Keep stray light out of the viewfinder

At the Garfield Park Conservatory on Saturday, Photo Venture Camera Club veteran Rich Phelan kindly reminded me of something I forget too often when shooting with a tripod: Before you trip the shutter you need to cover the eyepiece to block stray light from entering and altering your exposure.

He suggested trying this: Put your camera into P mode (for Professional, of course!) and put the lens cap on. Check the exposure reading on the LCD panel. Now cover the eyepiece and check the exposure again -- the difference may surprise you.

This image is a composite of two photos, focused at two different locations to keep as much of the flower sharp as possible. My key mistake? I forgot to note what kind of flower it is...