Shortening or lengthing the tube
Shortening or lengthing the tube
Would an adapter (RMS to M26 thread) that adds 5mm to the front the revolving nosepiece be considered as adding to the tube length? From what Ive seen tube length is measured from bottom of revloving nosepiece. On a similar point, what affect does lengthening or shortening the tube have?
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Re: Shortening or lengthing the tube
It depends whether the system is infinity or finite ?
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Re: Shortening or lengthing the tube
Either way that would le.gthen the tube. Infact it's simpler for finite as it's very obvious that you are change the position of the objective with respect to the eyepiece. In infinite systems there is a reference length but it's my understanding that objective performance will not suffer from changing the tube length
1942 Bausch and Lomb Series T Dynoptic, Custom Illumination
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Re: Shortening or lengthing the tube
The reference length is between the telan lens and eyepiece. Adding a small amount of length in the infinity space does not affect the reference length.BramHuntingNematodes wrote: ↑Tue Feb 14, 2023 9:02 pmEither way that would le.gthen the tube. Infact it's simpler for finite as it's very obvious that you are change the position of the objective with respect to the eyepiece. In infinite systems there is a reference length but it's my understanding that objective performance will not suffer from changing the tube length
Re: Shortening or lengthing the tube
Its a finite distance objective lens. Its a Nikon BD plan
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Re: Shortening or lengthing the tube
There is more effect upon long focal length objectives, mainly the working distance and parfocality. Above about 16mm , not so much.
- blekenbleu
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Re: Shortening or lengthing the tube
Nikon sold adapters for that purpose, e.g. to use M Plan objectives in a BD turret.
Those objectives are 210 tube length; a few mm has about 1/4 less impact than for 160 tube length objectives.
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic
Re: Shortening or lengthing the tube
So what would putting an adapter tube shorter that 45mm do? What about constructing an adapter with 5 mm increments marked thats two tubes that can slide one inside other thats at least 60 mm long to see what quality of image I get, from 40,45 and 50 mm?
Is there any way to improve the deptth of field without changing the lens?
Is there any way to improve the deptth of field without changing the lens?
- blekenbleu
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Re: Shortening or lengthing the tube
Much depends on objective optical design specifics.
https://blekenbleu.github.io/microscope/basics/#TL
Metaphot, Optiphot 1, 66; AO 10, 120, EPIStar, Cycloptic