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Shot Histogram Request

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Offline ahull

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Re: Shot Histogram Request
« Reply #220 on: 05 / April / 2013, 18:21:48 »
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I'm quite pleased with the results I got tonight, I put the 2361 frames shot on a single battery together at 6 fps, but I might redo at 12 fps, as at  6 1/2 mins it is a little long. However the result is very respectable, for very little effort on my part (and a great deal on the part of lapser, for which many thanks). I just set up lapser's script, grabbed a fairly large section in the middle of the frame to meter from. Dumped the camera on a fence post and took the dog for a walk. I left the camera to run till the battery went flat. 

Bear in mind this is shot unattended,  on an old Ixus 40 using the cameras battery, rather than an external power source, at 4Mp, and converted to 1920x1080 (HD). Not bad for a camera you can pick up for a song these days.

Ben Lomond sunset early April

The mountain is Ben Lomond in the Trossachs area of Scotland,

The frames are made in to a movie with mencoder using a Linxux PC and this simple bash script.
Code: [Select]
#!/bin/bash
# The Ixus 40 is set up to create a new folder for every 10 images
# I copy these folders to ~/Pictures/Timelpase
# Then the script grabs all of them and moves them to a folder called ./Pics
# it then builds te movie with mencoder.
#

for file in $(find . |grep JPG)
do
    mv  $file ./Pics/.
done

PIC_DIR="./Pics"

# For lower res, use something like..
#WIDTH="640"
#HEIGHT="480"

# 1920x1080 gives full HD
WIDTH="1920"
HEIGHT="1080"

FPS=12
BITRATE="1500"
DEST_VIDEO="timelapse6.mpg"

mencoder mf://$PIC_DIR/\*.JPG -mf w=$WIDTH:h=$HEIGHT:fps=$FPS:type=jpg -ovc lavc -lavcopts vcodec=mpeg4 -oac copy -o $DEST_VIDEO

« Last Edit: 05 / April / 2013, 19:05:23 by ahull »

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Offline lapser

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Re: Shot Histogram Request
« Reply #221 on: 05 / April / 2013, 19:29:53 »
I'm quite pleased with the results I got tonight, I put the 2361 frames shot on a single battery together at 6 fps, but I might redo at 12 fps
Very nice! That's a really beautiful place.

I usually shoot at 1 or 2 frames per second, and play back at 25 or 30 FPS. 2 or 3 minutes is a good target time for a sunset video.

From your previous posts, I was worried that the exposure adjustments weren't working right. Did you find a mode that worked? How did you set the focus? The tree at the left was in sharp focus, so I wonder what the focal length was.

If you set the log file parameter to 1, it will save a log that shows the focal distance, and a lot more.

Glad to see your having some success with the script, and the camera.

EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

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Offline ahull

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Re: Shot Histogram Request
« Reply #222 on: 06 / April / 2013, 06:44:26 »
I'm quite pleased with the results I got tonight, I put the 2361 frames shot on a single battery together at 6 fps, but I might redo at 12 fps
Very nice! That's a really beautiful place.
Thanks, it can be a very beautiful spot, particularly in the spring when the sunsets are long (we are relatively far north).
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I usually shoot at 1 or 2 frames per second, and play back at 25 or 30 FPS. 2 or 3 minutes is a good target time for a sunset video.

I just picked 6fps to see if it gave usable results on youtube, a bit of fine tuning is required I suspect, certainly 12fps is better, I am slightly limited in duration as this camera can only use up to 2Gb SD cards, so far the card has filled before the battery has gone flat, which is a little surprising as I didn't think I would get anywhere near this limit.  2000+ shots on one charge of an NB-4L is pretty good going I would say.

Quote

From your previous posts, I was worried that the exposure adjustments weren't working right. Did you find a mode that worked? How did you set the focus? The tree at the left was in sharp focus, so I wonder what the focal length was.

If you set the log file parameter to 1, it will save a log that shows the focal distance, and a lot more.

I got it working in manual mode with a little bit of trial and error, several combinations of settings froze the camera. If I get a chance I'll post the full details. I then set the camera for Scenery (Left arrow > Mountains), flash off (it tends to default to Auto every time you power on the camera), Continuous mode (down arrow) and focused the camera and started CHDK and the script. The script is set for focus at infinity, and I will check the SD card to see if I remembered to leave the logging on, if not I will try again tonight with logging enabled.

EDIT: Logging is enabled, log file attached from last night.

Quote

Glad to see your having some success with the script, and the camera.

Its fun to get such creative use out of what might be dismissed as an incapable old camera. Thanks mainly to being inspired by your results.
« Last Edit: 06 / April / 2013, 17:53:33 by ahull »

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Offline lapser

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Re: Shot Histogram Request
« Reply #223 on: 07 / April / 2013, 01:39:54 »
EDIT: Logging is enabled, log file attached from last night.
Thanks for posting the log file. It's interesting to see the comparison with an older camera.

