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Old 02-04-2018, 02:25 PM
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Merlin66 (Ken)
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EOS-EF lens to T thread?

Thinking about the video options with the fast CMOS cameras.....

Has anyone found a source for the EOS -EF lens to T2 thread adaptor??

I see ZWO sell their version for us$48 plus post.
https://astronomy-imaging-camera.com...os-t2-adapter/

and eBay has an adaptor for A$ 12 delivered
https://www.ebay.com.au/itm/EOS-M42-...amera-Adapter/

Then this would need the fiddle of additional T thread spacers etc etc etc.

Any comments??
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  #2  
Old 02-04-2018, 03:27 PM
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lazjen (Chris)
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I'd probably go with the ZWO one, especially if you've already got one of their cameras - the spacing should be correct then.

They've also got a version that works with their filter wheel that's been tempting me...
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Old 02-04-2018, 03:32 PM
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Merlin66 (Ken)
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Hmmm
You may be right, but A$70 is a fair price to pay just to try the concept...
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Old 02-04-2018, 08:09 PM
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lazjen (Chris)
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Why do you think it's just been tempting me and I haven't done it myself?
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Old 02-04-2018, 09:02 PM
JA
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Quote:
Originally Posted by Merlin66 View Post
Thinking about the video options with the fast CMOS cameras.....

Has anyone found a source for the EOS -EF lens to T2 thread adaptor??

I see ZWO sell their version for us$48 plus post.
https://astronomy-imaging-camera.com...os-t2-adapter/

and eBay has an adaptor for A$ 12 delivered
https://www.ebay.com.au/itm/EOS-M42-...amera-Adapter/

Then this would need the fiddle of additional T thread spacers etc etc etc.

Any comments??
Yes...... Not all M42 are created equal.

If you want to use an M42 to Canon EOS-EF adapter of the type typically found on ebay be careful which M42 you buy.

The M42 camera mount thread (as per the eBay M42 camera mount adapter you linked to at top of list and also the M42 camera mount standard in general developed and used by Zeiss/Praktica/Pentax etc...) has a 1mm pitch, whereas that on the male thread of the ASI1600 camera body and female thread of the supplied black ring is specified as M42 with 0.75mm pitch. It wont thread on properly or without possible thread damage.

So unless you can confirm the M42x0.75 thread and correct flange distance on any generic or eBay adapter, it might be easier to go with the ASI1600 adapter accessory as that should ensure that the thread and pitch is correct as well as the flange distance to the focal plane as it is specified for EOS-EF.

Of course you could use a T2 type adapter (which is M42x0.75) to EOS lens and possibly a spacer before or after the adpater, but it would require ensuring the appropriate dimensions are achieved for the EOS -EF flange distance and the sensor position on the ASI1600.

Best
JA

Last edited by JA; 02-04-2018 at 09:26 PM.
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Old 02-04-2018, 09:03 PM
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The ZWO has too much slop in the bayonet adapter and doesn’t hold a lens properly. Or at least mine doesn’t. It’s basically worthless as even a wide field lens (I tried 35mm) was hugely out of whack across the field of view.

YMMV.

I’d suggest looking st the Geoptik EOS adapter, or the Starizona one, although both are substantially more expensive.
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Old 03-04-2018, 12:13 AM
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Merlin66 (Ken)
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Yeah,
I know - I have a M42 to T thread adaptor left over from the old MX7 days.....

The adaptor would need to be (44-17.5 =) 26.5mm face to face. This is difficult to achieve with the usual T thread spacers...I've used camera extension tubes in the past as a starting point for adaptors......
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Old 03-04-2018, 07:36 AM
StuTodd
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Ken,

Have a play with https://www.preciseparts.com/ppmain//adapter.html and see how much that would be.

I suspect it may be pricey but would be a solid one piece option...

Stu
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Old 03-04-2018, 07:42 AM
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Stu,
Thanks.

I have an adaptor I made some years ago for the Zuiko lenses.

I think I'll use that for initial trials. I have 24mm, 50mm, 135mm and 200mm Zuiko lenses available.
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Old 03-04-2018, 08:03 AM
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Hmmm.............

Using the ASI 183 gives the following FOV:
24mm = 20 x 30 deg
50mm = 9 x 13.5 deg
135mm = 4 x 5.8 deg
200mm = 2.5 x 3.7 deg

Could be interesting.
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Old 03-04-2018, 09:16 AM
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Those small pixels will certainly be a good test for the glass
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  #12  
Old 03-04-2018, 09:46 AM
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Merlin66 (Ken)
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Bumma!

The old Zuiko adaptor is too long for the ASI 183!!!
The lenses won't come to focus.........

Back to the drawing board.
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  #13  
Old 03-04-2018, 10:03 AM
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Merlin66 (Ken)
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Ok...
Never give up.....

I found another Zuiko adaptor in the box (It's amazing the bits and pieces you collect over the years!!! - I made this one back in 2007) This one's slightly shorter - and appears to work!

Hmmmm
This could be interesting.....
The video file for a 30 sec capture is almost 12Gb!!!
It wouldn't take long to fill my SSD drive.

More for "live viewing" than recording?????

Onwards and Upwards
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