Type K - Combination of type A and J screens. Microprism and rangefinder black out at high focal ratios usually encountered in telescopes. Rest of screen not that bright. Focusing on fresnel portion of screen more difficult than on plain groundglass screens. Not that great for astrophotography, but usable.
Rangefinder blacks out at high focal ratios usually encountered in telescopes.
Rest of screen not that bright. Focusing on fresnel portion of screen more difficult than on plain groundglass screens. Not that great for astrophotography, but usable. Type M - Fine ground Fresnel field with 5.5mm clear spot and double cross hair for use in parallax focusing on aerial image, plus millimeter scales for calculations of individual magnification of objects for for measuring objects. Brilliant image in dim light, suitable for close-ups, photomicrography and other high magnification applications.