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proposal - script shooting hooks

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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #170 on: 29 / May / 2015, 16:09:59 »
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This is one of the pictures from last drtest.
Should I run this with a monitor again?
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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #171 on: 29 / May / 2015, 16:12:58 »
No, it fine, see edit on previous post.

It only looks at the area inside the white box.

edit:
The jpeg gives you a nice idea how much distortion correction and cropping the camera does in the jpeg.

Thinking out loud: By drawing a grid on the raw and using the jpeg, it should be possible to automatically generate lens calibration data to replicate the canon distortion correction.
« Last Edit: 29 / May / 2015, 16:16:01 by reyalp »
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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #172 on: 29 / May / 2015, 16:35:24 »
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By drawing a grid on the raw and using the jpeg, it should be possible to automatically generate lens calibration data to replicate the canon distortion correction.
Fantastic idea. For every zoom step…
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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #173 on: 08 / June / 2015, 02:45:32 »
Hallo reyalp.

I have seen the timelapse from the moon ;)
Looks good….

I think it’s really hard to try with condition behind the tree. On the beginning it looks a little bit overexposed. On the end you see really nice the structure of the moon. I would be interested, which parameter you are used (and focal length) and to see the plot from the run.

Is there any reason, why you limited minimum Histogram step to 9?
I know, smaller values increases CPU load but precision of histogram will be also increased.
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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #174 on: 08 / June / 2015, 17:00:48 »
Quote from: c_joerg on 08 / June / 2015, 02:45:32
I have seen the timelapse from the moon ;)
Looks good….

I think it’s really hard to try with condition behind the tree. On the beginning it looks a little bit overexposed.
At the very beginning, it takes quite a while for the algorithm to reach steady state, because the initial exposure is for the whole scene and very far from correct for the moon. When less than the whole moon is visible, there is still some over-exposure. Some issues with the exposure algorithm also make it react more slowly than it should.
Quote
On the end you see really nice the structure of the moon. I would be interested, which parameter you are used (and focal length) and to see the plot from the run.
This was some code I was testing that isn't in the last version I posted. I've spent some time working on getting better results from small over-exposure limits, but the current exposure code has some problems. There's a couple of other tests on my youtube.

In the original code, there was always a "meter limit", which eventually balances any change caused by over or under protection (by ramping up the "weight" described in http://chdk.setepontos.com/index.php?topic=11081.msg120803#msg120803) This doesn't work well for the moon at night, because the meter essentially goes to black level.

In the script used for that moon rise, I made the weight not ramp up. However, the meter still has it's normal weight, meaning that when the meter is far below the target value, it will still add up to 1/2 the "max ev change" in the wrong direction. This means that it still balances out the over exposure protection, just at a lower level. It also slows down the reaction time.

I have some ideas about how to deal with this (more options!) but I haven't gotten back to working on the code yet, which is why I hadn't posted.

The settings, aside from the customization above, were
meter size: 90% in each direction
meter step: 15
max ev change: 1/3
bv ev shift: 40
bv ev shift base: 9.5
max tv: 1 sec
iso adj tv 0.25 sec
max iso: 400
overexp thresh: 5 (0.05%)
overexp ev range: 1/2
underexp: disabled
histo step: 11

Focal length is ~211 (35 mm equivalent)

Note this was done on sx160, not the D10 I usually use for testing.

Chart and CSV are attached. Note the "over_frac" (in %) is on the right hand scale. You can see it does hover around 0.05 for most of the time. Because of the slope parameter in the over exposure weight calculation, it actually balances meter at 0.055.

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Is there any reason, why you limited minimum Histogram step to 9?
The histogram precision is parts per 100k. On a 12MP cam, 9 gives you ~300k samples, so I don't think going to lower step sizes will help much. The time required goes up quickly with smaller steps because it's a square. Higher precision is possible, but with the kind of calculations the current code does on the results, it is gets quite easy to run into overflow.

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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #175 on: 10 / June / 2015, 03:06:14 »
I found in the log file over_thresh_frac=50.
Any reason to log it at 50 and not as 5 or 0.05%?

May be I would be helpful, also log things like focal length, focus distance, camera and so on.

How did you focus the moon?

