This time I dried some cleaned ones on a slide and photographed them directly (no mounting or coverglass). The LWD 50X I normally use is excellent, it has plenty of working distance but the NA at 0.50 makes it less than ideal for fine diatom details. So I tried two higher NA objectives with much less working distance and was quite pleased with the outcome. The first image is with a Nikon CFI LU Plan 50/0.80 with a WD of 1mm. The last two are with my Olympus 100/0.95 M S Plan, which has a working distance of just 0.3mm. I was pleasantly surprised in two ways. First that I was able to get enough light on the diatom for an attractive shot, and secondly that there was really no noticeable chromatic aberration. This objective was one of Olympus' first infinity "M" series which were intended to be used with corrective eyepieces.
