Zeiss Optovar lens

Comparing effect with and without Optivar

I tried adding in the Optivar into the optical train today. This is an additional magnifying lens that does the same job as a Barlow lens on a telescope. In a previous post, I noted that this particular Optivar suffers from extensive delamination so today was my first chance to find out if this is a significant issue and what difference an Optivar makes on my microscope. When I purchased it and it arrived and I found that it had the delamination I managed to get a massive discount so I am not concerned if it isn’t that good but it would be nice if it worked!

The following two pictures show an image using 32x objective bright field with and without Optivar of the cell boundary area on the tulip stem from the previous post.

The Optivar loses some of the sharpness of the image and with higher power lenses in the Optivar (it provides 1x, 1.25x, 1.6x and 2x lens – photo below with 1x lens to compare with photo without Optivar) the image is not as well focused – sadly the delamination does affect the image. Mind you, the image is not that bad and it should still be helpful for some projects.

Andy

Without Optivar:

With Optivar 1x lens (Optivar provides 1x, 1.25x, 1.6x 2x lens):

Delamination of Zeiss Standard Optovar

The following pictures show this problem on an example of a Zeiss Standard Optovar. The lens elements are separating and this leads to the rainbow effect. I have slightly rotated the Optovar on the spot in same lighting between pictures and you can see that the inner edge of the rainbow rotates with the rotation of the whole instrument. This would not occur if it was due to defraction of light from the glass only.

Andy

Delamination in top lens

Delamination in bottom lens: