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Old 15-01-2008, 01:45 PM
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Another focusing aid for Canon DSLRs

This gadget is a super T-ring with the circuitry present to enable the autofocus mechasnism in the camera to function when mounted on your scope. This may not be the most accurate method - but it is certainly fast to use...I have a similar adaapter that I use to mount M42 lenses to my Canon20d...

http://www.kwtelescope.com/FotoSharp_page.htm

Last edited by JohnH; 15-01-2008 at 03:53 PM.
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Old 15-01-2008, 04:44 PM
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Too expensive

This is a rip-off.....
This guy (http://stores.ebay.com.au/big-is-camera) is much more affordable, and the gadget is basically the same thing.
He has the chip only (I bought it) and with a bit of DIY I will have very cheap solution to this problem (deliberately created by Canon IMHO)..
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Old 15-01-2008, 04:57 PM
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Good point on the cost - I guess it is a little meore costly if it is a proper T-ring with an adjustable inner ring etc. Still not worth $100 even if it is Canadian $$
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Old 15-01-2008, 07:58 PM
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I saw the add for this today while looking through the Canadian Astro magazine at Borders. Its seems expensive for what it is. As Bojan has pointed out you can get similar ones for other mounts. But Bojan i cant see the T-mount version there, is this why you DIY'ed one.

Regards
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Old 15-01-2008, 08:46 PM
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Quote:
Originally Posted by netwolf View Post
But Bojan i cant see the T-mount version there, is this why you DIY'ed one.

Regards
No, I DIY because it is how I operate

But, you are right, there is no t_mount version here... I have not thought about it to be honest.
T-mount is M42x0.75mm, unlike M42 lens mount (which is M42x1mm).
On my scope(s) all eyepiece (and camera) adapters have M42x1mm, so I use simple M42 -> EOS adapter to attach 400D. Obviously, I can attach film camera as well (Praktica), which was the original idea.

Last edited by bojan; 15-01-2008 at 09:17 PM.
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Old 15-01-2008, 09:24 PM
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OK I ordered mine back in December (7th I think). I was then told they were out of stock and that he was expecting more stock to come in by christmas. Ithen went to the web site and foun out that they were on christmas holidays until the 14 jan 08. I have sent 2 emails off to get in contact with them, but no replies as yet. I looked at the ebay ones and this unit and thought that this unit was worth the expense. Only time will tell, might even buy one from ebay just to compare.


From: Dr. Brady Johnson [mailto:info@kwtelescope.com]
Sent: Friday, 21 December 2007 2:41 AM
To: David Hough
Subject: RE: just wondering how my order for a fotosharp is going?



Hi David,



We do not have them yet but are hoping to see the components any time now. We will be shipping as soon as we can. Your patience is appreciated.



Thanks,

Brady Johnson

-----Original Message-----
From: David Hough
Sent: Wednesday, December 19, 2007 5:23 PM
To: sales@kwtelescope.com
Cc: David Hough
Subject: just wondering how my order for a fotosharp is going?
Importance: High

Just wondering if my order for one of the fotosharp’s has been sent to me yet?

David Hough
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  #7  
Old 22-01-2008, 06:58 AM
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Well the camera adapter arrived yesterday. And the cloud kept rolling in, LOL. I never got a chance to try it last night but I thought I should show everyone how it arrived.

It arrived in a small square brown box, no packing slip or instructions. Inside this box there was the package, a plain silver cardboard box. Now in the excitement, I thought I had misplaced the instructions/description/receipt. A further inspection of nothing revealed nothing. So documentation is not that high for the supplier – obviously? Starting to worry about the $100 Canadian I paid for this – I was thinking to myself?

SO the acid test – I thought I would call in on Scott Alder and get him to throw it on the camera to check it on the way home. Did that – didn’t seem to work? OK do I panic now or later? I thought later, and test it last night. So I mowed the lawn and never got back to it.

SO this morning, I thought I would put it on my 400D – snug fit and looks at though it would work. The build of the unit looks OK, as with anything that is glued together, but the machined parts look great, including the screw. I suspect I will have to try it tonight on a star or streetlight – as it does not work for a scene like a roof or trees (that’s what we tried the first time). So the jury is out until the evidence is there to condemn it, or praise it?
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Old 22-01-2008, 08:08 AM
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Hi David, If you see on the LCD screen F2.0 instead of F0.0 (at least this is what my adapter does), it means that the camera communicates with the adapter.
The focus confirmation (beep) will then work in the usual way it works with any other Canon EF lens in manual mode (because the focus circuit is in the camera).
BTW, I also have mine (perhaps not from the same vendor, however the PCB looks exactly the same) and I have some troubles with it, it is intermittent (I am not sure why, all the pins seem to be touching the contact pads in the centre or very near), so I am waiting for a replacement...

