MicrobeHunter.com Microscopy Forum

Recently I received a 2x objective. I do a lot of work with insects and the standard 4x objective offered too much magnification and reduced field of view. Some time ago I purchased a 2x objective from AmScope ( it was quite expensive) and was disappointed by the fact that the entire circumference of the field of view had a large dark ring. I contacted AmScope but they were unhelpful so I just returned it for a refund. This time I saw a 2x objective again on sale (less than half the previous price) with a qualification that due to the large Numerical Aperture it may require a special condenser lens.
Some time ago I posed the 2x objective problem on this website and someone responded by suggesting that I remove the condenser lens entirely to solve the dark ring problem. Unfortunately I had already returned the objective. This time I took the advice of the Forum member and it worked !!!! Now I have an objective lens that has more than twice the field of view of the 4x lens, perfect for my application.

I do not know who this Forum member was that offered the successful solution to my original problem, but I wish to thank them. It's unfortunate that AmScope was unable to offer any help.

The attached images demonstrate the field of view with the 2x and 4x objective. The horizontal distortion is due to the camera on my Iphone 12+ !!!!!

Hi Antoni,
without condenser you get an illumination of a wide field but the colours in the image are typically much worse than with condenser in the illuminated area - don't ask me why.
What helps is an improvised condenser lens, planconvex, plan side on top, focal lenght about 40mm. This placed in the right height between field aperture and slide gives a much better image. Zeiss sold these as "Brillenglasscondenser" = "Nose bicycle condenser".

Bob

MicroBob wrote: ↑

Wed Apr 21, 2021 12:14 pm

Zeiss sold these as "Brillenglasscondenser" = "Nose bicycle condenser".

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Please excuse the intrusion, Bob ... but
DeepL gave what appears to me to be a more elegant alternative translation:
= Spectacle lens condenser

is this reasonable ?

MichaelG.

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As referenced here: https://books.google.co.uk/books?id=jRV ... 22&f=false

Hi Michael,
that sounds a lot more elegant for sure!
Do you know of an actual use of this name by a microscope maker? It is a simple lens, so lots of other names could have been used. I know Zeiss West and Zeiss Jena used "Brillenglaskondensor", but I'm not aware of the names used by other german brands.

Bob

MicroBob wrote: ↑

Wed Apr 21, 2021 7:21 pm

Hi Michael,
that sounds a lot more elegant for sure!
Do you know of an actual use of this name by a microscope maker? It is a simple lens ...

Try page 95 of this, Bob
http://www.science-info.net/docs/zeiss/ ... ystems.pdf

MichaelG.

The responses to my posting are interesting. My need for great accuracy of image quality and colour were not a prority when using the 2x objective, although to be honest I have not seen any degradation of colour with the 2x objective. However, I have looked at the correct condenser for the 2x objective and they are very expensive.

I like to make whole mount insect slides, and some insects are too big for th 4x objective so the 2x suits my needs perfectly. Fortunately, removing my condenser takes just a few seconds.