Attaching Camera Lens to CCD

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kimo
 
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Attaching Camera Lens to CCD

Postby kimo » Sat Mar 29, 2014 8:33 pm

Hi,

How to attach zoom camera Lens to CCD camera with Female 42mm socket like other most of the CCD camera. what type of adaptor should I get?

Thanks
Kimo

kochu
 
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Re: Attaching Camera Lens to CCD

Postby kochu » Sun Mar 30, 2014 7:11 pm

Hi Kimo

Try with Robin Lee

http://www.cyclopsoptics.com/

Brgds

Kochu/30-3-14

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MooEy
 
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Re: Attaching Camera Lens to CCD

Postby MooEy » Mon Mar 31, 2014 8:14 am

This is the only usable one i have seen.

https://www.teleskop-express.de/shop/pr ... ripod.html

~MooEy~

kimo
 
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Re: Attaching Camera Lens to CCD

Postby kimo » Mon Mar 31, 2014 9:33 am

Thanks for info. I checked both but I am wondering that EOS camera lens to CCD distance should be 35mm+-. so if I want to attach filter wheel then it is not possible to get the right distance, right?

Thanks
Kimo

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Re: Attaching Camera Lens to CCD

Postby kochu » Mon Mar 31, 2014 9:38 am

This was the one, I tried once from Robin Lee for my QSI

http://www.cyclopsoptics.com/accessorie ... apter.html.

There is a difference between T2 and M42 threads.

A T2 or T-mount or T-thread has a dia of 42mm with a thread pitch of 0.75mm. An M42 is also 42mm, but with a 1mm thread pitch.

Kochu/31-3-14

kimo
 
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Re: Attaching Camera Lens to CCD

Postby kimo » Tue Apr 01, 2014 3:51 pm

Did you attached filter wheel with it?

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Re: Attaching Camera Lens to CCD

Postby kochu » Tue Apr 01, 2014 4:52 pm

No . Filters are inside Camera on a Filter wheel
Kochu

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MooEy
 
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Re: Attaching Camera Lens to CCD

Postby MooEy » Wed Apr 02, 2014 5:12 pm

Wrong, the distance for EOS lens should be 44mm instead.

Most ccd cameras takes 10-20mm, filter wheel takes another 19-20mm, and the adapter takes 19mm. You will not be able to focus at infinity.

Depends on the ccd model, you can check if the manufacturer has a EOS adapter designed for it. On the st-8300m, ccd and cfw takes 38mm, the SBIG EOS adapter gets you to the correct 44mm distance required.

~MooEy~

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Re: Attaching Camera Lens to CCD

Postby orly_andico » Wed Apr 02, 2014 5:48 pm

Peter Lee (tan14) sells a QHY8-to-EOS adapter for cheap. It's no longer listed on his site -

http://www.tan14.com/Others.htm

but he charged me HK$ 350 for it (S$ 57). He currently sells an ST8300 adapter as well.

Unfortunately the QHY8-to-EOS adapter it is quite thick, you would not be able to achieve focus if there is a filter wheel. However the adapter is internally threaded for 2" filters, so you can put a (single) 2" filter inside the adapter. One side is an EOS bayonet, and the other side is a T-thread.

Note that because it is for the QHY8, the registration distance would be wrong for other cameras (mainly it may focus past infinity). I used it with my ST8300M and 180mm lens and it works fine - because the 180mm lens has a very long throw (it is a macro lens) so it is possible to focus to infinity, however the lens distance scale won't indicate infinity.

I'll post a photo of the setup when I get a chance.

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MooEy
 
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Re: Attaching Camera Lens to CCD

Postby MooEy » Thu Apr 03, 2014 8:46 am

Wrong.

Macro lens allow the lens to go further out, not further in. Let's take for example a 180mm EOS lens, at infinity, the distance from the front of the lens to the sensor should be roughly 180mm. For objects that are closer to the lens, the distance from the front of the lens to the sensor will INCREASE significantly. Note this is increase and not decrease. And no, you can't move closer to objects that are astronomical distance away from us to increase the distance between front of lens and sensor.

Given that the flange distance of EF lens is 44mm, there should be around 136mm of distance from the front of the lens to the rear of the lens. What macro allows you to do is varying the distance from the front of the lens to the rear of the lens by a greater amount compared to a normal lens. This is also exactly why extension tubes work for macro photography. However another thing about macro lens is that there are generally oversized to reduce the amount of light falloff at closer distance, and the optics are generally design for performance at closer distance.

A macro lens does not allow u to shorten the lens, if the lens needs 44mm of flange distance, there's no magic in a macro lens that can shorten the tube below the distance to focusing at infinity.

The only thing that might help a little, and I mean a little, is the ability to focus beyond infinity. Older Manual Focus lens generally do not focus beyond infinity, rotate the focuser ring and it stops nicely at infinity. Modern lens, to compensate for various expansion/contraction issue and camera backfocus issue, tend to allow focusing beyond infinity. However, do note that this is normally a very small amount, maybe a few mm, which might be insufficient.

Another thing you can consider is lens with more flange distance, canon lens have 44mm, nikkors have 46mm. With some luck, you might be able to get away with those. For me, I'm using Medium Format lens which has a huge flange distance, those generally work well and come by cheaply.

~MooEy~

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