Sometimes there is a need for a lens that would be something between macro and tele lens. Something that could let you shoot from 3 feet distance (not to disturb shy bugs or reptiles) but give you fair magnification of 1/3 or even more. One of rare lenses that gives you exactly that possibility is Sigma 70-300mm APO II with it's macro mode. Since I've bought Sigma 50-500 I'm lacking this feature. So logical addition to Bigma would be front magnifying glass added, so called Macro close-up filter. Calculations predicted good results with +1 and +2 diopter filters. So I borrowed two prescription glass lenses with such focal lengths. With the help of millimeter grid paper and plain measuring tape, I've collected interesting results. It seems that +1 diopter filter would yield very useful distance range and magnification. I have found such filter at B&H (+1 diopter, 86 mm diameter) under the BWCU186 code. When I get one, I'll make some test shots and show them here!