Last edited by bojan; 22-01-2008 at 10:04 AM.
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Old 31-01-2008, 07:43 PM
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Quote:
Originally Posted by bojan View Post
Hi David, If you see on the LCD screen F2.0 instead of F0.0 (at least this is what my adapter does), it means that the camera communicates with the adapter.
The focus confirmation (beep) will then work in the usual way it works with any other Canon EF lens in manual mode (because the focus circuit is in the camera).
BTW, I also have mine (perhaps not from the same vendor, however the PCB looks exactly the same) and I have some troubles with it, it is intermittent (I am not sure why, all the pins seem to be touching the contact pads in the centre or very near), so I am waiting for a replacement...
that is exactly what i am waiting for too, theone I have does not want to work
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Old 31-01-2008, 08:31 PM
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I received my replacement today... I have not tried it yet but it seems those guys have real problems with quality.. PCB does not look tidy, there are visible traces of work with file, cutter and soldering does not look good on both of them.
The Russian version (Dandelion chip) which appeared on the market first looks much better (a friend of mine bought it last year but never glued it on the adapter so we do not know how it works).
Anyway, we shall see..
From what I managed to do with the first specimen, it seems that the better focus can be achieved with FocusAssist or similar application.
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  #11  
Old 06-02-2008, 06:23 AM
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I got the replacement today - the weather is not promising for testing it. might have to wait until next week?
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Old 06-02-2008, 09:15 AM
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Another problem?

There is another possible problem with this particular chip...
If they used glass reinforced epoxy board for the PCB, then it has a potential to damage the gold-plated contact pins of the camera by abrasion.
While inspecting the PCB under the microscope, I have seen some evidence of metal traces left by pins when sliding over the slopes of the board... I was not very impressed by this.

Last edited by bojan; 06-02-2008 at 09:57 AM.
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Old 06-02-2008, 11:03 AM
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Quote:
Originally Posted by bojan View Post
There is another possible problem with this particular chip...
If they used glass reinforced epoxy board for the PCB, then it has a potential to damage the gold-plated contact pins of the camera by abrasion.
While inspecting the PCB under the microscope, I have seen some evidence of metal traces left by pins when sliding over the slopes of the board... I was not very impressed by this.
never really thought about that, well if it does work it will never come off - be on the scope quite a lot so therefore the wearing would be reduced by heaps.
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Old 06-02-2008, 01:43 PM
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Quote:
Originally Posted by bojan View Post
There is another possible problem with this particular chip...
If they used glass reinforced epoxy board for the PCB, then it has a potential to damage the gold-plated contact pins of the camera by abrasion.
While inspecting the PCB under the microscope, I have seen some evidence of metal traces left by pins when sliding over the slopes of the board... I was not very impressed by this.
Good pick up there Bojan.

I used to work with Mil Specs and Standards, where the minimum number of coupling events for electrical connectors was specified before any changes to electrical and mechanical characteristics would become apparent due to contacts being abraded.

Not to mention loose flakes of plating floating around in-between densely packed conductors!

Cheers

Dennis
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Old 06-02-2008, 03:17 PM
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Yes, I know about those standards, used to work in manufacturing plant for military equipment...
Here, we are talking about only couple of couplings and we already have visible consequences...
Maybe this was what Canono was talking about when warning that third party lenses may damage the camera.
They should have been more specific, IMO...
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Old 11-02-2008, 04:38 PM
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Hi Guys
I've just received an AF confirm T ring from a guy on ebay in hong kong
Guess what? It doesn't seem to work

but before I start throwing it around the room,I thought I'd pick everyone's brains to make sure I've done everything right

it fits into the camera (40d) without force or complaint
the F0.0 changes to F2.0 when fitted
I'm currently testing it on some trees more than 100 yards away whereupon it focuses well & takes a clear shot
But it doesn't beep & the little focusing dot doesn't appear on the LED
Have I missed a step somewhere ?


Cheers
Bryan
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Old 11-02-2008, 06:02 PM
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Hi Bryan,
If it shows f2.0 then that means it is working the way it is supposed to (communicating with camera). (unless there is some issue associated with 40D, but I am not aware of that.. I have 400D and my adapter works OK - when it works, that is.. it is a bit intermittent, loosing that f2.0 from time to time).
The rest is up to your camera... because the actual focussing circuit (the array of small CCD or CMOS sensors) is in your camera, at the bottom of the mirror box (opposite to the focussing screen).
Most likely your lens does not produce enough contrasty image for circuit to decide you are at focus..
Try with the lens which has shorter focal length.. or use bigger f number, a great number of lenses do not perform well while wide open. Or try on bright star...

Last edited by bojan; 11-02-2008 at 06:15 PM.
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Old 11-02-2008, 09:25 PM
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Thanks Bojan

what you say makes sense, I spose when the whole feild of view is completely filled with trees, the chip would find it hard to register focus

you have to try these things as soon as you buy them - anyway you can!
roll on clear nites!

Cheers Bryan
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Old 24-04-2008, 06:26 PM
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H0ughy - did you ever get this thing working?
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Old 24-04-2008, 09:26 PM
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H0ughy - did you ever get this thing working?
rain...................... ................no chance yet
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