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Does anyone make thinner T-rings?

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15 replies to this topic

#1 joelin

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Posted 24 April 2019 - 11:30 AM

I know the T-rings for Nikon DSLRs are setup such that they bring you to 55mm backfocus.

 

However, what If I want something thinner...some applications I can think of...

 

1. reaching focus in a reflector

2. because I have a 5mm or higher spacer and need only 3mm of spacing and want to use the T-ring to shave some off distance

 

does anyone make a thin Nikon T-ring?



#2 james7ca

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Posted 24 April 2019 - 11:37 AM

Yes, Teleskop Service makes thin T-rings for both Canon and Nikon (and, I think, a few other lens mounts).

 

  https://www.teleskop...LR-Bayonet.html


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#3 joelin

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Posted 24 April 2019 - 12:10 PM

Does this one qualify as well?

 

https://www.amazon.c...ay&sr=8-58&th=1



#4 james7ca

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Posted 24 April 2019 - 12:23 PM

Does this one qualify as well?

 

https://www.amazon.c...ay&sr=8-58&th=1

Can't really say, the picture may or may not be accurate but it does LOOK thin. That said, I don't see that they state the optical thickness and if you purchased this expecting it to be a standard T-ring adapter you might be dissatisfied since it might not meet the common 55mm standard. Note that the other T-ring set that this company sells looks like a standard, thick, T-ring. But, for $10 it MAY be worth a try.


Edited by james7ca, 24 April 2019 - 12:26 PM.


#5 GraySkies

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Posted 24 April 2019 - 12:52 PM

I'm looking for a thin T-Ring for Z-Mount (Nikon) so I can put in an OAG and Filter Wheel/Drawer.

Any leads?



#6 joelin

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Posted 24 April 2019 - 12:52 PM

I bought it .. Why not?

I'll be satisfied if it does not meet the 55mm standard

As long as it comes under 55mm then I have some possibilities to with with

#7 james7ca

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Posted 24 April 2019 - 01:11 PM

I bought it .. Why not?

I'll be satisfied if it does not meet the 55mm standard

As long as it comes under 55mm then I have some possibilities to with with

Yes, when I looked at that ad I noticed that they had one for the Sony NEX series and I've been looking for a super-thin adapter for that camera body too. I already had one that was about 11mm, but the pictures on Amazon look even thinner. The Sony E-mount (mirrorless) has only an 18mm flange to sensor distance, so with the 11mm adapter I had 18 + 11 = 29mm which is certainly better than the standard 55mm. Needless to say, I ordered one of the DoubleSun Brass Sony adapters even before I read your last post (should be here on Friday). If the adapter is really chrome covered brass and if it has a decent leaf spring (like) to secure the bayonet [the spring is on the camera body, not the adapter] then for $10 it will be a real bargain. 


Edited by james7ca, 24 April 2019 - 01:44 PM.


#8 FebStars

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Posted 25 April 2019 - 07:53 AM

AS far as reaching focus on your reflector is concerned, you can sometimes remedy the problem by simply tightening or loosening the main cell screws of your primary mirror, bring it forward or backward.

 

Tom



#9 joelin

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Posted 25 April 2019 - 11:00 AM

I've done that before and then put it back.

It caused all my eyepieces to require an extension tube.

#10 Iamhondo

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Posted 25 April 2019 - 01:13 PM

Baader also sells one (anodized) but only for EOS, not Nikon. It might be worth an email to them to see if that's an oversight on the website or a market decision.

 

Another option is http://www.opticstar...=0_10_5_0_3_811 . Curiously low price for a brass product.

 

I think a lot of people with newts and the focus problem splurge on a low profile focuser. 

 

Also, the Nikon flange distance is totally irrelevant for pure prime focus with a DSLR. Flange distance is a rule for camera lenses and other focal/field adjusters like barlows, field flatteners, and field reducers. If you're doing naked camera-newt images you can ignore the flange distance.

 

HTH, Joe



#11 james7ca

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Posted 25 April 2019 - 01:29 PM

Interesting, those T-adapters from Opticstar look very similar to the parts that are being sold on Amazon (except that they are cheaper on Amazon).



#12 Melgabean

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Posted 26 April 2019 - 12:28 AM

I really like www.telescopeadapters.com they make quality metal cnc machined t rings.
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#13 joelin

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Posted 26 April 2019 - 02:06 AM

I ordered and tried the amazon thin t ring. 

 

 

It truly is thin as it appears. However the downside is that it’s a bit flimsy. I exerted a bit of force removing it at the wrong time and it got caught in the flanges of the camera. I then exerted more force and bent the T-ring flanges to get it out. 

 

 

Its also very easy to rotate off. The pin that holds the T ring down doesn’t have as much depth in the T-ring to enter because of the slimmer profile. A grip on the camera body while attached to something is enough to rotate the camera off of the T-ring. 

 

Overall it is usable, you just have to have an extremely light touch



#14 james7ca

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Posted 26 April 2019 - 05:13 AM

I really like www.telescopeadapters.com they make quality metal cnc machined t rings.

That's where I got my thin T-ring for the Sony E-mount (their so-called T-Minus ring). That said, I'm not sure they are of any better construction than what you typically see from China. Although the part is exactly as represented on their website.

 

As for joelin's report on the thin brass T-ring ordered from Amazon. If the mounting seems somewhat insecure and the grip is too loose then it may also cause tilt in the optical path. That, IMO, would make it unusable.

 

I should have the similar, thin ring for the Sony E-mount tomorrow and will also report on the fit and quality.


Edited by james7ca, 26 April 2019 - 05:13 AM.

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#15 james7ca

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Posted 26 April 2019 - 02:00 PM

Got the DoubleSun Brass T2-ring for the "Sony NEX-3 NEX-5 NEX-6 NEX-7 etc." Unfortunately, it's not for the Sony E-mount (way too big). I tried it on my Nikon DSLR (too big) and a Canon ES adapter (too small) that I happened to have and it doesn't fit those either. So, it's for some other camera make/brand. I suspect it may be for the Sony/Minolta full-frame (35mm) lens mount, the A-mount. The box is printed with the description for the NEX-5, so I wasn't sent the wrong stock item.

 

Too good to be true, I guess.

 

As for the construction, I didn't see anything that seemed that flimsy. I think you'd have to try very hard to bend the adapter. That said, I have no idea how it would actually fit since it was the wrong part for the Sony E-mount (or the Nikon and the Canon EOS).

 

It's going back to Amazon.



#16 KLWalsh

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Posted 27 April 2019 - 07:45 AM

“Also, the Nikon flange distance is totally irrelevant for pure prime focus with a DSLR. Flange distance is a rule for camera lenses and other focal/field adjusters like barlows, field flatteners, and field reducers. If you're doing naked camera-newt images you can ignore the flange distance.”

The Baader coma corrector is cleverly designed to work both with T adapters and M48 adapters for Nikons and Canons, probably other DSLRs as well, for standard ‘fast’ Newtonians
BUT for Schmidt-Newtonians the ideal flange-to-sensor distance is said to be 49 mm rather than 55 mm.
So one of those thin adapters linked-to above might be a better choice for people like me with SN scopes.
I’ve been trying to find a thin M48 Nikon adapter to use with my Nikon D810a and SN10, but with no luck. I might have to accept using the thin T adapter and just accept some vignetting.

Edited by KLWalsh, 27 April 2019 - 07:50 AM.



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