I don't know how many times I have done this but it is more than I should and enough that I shouldn't still do it on occasion. I am talking about shooting at night or shooting a landscape and then forgetting to update to the proper settings for my next shoot.
Here's an example. One summer I went to Rocky Mountain National Park to photograph the Milky Way and nightscapes. I was out until maybe 1 a.m. when I finally went to the campground for a few hours of sleep. I had plans to get up early to hike up to Dream Lake before sunrise to capture the first rays of light on Hallett Peak.
This is a frequently photographed location but clearing clouds and a calm lake for reflections can be a rare event. I was thrilled when I arrived at the lake in plenty of time to set up before sunrise to see perfect clouds above Hallett Peak and a perfect reflection in the calm waters of Dream Lake.
I picked a spot, set up my tripod and waited for one of the most beautiful sunrises I have ever seen in Colorado. The pink tones of the first rays of light filled the peak with color and the clouds turned into stunning shades of purple.
I quickly changed to a more appropriate ISO setting - ISO 100 - but the moment was lost.
This image of Dream Lake is still a favorite of mine but more because it brings out the memory of that beautiful morning. The image unfortunately loses some of its sharpness as I reduce the noise from shooting it at an ISO of 1600.
I will be sure to hike up many more times to Dream Lake for sunrise but next time I will definitely make sure I am set up properly for landscape photos. (And maybe a little more sleep to help me think clearly!)