Plan apochromatic lens for T490A?

[LeonhardEuler]

Is it possible to get plan apochromatic lenses for my T490A microscope?

I heard plan apochromatic was good

[PeteM]

You could - but it would be sort of like putting $4000 tires on the family car. There are probably more cost-effective ways to improve performance.

My recollection (?) is the the T490 doesn't have an iris in the field, making it a bit harder to control internal reflections in an objective. With the additional lenses and lens surfaces inside a Plan Apo, contrast is often lost if you don't have full control.

[LeonhardEuler]

You could - but it would be sort of like putting $4000 tires on the family car. There are probably more cost-effective ways to improve performance.

My recollection (?) is the the T490 doesn't have an iris in the field, making it a bit harder to control internal reflections in an objective. With the additional lenses and lens surfaces inside a Plan Apo, contrast is often lost if you don't have full control.

It has a diaphram iris is that what you were referring to? It is on the abbe condenser.

What about Plan Achromatic, I bet those are probably better than what I got?

[LouiseScot]

Hi

Higher spec microscopes sometimes have two iris diaphragms - 1. the aperture iris diaphragm on the condenser and 2. a field iris diaphragm as part of the light source. If you don't have one of the latter you can 'cheat' by buying a suitably sized iris diaphragm via Ebay. You can manually position it above the light source or, if you have a 3D printer, you could make a custom adapter/holder.
There's nothing wrong in fitting apo objectives to a T490, they are just very expensive! A plan achromat is a slight upgrade of a plain achromat. An intermediate upgrade would be a fluor or plan fluor objective which have better colour correction than an achromat and higher resolution. They are still quite expensive, though, and are mostly second hand for finite microscopes. Look out for the finite Nikon CF fluor objectives.

Louise

[LeonhardEuler]

Hi

Higher spec microscopes sometimes have two iris diaphragms - 1. the aperture iris diaphragm on the condenser and 2. a field iris diaphragm as part of the light source. If you don't have one of the latter you can 'cheat' by buying a suitably sized iris diaphragm via Ebay. You can manually position it above the light source or, if you have a 3D printer, you could make a custom adapter/holder.
There's nothing wrong in fitting apo objectives to a T490, they are just very expensive! A plan achromat is a slight upgrade of a plain achromat. An intermediate upgrade would be a fluor or plan fluor objective which have better colour correction than an achromat and higher resolution. They are still quite expensive, though, and are mostly second hand for finite microscopes. Look out for the finite Nikon CF fluor objectives.

Louise

I will keep my eye out for those, not sure if they are compatible with the T490A do you know?

Anyway I might just get a Plan Achromat 60X objective to replace my 100X Oil Objective, I really don't want to be messing around with Oil and I think a good 60X should be a nice replacement. Right?

[LouiseScot]

Hi

Higher spec microscopes sometimes have two iris diaphragms - 1. the aperture iris diaphragm on the condenser and 2. a field iris diaphragm as part of the light source. If you don't have one of the latter you can 'cheat' by buying a suitably sized iris diaphragm via Ebay. You can manually position it above the light source or, if you have a 3D printer, you could make a custom adapter/holder.
There's nothing wrong in fitting apo objectives to a T490, they are just very expensive! A plan achromat is a slight upgrade of a plain achromat. An intermediate upgrade would be a fluor or plan fluor objective which have better colour correction than an achromat and higher resolution. They are still quite expensive, though, and are mostly second hand for finite microscopes. Look out for the finite Nikon CF fluor objectives.

Louise

I will keep my eye out for those, not sure if they are compatible with the T490A do you know?

Anyway I might just get a Plan Achromat 60X objective to replace my 100X Oil Objective, I really don't want to be messing around with Oil and I think a good 60X should be a nice replacement. Right?

Nikon cf for finite 160mm tube should be fine. I use them on my Swift 380t I'm not sure about 60x plan achros - a 100x oil immersion is much better!

Louise

[farnsy]

If you don't have one of the latter you can 'cheat' by buying a suitably sized iris diaphragm via Ebay. You can manually position it above the light source or, if you have a 3D printer, you could make a custom adapter/holder.

Louise, have you done this with your microscope? You seem like the kind of person who could pull it off but I'm curious how it performs. I understood that it was important that the field diaphram be in a plane that is conjugate with the specimen. I'm not sure where that would be on a microscope like the T490 or your swift.

[LouiseScot]

If you don't have one of the latter you can 'cheat' by buying a suitably sized iris diaphragm via Ebay. You can manually position it above the light source or, if you have a 3D printer, you could make a custom adapter/holder.

Louise, have you done this with your microscope? You seem like the kind of person who could pull it off but I'm curious how it performs. I understood that it was important that the field diaphram be in a plane that is conjugate with the specimen. I'm not sure where that would be on a microscope like the T490 or your swift.

Hi - yes, only on my Swift. However, I'm not sure it makes a huge difference over using a diffuser (Swift has a diffuser built into it's screw-in, plastic illuminator). Here's a diagram showing how a field diaphragm should be positioned for Kohler:

https://www.microbehunter.com/microscop ... %20slide).

I don't believe it's really quite the same when (as with the Swift) you have a LED light source since there's no filament involved. A simple field diaphragm can cut down on extraneous light though. The addition of a lens of the right focal length would enable you to properly add a field diaphragm for Kohler, if you really feel the need! On the other hand, even if you have a filament light source and don't want to mess about with adding a field diaphragm and lens, I reckon the simple addition of a diffuser (either a ground glass or translucent plastic one) is a simple way to give you more even light. I don't have a bulb-lit AmScope to try it.

Louise