FPS Override

[ybouchard72]

Hi,

I am a enthusiastic user of BYE. I am using it mainly for deep sky but and less frequently for planetary work.

 

I am also a enthusiastic user of an Canon EOS Firmware add-on called Magic Lantern (http://magiclantern.fm/). Before BYE, I was using ML to control intervalometer and data capture. Now, the only one feature that impose me to keep ML is something called FPS Override.

 

FPS Override is an enhancing tool to drastically increase the sensitivity of the live view. In addition of being vastly more sensitive than just cranking the ISO (you can even do Deep Sky Object image composition in live view) but it drastically decrease the sensor heating that plages the traditional live view sessions.

 

The principle is simple and elegant: it increase the exposure time of the live view that is typically max 1/30s and reduced the refresh rate. As long as 1 images per 5 seconds if you want. FPS stands for Frame Per Seconds. Live view typically does it at 30 FPS. Therefore, the max exposure of a live view is typically topped at 1/30s. In addition, since the heating of a sensor is typically related to the "read" cycle, to read 30 times per second drastically increase the sensor temperature, spoiling the first images of the astro sessions.

 

To modify the FPS means to get it all good. Less FPS means colder sensors, increased sensitivity, etc. It drastically help routine tasks like adjusting focus, even image composition of deep sky object becomes possible!

 

Magic Lantern firmware add-on (http://magiclantern.fm/) uses two internal clock to fool the DSLR into increasing the exposure time of a live view image and decreasing the FPS. The FPS is easily customizable down to FPS of 0.10 FPS (or 1 frames per 10 seconds). In astro, I typically FPS override it a 1 FPS, and not so frequently at 0.33 (or 3 FPS).

 

This FPS override would become a drastic upgrade compared to the live view that BYE currently carries.

 

I ask you: please, consider this feature.

[admin]

I'm well aware of ML... but some of these firmware changes are NOT available as options via the SDK and therefor I have no means of accessing them so I'm caught between a rock and a hard place given that my only method of communicating with the camera is the Canon SDK... so I'm limited by what it exposes in terms of function calls.

 

I will eventually try ML myself and I will give it a good go one of these days and well see if it can be done via the SDK.

 

Regards,

[s3igell]

Remember that MagicLantern is actually Alternative Firmware running ON THE DSLR Digic Processor (bypassing some of the Canon DSLR Firmware while augmenting other parts), while BYE is an App running on the PC communicating to the Canon SDK running on the PC, which the SDK is in turn communicating with the Canon API built-in to the Canon Firmware running on the DSLR.

 

BYE is at least One Layer Removed from being able to communicate with - or bypass or supplant - the Canon Firmware and the Digic Processor.

 

I can confirm that BYE works successfully WITH MagicLantern (or as likely AROUND it - because the Canon SDK doesn't seem to Allow / Recognize any of the MagicLantern Features).

 

If you wished to pursue this, I'd suggest that you actually need to get the MagicLantern Developers interested in finding how to get ML to Interface and Act upon the Canon SDK...

[dts350z]

That FPS feature in ML sounds awesome though, both for DSO in live view and the lack of heating.

 

However, I don't have a camera with me at the moment, but couldn't you achieve the same results with looping, under frame and focus?

[s3igell]

Actually, the Looping in Frame&Focus could approximate one of the purposes of the ML FPS Override - the equivalent to Video Image Accumulation.  

 

However, since Snapshots are being provided via actual Still Images, Looping Snapshots has the detrimental effect of increasing the Shutter Count.

It would, however, actually improve the Heat Mitigation even a bit more than FPS Override - both because the Snapshots are delayed while the actual JPG is being Downloaded then Opened (instead of Streamed); and because those Extra Shutter "Flaps" would actually work to bring Fresh Air up to the Sensor (minorly cooling it).

 

But, it would be nice if the ML Folks would turn their "Magic" upon the Canon SDK...

[admin]

Ummm, there is already a frame rate threshold in Settings.  The value introduces a small pause between each live view frames, it is in milliseconds and the default I think is 50 milliseconds. 

 

If you want roughly 4 frames per second set this value to 250 milliseconds.

 

This value is ignored during planetary recordings because during a recording we want the maximum number of frames in a small period of time.

 

This value is active in F&F, Planetary (except during a recording), and drift align.

 

Would that already do what you want?

[ybouchard72]

Hi,

@dts350z, s3igell: I ear your suggestion of Looping in Frame&Focus. As s3igel have mentioned, it adds to the shooter count. Furthermore, it also adds a lags because each images has to be downloaded. I And the "hypothesis" of flapping the shutter to cool down is interesting but I am quite convinced would be counteracted by the eat generated by the mirror solenoids and shutter mechanism. Anyway, my point, it is an interesting hypothesis, nothing more.

 

@Guylain: I would like to highlight that ML is externally controllable. I am not asking to reinvent the wheel. I am merely asking to issu a command to already installed ML to turn on FPS override and start a session of live view. See this post:

 

https://groups.google.com/forum/#!topic/ml-devel/Sw0B1kpFlIU

 

Up to now, PTP as well as Python implementation has been made. Furthermore, "handles" or "hooks" are already available within ML to be externally controlled. My skills in programming are limited. But just enough to see the feasibility.

 

So I am just asking. The feature does make sense. I am using it as we speak: If I manually press the preview button from my DSLR with ML FPS override ON, then activate the live view in BYE, the live view showed by BYE is FPS Overrided. So what we need to do is just a way to trigger this live view button remotely. And ML is there to help us.

 

What do you think?

[s3igell]

Your reference to a rather dated Google Group points out an Important Issue - those ML connection tricks require the DSLR be in PTP mode.  PTP mode disables the Canon SDK, thereby disabling all the other Functionality of BYE.

 

This still leaves us that ML needs to provide a manner to Interface that is not PTP mode...