what is a 1x objective ?

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wild2020
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Joined: Wed Dec 23, 2020 11:23 pm

what is a 1x objective ?

#1 Post by wild2020 » Wed Apr 07, 2021 6:12 pm

Hi,

I don't really understand what 1 x objective is doing, if it was lower or higher that makes sense but why have a 1x lens instead of air?

thanks

hans
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Joined: Thu May 28, 2020 11:10 pm
Location: Southern California

Re: what is a 1x objective ?

#2 Post by hans » Wed Apr 07, 2021 6:51 pm

Probably many other subtleties, but one basic issue is working distance. You can use an eyepiece as a simple magnifier by putting an object directly in the intermediate image plane and get the same magnification as with a 1X objective but the working distance is very small. (Intermediate image typically ~10 mm below the top of the eye tube where the eyepiece sits.)

Greg Howald
Posts: 516
Joined: Tue Oct 20, 2020 6:44 am

Re: what is a 1x objective ?

#3 Post by Greg Howald » Wed Apr 07, 2021 8:00 pm

I think it has a lot to do with protection. If you get a 1x Barlow lens for a stereo scope its main purpose is to protect the other objectives and keep dirt out.

dtsh
Posts: 268
Joined: Wed May 01, 2019 6:06 pm

Re: what is a 1x objective ?

#4 Post by dtsh » Wed Apr 07, 2021 8:25 pm

I believe hans is correct. For example on my Cycloptic, the CMO (Common Main Objective) is 1x, next up the path is the magni-changer where I can select 7x, 10x, 15x, 20x, or 25x, then on up to the prisms and eyepieces. If I select 10x as the magnification, the magnichanger is just air with no elements, so the 1x is designed to put the corrected image at the right point to be picked up by the eyepieces, but not to add any magnification, just working distance (from 10mm in the tube to several inches below the CMO. If I want more working distance I have to give up magnification such as with a 2/3x barlow or to gain magnification at the cost of working distance with say a 2x barlow.

It's a 1x and isn't adding magnification, but it does (or should) add corrections. In the Cycloptic, the CMO is an apochromatic tripple.

Scarodactyl
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Re: what is a 1x objective ?

#5 Post by Scarodactyl » Wed Apr 07, 2021 11:45 pm

Remember that '1x' is just relative to the field number, and in a microscope the image will always be further magnified (either by the eyepieces or from the small camera sensor to a large monitor.)

A few sellers might label a flat shield as a '1x' auxiliary objective (since it does not change the magnification), but that's different an actual 1x objective.

When you're dealing with a variable magnification system like a cmo stereo the '1x' designation is a bit more arbitrary than usual, since it only achieves its final magnification in combination with one or more lenses which also affect the magnification. On the Wild m3 the setting without any extra lenses between the objective and head is labelled 1.6x.

apochronaut
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Re: what is a 1x objective ?

#6 Post by apochronaut » Thu Apr 08, 2021 2:33 pm

Corrected wide field.

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