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Synchronising two S110's via the AF lamp

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Re: Synchronising two S110's via the AF lamp
« Reply #50 on: 09 / May / 2014, 11:28:00 »
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I took lots of photos yesterday with my SX220hs stereo rig.
I used SDM focus-cancel mode with the usb switch.
One click to focus, longer press-and-release to take photos.

They are all in-focus, of course  :)


David

Yeah I don't really have a problem with focus on the S110 rig, but when trying to photograph an (low-flying) aeroplane or any sort of moving object with the SX40 rig (fully zoomed in) it's hard enough to get one camera to properly focus on it, let alone both at once. But I guess I might not have this problem on the SX40s, I haven't tested it yet.

Re: Synchronising two S110's via the AF lamp
« Reply #51 on: 09 / May / 2014, 12:11:26 »
when trying to photograph an (low-flying) aeroplane or any sort of moving object with the SX40 rig (fully zoomed in) it's hard enough to get one camera to properly focus on it, let alone both at once.

Very difficult
With my SX50hs I use manual focus set to infinity or the camera will keep losing focus anyway.
There is no way your rig can solve this problem, in my opinion.
The aircraft are high enough that they are in-focus at infinity even with 1200mm setting.
Trying to keep them in-frame is VERY difficult if you are shooting movies.

Re: Synchronising two S110's via the AF lamp
« Reply #52 on: 09 / May / 2014, 12:48:39 »
when trying to photograph an (low-flying) aeroplane or any sort of moving object with the SX40 rig (fully zoomed in) it's hard enough to get one camera to properly focus on it, let alone both at once.

Very difficult
With my SX50hs I use manual focus set to infinity or the camera will keep losing focus anyway.
There is no way your rig can solve this problem, in my opinion.
The aircraft are high enough that they are in-focus at infinity even with 1200mm setting.
Trying to keep them in-frame is VERY difficult if you are shooting movies.

Hmm I guess I could probably try that. I'll have to figure out what values set the focus at actual infinity, as the camera seems to focus beyond that.
They are indeed difficult to keep in frame even when shooting normally (these are usually small two-person aeroplanes that are flying overhead) so I'll have to come up with a solution to the momentary lack of preview when using the precision sync. I'm thinking perhaps a binocular/monocular as an optical viewfinder might be suitable. With a crosswire/mesh or something embedded in it. I might even steal the one off of my telescope if it didn't invert the image.

How difficult do you think it might it be to implement the synced video in this thread? Does any code already exist or will I have to write something from scratch?



On the topic of zoom, would anyone know of any other ways to sync the zoom other than simply checking the propcase (which only updates when zooming is finished) or simulating the zoom buttons (which won't be very accurate)?

Re: Synchronising two S110's via the AF lamp
« Reply #53 on: 09 / May / 2014, 15:56:35 »
these are usually small two-person aeroplanes that are flying overhead) so I'll have to come up with a solution to the momentary lack of preview when using the precision sync.

You are trying to do this in stereo ?
If so, you will need two people standing some metres apart using cameras that are synchronised.
The beta version of SDM 1.86 can certainly do that.
However, with no reference background you will not get much of a 3D effect.

Quote
How difficult do you think it might it be to implement the synced video in this thread? Does any code already exist or will I have to write something from scratch?

Well, the original code that 'karmaschinken' claimed he would study (but never reported back on) has changed completely.
In fact, I took some test movies a few days ago but have not had time to process them yet.
The original code required an opto sensor to be fixed over the left camera.
The code being tested uses an inexpensive microcontroller instead.

I am working my way through the SDM features, changing code or even devising completely new ways of doing certain functions.
In addition, new documentation is required, it is all very time consuming and I can only devote a limited amount of time, I am too busy doing photography.

Quote
On the topic of zoom, would anyone know of any other ways to sync the zoom other than simply checking the propcase (which only updates when zooming is finished) or simulating the zoom buttons (which won't be very accurate)?

Well, with an SDM rig you just use the usb switch.
I guess your rig could simulate the same method.


Re: Synchronising two S110's via the AF lamp
« Reply #54 on: 09 / May / 2014, 19:11:38 »
I was using shooting_get_subject_distance() to read the focus, and shooting_set_focus(distance, SET_NOW) to set it. It worked, but the slave was massively short-sighted (if the master was focused, say 2 metres away, the slave would be focused to about a foot). So I tried using shooting_get_subject_distance() to read the distance the slave was actually focused at, and found it was about 43 units less than the number being put into shooting_set_focus.
I've noticed that while you can try setting focus where you want, the camera may only work in discrete steps.  You've mixed metric and imperial units and then thrown in a "43 unit" measure so its hard to tell if this might be happening in your case.   Should be possible to test with a single camera - just  read the value from shooting_get_subject_distance() and set it back into shooting_set_focus() and see if it moves the lens.

If you want to use the built-in USB remote functionality,  either the "one push" or "two push" modes will cause the camera to focus perfectly when the remote is first activated.  One push fires right away when the button is released,  two push will fire if you quickly press the button again.  Precision sync is available in both modes.



On the topic of zoom, would anyone know of any other ways to sync the zoom other than simply checking the propcase (which only updates when zooming is finished) or simulating the zoom buttons (which won't be very accurate)?
I guess you could use a hybrid approach?  When your master camera is told to zoom,  send a message to the slave to start zooming in the same direction.  When the zoom button on the master camera is released, read back the zoom position, send that to the slave, and have it set zoom to the absolute position.   It should appear to track pretty closely that way with minimal delay to getting to final position.

If you want to use the built-in USB remote functionality, documentation on how that works is here : http://chdk.wikia.com/wiki/USB_Remote#Zoom
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