Top eyecup (18mm intake) eg for Canon EOS 300D, 350D, 400D, 450D, 500D, 550D, 600D, 650D, 1000D, 1100D, 30D, 40D, 50D, 60D and many more (electronic) 5
One can 100% focus and make optimum scene settings here without lateral interference. The display is not affected by the nose, so that no contamination caused by fatty deposits.