Hi everyone! Canon A60, found interesting things - page 2 - General Discussion and Assistance - CHDK Forum
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Hi everyone! Canon A60, found interesting things

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Offline Leonardo Miguel Delgado

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Re: Hi everyone! Canon A60, found interesting things
« Reply #10 on: 04 / July / 2008, 16:28:38 »
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Quote from: Microfunguy on 04 / July / 2008, 06:09:45

Did you manage to obtain the datasheets for any of the chips in the camera ?

You say that you took a photo of the moon.
The moon is very bright, it is always a sunny day !
But, your camera does not have a shutter that can close AFTER the photo is taken.
Do you get an interlacing effect and strange colours if you try to use the camera normally (by holding a lens against the 1.25" adapter) in daylight ?


David


I have the datasheet of the CCD driver chip. For fast exposures (up to one second) the camera doesn't make a dark frame, so there's no need for a shutter. After one second, it makes dark frame substraction. For the moment, when the camera is about to make the dark frame I put the dust cap on the telescope...

There ain't any strange colors, but the CCD is VERY sensible to IR light. A cigarrete near the sensor will make the screen look white or purplish.
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Offline RaduP

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Re: Hi everyone! Canon A60, found interesting things
« Reply #11 on: 04 / July / 2008, 19:05:01 »
I think Microfunguy meant that without a shutter, on short exposures, you will get lines in the picture, because the sensor is still reading the light as it transfers the data, so the lines that are being read last are more exposed than those that are read first.
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Offline PhyrePhoX

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Re: Hi everyone! Canon A60, found interesting things
« Reply #12 on: 04 / July / 2008, 19:06:03 »
well, show some pics you made with that modified cam please, so we can judge for ourselves :)
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Offline oversky

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Re: Hi everyone! Canon A60, found interesting things
« Reply #13 on: 05 / July / 2008, 00:22:04 »
I have two suggestions.
First, can you try to decrease the variable from 15" to 5"? This should verify that we are looking for the correct variable.
Second, I remember there are firewares for A70 or A95 that can break the 30" limit on 320x240 video. Maybe you can compare the origianl firmware with the modified version and learn how canon set the time limit.
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Offline Microfunguy

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Re: Hi everyone! Canon A60, found interesting things
« Reply #14 on: 05 / July / 2008, 06:23:30 »
Quote from: Leonardo Miguel Delgado on 04 / July / 2008, 16:28:38
For fast exposures (up to one second) the camera doesn't make a dark frame, so there's no need for a shutter.

Yes there is  :)

I have removed the lens and shutter from a number of simple, fixed-focus Vivitar cameras.

After the electronic exposure, the tiny mechanical shutter is very briefly closed while the charge is transferred from the CCD.

If a home-made shutter does not close fast enough (and it probably will not) you get an interlacing effect and distorted colours.


David
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Offline brainwash

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Re: Hi everyone! Canon A60, found interesting things
« Reply #15 on: 09 / July / 2008, 07:15:18 »
I like what you did there with the A60 :) Perhaps you can help me put back together my A70 - it was dismembered to get rid of the E18 error and convert it to infrared, but when assembling it back a one of the wires from a 5 wire ribbon broke.
Unfortunately I don't recommend you to take exposures longer than 15" with these simple CCD sensors. Rather, you should approach a multi-shot technique. It is described here on the forum, for astronomy you would have to have a star-fixed mount and trigger several shots, then overlay them with averaging for minimum noise and maximum resolution.
To trigger the shots you could have the default Canon software (I can't remember the name, is Windows-specific) and for post-processing CombineZM, PhotoAcute or any other image-stacking software.
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