Friday, August 15, 2008

High speed photography!


(Canon S5 IS 1/16000 F7.2)


Upon the start of "hacking" my Canon I found that quite a few features were available to me that weren't before I began using the firmware.
I was quite excited when I discovered that it was possible to take pictures up to 1/64 thousandth of a second with my Canon cameras while using "CHDK" firmware.
On closer review the actual limits of the camera's own firmware, and the "improvements" that the "hacked" firmware allowed, were not all that different. All of the photos below were taken with the macro, camera flash, and manual settings on. (unless otherwise specified)
Full size pictures are here.





(Canon S5 IS 1/64000 f8.0)

Using the CHDK firmware, I took a few pictures of water flowing in our sink.
I was begining to wonder at what speed the camera was actually taking the picture.



(Canon S5 IS 1/64000 f8.0)

I took our 10k RPM grinder for a spin... (sorry)
I drew lines on the blade to make sure that I could see any motion blur.


(Grinder stopped)(Canon SD1000 1/60 auto setting)




At full speed My SD1000 couldn't keep up no matter how hard I tried.. and every shot I received about the same level of motion blur.

(Grinder in motion 10k rpm)(Canon SD1000 1/16000 f6.2)



Trying the same thing with our more expensive S5, I received much better results.. no motion blur was visible.

(Grinder in motion 10k rpm)(Canon S5 IS 1/64000 f8.0)



And just to be fair, I tried it with another camera without any fancy firmware.


(Grinder in motion 10k rpm)(Hp "el cheapo" full auto settings)


After wondering how much the firmware was effecting the actual picture, I decided to take a picture of our Dremel (30k rpm) with the cameras.
I only decided to post one of the pictures, because most were either too blury, or just the same.

(Dremel 30K rpm)(Canon S5 IS 1/60000+ f8.0)

To find out the speed of the shutter, I used a formula stolen from CHDK's wiki
"A smaller well-defined highlight at the very edge of the disc's abrasive, one with easily discernible starting and stopping points, was used to better measure the angle of rotation. This way the measurement wouldn't also be thrown off by the diameter of that highlight that moved during the exposure.


Dremel Drill: 30,000 rpm = 500 rotations per second = 1 revolution every 1/500th second.
Motion blur: 2.97 degrees, let's safely round that to 3 degrees = 1/120th of a revolution.
This means that 120 units of measure can fit into a 1/500th of a second rotation.
500 x 120 = 60,000
The highlight's motion blur occurred during an exposure of 1/60,000th of a SECOND! "

Though CHDK's firmware is nice, it didn't really help the shutter speed any.
I decided to go back through all my tests only using the camera's built in firmware, and I got the same results. The only difference that I could see is when I took manual control of the aperture with CHDK, in that the pictures came out darker. (less light, faster exposure but not by much)

So, what does this mean in the real world? It means that most digital cameras even cheap ones, while the macro is turned on, are coming close to 1/10000th of a second in their shutter speeds.

I am in no way saying that I know anything on this subject. 99% of this could be junk, but I found it fun to write anyway!

2 comments:

Mr. Creep said...

WOW! That's pretty cool, Steve! Thanks for posting!

Peter said...

interesting pictures, very cool!