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New releaser - Allbest. His build.

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Offline Barney Fife

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Re: New releaser - Allbest. His build.
« Reply #120 on: 26 / December / 2007, 03:17:58 »
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« Last Edit: 22 / April / 2008, 07:51:11 by Barney Fife »
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Offline hailstorm

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Re: New releaser - Allbest. His build.
« Reply #121 on: 26 / December / 2007, 22:09:52 »
One hell of an explaination barn..thnx...take the mid-day sun pics... same 1/10000, 1/20000, 1/50000, 1/100000..exposures and histogram included :xmas
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Offline Barney Fife

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Re: New releaser - Allbest. His build.
« Reply #122 on: 26 / December / 2007, 22:57:24 »
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« Last Edit: 22 / April / 2008, 07:51:30 by Barney Fife »
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[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye
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Offline hailstorm

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Re: New releaser - Allbest. His build.
« Reply #123 on: 27 / December / 2007, 00:54:09 »
Quote from: Barney Fife on 26 / December / 2007, 22:57:24
I found that when taking pictures of the sun, and so as to avoid burning the CCD while doing so, that there was too much variability in how the sun was framed in the image (never in the same place twice). This compounded with the amount of flare around the image, that sometimes even the slower shutter speeds showed darker histograms.

If you really want to test for accurate speeds you should do something like the Dremel Drill test. You CANNOT accurately test for speeds by using image intensity. The problem if you use a flash for your light source will be that you don't know if the flash is defining the shutter speed or if it's the CCD shutter-speed that you are capturing in your image. However, if you crank up the flash output to full, then adjust either distance or f/stop to get proper exposures, you can be sure then that you will be measuring CCD shutter speed.

I've tried to find some data online that would tell me the flash duration at various flash output levels, but outside of some generic information about all xenon flash units I can't find anything in particular for Powershot cameras. The best that I can come up with is that the flash output will be as slow a 1/1000 second (typically 1/2000) at full output, to the highest speed measured so far at dimmest output of 1/60,000 second. Now, if you put the flash output on full, then adjust your moving target (dremel-drill cutoff wheel) for the right distance (using zoom and macro lenses to get a large enough image to measure from), your motion will be stopped by CCD shutter speed alone.

I have not tested the automatic flash output levels to see if speeds of flash can exceed the 1/60,000 speed, but GrAnd suggests that speeds up to 1/100,000 flash might be available. (It would be nice if we had a flash-output override too, I've already submitted that as a feature-request quite a few times so ... if possible maybe they'll find a way to provide it. Quite frankly, for macro photography needs, that could be more beneficial than high shutter speeds and small f-stops.)

Anyway, if you know that your flash's duration is 1/1000 to 1/2000 second, then any CCD shutter speed faster than that will only use a portion of it. The flash then will not interfere in your shutter-speed tests.

Also, to find a more accurate top-speed limit, you would do better by using the Tv Bracketing feature set for 1/3EV steps, and a - (minus) direction of change. Start out at a shutter speed of a known limit, say 1/10,000, then fire off enough frames so that by 1/3 EV steps you will go beyond what you think is your camera's limit. This affords you many more intermediate shutter speeds.

1/10000, 1/12500, 1/16000, 1/20000, 1/25000, 1/32000, 1/40000, 1/50000, 1/64000, 1/80000, 1/100000

The above expanse needing 11 Tv bracket frames. I inadvertently, when testing things early on, let a bracketing sequence run quite long. According to EXIF info, obtained one frame with a shutter speed of 1/326,215,479. Using Tv bracketing allows you to greatly exceed the 1/100k limit. Not that you will get any useful speeds beyond the suspected 1/50-60,000 top limit, but just to show you that it can be done.

This was found by running Exposure Plot on a batch of folders full of test images, after having used the Auto CHDK to EXIF utility on them.


p.s. While I can understand your excitement and wanting to prove the top shutter speeds produced by your camera, keep in mind that acseven (the person who is providing this site for us) would like to keep attachments to a minimum if possible so this forum is not interfering in his server's main use. Tomes of posts of images (mostly reruns of earlier inaccurate experiments that provide no useful information) is probably not going over very well as a good use of server space.

It would also have been better to start a new thread about shutter-speed tests, rather than hijack this one about AllBest's build just for this purpose of yours.

Ok barn..I agree..but i believe the scenic pics  might give some proof..
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Offline hailstorm

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Re: New releaser - Allbest. His build.
« Reply #124 on: 28 / December / 2007, 22:53:27 »
ok..a question.. i downloaded the latest build ver15...what does the develop RAW do??
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Offline Barney Fife

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Re: New releaser - Allbest. His build.
« Reply #125 on: 28 / December / 2007, 23:04:39 »
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« Last Edit: 22 / April / 2008, 07:51:55 by Barney Fife »
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[acseven/admin commented out: please refrain from more direct offensive language to any user. FW complaints to me] I felt it imperative to withdraw my TOTAL participation. Nobody has my permission, nor the right, to reinstate MY posts. Make-do with my quoted text in others' replies only. Bye
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Offline hailstorm

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Re: New releaser - Allbest. His build.
« Reply #126 on: 31 / December / 2007, 00:39:53 »
I tried to do some high speed shutter tests..my conclusion is that 1/60000 is the max out i could get..anyways hell of a lot..faster than my thought process at times ;) HAPPY NEW YR IN ADVANCE TO ALL
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Offline scribble1

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Re: New releaser - Allbest. His build.
« Reply #127 on: 03 / January / 2008, 14:53:43 »
I was playing around with the Allbest build features for the first time this morning--checking out the high speed shutter speeds so I can try to used them for some water drop photos. I was photographing a compact flouresent bulb up close with and without flash.  Using the eyeball brightness test on the flash photo, they seem to dim as expected up to 1/12000 of a second with my S3IS. Then things became less consistant.

So does anyone have info on how fast a typical camera flash turns ON--I'd expect it isn't instantanous. And would it be possible to add a small delay before the electronic shutter opens and closes--so that you could shoot at the flash's maximum intensity.

Thanks
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Offline sherrystone

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Re: New releaser - Allbest. His build. Zebra
« Reply #128 on: 03 / January / 2008, 17:00:17 »
Dear Allbest,
thank you for the excellent new release.

On an S3:
During video the Zebra is a little better now   
Now it highlights the overexposed section properly, but in addition, it smear beyond it.
Zebra for still pictures is spot on (as it always was)

Also, when both Zebra and Histogram are on, the histogram is not displayed.
Also, when both Zebra and a lot of OSD parameters are on, the OSD's don't show.

Also, may we suggest, if you are so disposed, to have one 'master' screen
where all the parameters may be seen at an glance and where they may be set on or off
ie, histogram on/off,  shutter speed, bracketing...

We are very happy with your build as is,
just thought to point these things out.
S




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Offline brainwash

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Re: New releaser - Allbest. His build.
« Reply #129 on: 16 / January / 2008, 05:57:40 »
Ok, here's my shot of the moon:
12x zoom, about 1/250 sec, f 3.5, ISO 50, handheld, RAW
I think this is without CHDK
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