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save the focus screen

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Offline 74prof

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save the focus screen
« on: 12 / August / 2013, 17:46:31 »
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In all modes except movie and automatic, selecting focus provides a magnified rectangle in mid-screen.
I would like to capture the middle rectangle.
Failing that I would like to do a screen capture in that situation.
That can now be accomplished, but only by using chdkptp and screen capturing the computer screen.
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Offline waterwingz

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Re: save the focus screen
« Reply #1 on: 12 / August / 2013, 19:22:17 »
Quote from: 74prof on 12 / August / 2013, 17:46:31
In all modes except movie and automatic, selecting focus provides a magnified rectangle in mid-screen.
I would like to capture the middle rectangle.
There is currently not way to do that with CHDK.  If you had the skills and time,  you might be able to customize the CHDK code to do something like that.  But first you would have to discover where the Canon camera gets the dimensions of the rectangle. This would require some reverse assembly code digging detective work.

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Failing that I would like to do a screen capture in that situation. That can now be accomplished, but only by using chdkptp and screen capturing the computer screen.
A "screen print" button in the chdkptp GUI might be a nice feature.  Perhaps reyalp will put it on his "round-tuit" list.

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Offline reyalp

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Re: save the focus screen
« Reply #2 on: 12 / August / 2013, 22:44:11 »
The magnified focus area is not part of the normal viewport (on all the cameras I know about, at least) So  neither chdk not chdkptp can capture it. If you run chdkptp live view with this active, you will just see the normal screen buffer.

IIRC srsa has found the magnified buffer on some camera(s), I think this was discussed in one of SticKs threads.

Screenshot ability in chdkptp is indeed on my list.
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Offline 74prof

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Re: save the focus screen
« Reply #3 on: 13 / August / 2013, 10:41:29 »
I can with chdkptp see the focus frame on my computer screen, but cannot as was said, view the magnification in that frame.
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Offline reyalp

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Re: save the focus screen
« Reply #4 on: 13 / August / 2013, 16:27:43 »
Quote from: 74prof on 13 / August / 2013, 10:41:29
I can with chdkptp see the focus frame on my computer screen, but cannot as was said, view the magnification in that frame.
Right, the box is just a box in the Canon UI overlay. I'm assuming this is not what you wanted?
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Offline 74prof

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Re: save the focus screen
« Reply #5 on: 13 / August / 2013, 20:08:12 »
No, what would be ideal would be to zoom in on the part of mid screen that when manual focus is turned on is magnified.  If I followed the math of someone else here who actually looked at captured code, this should give much higher resolution than very fine jpeg.

I think this might be what Canon (or ML?) on a couple of cameras calls crop mode.
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Offline reyalp

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Re: save the focus screen
« Reply #6 on: 13 / August / 2013, 21:51:07 »
Quote from: 74prof on 13 / August / 2013, 20:08:12
No, what would be ideal would be to zoom in on the part of mid screen that when manual focus is turned on is magnified.  If I followed the math of someone else here who actually looked at captured code, this should give much higher resolution than very fine jpeg.
This makes no sense. The viewport is very low resolution. The magnified part can't have better resolution than the sensor, it's just showing you something that is downscaled less than the rest of the viewport.  The max resolution jpeg is very close to the resolution of the sensor, and of course the raw (including DNG) is full resolution.

If you can like to where you found "someone else here who actually looked at captured code" that might help me understand.

The actual magnified images is very small, according to srsa's post here http://chdk.setepontos.com/index.php?topic=8613.msg91453#msg91453 it's 360x121 on the camera he looked at.
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Offline 74prof

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Re: save the focus screen
« Reply #7 on: 14 / August / 2013, 05:12:37 »


« Reply #337 on: 01 / October / 2012, 01:45:27 »

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From the link you cited above:

As I said, I wasn't sure I followed the math correctly.

A small piece of added info on AF point zoom on S90 that I think I was able to determine ... with a vernier I measured subject magnification to be 2X over the 640x480 // like having a "background" 1280x1024 view but just cutting out 1/8th the area from its center and then superposing it on 1/4 of the central area of the 640x480 liveview.  Thus my *guess* is that the AF point zoom buffer is 320x240 on the S90 and has an equivalent resolution of 1280x1024.  If true and can be implemented, that would be slick.




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Offline srsa_4c

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Re: save the focus screen
« Reply #8 on: 14 / August / 2013, 14:30:42 »
Some help to show how the live buffers really look like (6MP camera, unscaled, the a540 may have slightly different buffer dimensions).

One of the 3 "normal" live buffers (720x240):


One of the 3 "MF point zoom" buffers (360x120):


The highest available live view resolution is 720x528 (in VGA movie mode). I would expect that the above buffer contents are all made from the same source - the normal buffer is downscaled, the MF point buffer is probably an upscaled center crop of the 720x528 source.

This is the last (3rd) live buffer and the 3 "MF point zoom" buffers (part of the camera RAM, visualized):

« Last Edit: 14 / August / 2013, 14:58:47 by srsa_4c »
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