When I use an external ND filter on G1X, I have much problems to focus. Manual focus while staying in the water and having the sun behind you is really hard. ;) I think manual focus setting in the script to infinity or hyperfocal distance would be really helpful.
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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #176 on: 10 / June / 2015, 16:10:29 »
Quote from: c_joerg on 10 / June / 2015, 03:06:14
I found in the log file over_thresh_frac=50.
Any reason to log it at 50 and not as 5 or 0.05%?
The exposure code uses parts per 100k internally, and just logs all the raw values it uses.

Quote
May be I would be helpful, also log things like focal length, focus distance, camera and so on.
Yes, that's a good idea.

Quote
How did you focus the moon?
Just manual focus in the camera UI at maximum distance.

Quote
I think manual focus setting in the script to infinity or hyperfocal distance would be really helpful.
Agreed, but focus override in CHDK has a lot of camera specific quirks and bugs so I've left it alone for now.
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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #177 on: 30 / June / 2015, 05:30:28 »
Hello reyalp,

I’m getting Addicted making time lapse with rawopint  ….
Unfortunately I haven’t found a good situation with the moon yet…

I try to make a Boat time lapse ride with a minimum interval in continues mode with G1X or S110.
Do you think, it is a good idea to set the interval to 0?

I think, I will get a big jitter in time.
Which is the best value from the log file to analyses, to see how big the jitter is?
Is there any timestamp in jpg which is more accurate then 1s?

I analyzed  time tick / start tick from my lust run with 3s interval. I found a jitter from around plus/minus 20ms.
This looks really good.

Do you think it is a good idea, to set the interval a little bit higher (0.7s) as the maximum speed (0.6s) from S110 to avoid time jitter?

« Last Edit: 30 / June / 2015, 05:32:36 by c_joerg »
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Offline reyalp

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Re: proposal - script shooting hooks
« Reply #178 on: 30 / June / 2015, 23:25:47 »
Quote from: c_joerg on 30 / June / 2015, 05:30:28
I try to make a Boat time lapse ride with a minimum interval in continues mode with G1X or S110.
Do you think, it is a good idea to set the interval to 0?

I think, I will get a big jitter in time.
If you set the interval to 0, then the script will shoot as fast as it can and the time between frames will vary a lot.

Quote
Is there any timestamp in jpg which is more accurate then 1s?
AFAIK there is not.

Quote
I analyzed  time tick / start tick from my lust run with 3s interval. I found a jitter from around plus/minus 20ms.
This looks really good.

Do you think it is a good idea, to set the interval a little bit higher (0.7s) as the maximum speed (0.6s) from S110 to avoid time jitter?
Yes. I would look at the "sleep" column. This is the number of milliseconds the script waited to maintain the proper interval. If it's less than 0, then shooting took longer than the interval. I would aim for a sleep of ~100 ms, keeping in mind that exposure time can be a big factor if you aren't full sun.

As long as the sleep is greater than 0, the jitter should be very low in this script, probably something like +/-20ms.

The columns shoot_ready, exp_start, raw_ready and raw_done are all ms offsets from "start", which is the tick time the shooting iteration started.

"exp_start" is some very short time (tens of ms, probably) before the exposure started, so if you want to measure the time between exposures it would be

(start[n] + exp_start[n]) - (start[n-1] + exp_start[n-1])

but unless there is a bug it will be exactly equal to the interval in ms as long as sleep is > 0. This doesn't mean there is 0 jitter: The tick counter only has 10ms resolution, and there is some room for variation after exp_start.
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Offline c_joerg

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Re: proposal - script shooting hooks
« Reply #179 on: 01 / July / 2015, 04:07:34 »
I made just a test in continues mode with S110. I have probably not much chance for the run.
50 pictures with interval = 0s, 50 pictures with interval =  0.8s.
I wondering, that the parameter of interval is not in the log, or I have not seen ;)
 
I put both runs in one plot, so jumps between both runs can be ignored.
Exposure time is less than 2ms so can be ignored.

As you see something is happens with interval 0.8s around shot 80. May be SD card is blocking..

When I calculate
 (start(n)-exp_start(n))-(start(n-1)-exp_start(n-1))
It looks like that jitter is still with 0.8s interval higher than +/-100ms. But better than interval = 0.

But what does
tick(n)-tick(n-1)
Says? It looks like less jitter.

So when I have the chance for the run, I will try it with interval =  0.8s.

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