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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Noctivid - exit pupils on your sample perfectly round? (1 Viewer)

Troubador said:
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The dent or 'tangential intruding chord' or TIC is clearly visible, but does this disappear with careful eye positioning?

Lee
Click to expand...

Yes, it does - at the price of creating „dents“ in other places.

I have seen another sample where you could get a perfectly round EP by carefully positioning the binocular. Not in my sample, though.

But you point out an important observation: the Noctivid is prone to substantial vignetting, more than most alphas I know. Both samples I have reviewed showed this clearly.
Is this also the experience of other users ?
 
Canip said:
But you point out an important observation: the Noctivid is prone to substantial vignetting, more than most alphas I know. Both samples I have reviewed showed this clearly.
Is this also the experience of other users ?
Click to expand...

I have to say that I've never been aware of any vignetting with mine, and now that I've actually looked for it I can't see any either. Tested with an artificial light source and a plain grey sky.
 
henry link said:
The eyepieces are mounted in eccentric rings for purposes of collimation. If only a little eccentricity is needed to collimate a particular unit then the prism edges will remain invisible when the eye (or camera lens) is centered on the exit pupil. If an eyepiece or both eyepieces need to have a large amount of eccentricity applied that may introduce enough misalignment between the eyepiece optical axis and the optical axes of the fixed prism and objective to cause one or more prism edges to come into view just as if the pupil of the eye had been decentered.
Click to expand...

Henry, thanks for this. Great knowledgeable information as ever. I notice that the TIC that I can induce in both tubes on my NV is in the same position, i.e. 12 o'clock. I can't help wondering if there is any significance, or difference in optical effect, if these are in the same or different places? Please forgive my doubtlessly ignorant question!

As you see though from my earlier post, I actually have to induce these by off-axis positioning so they are not an issue for me anyway.
 
Last edited:
My new binocular has the out-of-round exit pupil.
I am waiting to hear back from the manufacturer so I am withholding their name until they respond.
I did get a picture of the problem.Left 1.JPGLeft 1.JPG
 
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