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View Full Version : Modifying a Canon TX1 for Genlock ?


Brandon Yates
June 23rd, 2007, 09:08 PM
Does anyone know how to modify a canon TX1 so two of them could be genlocked?

I need the shutters to be in sync.

Any information would be helpful,
Brandon

Klaus Esser
June 24th, 2007, 07:02 AM
Does anyone know how to modify a canon TX1 so two of them could be genlocked?

I need the shutters to be in sync.

Any information would be helpful,
Brandon

GENLOCK??? With a digicam-hybrid??? :-) :-)
Genlocking is a very expensive item and i know it only from prof. videocameras.

What would you use it for? What do you mean: "shutters in synch" - while taking photographs or taking movies?
To release a photographic shot you can solder two remote releases together and release both shutters simultanously by pushing one button.
Doing it while taking a movie-sequence might work also, i donīt know.

What would you use a genlock for, precisely?

best, Klaus

Asher Kelman
June 24th, 2007, 09:28 AM
I'd start one camera then the other and use and a clapper sound. Then you can line up the sound peak waveform in your video or sound editing software and you will be in synch.

Asher.

Klaus Esser
June 24th, 2007, 10:02 AM
I'd start one camera then the other and use and a clapper sound. Then you can line up the sound peak waveform in your video or sound editing software and you will be in synch.

Asher.

Hi Asher!

That only works if the picture-frequency of both is locked identically. Thereīs no two cameras (especially in that range) that work identical. Thatīs what gen-locks are made for. But there is no gen-lock-option on consumer-cameras of that kind.

For that reason, more information would be essential about what he wants to do!

Asher Kelman
June 24th, 2007, 11:05 AM
Hi Asher!

That only works if the picture-frequency of both is locked identically. Thereīs no two cameras (especially in that range) that work identical. Thatīs what gen-locks are made for. But there is no gen-lock-option on consumer-cameras of that kind.

For that reason, more information would be essential about what he wants to do!

For sure, Klaus! I was thinking that with shrt runs it would be fine.

One thing I have done is use sound from one camera and then cut in the shots fro mthe orther and manually adjust where you swop the frames.

Asher

Brandon Yates
June 24th, 2007, 12:19 PM
I need the shutters to be in sync for movies. I want to use them for stereoscopic video work. This is not a matter of just starting the recording at the same time, but having the shutter frame rate of both cameras going "in time" with each other.

I have done this with stanadard definition cameras but would like to use high definition. There are no consumer (or pro) HD cameras with a genlock that syncs the shutters. (Canon makes a higher end HD camera is a 'genlock input' but it is just a TBC for the output of the camera, it dosen't sync the shutters.)

I would like to use the Canon TX1 because it is small, 720p@30fps HD, MJPEG, Tapless, and only about $500.

I have pictures of some of my older SD 3d systems but don't know how to upload them :)

Thanks,
Brandon

Asher Kelman
June 24th, 2007, 12:25 PM
Hi Brandon,

What are you shooting and what's the duration of each individual "take"?

Asher

Brandon Yates
June 24th, 2007, 12:36 PM
Hi Asher,

This may sound a bit crazy, but I will be shooting other skydivers in freefall, each take would only be about 3 minutes. I have jumped with my standard def systems and everything works, but would like better quality, the TX1 seems almost perfect. (BTW I have over 300 jumps)

But, let me just stress, that it is not important if the cameras are started at the same time, that is easy to fix in post. The problem is having the shutters in time with each other. If they are not, any movement in the video will be from different times in each eye and cause eye-strain, or break the 3d effect all together. Starting the two cameras at the same time will not cause the shutters to be in sync, and even if it did, they would drift very quickly out of sync.

Thanks,
Brandon

Asher Kelman
June 24th, 2007, 12:46 PM
Great to be so accomplished! Just be careful, Brandon!

I now understand thew problems. Two possibilites.

1. The solution already exists and is on one of the video Journal Websites.

2. Ray West, our very resourceful imaginator and engineer, might tell you how to do it or do it for you.

Asher

Brandon Yates
June 24th, 2007, 12:52 PM
Thanks Asher,

I have searched High and low on the web and can't find information about what I want to do.

I would love to speak/email Ray West! I am a video engineer but this problem is outside my skill set. What is the best way to contact Mr. West?

