Frustrated with C-Mount Celestron Nex Camera Imaging Adapters

[SilverScreen]

Help please, advice needed...

Now I know what I planned is right and the pieces I got are the right ones. Still when the pieces arived they did not fit together and I simply don't know why I am sort of stranded as what this was about is a trivial issue.
I got C-Mount - Nex adaptor I bought in Hongkong and for that I found a C-Mount - 1,25" adaptor I found in england, --- when they arived same day, I tried to put them together, to get that "short" Nex-1,25" adaptor, Now after I measured how much extra back-focus it will allow compared the "Long" normal Nex-1,25", I found stunning 35 millimeter, a lot extra room to focus allmost anything.
See with the Nex camera, there are no mirror as in tradisional Dslr's, but that story I guess you know, anyway tha way to profit from the Nex camera, is not to use the long adabtors that compensate for the missing mirror, but put the adabtor together from for example the pieces I found --- but then why do the treads get stuck ?

Why don't the "C-Mount" treads in both pieces fit together ; are there different "C-Mount" standards, or is either the chinese or the english piece badly treaded ?

Now I contacted both firms to tell that the pieces could "just" be put together 1/6 round and then they stuck, --- just like trying force a T2 and a M42 together, can be done, and both treads are ruined, --- but realy I thought C-Mount and C-Mount are the exact same thing, -- any clues ?



The Nex - C-Mount with an extra body cap -- chinese.



The "expensive " 1.25" dmk-video camera C-Mount adaptor.

Now as I couldn't sort it out, and the firms did not answer, I started from scratch and bought another chinese Nex - C-Mount, then I find out if it is the first one, that have a bad tread.



This image explain the huge gain. The right one are the way you do it tradisionaly, -- a Nex - T2 put together with a T2 - 1,25" to fit into the focuser. But see how much extra room for focusing the other solution offer, -- doing it so I guess there will be almost no telescope, that can't be put together with a Dslr, Still it is only the "mirrorless" Dsrl that offer these 35 extra millimeters, and only if the C-Mount standard it seem, realy are a standard and not a multible different 25 mm. treads.

[BobDob]

Hello! To get proper attention, I've take the liberty to move your thread to a Forum which may get your question(s) answered. I hope it works!

Good luck, and Clear Skies!

BobDob

[KeithBC]

I feel bad that this thread hasn't had an answer. Unfortunately, I can't contribute an answer since I don't know the Nex camera or the C-mount adapters.

I wonder if Bob or another moderator could re-title the thread to something more meaningful that might attract the attention of someone who would know the answer.

[SilverScreen]

Yes it was difficult to find the right fora for me when I posted this, but I thought like this, that the issue ---- could be foult in manufactoring, factoryes who don't follow the standards or whatever people could experience esp. when more and more very cheap equipment surface. My problem are that things should fit, I bought the right things --- and then what can you do to solve the problem esp. if you don't know that much.
Anyway I got a reply from both firms so within a few weeks a solution proberly are found, --- but those replies go exactly as how problems often just evolve ; first firm replied and Thanked me, as they realy found their treads was foulty and will get back when they been in contact with their deliverer. But the other firm proberly didn't bother and made a joke about it, in fact they just read that I couldn't get two treads together, and suggested the reson was that I tried put two male treads together.
From my experience standing there one could hope firms atleast look at the problem as if they did, therir reply would be that it could not be their product that had a foult. ---- now ontop but off-topic, the same day I recived a remote control for my compact camera, not the Nex --- guess what, also that was the wrong one they simply made a shipping foult.

Still the first firm will be back and I guess within a week I can happily display this Nex - 1,25" adaptor made from two standard items and then the Nex5 will finaly be what it offer --- I got the long version of Nex - 1,25" and realise the reson it is so long, is exactly what otherwise make Nex5 a promising choice for camera if you have a smaller Newtorian, but not with the long adaptor assembly. But with the short version I suddenly realised was possible, putting these two together, you gain stunning 35 millimeters --- and winning that, is what this battle is about. Right now it is standing on my table beside the long one, but I can only turn the tread one fifth round before it stuck, well it will hold like that, but it is not perfect and I would be waiting for the camera to fall off as this is not how it is supposed to assemble.

But I am still an amature and only slowly progressing, by building up the nessery pieces, --- when this work, I will borrow a skywatcher go-to 130 something, where there are problems with back focus with the standard long adapter, as I can allerady hold the nex there and see it will work.



In this posision a Nex and proberly other mirrorless cameras focus, that would not happen with a Dslr with a mirror.

