On a recent cruise, I ran into a number of situations in bright light where I really couldn't see enough on the LCD to frame the image.

My best solution so far is the Peak 4X magnifier (available online from B&H Photo for US$56). It fits the screen exactly and can be attached with an elastic secured to the two pins at the rear of the magnifier.

This is a very high quality optic with diopter adjustment, if a little bulky.