EOS Lens & Filter Wheel

[Coco]

When I bought the 383 I really wanted to use my EOS lenses, the problem was that the lens registration is 44mm, not a problem if you’re not using a filter wheel or a very thin Filter drawer. The 314L+ wasn’t a problem either.

The problem with filter drawers and single mount filters is that in a winter session it’s going to be a royal pain swapping stuff about, what if you so much as touch the glass you’re going to waste time cleaning and re setting, also lights are going to have to be done there and then, otherwise any dust motes etc are never going to be back in the same place, it’s bad enough having an electronic filter wheel not parking properly!

Here is my solution..

ATIK manual filter wheel modified. leaving a generous 1.76mm left to play with.

[steppenwolf]

Well done, Guy similar to one of my own (many!) thoughts on this but my maths still doesn't allow. What is the distance from your sensor to the front face of the 383?

[Tom How]

What is the distance from your sensor to the front face of the 383?

For my own future planning, I'd love to know this as well...

[Coco]

For my own future planning, I'd love to know this as well...

Tim,the ATIK 383 is 17mm and the ATIK 314 is 11mm , not sure anout the Artemis 285, 11mm and the filter wheel would not have needed cutting out.

[Psychobilly]

Nicely done Sir - Proper Job...

[Astro-Geek]

I found this thread in an online search, where Guy has modified a manual filter wheel in a way that I'd been thinking about. 

The problem it overcomes is to be able to attach Canon Eos lenses to Mono T2 astro cameras with a backfocus of 17.5mm.

The Eos camera mounting has a standard backfocus of 44mm, from the front plate, (and therefore the back flange of Eos lenses) to the CCD sensor.

So 44mm minus 17.5mm gives 26.5mm maximum thickness for the wheel and EOS adapter.

I already have the Geoptik T2 to Eos adapter, but that is already 19mm thick, and I haven't found any filter holders (wheels or drawers) as thin as 7.5mm.

The Geoptik does have the facility to hold 1.25" filters within it's body, but then the lens would need to be removed between LRGB changes.

TS do a very neat T2 to Eos adapter that incorporates a magnetic drawer that is just the right thickness, but it's over £200 delivered to the UK with 4 drawers, (that's the unit kit plus two extra drawers).

...and the Artesky Italian ones are even more expensive. 🥴

I couldn't find any (thin) Eos adapters with filter holders on the FLO website.

...so, back to Guy's idea, I'm thinking of modifying my old redundant manual filter wheel with the Eos lens flange from an old Eos film camera, (dirt cheap now, secondhand...)

The wheel and Eos flange are just the right thickness, (as Guy also found), and is not only considerably cheaper than the TS drawer, but more convenient, I guess...

Before getting the Black & Decker out, I thought I'd just ask on here to see if anyone else had found other solutions to EOS lens adaptations with filter wheels or drawers...

 

[Coco]

There are none,  you will find more photos of this here..

https://pbase.com/walshy/my_observatory&page=all

Cheers
Guy

 

 

[Astro-Geek]

Thanks for confirming it Guy.

I'd scoured the Internet and hadn't found any other than that expensive TS drawer system.

I've marked out my cheapo wheel and will start cutting the hole this afternoon....  🤓

I'll post the result on here, (if successful), and if not, I'll slink quietly away....  🥴

[carastro]

I got an EOS to CCD adapter for mine.  

I'll PM you about it.

Carole  

[Coco]

2 hours ago, Astro-Geek said:

Thanks for confirming it Guy.

I'd scoured the Internet and hadn't found any other than that expensive TS drawer system.

I've marked out my cheapo wheel and will start cutting the hole this afternoon....  🤓

I'll post the result on here, (if successful), and if not, I'll slink quietly away....  🥴

Go slowly measure 3 times

 

[Astro-Geek]

7 minutes ago, Coco said:

Go slowly measure 3 times

 

Been there, done that, got the T Shirt....  🤓

I'll be cutting  the hole in the filter wheel faceplate very carefully with my metal scrollsaw, (very slowllllly).

It's fortunate that the Eos lens plates are readilly and cheaply available, that precision would be way beyond me......

Edited July 3, 2020 by Astro-Geek

[Astro-Geek]

Well I didn't slink quietly away, it turned out to be quite successful, ( the mark two version anyhow 🤓)

My generic unbranded cheapo manual filter wheel was ideal for the conversion because it had just enough area around the front T mount opening to accomodate the larger EOS lens mount ring donated from an extension tube.

I cut the hole very carefully and incorporated the original spring loaded latch.  In order to get it thin enough to give me enough backfocus with my Altair 1600M (17.5mm), leaving just 26.5mm max from the EOS's 44mm BF), I had to mill the centre framework thinner by 3mm  (it was just plastic so that was fairly easy).

My original mark one version rigidly mounted the filter wheel on a short vixen bar, which then supported the camera and lens, but that was not practical, as it was awkward to rotate it to align the camera's  chip square to the subject.

The mark two version was to use a couple of spare 100mm scope rings lined with cork to hold the camera instead, leaving it free to rotate.

I now have the ability to use any of my photo lenses and still have a backfocus safety margin of a couple of mm.  The beauty of using an EOS lens flange is the multitude of cheap adapters available for it (Nikon, Pentax, Olympus etc.)

The final photo shows my Olympus Zuiko 135mm lens mounted on the Altair.

Thanks for the original thread Guy, it spurred me on to do the same..... 👍

 

Edited July 15, 2020 by Astro-Geek

[Coco]

Brilliant result and very well done,  I piggybacked mine on top of my APM 107  gathering wide fields via a Samyang 135 /Atik 383   I really must process the thousands of hours of data, I guess I found the challenge better than the reward..  

I use binoculars exclusively, sold all my kit, but just bought a Nexus II kit with 10k encoders plus video  fluid head..    😁