Thanks,
Brandon

Asher Kelman
June 24th, 2007, 12:58 PM
I already sent Ray a PM! Where are you located? It's helpful to add it to your profile to see if he's a neighbor! This idea will be useful to others I'm sure.

I guess Canon didn't want to cannablize it's higher end sales!

Asher

Brandon Yates
June 24th, 2007, 01:03 PM
Thank you very much Asher.

I am located in NYC. I'll add my info to my profile.

Klaus Esser
June 24th, 2007, 01:11 PM
I need the shutters to be in sync for movies. I want to use them for stereoscopic video work. This is not a matter of just starting the recording at the same time, but having the shutter frame rate of both cameras going "in time" with each other.

I have done this with stanadard definition cameras but would like to use high definition. There are no consumer (or pro) HD cameras with a genlock that syncs the shutters. (Canon makes a higher end HD camera is a 'genlock input' but it is just a TBC for the output of the camera, it dosen't sync the shutters.)

I would like to use the Canon TX1 because it is small, 720p@30fps HD, MJPEG, Tapless, and only about $500.

I have pictures of some of my older SD 3d systems but don't know how to upload them :)

Thanks,
Brandon


Brandon - the quality of "HD" out of those little consumer-devices ist TERRIBLE compared to just a non-HD-videocamera! They use ultra-ultra-compression to handle movie sequences of that size and resolution.
Especially for stereo-use it will be counterproductive. And you can no way "synchronize the shutters" . .

To use that kind of camera for "HD" is what we call "Augenwischerei" over here - itīs a pure marketing-gag.

best, Klaus

Asher Kelman
June 24th, 2007, 01:22 PM
Brandon!

Actually, the 64x48 is the only size that is sharp! The higher levels look very fuzzy and have a lot of artifacts, so Klaus is correct!

The images are shown here (http://www.dpreview.com/reviews/canontx1/page4.asp)!

Asher

Brandon Yates
June 24th, 2007, 01:26 PM
Hi Klaus,

I am aware that many of the consumer HD video cameras have highly compress, terrible video quality.
This is mostly do to the fact that they use mpeg4 at a very high compression rate.
Some use mpeg2 but you still end up with bad quality video.

The canon Tx1 is different, it uses MJPEG, which most people would laugh at because it is such an old compression scheme. But this is why I like the camera. MJPEG uses only spatial compression and not temporal. This ends up with bigger files but better quality.

I have downloaded samples from all the HD cameras and as we say "the proof is in the pudding".

Please take a look at one of these video clips and then tell me what you think about the quality of the TX1:

Sample video from a Japanese web site:
http://www.watch.impress.co.jp/av/docs/20070307/zooma298.htm

Brandon

Brandon Yates
June 24th, 2007, 01:29 PM
I know you mean 640x480, that web site is misleading. Please take a look at the raw, un re-compressed camera samples at the web site I just gave.

I'd think the quality is great for such a small camera.

Asher Kelman
June 24th, 2007, 02:56 PM
RAW stilol image? That's fine! I have no doubt that is great. It's the vido that you need. AFAIK that is not RAW, but I could be mistaken, after all, 30 frames per second RAW images would make it the best camera on the planet! Or maybe I misunderstand you!

Asher

Brandon Yates
June 24th, 2007, 03:36 PM
Asher,

I just mean look at the unaltered video samples. Most web sites that have sample video clips from the TX1 recompress them to put them on the web making it pointless to compare quality.

Take a look at the camera original 1280x720@30fps MJPEG video sample:

ezsm1.avi

http://www.watch.impress.co.jp/av/docs/20070307/ezsm1.avi

I didn't mean raw as in RAW for still images, sorry for the confusion.
Brandon

Ray West
June 24th, 2007, 03:41 PM
Hi Brandon,

My first answer is 'it can't be done'. My second answer is 'it can be, but not easily'

You need to buy at least half a dozen of the cameras, because you are going to wreck many of them. You need to get the hang of dismantling them, and replacing the separate timing circuits with a single common circuit. It may or may not be simple on that particular camera. It would help if you could get the circuit diagrams. For stereo, you will need a common timing circuit, although the modern cameras have crystal oscillators, over half an hour or so they will get out of frame synch, sometimes by half a frame or so. If you're skydiving, then I guess size and weight is important. I believe some of the bullet/lipstick cams have synchronising pulses, but they may not be high def. If you were happy with half the resolution, then maybe a prism device, and use one camera.

