I use eyeglasses with -1 diopter correction. Few days ago, I photographed the moon during night with my Canon 2000D DSLR. When looking at the moon through the viewfinder, I saw the moon as two distinct bright objects. I thought that there might be something wrong with the diopter adjustment of my 2000D DSLR. The image that I took was just fine, and not out of focus. The viewfinder was practically useless due to the severe dual vision effect. Unfortunately, I didn't test the viewfinder without eyeglasses that day, and today it's rainy and cloudy so I can't repeat the test today.
Today, I tried to replicate the effect indoors with eyeglasses by using the same focal length (250 mm) and focusing at over 5 meter distance. I couldn't replicate the effect. I didn't touch at the diopter adjustment of the DSLR at all, so the same settings were used for astrophotography and this test.
I haven't yet tested looking at the moon through the viewfinder without eyeglasses during the night, so I can't say if the effect appears without eyeglasses. I suspect it might be related to eyeglasses.
- Why do I see the moon as two objects through the DSLR viewfinder?
- Is seeing the moon as two objects related to me wearing eyeglasses?
- Can the effect be caused by incorrect diopter adjustment setting on the DSLR?