I would like some advice. I am new to DSLR and using a Nikon D300s. As per manual to adjust the diopter, I found that when focus is locked on and I adjusted the diopter to clockwise maximum its almost sharp (I presumed) but I have a feeling it could be sharper but I can't find out since its at the maximum. The manual suggested getting the DK-20C to further compensate. What's your expert advice?
I mostly shoot on tripod and manual focus but the shots came out not sharp even when subject is within 10 meters range. Most probably one in a hundred is sharp. Is this diopter issue the cause? Where can I purchase the recommended DK-20C? Does any of the regular camera stores have it or only Nikon S'pore since I couldn't find this particular model on their website?
Note : I don't wear glasses but do experience slight dispersed lights in the night (San Guang). Think its called astigmatism.
Thanks in advance.