I think my first answer is the best - get a different camera.

Best wishes,

Ray

Klaus Esser
June 24th, 2007, 03:49 PM
I know you mean 640x480, that web site is misleading. Please take a look at the raw, un re-compressed camera samples at the web site I just gave.

I'd think the quality is great for such a small camera.

Brandon - iīm really sorry - but the quality of the still-images is a mess. And thereīs no other way it could be!
The quality of the video i canīt judge because i donīt know what theyīre writing there in Japanese and how the videos were made . . .

Anyway - itīs absolutely impossible to synchronize two cameras of that class.

best, Klaus

Brandon Yates
June 24th, 2007, 04:03 PM
Thanks Ray,

I fully get that it would not be easy. But assume that I could isolate the timing crystal oscillator, can two cameras be driven by one crystal? or would some other timing device need to be used? (I know how to program PIC chips) Maybe a PIC could be used as an external sync generator for both cameras?

And yes, if modifying two HD cameras is too hard I have thought of using a Prism, actually front surface mirrors and use one camera, but I would loose half my horizontal resolution and have a rather narrow frame. I have considered using anamorphic lenses on the prism/mirror but now the system is getting bigger and more complicated and adding optical distortion.

I am trying to get the service manual from Canon but they really don't want to sell it to anyone.

thanks everyone,
Brandon

Ray West
June 24th, 2007, 04:31 PM
Hi Brandon,

None of the camera makers will release information - dead worried about Indian/Chinese rip offs. I was thinking maybe use one of the existing circuits to feed both cameras. Now, this stuff will be small, well integrated sm chips. I can only wish you the best of luck.

Now, of course the image size (zoom), focus, colour balance will need to be identical too...

Here's an expensive bullet cam - with internal/external synch. http://www.cameras4sports.co.uk/product.asp?id=157 You will get it half price in usa, and other versions will be cheaper.


Best wishes,

Ray

Brandon Yates
June 24th, 2007, 04:49 PM
Thanks Ray,

I may just have to take apart a TX1 and start probing it with an oscilloscope.

I have not been able to find any HD video cameras that are 'sync-able'. The closest thing I have found are firewire cameras with ext. triggers with high res and 30 fps, but to record two streams would involve using a computer, I don't feel like jumping with a laptop strapped to me :).

As for SD cameras, thanks for that link, i have never seen that web site. But I already have working SD systems, if I put any more money into them I would like to go to HD.

(I leave the two cameras on wide angle, manual focus, manual color balance and tweak them in a computer if they don't match.)

Thanks for you help,
Brandon

Ray West
June 24th, 2007, 06:42 PM
I think Samsung do a notepad pc, 5*7 screen, iirc, runs xp, no idea about firewire. Or, get micro atx mb, with flash memory, if 2.5 hdd too flimsy. I'd think a stripped down linux os - you just need firewire to hdd interface. They are using fw in car systems, nowadays. Maybe a single chip solution. I guess you only need to record 5 mins at a time, may not need much memory. Microchip pic have done a usb (slave) for a year or two, they may do firewire now.

Alan Hunter
March 6th, 2008, 06:15 PM
Does anyone know how to modify a canon TX1 so two of them could be genlocked?

I need the shutters to be in sync.

Any information would be helpful,
Brandon
Brandon, did you ever get a service manual for the TX1? I was looking for one today and I saw your post here. I am also thinking of shooting stereoscopic video with a pair of TX1's. There is an outside chance that an offshoot of CHDK could be used to sync a pair of TX1's via the USB port. People are doing this with Canon still cameras, but the DIGIC chip is different in the TX1. Check out StereoDataMaker@yahoogroups.com.

Dennis Williams
May 26th, 2008, 06:31 AM
Start with this: http://chdk.wikia.com/wiki/CHDK
and then go to their forum to find the Stereo Data Maker version of CHDK, authored by "Microfunguy". He has his own site dedicated to stereo photography, and can probably help you with all of your needs. "Cybercom" on the CHDK forum, and on the TX-1 forum, is doing stereo shooting with twin TX-1s using the SDM version of CHDK firmware.