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USB remote shoots multiple shots on fast cameras

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Offline reyalp

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USB remote shoots multiple shots on fast cameras
« on: 22 / December / 2019, 21:49:35 »
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I noticed this working on the sx730 port, but it seems to apply to all my digic 6 cams:
With the camera set to jpeg only, continuous mode, CHDK remote options
Enable Remote: On
Switch type: OnePush
Control Mode: Normal
Enable Sync: Off

Apply USB power, cameras goes to half press.
Remove USB power, camera takes 3-6 shots.

This seems like it's due to usb_remote.h FULL_PRESS_PULSE_TIME being 1000. Per specs, these cams should take ~6 FPS (my tests that took 3 were in low light). Reducing to 100 seems to resolve the issue, but I haven't tested extensively.  I'd generally expect 100ms to be enough to trigger a camera sitting in half press.

It might be preferable to detect when the shot has been started. On most cameras this could be done in the remote hook, but there's a few that don't implement it. I believe the raw hook can be too late on some cams, since scripts like hooktest and rawopint occasionally take an extra shot when the release is after the raw hook. Detecting remote hook with hard coded time as a fallback might be a reasonable option.

Thoughts, @waterwingz?
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Offline waterwingz

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Re: USB remote shoots multiple shots on fast cameras
« Reply #1 on: 23 / December / 2019, 01:02:14 »
Quote from: reyalp on 22 / December / 2019, 21:49:35
With the camera set to jpeg only, continuous mode,
I guess my question is why you'd want to have the USB remote code take just one shot when the camera has been set to Canon continuous mode?  If that's what you want to do, why is the camera set to continuous mode?

A different option might be updating the USB remote to work usefully with continuous mode?  Have not thought much about that code in a few years but I don't recall it trying to actually work with Canon's continuous mode?
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Offline reyalp

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Re: USB remote shoots multiple shots on fast cameras
« Reply #2 on: 23 / December / 2019, 01:44:58 »
Quote from: waterwingz on 23 / December / 2019, 01:02:14
I guess my question is why you'd want to have the USB remote code take just one shot when the camera has been set to Canon continuous mode?  If that's what you want to do, why is the camera set to continuous mode?
Because I habitually leave my cameras in cont mode  :haha

More seriously, my expectation in "normal" mode was that one pulse would be one shot, like script shoot(). This is generally true on older cameras and when raw is enabled.

Also, the Canon cont setting isn't easily controllable by script, so it would be nice to have predictable behavior without changing it.

The (excellent, thank you :)) documentation doesn't mention taking a 1 second burst. (Edit: actually, it says 'Releasing the switch initiates a "full-press" state for 100 mSec.')
Quote
A different option might be updating the USB remote to work usefully with continuous mode?  Have not thought much about that code in a few years but I don't recall it trying to actually work with Canon's continuous mode?
In two push mode, it appears to hold the shutter button down for the duration of the second push, which seems like the right thing to me.

For one push + normal, I'd think either a specified duration (1s = current behavior) or shot count.
« Last Edit: 23 / December / 2019, 02:13:06 by reyalp »
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