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EOS Lens protocol analyse - anybody intresting?

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Offline _MAG_

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EOS Lens protocol analyse - anybody intresting?
« on: 11 / May / 2008, 12:58:21 »
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Hi all! I wish to create software emulator for eos lens. I sink we can (in future) acess to EOS contacts from firmware.
I cant wait and i have some idea to connect body and lens to PC, store and decrypt their dialog.
I use public information about null modem com cable, electrical and protocol of EOS camera to make this little doc.
I need help. Need decrypt data protocol.   
I thing my cable work but i dont test it.

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Offline _MAG_

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #1 on: 12 / May / 2008, 00:57:23 »
I found some info about lens request. They transmit:
lens name (255 symbols)    - example "Canon 28-80" (i not fully sure about example but lens name transmited first)
----- i not sure about order of this info-------
minimal focus distance        - example "28"         from 00 00 to FF FF
maximax focus distance      - example "80"
current  focus distance        - example "35"
minimal aperture (on this angle???) - "3,5"   maybe from 1 to 64 in dec. 2 bytes. (for transmit aperture like 5,6)
maximal aperture

if minimal focus distance = maximax focus distance = current  focus distance - lens determines like fix focal. Else like zoom
if minimal aperture = maximal aperture - body dont send command for close or open aperture
« Last Edit: 12 / May / 2008, 02:21:29 by _MAG_ »

Re: EOS Lens protocol analyse - anybody intresting?
« Reply #2 on: 12 / May / 2008, 08:51:26 »

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Offline _MAG_

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #3 on: 12 / May / 2008, 13:32:25 »
they not release protocol. they sell only a device. I think we need undersand protocol to add no-af lens af confirmation in firmware. Of course maybe in firmware this been simple (disable check) or maybe needed transfer "virtual data" from "original lense"


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Offline _MAG_

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #4 on: 13 / May / 2008, 14:50:51 »
Today i lost many time trying to connect lens and body. But pins in body too small. I read servise manual and begin to open my kit (28-80) lens to got internal access to chip pins.
Warning! if you do sothing like me you do this at you own risk!
to acess chip internaly in kit lens you need:
1. move rubber (see img)
2. remove 3 screws (you see 1 near 50)
« Last Edit: 13 / May / 2008, 16:02:04 by _MAG_ »

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Offline PhyrePhoX

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #5 on: 13 / May / 2008, 16:20:43 »
may ask why you are doing this? i dont own a dslr so i have no clue why one would need to analyse the Lens protocol?

Re: EOS Lens protocol analyse - anybody intresting?
« Reply #6 on: 13 / May / 2008, 18:20:58 »
Lens protocol! very good idea. More we know More we can do :D

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Offline _MAG_

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #7 on: 14 / May / 2008, 01:26:44 »
may ask why you are doing this? i dont own a dslr so i have no clue why one would need to analyse the Lens protocol?
In future i wish to have digital SLR camera. I can to fit many non-AF lens (they are cheap and have good quality), but i need to focus by hands. In DSLR with crop factor 1,6 this is very hard.
DSLR and SLR have AF sensor but hi is activates only with original lens. 1 man decompile EOS lens protocol and create chip, who emulate 45 1,4 EOS lens and  activate AF sensor. With AF confirmation chip focusing by hand easier and faster. Of course i can buy chip, but I wish to try making camera "software" version of this chip.

For better analyse lens protocol need osciloscope but i dont have it. Need measure Hz of clock pin. I know in new lens Hz are change in time so need measure old lens (older - better) like my 28-80.
If someone have EOS EF Extension tube, osciloscope and old eos lens pls measure clock pin. In macro ring you have access to all pins (of course you need detach something). 
to open EF Extension tube you need Remove 4 screws in camera mounting ring.
detail see Modifying Canon EF Extension tube for EOS 300D lens link

Added: Good news. I found internal servise manual in public acess. They got some info about Lens-Body protocol
http://ozerki.net/photosight/PhotoDocs/Manuals/partlist/Lens/CanonServiceManual(EF-50-28-15).zip (page 22 -30)
« Last Edit: 14 / May / 2008, 09:13:37 by _MAG_ »


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Offline _MAG_

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Re: EOS Lens protocol analyse - anybody intresting?
« Reply #8 on: 18 / May / 2008, 05:26:36 »
I remove 40% of my kit lens (28-80) and attach 1 cable to "Body to lens data" pin.
For better analesing need to connect "Lens to body" and "Clock" pins

Re: EOS Lens protocol analyse - anybody intresting?
« Reply #9 on: 19 / May / 2008, 12:35:56 »
nice electronic work :-)

in the body of 400D there is some pins in the battery place. did you see them ? do you have an idea how to start to analize them ? a have even problem to make a connector without demounting the body.

 

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