Today’s Question: I was inspired by your recent photo “Sunrise in the Palouse”, and went out to try capturing photos that include the sun in the frame. I was able to get the exposure pretty good (setting a minus exposure compensation), but ended up with lots of somewhat bright (but not colored) circles in the photo. Is that lens flare of some sort? What can I do to avoid these circles?
Tim’s Quick Answer: Your description sounds like the effect from having dust or other debris on the front element of your lens. When including the sun in the frame (or nearly in the frame) it is critically important to clean the lens. I recommend making use of a lens cloth, brush, blower, or similar device to clean the front of the lens frequently when photographing with the sun in (or near) the frame.
More Detail: Fortunately, in most cases it is relatively easy to clean these spots after the capture, especially if the spots appear in an area of open sky. However, because the sun will cause the dust or other contaminants on the front lens element to “glow” with light, then can interfere with textures and details within the photo. Therefore, it is important to try to avoid this issue in the first place.
I make a point of cleaning the front lens element once I’m ready to capture my shot whenever I’m including the sun in (or near) the frame. I’ll then keep an eye on the front lens element, especially when I’m in a dusty area, and clean the lens as often as is needed (or more often than that!).
The photo referenced in today’s question can be found on my 500px page here:
In this case I was working before (and during) sunrise in a very dusty area, and ended up with some of the spots referred to in today’s question even though I had cleaned the lens a few frames before the image seen above was captured. Even though I was trying to be careful, I didn’t get the front lens element completely clean (or more dust accumulated after I cleaned the lens), so I had a bit of cleanup work to do after the capture.
If you are very careful to keep the front lens element clean, you’ll able to minimize the effect of these glowing circles, which can be very distracting in the photo. Lens flare, of course, can’t be completely avoided if you are including the sun in the frame. But even that can often be cleaned up or minimized in post-processing.