160mm Objectives on Orthoplan

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JGardner
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160mm Objectives on Orthoplan

#1 Post by JGardner » Wed Mar 25, 2020 9:14 pm

Sorry to open this can of worms again. I've read various articles on using 160mm objectives on Orthoplans, and I've read the Leitz memo addressing this topic. Basically, the memo says that 160mm objectives of 16x or higher magnification work fine on 170mm tube length microscopes such as the Orthoplan.

What I'm asking for here is first-hand experience with using 160mm objectives on Leitz microscopes designed for 170mm objectives. Has anyone done this? What were the results? Did you notice any image degradation?

Leitzcycler
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Re: 160mm Objectives on Orthoplan

#2 Post by Leitzcycler » Wed Mar 25, 2020 9:33 pm

Yes, I have PL Fluotar 40, PL Fluotar 100 oil and a normal 100 oil of 160 mm in my Orthoplan. They work well, no problem.

JGardner
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Re: 160mm Objectives on Orthoplan

#3 Post by JGardner » Wed Mar 25, 2020 11:10 pm

Thanks! That's exactly the first-hand experience I was hoping to hear.

MicroBob
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Re: 160mm Objectives on Orthoplan

#4 Post by MicroBob » Thu Mar 26, 2020 1:31 am

I actually have a pair of similar Leitz objectives, one marked for 160mm, one for 170mm - no difference.
The 170mm objectives were used with eyepieces with a pick up point 18mm down the tube, the 160mm with eyepieces with a pick up point 10mm down the tube. This allows to calculate which objective/tube/eyepiece combinations will work well and which might not.

BUT: I have a Leitz 10:1 multi immersion Apo objective from the 170mm/37mm era that I use with a 8mm spacer. Here is a clear deviation from the calculated tube lenght and the objective gives a very nice image nontheless. So only a test can reveal whether this is actually a problem or not.

Rorschach
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Re: 160mm Objectives on Orthoplan

#5 Post by Rorschach » Thu Mar 26, 2020 5:41 am

Bob, when you use 160mm TL objectives on it, do you also use Periplan eyepieces intended for 160 TL? What about photo projection eyepiece in the photoport, would that also need to be 160mm TL in that case?

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Re: 160mm Objectives on Orthoplan

#6 Post by MicroBob » Thu Mar 26, 2020 8:39 am

I only use microscopes with 160mm tube length of differnt brands. The 160mm Leitz objectives are used with 160m Leitz eyepiexes (like 10x18 designation) or 170mm Leitz eyepieces with an 8mm spacer.

Look here: https://www.mikroskopie-forum.de/index. ... 7#msg87737

This applies for all ports of the tube head.

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75RR
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Re: 160mm Objectives on Orthoplan

#7 Post by 75RR » Thu Mar 26, 2020 9:00 am

So what JB (on the mikroskopie-forum) is saying is that on a Leitz 170 tube microscope there is no need to swop eyepieces when using a 160 tube objective,

one can simply lift the 170 tube eyepieces by 8mm using a spacer ... (see example #6 on chart)

That should save some pennies.

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Re: 160mm Objectives on Orthoplan

#8 Post by Rorschach » Thu Mar 26, 2020 9:35 am

This is great.

What about infinity objectives? I have a Metalloplan coming up and it has a set of Leitz infinity (incident illumination) objectives installed on a Leitz 0.8x infinity nosepiece. Wouldn't this affect the eyepieces? And a related question: which photo eyepiece should be used in the trinocular in this case? Infinity objectives should be corrected, right? Which would mean that the corrections that the Periplans have, would be causing problems?

JGardner
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Re: 160mm Objectives on Orthoplan

#9 Post by JGardner » Thu Mar 26, 2020 3:54 pm

75RR wrote:
Thu Mar 26, 2020 9:00 am
... (see example #6 on chart)
Dang! That's a nice chart, but it seems to cover every scenario except the one I'm interested in, e.g. 160mm objectives and 170mm eyepieces on a 170mm microscope.

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Re: 160mm Objectives on Orthoplan

#10 Post by 75RR » Thu Mar 26, 2020 4:01 pm

That's a nice chart, but it seems to cover every scenario except the one I'm interested in, e.g. 160mm objectives and 170mm eyepieces on a 170mm microscope
You are describing #6 on the chart.

When using a 160 objective on your Orthoplan raise the 170 eyepiece 8mm with a spacer.

(That will bring the eyepiece diaphragm onto the same plane as the intermediate image produced by the 160 objective.)
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

JGardner
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Re: 160mm Objectives on Orthoplan

#11 Post by JGardner » Thu Mar 26, 2020 4:09 pm

75RR wrote:
Thu Mar 26, 2020 4:01 pm
That's a nice chart, but it seems to cover every scenario except the one I'm interested in, e.g. 160mm objectives and 170mm eyepieces on a 170mm microscope
You are describing #6 on the chart.

When using a 160 objective on your Orthoplan raise the 170 eyepiece 8mm with a spacer.

(That will bring the eyepiece diaphragm onto the same plane as the intermediate image produced by the 160 objective.)
I'm confused... From looking at #6 in the chart, it looks like I need to lower the 170mm eyepiece by 2mm. What am I missing here? Doesn't #6 apply to a microscope with a 160mm tube length, not 170mm?

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75RR
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Re: 160mm Objectives on Orthoplan

#12 Post by 75RR » Thu Mar 26, 2020 4:11 pm

I think you may be right. I have misread the chart.

There is no diagram for a 170 microscope with a 160 objective and a 170 eyepiece

Those 2mm would not seem to be critical according to Leitzcycler and MicroBob


Perhaps the best solution would be to see for yourself with an 'economical' leitz objective.
Zeiss Standard WL (somewhat fashion challenged) & Wild M8
Olympus E-P2 (Micro Four Thirds Camera)

JGardner
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Re: 160mm Objectives on Orthoplan

#13 Post by JGardner » Thu Mar 26, 2020 4:19 pm

75RR wrote:
Thu Mar 26, 2020 4:11 pm
Those 2mm would not seem to be critical according to Leitzcycler
Thanks for clarifying. I'll look for a 160mm objective on eBay to try before I look for a whole set.

Anyone know how much degradation is visible when using 160mm objectives at magnifications less than 16x on an Orthoplan? I'm thinking of 4x and 10x objectives here.

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Re: 160mm Objectives on Orthoplan

#14 Post by MicroBob » Thu Mar 26, 2020 6:27 pm

Tube 170mm
obective projects at 150mm (160-10)
eyepiece older Leitz like 10x and no field number, pick up point 18mm down the tube
170-18=152
Difference 2mm, not dramatic.

The biggest difference will be seen in very low power objectives where a bit more refocussing than usual may be needed.
So mixing is no problem as long as you know what you do and check the results carefully as soon as you leave the recommended combinations. There are combinations that just don't work well. And then there are some that shouldn't but do, for whatever reason. Like my old 10:1 Apo multi immersion.

BTW: The newer Leitz stuff adheres to the values given in that DIN norm, which is based on Zeiss West values. Zeiss Jena eyepieces have a pick up point 13mm down the tube. So Leitz 45mm (170 or 160), Zeiss West and Zeiss Jena can be mixed quite well on a 160mm microscope. The CVD correction fits also quite well.

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