[SilverScreen]

Hi.
Both firms replied and it seem one of them are very happy that I contacted to tell about this problem, as the pieces should fit together -- C-Mount is C-Mount only one standard but, their adaptors show some tread foult, and they will get back when they contacted their supplyer. Still the other firm --- well it is proberly not their piece that carry the foult but, from their reply it is obvious that they havn't looked at their product to check, if the tread are foulthy. Ontop their answer are more kind of a joke on my behave, becaurse what they suggest is simply not a possible foult Gee, --- they suggested I made a foult trying to fit two male treads together, but their piecs do not carry a male tread it's a female tread, so ..... is my english so bad, I do not think so.

Anyway, --- I can see this tread do collect a number of visitors, so I will be back and continue the tale , now I know it is the C-Mount - 1,25" tube adapter that has a foult, the problem proberly are solved but I owe you guy's the rest of the story making the Nex camera work with a Newtorian that is othervise said, not to work with a Dslr.

[Gandalf223]

Holding my breath and waiting for the happy conclusion to this quest. My NEX-5 hasn't made it onto a telescope yet, but...

[SilverScreen]

Just recived another C-Mount-1,25" adapter tube one where the tread fit so now the focusing with a short Nex-1,25" can be tested. Hope this will be soon as it seem many have this back-focus problem, beside I can now measure how much shorter the short adapter is compared the standard adapter, --- the one you get if you get a standard Nex-T2 plus a T2-1,25" adapter, --- I put foto's of both at the bottom.

Now the two assembled adapters vary also in detail, --- the short one opposite the short one is hollow inverds it is not flush vith the flange but a grove add some 2-3 millimeter extra, if you look at the adapter ring this is obvious and if the adapter had been flush, it would proberly offer only 30 millimeter extra back-focus, where as it is made with an invert grove, it realy offer 35 millimeter extra, or in other words ; the Dslr will be placed 35 millimeter more inverts on the focuser, ---- I am quite sure even I havn't yet tested this, that that will make many Newtorian telescopes an option with Dslr. Those that could not be fittet with tradisional Dslr's like the one I will test it with, the Skywatcher 130P.





Guess it is not much progress, but now the short adapter is there, remember I had to wait for a replacement c-mount-1,25" tube.

Btw, --- the small square thing on the camera, is a Gentled Auto, a intervalometer, -- an adjustable Ir remote, - that automaticly trigger the camera.

[BobDob]

I'm happy to see you are approaching a solution. Do keep us posted on how it works out.

Clear Skies!

BobDob

[SilverScreen]

Well thank's, -- but today frustration turned into confusion.
See, -- Not to be stuck in this situation, I decided to order two other items of the same types. And as my previous mail said, one arived and the new tube adapter -- C-Mount-1,25" fittet gently into the Nex-Cmount adapter so I thought problem was solved and conclution could be reported.
But today the other Nex-Cmount adapter ring arived and just for fun, I tried what I thought to be a foulty C-Mount-1,25" adapter tube, and guess what ; it fit perfect in the tread of new Nex-Cmount ring, but still not in the old adapter, where now the other tube adapter fit. ......

I am very confused ---- but the old tube that now work perfect also is better than the tube I got that fit both, see the 1,25" diameter is not good on the one that fit both, I have not yet measured, but a round of thin tape seem nessery, to make it exact fit a focuser. I be back with images.

[SilverScreen]

Here the 3 assembled adapters, the one rear is the tradisional Nex-1,25" , the long type that is calculated from the camera lens demands. As The Nex and other 4/3 cameras have the chip much nearer the lens flange the camera adapters are longer than the adapter rings.



The two short adapters taken apart, --- note my problem was, that the C-Mount-1,25" tubes have to be fitted each their adapter ring, you can't switch them over as then one of them get stuck. but one of the two tubes fit both, it's the one to the right. But that seem a bit overworked as it's diameter outside is slightly smaller than the gloss surfaced one to the left.
Now I hope someone who want such short adapter for a Nex or a 4/3, -- the chip in the Nex is a bit bigger than in other 4/3 cameras --- but I hope others will not experience my frustrations with these adapters, also I hope manufactors will test their items. I found only two places to buy the C-mount-1,25" tube, but from the images you should be able to see what adapters to buy for what adapter ring-

Anyway this way are the only way to solve the problem, that the tradisional Nex-1,25" adapter, the rear one, work against the good news with Nex and other 4/3 cameras. The manufactor of the left tube adapter have been most helpfull and is even investigating, if Sony's minolta bajonet, could be the same as the bajonet used in the Nex. This was a dead end while I tried to find the short adapter option, as everyone I asked just answered ; "No Minolta adapters don't work with Nex --often I realy thought of asking "well have you tried or only read what Sony say". but that question will also be answered here, when I get the reply.