My SX50 takes about .25 seconds to process a shot, and your camera takes about .50 seconds. The minimum time between shots also depends on the speed of saving the files, so I can't sustain 4 shots per second (more like 2).

The exposure went to 800 ISO maximum, but that's probably a little too noisy on your camera. I'd set it to 400 ISO, although the time between shots will increase to as much as 10 seconds as it gets darker.

There's a little "fluttering" of exposure when it got dark. I didn't notice anything in the video, though.
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I've made some progress with the script and CHDK patches in the last few days. First, I was able to apply the patches to the latest CHDK build. Phil updated Lua from 5.1.3 to 5.1.5, so I have high hopes that the problem I had with Lua yield/resume halting the script will be fixed now. I'll change the script to add the sleep(10) loop back in, or maybe coroutine.yield(), and leave a camera or two running overnight to see if the script works right now.

I'm also pretty satisfied with the script smoothing code. I fixed the rounding error in the shot meter for negative values, and added code in the script that minimizes each change (usually just 1 or -1), and spreads out the changes instead of bunching them up 3 or 4 at a time. The test videos are coming out pretty smooth.

I did have a "glitch" last night where one picture was darker by 43 and the next picture went back to normal. This happened once in 10,000 pictures. I also noticed a "glitch" during my 17,000 picture overnight camping trip, where one picture flashed much brighter. I had logging disabled, so I wasn't sure what happened. But the new "glitch" was logged, and showed that the picture that triggered the glitch looked the same as the the previous pictures. That is, it must have been an error in the value the meter returned. I'm not sure why this happened, but I added a "glitch" detector to the script. If there's a single change over 16, I ignore it, and disable the glitch detector for the next 5 shots. So it will take 2 shots to respond to sudden changes in brightness, instead of 1. But for sunsets, there shouldn't be any sudden changes, except for glitches.

Now that I've figured out a pretty simple and effective smoothing algorithm in the script, I'll see if I can move it to the shot meter code in C, adding a smoothing parameter to the shot meter enable function. I might be able to use the (double) values from the shot meter instead of the rounded integer values the script gets.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos


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Offline ahull

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Re: Shot Histogram Request
« Reply #224 on: 07 / April / 2013, 12:14:45 »
If you have merged back in to the "bleeding edge" build, does that mean I can try you script out on a couple of other models now?


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Offline lapser

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Re: Shot Histogram Request
« Reply #225 on: 07 / April / 2013, 13:19:04 »
Sure. Give me the models and firmware versions and I'll post builds for you.

I've attached the latest script and ixus40 build
If you have merged back in to the "bleeding edge" build, does that mean I can try you script out on a couple of other models now?
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

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Offline ahull

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Re: Shot Histogram Request
« Reply #226 on: 07 / April / 2013, 13:30:47 »
If it isn't directly available from the download server - "The Latest Builds - Unstable New Development Version 1.2" - link, how about rolling a version for the Ixus 115 HS and the Powershot A2200, I'll give those two a try for starters, would be interesting to compare all of the results (assuming the weather improves, gone very overcast here after a week or more of great sunsets).

I'll also stick that new version on the Ixus 40, and see if I can break anything  :P

Edit: The new version of CHDK works fine, however I forgot to update to your new lua script, before I left the camera out filming the local farmer ploughing in the twightlight and the dark.

I might get some interesting effects from the lights on the tractor, but even if I don't, it should be a fairly good test.  Tomorrow I will try something similar with your updated lua script.

 
« Last Edit: 07 / April / 2013, 16:04:37 by ahull »

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Offline lapser

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Re: Shot Histogram Request
« Reply #227 on: 07 / April / 2013, 14:33:22 »
how about rolling a version for the Ixus 115 HS and the Powershot A2200
I need the firmware versions.

My time lapse mods are too experimental for the "experimental" trunk, so you'll have to get the build from me for each camera.
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos


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Offline ahull

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Re: Shot Histogram Request
« Reply #228 on: 07 / April / 2013, 17:37:34 »
how about rolling a version for the Ixus 115 HS and the Powershot A2200
I need the firmware versions.

My time lapse mods are too experimental for the "experimental" trunk, so you'll have to get the build from me for each camera.

OK lapser I'll get the versions for you soon.

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Offline lapser

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Re: Shot Histogram Request
« Reply #229 on: 07 / April / 2013, 18:33:08 »
OK lapser I'll get the versions for you soon.
Start by installing the "full" version 1.2 from the main download page for each camera. My builds install over the full version, since they don't include all the files. They only work with the card locked (auto boot).
EOS-M3_120f / SX50_100b / SX260_101a / G1X_100g / D20_100b
https://www.youtube.com/user/DrLapser/videos

 

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