10 replies to this topic

[astronomia]

If you want to use the TNVC/TV  afocal adapter on your c-mount NVD that uses a Computar v2513 objective (25mm, f/1.3), the adapter will not attach to the lens. The adapter is machined to attach to the PVS-14 objective or similarly threaded objective.

 

My experience:

I wanted to use the TNVC/TV adapter with the Computar lens so I tried the step-up/step-down adapters suggested by guangtou (30-37mm, then a 37-40.5mm). Unfortunately the 30mm did not attach very securely in my case to the TNVC/TV adapter. It did not feel like the thread pitch matched to me. The other interfaces were perfectly matched.

 

I went to Precision Parts website and ordered the following custom adapter: telescope side selected Televue, on Camera side selected Other brand names. Next, selected TV TNVC Night Vision A-focal Adapter on the Telescope side, 0 mm for Adapter Effective Length, and Computar v2513 CCTV lens, and clicked “Build”; reviewed adapter design for accuracy and payed the man and waited for the custom adapter. (A bit pricey, but I felt worth it for the extremely high quality.)

 

Kudos to Precise Parts, great email communication and quick service. I received the precision adapter in less than a week. My adapter had an effective length of about 1 mm. The adapter has a “precision” fit to both the TNVC/TV adapter and my Computar v2513. I also have a Navitar lens that uses a 40.5mm filter. The adapter also fits that lens “like a glove.”

 

To be complete, there are other methods mentioned in other threads to use your NVD Afocally.

However, I preferred to use the TNVC/TV adapter.

 

Tom

[chemisted]

This is great news.  Some months ago I attempted to use Precise Parts and they did not list the TNVC/TV adapter in their pull down menus. I am glad to see they added it.

[moshen]

Nice findings Tom 

 

If someone sends PP the threading specs for Dioptrix then it may be easier to just go directly from Dioptrix to Computar threads. It would make for one adapter instead of two and make the price for total connection setup lower. 

This will also avoid any issues due to increased optical length from adding two adapters (vignetting, etc) and insure objective placement is in the optimal spot.

Edited by moshen, 26 April 2018 - 07:02 PM.

[Eddgie]

Nice findings Tom 

 

If someone sends PP the threading specs for Dioptrix then it may be easier to just go directly from Dioptrix to Computar threads. It would make for one adapter instead of two and make the price for total connection setup lower.

Brilliant idea.  

[astronomia]

Unfortunately, unless I am missing something, there are no threads on the eyepiece that the Dioptrix attaches to. It appears that the TVNC/TV adapter utilizes the same attachment design/mechanism that the Dioptrix uses...a compression type system that utilizes the depression that the rubber eyeguard normally snaps into to hold it in place. I have three “Dioptrix ready” Televue eyepieces and all have that indent and no attachment threads.

 

Tom

[moshen]

Unfortunately, unless I am missing something, there are no threads on the eyepiece that the Dioptrix attaches to. It appears that the TVNC/TV adapter utilizes the same attachment design/mechanism that the Dioptrix uses...a compression type system that utilizes the depression that the rubber eyeguard normally snaps into to hold it in place. I have three “Dioptrix ready” Televue eyepieces and all have that indent and no attachment threads.

 

Tom

Tom,

 

Ah, I stand corrected. I don't have a Dioptrix eyepiece and only use prime focus with reducer/barlow combo. I assumed the Dioptrix was a thread.

[astronomia]

No problem, I thought maybe I was missing something...certainly wouldn’t be the first time.

 

It definitely would have been nice to be able to have just one attachment and save some cash at the same time!

 

Tom

[KJL]

Kudos to Precise Parts, great email communication and quick service. I received the precision adapter in less than a week. My adapter had an effective length of about 1 mm. The adapter has a “precision” fit to both the TNVC/TV adapter and my Computar v2513. I also have a Navitar lens that uses a 40.5mm filter. The adapter also fits that lens “like a glove.”

 

To be complete, there are other methods mentioned in other threads to use your NVD Afocally.

However, I preferred to use the TNVC/TV adapter.

This is beautiful, and almost exactly what I was looking for. Just have one question: do you see any difference in vignetting between putting the Computar lens directly on top of a TV eyepiece vs using the TNVC + PreciseParts adapter?

 

That 1mm of height was enough to create vignetting even in long eye-relief models like the TV 32mm Plossl when I tried to adapt the same Computar lens to a TV afocal camera adapter with a ~1mm-thick thread adapter in between. The only way to avoid vignetting was to place the Computar lens directly (but loose) on top of the afocal adapter.

 

What would be ideal is a 0mm adapter with Computar male threads on the outside and TNVC female adapter on the inside ... but this adapter may simply be too weak for PreciseParts to machine. They tend to err on the side of robustness, even if the threads technically will nest.

 

Anyway, still awesome work. I'm going to take a look at PrecisePart's NV parts again.

[astronomia]

KJ,

Sorry to say I have not yet tried this setup “live.” I’m still waiting on my MOD3 c-mount monocular!

 

Reportedly, I should be receiving it soon.

 

Tom

[The Ardent]

Folks.
The TNVC adapter threads directly to lenses with a 30.5mm filter thread .

The problem is , most c-mount lenses don’t use this size.

A few do, like the Tamron 25mm I reviewed here.

https://www.cloudyni...view=getnewpost

When shopping for c-mount lens, always check front filter size = 30.5mm. Or you will need an adapter.

[Jeff Morgan]

Tom,

 

Ah, I stand corrected. I don't have a Dioptrix eyepiece and only use prime focus with reducer/barlow combo. I assumed the Dioptrix was a thread.

 

Still, an A+ for creative thinking.

 

The TNVC adapter effectively clamps onto the the eyepiece flange.

 

Maybe in the future TNVC will make the adapter with threads lenses other than PVS-14/ENVIS?