Shutter Speed Tests - page 2 - Creative Uses of CHDK - CHDK Forum  

Shutter Speed Tests

  • 27 Replies
  • 16211 Views
Re: Shutter Speed Tests
« Reply #10 on: 08 / January / 2008, 12:31:57 »
Advertisements
Deleted
« Last Edit: 22 / April / 2008, 09:27:14 by Barney Fife »
[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

Re: Shutter Speed Tests
« Reply #11 on: 08 / January / 2008, 13:01:38 »
Nice sleuthing. But I'm still not convinced that 1/30,000 is the fastest/shortest.

Look at the shadow on the ground too. The tail rotor's shadow is 90 degrees to its true position in the photo. Caused by the HUGE

Nice rubber helicopter!

I agree that the speeds are probably higher.  In some tests on my A570, I was able to somewhat verify a 1/64,000 shutter speed.  I took a series *identical* photos (yay scripting) with halving shutter speeds of an outside window on a bright day.  I then checked each phot against the next one to see if it got dimmer (should get ~1/2 as bright).  Of course there is a limit to the difference I can percieve with my eye, so at the faster shutter speeds, I used frame subtraction (I'm using HDR Shop because it lets me bump stops up easily) and looked at the result.  Ideally, the differenced image should be of equal brightness (approximately) to the faster shutter speed (because I was using full stops, 1/2 shutter speed steps = 1/2 brightness, 1 - 1/2 = 1/2). I the frames are equal, ideally you should be left with a black image.  This is all discounting the noise of course.  But I was able to get a discernible difference between 1/32000 and 1/64000, beyond that, the relative noise was getting brighter than the image.  Perhaps not the most scientific testing method, but it seemed to do the trick in the absence of more sophisticated equipment.

*

Offline e2b

  • *
  • 37
Re: Shutter Speed Tests
« Reply #12 on: 08 / January / 2008, 22:57:46 »
I swear, I'm just going to have to dig out my silly-scope (oscilloscope) out of storage in the barn

The oscilloscope sounds like the best hope so far - if it is bright enough for an image.

I have just tried photographing a set of diagonal black lines lines on a white background displayed on a 60kHz CRT monitor (S3: F2.7, ISO 800). The persistence of the phosphors was too long to allow me to draw any real conclusions - I could see the difference between 8/100kand 4/100k, but could not discern any clear differences at nominally shorter times.


*

Offline hailstorm

  • *
  • 38
  • Canon S3 IS, Marumi 0.5 X Lens,Hoya CPL+CHDK
    • My pic page ;)
Re: Shutter Speed Tests
« Reply #13 on: 09 / January / 2008, 04:39:46 »
i am confused even more.. I went for Tv bracketing in 1/3 steps and the pics r given along with the histogram..the results and pics given are ...1/3200, 1/33000, 1/64000..


*

Offline mx3

  • ****
  • 372
Re: Shutter Speed Tests
« Reply #14 on: 09 / January / 2008, 08:12:25 »
Here's a fun image that I like to show others when they want to tell me about the wonderful superiority of focal-plane shutters in DSLRs. :D

is it a joke?
are you realy made this image with your cam?
is it a true photo?
I can't believe curves of blades.
skype: max_dtc. ICQ: 125985663, email: win.drivers(at)gmail, eVB decompiler

Re: Shutter Speed Tests
« Reply #15 on: 09 / January / 2008, 20:08:31 »
Deleted
« Last Edit: 22 / April / 2008, 09:26:33 by Barney Fife »
[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

*

Offline e2b

  • *
  • 37
Re: Shutter Speed Tests
« Reply #16 on: 09 / January / 2008, 22:16:43 »
I wonder when all digital cameras will use all-electronic shutters - the mechanical shutter certainly appears to be an anachronism in 2008.

*

Offline e2b

  • *
  • 37
Re: Shutter Speed Tests
« Reply #17 on: 11 / January / 2008, 22:01:24 »
The amount of money changing hands on horse racing results led to the development of photo-finish cameras (in the late 1930s). They avoid timing distortions that occur with focal plane shutters through the trade-off of introducing their own strange visual distortions. So, whatever other 'factors'  ;) might be involved in race results, at least the order in which runners cross the finish line should be OK. See http://en.wikipedia.org/wiki/Photo_finish for a starting point, and there is plenty on Google for those who may be interested.

As for focal plane shutters, that helicopter picture says it all!


Re: Shutter Speed Tests
« Reply #18 on: 11 / January / 2008, 22:35:54 »
The amount of money changing hands on horse racing results led to the development of photo-finish cameras (in the late 1930s). They avoid timing distortions that occur with focal plane shutters through the trade-off of introducing their own strange visual distortions. So, whatever other 'factors'  ;) might be involved in race results, at least the order in which runners cross the finish line should be OK. See http://en.wikipedia.org/wiki/Photo_finish for a starting point, and there is plenty on Google for those who may be interested.

As for focal plane shutters, that helicopter picture says it all!

I like that slit camera method.  I never knew that before.

Can we get that in CHDK? ;)

-tgq

Re: Shutter Speed Tests
« Reply #19 on: 12 / January / 2008, 07:10:41 »
Nice sleuthing. But I'm still not convinced that 1/30,000 is the fastest/shortest.

I swear, I'm just going to have to dig out my silly-scope (oscilloscope) out of storage in the barn this winter and let it warm up for a few days (old tube-type, about the size of a large TV set and weighs almost 200 lbs.) Photographing a 20kHz scan line against a lit scale will be the definitive test.  I only worry that all that finding and hauling it out and setting it up will be for naught, I'm not sure if that old sillyscope will have a bright enough electron gun to photograph. Nor if its 70 year old phosphors on the screen will cause a persistence problem. Like what I ran into when photographing scan lines on a TV.

p.s. Don't worry about the rotating target being a problem for deducing shutter speeds with these cameras. They don't have a focal-plane shutter. That problem only exists with DSLRs, and its exactly why they can NEVER have high-speed flash-sync. (Badly implemented fake high-speed sync, yes, but not real high-speed sync.)

Here's a fun image that I like to show others when they want to tell me about the wonderful superiority of focal-plane shutters in DSLRs. :D


Look at the shadow on the ground too. The tail rotor's shadow is 90 degrees to its true position in the photo. Caused by the HUGE delay in a focal-plane shutter having to traverse the width of the sensor. You can't even use a focal-plane shutter for accurate "photo finish" sports events. A person's foot could be touching the baseball base before he was tagged "out", but the photo would never reveal that due to the focal-plane shutter's inherent flaws and limitations. All those photo-finish events all throughout history could be 100% in error, unless they are analyzed for the type of shutter used to take the image. The speed, direction, and duration of all items in motion in the image would have to be reanalyzed to find any "truth" in them whatsoever. The use of focal-plane shutters all last century have given us a FAKE representation of reality. And nobody cares. :-)





a few nooby questions here

how do we sync the flash in s3 for high speed shooting ? is it possible for continuous shooting ?

if not how to make use of the extra high speed continuous shooting in S3, apart from increasing the aperture to the lowest possible ??? what is the widest aperture override if any ????

thanks ????


 

Related Topics