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Source for T-Mount adapter (NON threaded type)
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PostPosted: Sat Oct 06, 2018 9:29 pm    Post subject: Source for T-Mount adapter (NON threaded type) Reply with quote

Hi all,

I have been searching to see if there is a source for non threaded T-adapters to either modern camera mounts or 1980's SLR mounts. My search only seems to reveal threaded T2 mounts but some lenses came with a mount as shown below, held in place by grub screws. Would anybody here know of an online vendor?




(p.s. Not sure if the picture will show, as this is only my second post on this site)


PostPosted: Sat Oct 06, 2018 9:37 pm    Post subject: Reply with quote

All the T-mount adapters I've ever seen are two pieces. And the two pieces are usually held together by grub screws. So what is almost certainly the case with your lens is that the inner portion of your T-mount adapter is still mounted to the lens. It will unscrew. It's probably just tight, is all.

The reason why T-mount adapters are made as two-piece affairs is because when the lens is mounted to the camera, the top of the lens may not be on top. It may be off to one side or the other. Loosening the grub screws allows one to rotate the lens in the adapter so its top will be up. Then one tightens the grub screws once the lens has been recentered.


PostPosted: Sat Oct 06, 2018 10:05 pm    Post subject: Reply with quote

There are lenses that look exactly as if somebody removed the grub screws leaving the inside of the T-adapter screwed on the lens, however, the inside part isn't screwed on but is integral part of lens body. Outer rings were sold in various ccamera mounts.

Sometimes the inner part of T2-adapter can be used. Sometimes the lens needs another diameter.


PostPosted: Sat Oct 06, 2018 10:50 pm    Post subject: Reply with quote

I believe that to be the case here. From the wikipedia entry: "Some T-mount lenses accept a T-adapter that lacks its threaded inner ring, and simply slides onto the T-mount lens. It is secured only by 3 set screws that match a channel on the lens barrel, such that the barrel is not deformed by the set screws and the adapter can therefore be removed with no damage."

I have two lenses with the same diameter adapter of this type, the picture I posted is a Soligor 180 F/3.5 preset lens. The other lens I have is of modern manufacture, a Kenko 400mm F/8 reflex lens. What I would like to do is change the adaptor on that one to a different type.

I took a couple of extra photos:

[img]

The adaptor has a flat section protruding which is 42mm O.D, however this is not threaded, so the other part doesn't seem designed to unscrew.

[/img]

The mount does look like it may unscrew from the other part, but this would leave a female threaded part. I'm not sure of the diameter, as this part would not unscrew easily.


PostPosted: Sun Oct 07, 2018 11:39 am    Post subject: Reply with quote

The T mount (AKA T2) describes a M42x0.75 thread with a flange distance of 55mm

Without the threaded part it's no longer a T mount!
However If it's just the other mount you want then getting a T2 adapter & separating the parts is child's play. (My kids used to play with Mechano)

I've used this to get a PK mount to attach to a lens, the threaded core still being a potentially useful bit to keep in my spares.