Barlow lens

[Peat Burns]

I have a trinocular boom-arm stereo "dissecting scope" from USA Scopes (SMT-3412 SM), and the working distance is terrible.  I want to buy a barlow  (reduction lens) to increase working distance. My understanding is that they are attached to the existing objective lens rather than replacing the objective lens. I wrote USA Scopes, and they said they have a 0.5x auxiliary lens, but the thread diameter is the same as the objective lens (where it screws into the scope) and not the same as the "distal" threads on the objective lens.  Is my understanding of the Barlow lens correct?  I.e. the Barlow should be attached to the objective rather than a replacement of the objective? @Ptychodus04?

[Ptychodus04]

@Peat Burns, the .5x objective replaces the 1x objective currently on the microscope. Your magnification is achieved by dividing the focal length of the objective by the focal length of the ocular (eyepiece). The .5x objective has 1/2 the focal length of the stock objective.

 

This is not a true “Barlow” but is effectively the same thing.

[Peat Burns]

5 hours ago, Ptychodus04 said:

@Peat Burns, the .5x objective replaces the 1x objective currently on the microscope. Your magnification is achieved by dividing the focal length of the objective by the focal length of the ocular (eyepiece). The .5x objective has 1/2 the focal length of the stock objective.

 

This is not a true “Barlow” but is effectively the same thing.

Thank you Ptychodus04.  That is very helpful. Just wanted to make sure it would help before I drop $200. 

[Ptychodus04]

31 minutes ago, Peat Burns said:

Thank you Ptychodus04.  That is very helpful. Just wanted to make sure it would help before I drop $200. 

 

It should double your working distance.

[Peat Burns]

19 minutes ago, Ptychodus04 said:

 

It should double your working distance.

That will be a big help.  Thank you!