It may be worth mentioning if anyone here is a software guru or twelve year old, there are some really cool things you can do with photomicrographs nowadays to remove all blurring from limited depth of field. It involves taking several images where the only thing you change is the focal distance and then create a composite saving only the in-focus parts of each image. This is surprisingly simple for digital images since a sharp sub-image or neighborhood is defined by high local variation in brightness as measured by standard deviation or range.