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Canon EF adapter for astro cameras with focus control?

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15 replies to this topic

#1 pesa

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Posted 08 October 2017 - 09:29 AM

Is there such a beast?

Since Canon cameras can Control focus of an AF-lens it should be possible to do so from an astro camera-adapter,right?

That would be much more convenient for a user than some belt drive focuser.

For a remote user (as I am) I guess that manual focus wont be stable enough (with temp changing), especially Especially at small f-numbers.

In my case it would be a samyang 135mm. Very low coma even at full opening.

 

pelle


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#2 cfosterstars

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Posted 08 October 2017 - 09:46 AM

With BYEOS, you can control the focus of Canon lens in the frame and focus setting that uses live view. It should work with lenses that are compatible with auto focus on the Canon for regular photography. I have used it and it works well. It is not automated, but you dont have to touch the rig. There is not autofocus routine in BYEOS unfortunately. I have requested such a feature be added to SGP and was told that it would not be done due to too little demand. Maybe if you ask also, we can get that added to SGP. 



#3 telfish

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Posted 08 October 2017 - 10:36 AM

The lens needs instructions from the Canon camera body to move the focus motor inside the lens. There is no adapter on the market that can pick up those signals from a PC and instruct the lens to move elements to focus. There may be a way to kludge something using an arduino.

 

https://www.youtube....h?v=7fM5RKraDdA

 

https://www.youtube....h?v=tZco-UE9KRM

 

http://howiem.com/wo...f-lens-hacking/


Edited by telfish, 08 October 2017 - 10:41 AM.


#4 roofkid

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Posted 08 October 2017 - 03:06 PM

The dragonfly array uses special adapters that drive the lens AF systems. Edit: These are pretty expensive though.

 

Quote:

 

 

 

The Dragonfly lenses are focused using their internal autofocusing motors. These motors are driven by custom adapters, made by Birger Engineering Inc, which connect the SBIG cameras to the lenses. The adapters have no optics and do double duty as spacers  necessary to project the focal plane onto the CCD. The internal stepping motors are fast and allow movements of 20,000 digital set point increments (covering the full mechanical motion of the internal focus mechanism) in under 1s. A digital step corresponds to about 3.15µm of focus motion.

 

Source: https://arxiv.org/pdf/1401.5473.pdf

 

Product Website: https://psv.birger.com/products/


Edited by roofkid, 08 October 2017 - 03:08 PM.


#5 ccs_hello

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Posted 08 October 2017 - 03:29 PM

Similar conversation:

https://www.cloudyni...anon-ef-lenses/

https://www.cloudyni...hru-ef-adapter/

 

Bottom-line is reverse engineering is a niche and price point is market driven by supply and demand.

 

Clear Skies!

 

ccs_hello


Edited by ccs_hello, 08 October 2017 - 03:32 PM.


#6 ISSI

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Posted 14 December 2017 - 05:18 PM

I think I have something that should fit your needs. PM me and I will give you the details.



#7 Richard T

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Posted 26 December 2017 - 01:32 AM

Hi All

My first post after reading many many posts for support over the years.

I use Canon lenses, often with teleconverters and often with stacked teleconverters.

Using a Canon DSLR is all good re focusing as a number of programs give you control of the lens’ built in focusing system.

Using an astro CCD camera however is a different story and I’ve come to the conclusion, after trying a few methods, that manual focus is not the way to go. After all, these lenses have state of the art USM focusing systems built in, you just have to take control of them whilst not using a Canon DSLR for imaging.

Searched the internet and various solutions are out there however a bit complicated and some a bit expensive. Then I thought of a hybrid system that seems quite straight forward.

Basic idea is to run an 8 core cable (eg LAN cable) between the pins of a teleconverter to the pins of an extension tube. Extension tube with camera cap is attached to an EOS camera and the teleconverter is in place with the lens and CCD camera.

Connect EOS camera via normal USB cable and use EOS Utility or BYE or …… and you have control of the lens focusing system. Different program is controlling and showing Live View of the CCD camera.
There are cheap extension tubes out there that have metal rods connecting their camera end pins to the lens end pins.

A teleconverter such as the Yongnuo YN-2.0X II has the same type of metal rod arrangement between pin sets. In theory you don’t even need to solder any wires. Just use wire shrink tube on each metal rod with the stripped wire inside. I did this with my Yongnuo but put in too much heat and melted the plastic holding the rods. Place the plastic in ice water and use more care, all should be fine. Be careful of all the pins and springs, pins different sizes etc.

If you have success using shrink tube method, teleconverter should work with either DSLR or CCD attached to the teleconverter / lens system. That is, still has connection straight through or via cable to ‘secondary EOS focusing’ camera.

I’m half way through this “project”, now waiting on some deliveries and away on holidays in January.

Nevertheless, I thought I would share my idea and I believe in theory this should work.



#8 Richard T

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Posted 26 December 2017 - 07:24 AM

UPDATE

Hi

That post was from a couple of days ago. I had some issues in actually posting it.

Since then I got impatient and decided not to wait for various parts. Went and bought a used EOS 1000D with kit lens.

Removed the lens' bayonet plate with pins in place, soldered the 8 wires to the pins.

Bottom line is that it works including correct f stop for lens + teleconverter.

A few pictures attached.

 

FullSizeRender~1.jpg

IMG_6226.jpg

IMG_6231.jpg

Snap1340~1.jpg


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#9 austin.grant

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Posted 26 December 2017 - 08:33 AM

This looks promising:

http://psp-tsp.com/lenscontrol

#10 Richard T

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Posted 12 February 2019 - 02:25 AM

Just as an update. The 'hack' above works but I also ended up purchasing an ISSI system as per the above link. It's not cheap but it's very good. Adds aperture control as well. Will buy another one. One for guide lens (70-200mm) and one for the main imaging. It's really good !



#11 ISSI

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Posted 12 February 2019 - 12:01 PM

Thanks for the feedback on the lens controller Richard. We're glad it's working well for you!

 

-ISSI



#12 dragracingdan

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Posted 12 February 2019 - 12:56 PM

Does the ISSI system have a Ascom driver?

Thanks,
Dan

#13 ISSI

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Posted 12 February 2019 - 02:08 PM

Dan, we don't currently have an ASCOM driver but do have API commands for python scripts (or any language you prefer) to integrate the control into existing software.

 

-ISSI



#14 cfosterstars

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Posted 18 February 2019 - 04:23 PM

An ASCOM driver would make your product much more appealing to the AP community. Also a USB interface is much more common than Ethernet, but that is workable. With an ASCOM driver, it should be compatiable with most software packages that APer use.



#15 rpineau

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Posted 18 February 2019 - 04:47 PM

You guys might be interested in this : https://astromechanics.org/index.html ( and this https://astromechanics.org/ascom.html ).



#16 cfosterstars

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Posted 18 February 2019 - 05:22 PM

That looks very promising. Has an ASCOM interface and 185$. Not bad. 




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