Shot Histogram Request - page 33 - CHDK Releases - CHDK Forum

Shot Histogram Request

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Offline ahull

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Re: Shot Histogram Request
« Reply #320 on: 14 / July / 2013, 16:04:22 »
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Lapser, I'm running a test on the a2200, its currently strapped to a fence post in my "quick weatherproof camera box" fitted with a polariser..

I'll post the results if and when I get them. The A2200 was a little quirky to set up, but I got it going.

« Last Edit: 14 / July / 2013, 16:07:37 by ahull »

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Offline ahull

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Re: Shot Histogram Request
« Reply #321 on: 14 / July / 2013, 18:21:26 »
The first results are in... Lots of blunders on my part, I should have taken more time setting up the metering, not shot all the images at the full resolution of the camera, and offset the path of the sun to avoid some of the nasty flare. Youtube has also added a bit of mosaicing which is not in the original, but all in all, not bad for a first attempt..

Sunset in the Trossachs July 2013


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Offline lapser

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Re: Shot Histogram Request
« Reply #322 on: 14 / July / 2013, 23:06:17 »
@ahull,

Looks great! It's really hard to get a good picture with the sun in the frame, especially with clouds moving in front of it.  My 3 cameras all have an ND filter, although only the G1X is documented by Canon. It would be nice to have the script control the ND filter, which I plan to do soon. The sun tends to max out the shutter speed, so the ND filter would help.

When bright and dark areas are in the frame, there always seem to be video compression artifacts in the dark areas, even with commercial video. The main thing is that the script seems to be smoothing out the exposure changes in your video, so there isn't any "fluttering" of exposure like I used to get.

I'm looking forward to seeing your next video.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

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Offline lapser

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Re: Shot Histogram Request
« Reply #323 on: 27 / July / 2013, 15:24:14 »
I was able to get my time lapse mods working with the latest trunk revision today.
set_console_layout() is working now (thanks Phil). I also removed the Lua bug code since that one is fixed (THANKS Phil).

I'm interested in doing something with the new filewrite hook. Is there a thread or some documentation about it somewhere?

I discovered that the shutter time gets a little inaccurate on the SX50 when it's less than about 1/1600 second. It goes all the way to 1/3200, second but when shooting multiple pictures the exposure varies by about 15/96 ev between pictures. This leads to "flashing" in a time lapse video. This also happens slightly with multiple pictures without CHDK taken at 1/2000 second, so I don't think it's a CHDK issue. It DOESN'T happen with the SX260 at 1/3200 second.

Here's an example. The time lapse starts out with the sun in the frame, and 1/3200 shutter time. It flashes until the sun goes down and the shutter time reaches about 1/1600. The rest of the video looks very smooth. By the way, CHDK is not doing any exposure changes at the beginning. The exposure is a constant 1/3200 during the flashing.

http://www.youtube.com/watch?v=NLSbSRq3JhY#ws


Below is a more interesting time lapse from the same spot, which shows flashing at the beginning and very smooth exposure changes later.

http://www.youtube.com/watch?v=3RPLgJYyNCA#ws

The next time lapse was done with the SX260 starting at 1/3200 sec, and ending at 1/154 sec, with no flashing:

http://www.youtube.com/watch?v=AvflNryCscw#ws

The G1X doesn't have any flashing at 1/4000 second, but it did show some single flashes as the sun went down in this video. I'll have to do some more testing on this one, but I think it may be related to inaccurate shutter time when changing exposure. It's possible I changed the exposure during the shot or something :

http://www.youtube.com/watch?v=bPYX9keMisk#ws

By using the ND filter and stopping down to F16, the G1X starts at 1/558 sec in this video without any flashing. My script can't change Av or the ND Filter yet, so the shutter time goes to 3.17 seconds at the end. I stayed until 2200 this night, so you can see Venus appear at the end of the video:

http://www.youtube.com/watch?v=CDpFKfmS0Sk#ws
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos


Re: Shot Histogram Request
« Reply #324 on: 08 / August / 2013, 22:59:10 »
Okay - so over the last couple of days I've tried the various drivelapse and carlapse scripts.

Frankly - while they mostly work,  the resulting videos pretty much suck.

At highway speeds,  one frame per second is the minimum standard for a reasonable timelapse video and none of the current scripts give you that. 

And driving under underpasses makes the next shot wildly over exposed.

So,  jamming the camera in continuous shooting mode seems to be the order of the day.   Except doing that locks the exposure on the first shot ... which just made a mess of the end of my 30 minute commute home today as the sun started to set.

So lapser,  we need your mods!  Please.  Would you like me to work with you on a "releasable" version to the trunk ?

Ported :   A1200    SD940   G10    Powershot N    G16

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Offline lapser

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Re: Shot Histogram Request
« Reply #325 on: 09 / August / 2013, 02:05:20 »
So lapser,  we need your mods!  Please.  Would you like me to work with you on a "releasable" version to the trunk ?
That sounds great. I've got a lot of travel and camping trips planned over the next 6 weeks, hopefully getting some nice time lapses. I'm leaving for a 3-4 day trip tomorrow morning. I'm hoping to get some good shots of the Perseid meteors.

I'll try to have a new diff file and time lapse script for you by the end of the week. I haven't tried it in a moving car for awhile, but it should work well. Here's some of my favorite recent time lapses:

http://www.youtube.com/watch?v=7Wym42H7S7Y#ws

http://www.youtube.com/watch?v=96hGKyxMavQ#ws

http://www.youtube.com/watch?v=Mr1SguBQ-eo#ws

http://www.youtube.com/watch?v=odKcq9HqLwc#ws
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

Re: Shot Histogram Request
« Reply #326 on: 09 / August / 2013, 09:55:10 »
I'll try to have a new diff file and time lapse script for you by the end of the week.
You sound busy.  Just send me what you have now?
Ported :   A1200    SD940   G10    Powershot N    G16

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Offline lapser

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Re: Shot Histogram Request
« Reply #327 on: 09 / August / 2013, 11:32:49 »
OK, here's what I have that was working for me. The diff is for 1.3, and won't work with 1.2. I'll attach a diff for 1.2 to the next message.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos


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Offline lapser

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Re: Shot Histogram Request
« Reply #328 on: 09 / August / 2013, 11:34:00 »
I'll attach a diff for 1.2 to the next message.

OK, my ride is here.. gotta go. Good luck.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

Re: Shot Histogram Request
« Reply #329 on: 09 / August / 2013, 21:04:51 »
OK, here's what I have that was working for me. The diff is for 1.3, and won't work with 1.2. I'll attach a diff for 1.2 to the next message.
OK, my ride is here.. gotta go. Good luck.
Did a bit of cleanup on the 1.3.0 patch file - converted to a patch file for an svn local repository and removed everything not related to shot_histogram_request (including the Lua bug chasing code and backlight control).  Seems to run well with your script - I'll do a simpler script for car lapse shooting I think.    Once I put more mileage on the code and cleanup the patch file a bit more,  I'll post a final patch file here.   

Hopefully reyalp, philmoz and srsa_4c (and anyone else who cares) can take a look and comment at that point.
Ported :   A1200    SD940   G10    Powershot N    G16

 

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