AmScope PA40XK-V300 40X Plan Achromatic Objective, Knurled Ring

An excellent lens for its purpose, which is to focus on tiny things in nearly a single plane. Great for larger bacteria, or with a higher power eyepiece (15X, 20X, 25X...), for typical-sized bacteria, blood-cell counts, etc. A "Plan" or "Planar" lens also provides the widest field of view, but does not have great depth of focus for larger objects, so this is a specialized lens for a specific purpose. One problem, though...when it arrived, the outer lens casing was loose, not properly tightly screwed on, and this was the case with some of the other objective lenses I've purchased...

Good lens, poor shipping If you’re building the openflexure, this will work great. However, the shipping was a bit careless. It comes in a case which threads the lens to prevent shaking but in transit, my case was cracked, although the lens was OK after confirming as it was nose to nose with the plastic case and could have scratched the objective. This was an unnecessary annoyance but overall the optical quality is fine.

Works great without the edge effects you would get in non-plan objectives.

Eh, it is an okay step up from normal achromatic, but not a huge difference. Save your money.

Everything good

A very worthwhile upgrade to a std acrho IMO. Very nice edge to edge resolution and contrast in brightfield. Viewing live blood slide in darkfield thru this objective is truly amazing; very detailed and sharp across the entire circle. Its way sharper than the best YouTube videos of live blood in darkfield.