3 microscope objectives, ? quality

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Ben P Botha
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3 microscope objectives, ? quality

Post by Ben P Botha »

Hi,

I am a new member. I have been using a Canon MPE 65 and a Canon R5 for macro photography. I have a Wemacro rail and would like to start using Microscope objectives.

I have received 3 objective lenses. All infinity corrected. I have no idea about the quality of the lenses. Images attached.

1. Zeiss Winkle 10x 160 AP 0,25
2. Motic SP 10x 160 0,17
3. Zeiss APlan 20x 160 0,45

To be used on 150 mm tube on Canon.

Regards,

Ben
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PeteM
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Re: 3 microscope objectives, ? quality

Post by PeteM »

Ben, these are all finite objectives (not infnity) with a 160mm tube length.

All should be usable for routine microscopy. The Motic is semi-plan and a pretty routine objective. The Zeiss 20x is Plan - and likely wants to be paired with correcting eyepieces. I'm not sure about the correction requirements or the reputation of the 10x Zeiss Winkle.

There would be better choices for a macro rig.

Ben P Botha
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Location: South Africa

Re: 3 microscope objectives, ? quality

Post by Ben P Botha »

Thanks for the info and reply! Appreciated. I am still battling with all the terminology, thanks!

My knowledge is definitely not infinite :D :D !

Regards,

Ben

Ben P Botha
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Re: 3 microscope objectives, ? quality

Post by Ben P Botha »

Hi,
If the Zeiss lens is mounted on a 160/150 mm tube and connected to the camera, where does the correcting eye pieces fit in the setup?

Sorry for the ignorance!

Ben

JKT
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Re: 3 microscope objectives, ? quality

Post by JKT »

Ben P Botha wrote:
Thu Feb 24, 2022 6:37 am
If the Zeiss lens is mounted on a 160/150 mm tube and connected to the camera, where does the correcting eye pieces fit in the setup?
That's the problem - it doesn't. Well - not in the simple setup anyway. It is possible, but takes some more parts and I'm not familiar with that setup.

Alan Wood
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Re: 3 microscope objectives, ? quality

Post by Alan Wood »

The best finite objectives (e.g. 160 mm) for use on a tube with no other lenses are ones that are fully corrected for chromatic aberrations, such as Nikon CF ones.

Leitz, Olympus and Zeiss 160 mm objectives were designed with only partial correction in the objective and residual corrections fixed by compensating eyepieces. So if you use them for direct projection onto the sensor you must expect some aberration at the edges and in the corners.

Alan Wood

Troels
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Re: 3 microscope objectives, ? quality

Post by Troels »

Ben,
I also noted an error, either a misunderstanding or a typo:
"All infinity corrected."
That is obviously not the case. On 'infinity' objectives the inscription is a "sleeping" 8 instead of the number 160.
So all your objectivers are finite.
With infinite objectives you don't need correcting oculars. That is why they are so popular among photographers.
On the other hand the infinity objectives need a 'Tube Lens'. That is why the finite, color-corrected CF Nikon objectives are also popular.

Troels
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Scarodactyl
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Re: 3 microscope objectives, ? quality

Post by Scarodactyl »

Older zeiss objectives had much less strong corrections. It is possible the winkel one will actually give OK results (zero promises though).
No idea on the Motic. It is styled after an Olympus objective but may or may not require corrections. Quality is probably not that high.

enricosavazzi
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Re: 3 microscope objectives, ? quality

Post by enricosavazzi »

Ben P Botha wrote:
Thu Feb 24, 2022 6:37 am
If the Zeiss lens is mounted on a 160/150 mm tube and connected to the camera, where does the correcting eye pieces fit in the setup?
Zeiss objectives need a correcting eyepiece because the objective itself, by design, does not correct all aberrations but only parts of them, and relies on the presence of a correcting eyepiece to finish the job. As far as I remember, this includes both the finite 160 mm objectives and the early series of infinity corrected ones. I am not sure if this is still true of more modern Zeiss eyepieces for infinity scopes.

If you don't use a correcting eyepiece, for example in direct projection onto a camera sensor, you will get more uncorrected aberrations in the image than with a proper eyepiece.

Another important thing to know is that a given series of objectives need a matching type of correcting eyepiece. You cannot use a correcting eyepiece from a different series and/or brand and expect the same results as with the proper correcting eyepieces. In practice, this means that mixing finite objectives and eyepieces of different brands is generally not a good idea, although sometimes the results are not too bad.

Most modern infinity corrected objectives these days fully correct all aberrations in the objective, and it is therefore much easier to mix objectives of different brands on the same scope and/or to use one of these objectives with eyepieces of a different brand. An infinity corrected objective does require a tube lens between objective and eyepiece. With a relatively small camera sensor (3/4 or sometimes APS-C) you also can directly project an image onto the sensor with an objective and its tube lens, without an eyepiece or so-called "relay lens". The focal length of the tube lens varies somewhat among brands (most are 200 mm, but Olympus uses 180 mm). Often you can use a tube lens of slightly different focal length than the one specified for a given objective, but image magnification will differ somewhat from the nominal.

Most of the modern infinity corrected Nikon CF (= color free) objectives and modern objectives of other brands, for example Olympus UIS and UIS2, do not require a correcting eyepiece, and you can safely use these objectives for direct projection (with a proper tube lens) or mix objectives and eyepieces of different brands. Even so, eyepieces differ in the size of their field aperture, and tube lenses and objectives in their usable image circle, so it does pay off to match these parameters. The easiest way to avoid trouble is to use objectives, tube lenses and objectives specified as compatible by their maker.
--ES

Ben P Botha
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Re: 3 microscope objectives, ? quality

Post by Ben P Botha »

Hi all,

Thanks for all the responses and info.

Please correct me if I am wrong.

1. I have finite objectives
2. They might not be color/aberration corrected and if not, requires a correcting eye piece if used on a microscope.
3. The finite objectives are mounted on a tube with a total length of 150-160 mm depending on camera flange distance.
4. No correction lenses possible with finite objectives mounted in a tube and projecting to camera sensor via the tube.
5. Quality of the objectives not 5 star.
6. Play with objectives to determine quality, aberrations etc.
7. CF objectives might be the way to go if my ones are not performing properly.

Regards,

Ben

JKT
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Re: 3 microscope objectives, ? quality

Post by JKT »

Ben P Botha wrote:
Thu Feb 24, 2022 1:21 pm
3. The finite objectives are mounted on a tube with a total length of 150-160 mm depending on camera flange distance.
Total length of tube is indeed about 150mm, but the part inside the camera is included in that length. So the total length is not affected by the flange distance, but the length of the tubes in front of the camera flange is. Just wanted to make that clear as there has been misunderstandings.

zzffnn
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Re: 3 microscope objectives, ? quality

Post by zzffnn »

Ben,

The Zeiss objective, having a numerical aperture of 0.45, would need to be used with 0.17mm cover slips over your subjective.

It would produce too much spherical aberration for macrophotograpby, unless you glue a 0.17mm cover slip over its top lens.

You may want to get a metallurgical objective corrected for 0mm cover slip for macro.

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