O for Objectives

Objectives! It's hard not to be subjective when it comes to the most expensive part of the microscope.

Microscope objectives are typically sold in three different tiers with widely differing price tags: Achromats, Fluorites and Apochromats. Often in combination with the word Plan, which is a buzzword for letting you know that the focal plane is approximately flat within the field of view.

No doubt, you have already read something about these three tiers on internet forum XYZ.

I'm going to try and give you my take on the subject matter. With that in mind, I'm not into resolution measurements. What I care about is how the objective works in practice. 

Short answer first: modern achromats are very good for most applications. In fact, most people would not be able to tell the difference between an image taken with an achromat or an apochromat. In the eyepieces, the difference is even smaller. Your eyes simply lacks the resolution to see the difference.



Now we need to two keep to things in our head at the same time. Fancy objectives is a good way for the big four (Olympus, Nikon, Leica and Zeiss) to sell expensive gear to researchers with big grants. A specialised objective can easily cost $10,000. Sadly, few researchers know how to utilise their gear to the max.

On the other hand, a good objective can make the difference in certain applications. But in about 90% of routine microscopy, other factors will be more important.

Most techniques will work fine regardless of the price of the objective, for instance phase contrast and dark-field microscopy. For example, the amazing Youtube channel ”XXX Microcosmos” filmed most of their footage using Plan Achromats.

On the second hand market, things are of course a bit different. I have a lot of fancy objectives, but I usually pay between 10-20% of the retail price. And I'm a nerd… 



If you want fancy glass, yet don't want to overpay you can easily pick up a set of plan fluorites for a reasonable price. Of course, you can also mix and match! Try to find out what your favourite magnification is, and spend your money there.

If you wan't to read more, read my longer post on microscope objectives.