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Recommendations and advice for long construction project

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Offline Steveo81

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Re: Recommendations and advice for long construction project
« Reply #20 on: 25 / March / 2012, 20:00:04 »
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Quote from: Microfunguy on 25 / March / 2012, 19:27:08

How many cameras do you need, where will they be located ?

I intend to shoot with at least two cameras to ensure some redundancy should one fail and I'll also shoot addition footage with a third camera at different times so that when edited I can switch between all positions for added interest. Two cameras will be mounted on platforms overlooking the site whilst the third will be moved around.
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Offline Microfunguy

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Re: Recommendations and advice for long construction project
« Reply #21 on: 25 / March / 2012, 20:07:55 »
Quote from: Steveo81 on 25 / March / 2012, 19:52:30
My time-lapse experience has been limited to using DSLR's locked down on manual exposure, white balance, focus etc, so that exposures do not fluctuate.

Then the camera needs to have a true manual mode, many recent ones do not.

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cant you chance the aperture on these Powershot cameras?
Not if they have not got one.
Even if they have, they are of a limited range exposure wise.
Small sensor cameras do not need an aperture for depth-of-field control because it is so great anyway at full aperture.
Apart from such apertures being physically tiny, in 35mm terms they are equivalent to apertures 4.5x smaller (approximately).
So, f5.6 is equivalent to f22/32 !
If you stop down any more diffraction would reduce resolution.

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If not how are you guys producing your videos without huge amounts of flickering. Software can presumably only stop so much?

You can set shutter speed from about 1/2000sec to 65 seconds (and even longer).
You can also set auto exposure mode.


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Offline Steveo81

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Re: Recommendations and advice for long construction project
« Reply #22 on: 25 / March / 2012, 20:28:22 »
Ok, so when you shoot a time lapse with a Powershot are you just leaving the camera on auto exposure and if so don’t you get a problem with flickering as the camera varies its settings to keep an accurate exposure?
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Offline Microfunguy

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Re: Recommendations and advice for long construction project
« Reply #23 on: 25 / March / 2012, 20:44:55 »
I have only done a couple of short-duration sunset timelapses and set the camera to Auto.
There was no flicker in that brief instance.

Almost 1:45 am here so for now you need to search the forum for timelapse, there is a lot of information.
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Offline powershooter

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Re: Recommendations and advice for long construction project
« Reply #24 on: 25 / March / 2012, 22:00:57 »
It is very possible to write a script that slowly changes the exposure properly mabey something like this:
lets say you want a picture every 5 seconds
So the script starts and takes a picture
It takes .25 seconds to save the picture
we then save the shutter speed value and iso into a variable
We then wait 4.75 seconds
Now after that is done we will enter our loop
Loop:
meter the image and then find the difference between this exposure and last exposure we then divide the difference by 4 and then add it to the old exposure varible (if the difference is a negative value it will still work as it will just end up subtracting)
now we take a picture with the calculated exposure
see how long that took and subtract it from 5 (in this case)
we wait for that time we then
goto loop (we can just wait till it is interrupted by the way checks just make the code unnecessarily complex )
After writing this post it just inspired me to write the script as I already have it all figured out but just one question how do we figure out how long it took to run the shoot command?
« Last Edit: 25 / March / 2012, 22:03:04 by powershooter »
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Offline waterwingz

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Re: Recommendations and advice for long construction project
« Reply #25 on: 25 / March / 2012, 22:12:25 »
Quote from: powershooter on 25 / March / 2012, 22:00:57
just one question how do we figure out how long it took to run the shoot command?
Get the tick time before you start to shoot and then again when shooting completes.

x=get_tick_count
shoot
y=get_tick_count
t=x-y

You might want to look at the sunsetF16 script(s) posted on the forum before you spend too much time doing this on your own.
http://chdk.setepontos.com/index.php?topic=3079.0

« Last Edit: 25 / March / 2012, 22:16:47 by waterwingz »
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline powershooter

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Re: Recommendations and advice for long construction project
« Reply #26 on: 25 / March / 2012, 22:19:42 »
Thank you exactly what I needed. But it appears as thought I have to charge my battery before I can test it but I know it will work and besides I have more time to focus on the theoretical side of the script.
Edit never mind after reading about sunset 16 I will just use that instead as it is far more advanced.
« Last Edit: 25 / March / 2012, 22:27:16 by powershooter »
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Offline waterwingz

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Re: Recommendations and advice for long construction project
« Reply #27 on: 25 / March / 2012, 22:22:24 »
Quote from: powershooter on 25 / March / 2012, 22:19:42
but I know it will work
hmmm ... never heard that before :)
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Ported :   A1200    SD940   G10    Powershot N    G16
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Offline Microfunguy

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Re: Recommendations and advice for long construction project
« Reply #28 on: 27 / March / 2012, 09:45:59 »
@steveo81

When is the project due to start ?

I would obtain a camera and DC/DC converter as soon as possible so that we can get it running for one week and sort-out any problems.

David
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Offline Steveo81

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Re: Recommendations and advice for long construction project
« Reply #29 on: 02 / April / 2012, 18:27:28 »
Quote from: Microfunguy on 27 / March / 2012, 09:45:59
@steveo81

When is the project due to start ?

I would obtain a camera and DC/DC converter as soon as possible so that we can get it running for one week and sort-out any problems.

David

Hello David

The requirements have now changed and we will only be time-lapsing at key stages of the build. This means that I will probably be filming a day or two every week or so when something significant is happening.

This takes the pressure off a bit as I know I can cover over four hours with the existing equipment I have, so a visit half way through the day to replenish batteries and cards would suffice if necessary.

I do want to get something more suitable for longer periods though so am still keen to take things further and am looking to purchase a Powershot or two.
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