Priority
Focal Length: 300mm (35mm equivalent - 600mm)
Shutter Speed: 1/4000 s
Exposure Compensation: -5 EV
Two things are worth noting with regards to these settings.
1. The shutter speed is so fast that a tripod was not needed. I could have reduced my ISO significantly and still been able to hand hold the camera. Normally I always use a tripod when composing night sky shots. This illustrates just how bright a full moon is.
2. More importantly is the exposure compensation. In order to bring out the details in the surface of the moon I dialled down the exposure by a full 5 stops of light. Exposure compensation is a way for you to override your camera's natural tendency to search for middle grey.
Although spot metering seems easier, I usually find myself sticking with matrix metering and using exposure compensation. With the ergonomics of the Olympus E-M1 it takes no time to dial down the exposure compensation a few stops and the electronic viewfinder shows me the exact results I will I get.
The real problem comes when trying to incorporate the full moon into a landscape scene. Now you have multiple objects to expose for.
The situation is quite manageable if you are trying to photograph the moon as it rises. Most of the time the full moon rises just as the sun is setting. Therefore, there is enough light in the atmosphere to achieve a decent exposure setting and still capture some details in the moon.
Using multiple exposures
There are a few ways of achieving the above results, but the technique that works best for me is...
1. Photograph the moon with no other distractions in the frame.
2. Set the camera to multiple exposure mode.
3. Compose the second frame by placing your moon wherever you'd like and click the shutter.
Those are the condensed steps. Let's look at the more detailed procedure with regards to how I created the photograph below.
Photograph the Moon
- I used the Olympus 75-300mm lens to zoom into the moon and adjusted exposure to bring out the details on the surface.
- I purposely positioned the moon in this location within the frame because I knew that I wanted the final image to have the moon framed within the branches of the white pine tree.
- Once you select "Overlay", all of your images will be displayed on the LCD. Select the moon photo that you just shot.
- You should see an overlay of the moon floating in your viewfinder or LCD which allows you to place it wherever you would like in your second frame. In the above example I placed it within the opening of the two branches.
- Press the shutter release. Once the frame is exposed you should briefly see the resulting image.
- The overlay will remain active in your viewfinder until you hit Menu to turn it off or hit the Play button to view your images. Have some fun creating new compositions.
You may have noticed the Auto Gain setting within the Multiple Exposure menu. What is it?
Auto Gain is a built-in form of exposure compensation to help prevent overexposure of your final image. Essentially it cuts the exposure of both frames in half. For each of the images posted in this blog I left auto gain in the default ON position but feel free to experiment by turning it off.
Avoid the Edges!
When I first started using this technique I discovered one important issue that you should also be aware of. For each of my double exposure images above, you may have noticed that I positioned the moon near the center of the frame. This isn't simply an artistic choice. There is a very good reason for this. I like to switch lenses between frames. I will use my longest telephoto lens to capture the moon and then switch to a wide-angle lens (like the 12-40mm PRO) in order to capture a wider field of view and create a more interesting landscape image. The above image illustrates this well. The problem occurs when you position the moon in one of the corners of your frame or too close to the edge.
The photos below illustrate what happens if you position the moon in a corner and switch focal lengths. Placing the moon that you shot at a long focal length into a second frame taken at a short focal length, distorts the moon. Essentially it becomes a stretched oval. This is not an issue if the focal length remains the same for both frames as was the case for the lighthouse photo and the white pine photo above.
The ability to create multiple exposures is certainly not new to photography and definitely not propriety to Olympus cameras. Most newer models of digital cameras have this setting and they all work in basically the same way. If you are looking for a way to add interest to your next shot of the full moon, try experimenting with multiple exposures.
There is one other technique that you can use to achieve well-exposed landscape shots that include the moon and that is bracketing. This involves taking several photographs at different exposure values and then combining them in Photoshop or other editing software. This is a common technique for creating HDR images during the daytime. Once I experiment with this technique a bit more I might write another post.