Originally posted by todd Eye-Relief Length Approx. 20.6mm (from the view window), Approx. 21.7mm (from the center of lens)
I haven't seen eye relief quoted for cameras, but it is commonly quoted for binoculars because of its importance to the birding market. The specification for eye relief enables potential eyeglass-wearing customers to judge whether they will be able to see the entire field of view when looking through the binoculars while wearing eyeglasses. Taking the time to lift the eyeglasses out of the way to see the entire field of view is not a viable option since this often means the bird is gone by the time you get your binoculars trained on the bird's location, not to mention the fact that birders raise binoculars to their eyes dozens to hundreds of times per day. 21 mm or greater eye relief is suitable for eyeglass wearers.