Stabilizing Kodak Zx1 image on bike mount

Hi,

Phil W Lee wrote:
Bernhard Agthe considered Tue, 11 May 2010
set it to "Tv" mode

Do you mean "record"?
Would that be in 30 or 60fps 1280x720, or 30fps vga mode?

Just for the purpose of discussion I'd like to treat a video as a series
of still images.

No matter whether 25fps, 30fps or 60fps, I do assume that a video camera
has no (or does not make use of) a physical shutter device, but rather
exposes each image for about the time between frames, i.e. 1/25sec for a
25fps video. So, basically it doesn't matter, which mode you use, you
get shutter speeds in the 1/25sec to 1/60sec range. Even though,
experience with typical cameras that are advertised for 1/25sec shows
that they don't keep that frame rate very well and are likely to drop to
1/20sec or slower, depending on the light. So, lets just stay with the
1/25sec figure for a 25fps camera (same principle applies to others)...

and manually set 1/500sec or faster shutter speed and high
ISO.
Not possible - it's auto everything except recording mode.

OK, so let's just assume this camera behaves like any other video
camera. It takes a series of still images with maximal exposure time and
wide open aperture (which ain't wide, anyway) on a small lens. The only
thing that gets adjusted is the "Gain" feature via "AGC".

("Tv" mode)
No such mode, although you can choose (in 1280x720 mode) between 30 &
60 frames per second.

Which basically is "Tv" mode, but the value is either "1/30sec" or
"1/60sec", so we just assume the typical 1/25sec like I pointed out above.

The Zx1 is a VIDEO camera although it does have the capability to take
stills. It will produce videos at 60fps, so is not likely to be using
1.25th shutter speed.

Yeah, but 1/30 sec or even 1/60 sec is stupid to do calculations with,
so 1/25sec provides an easier point of discussion for what I want to
point out.

You also seem to be badly in need of some education about image
stabilisation as used in video cameras - the more recent Kodak
Playsport has electronic image stabilisation built in.

OK, that's where I was heading.

With our 25fps camera we have an exposure time of 1/25sec which is 40ms.
Now, as you're riding at a speed of just below 30 km/h, that makes about
8 m/sec. Now, within the 40ms exposure time, you ride about 0.3m (1
foot) far, which creates a considerable motion blur. On a still image
camera you'd be in for a disappointing photo headed right down into the
thrash. Considering the fairly small resolution you mentioned, in VGA
mode a single image might be even marginally viewable. Considering the
fact that the camera does not have a VGA sensor, but rather a 1280x720
sensor, the VGA mode you get is either cropped or downsampled after
capture which means you have to take the 1280x720 pixel size into
account, so you have "small" pixels which don't help you with the motion
blur.

No matter how good the Anti-Shake in the camera body is, it would have
to keep the camera in a single spot (relative to the scene you're
capturing) for the complete exposure time. That would be (as seen above)
roughly 0.3m (1 foot), which is highly unlikely?!

Even with a 1/500sec exposure time, you'd be in for massive motion blur,
as the camera would move ~15mm during exposure time, but with the low
resolution typical to video I guess that would be acceptable. As a still
image, this would still have a somewhat "artistic" touch. My camera
allows me to set a shutter time as fast as 1/8000sec, but as I said
earlier if I want to use that kind of shutter speed, you'll need lenses
that cost many 1000$ and up, just for the glass. Even in bright
sunlight, the camera will need to be set to high ISO (gain), but as you
said, that's outside the scope of the camera in the topic, anyway.

You can easily adjust the calculation to 30Hz, but I guess I made my point.

I think you are talking about images stabilisation for reducing camera
shake on stills, not the type used for producing stable video footage.

In lengthy discussions with my peers I have come to the conclusion, that
any Anti-Shake is great for reducing camera shake on long exposures (and
1/25sec is considered a long exposure), but does not help with moving
scenes at all, because all that will help you capture motion is a short
shutter speed, which results in all the stuff I mentioned in the first
post. Again, as pointed out, even if the Anti-Shake works miracles in
video, I seriously doubt that it can adjust to 0.3m of "shake".

How is the kind of mount you describe going to provide evidence of the
smidsy when you are lying in hospital?

It ain't, but neither is your video device going to help you with your
injuries. I'd prefer spending energy to prevent accidents over trying to
capture an accident on video?

Anyway, I made some experiments with a still camera in video mode (from
a car), trying to capture video of other cars passing. I wanted to find
out whether I could use a video device to film cars that overtake much
too closely, to blame them at the next police station, but it's no use
if you can't even read the license plates, is it? So much for motion
blur and fast shutter speeds...

Have fun, anyway.

Ciao..

Hi,

Andre Jute wrote:
Hey, Bernard, whatever it is you're smoking, send me some. I'm talking
about a humble little action cam to capture the license plates of
roadhogs. It is also cheap enough to leave on the bike outside the
supermarket. What do you expect from it, an Oscar-winning movie? --
Andre Jute

Read my other reply. I do hope it explains carefully enough.

As for what I'm smoking, it's badly smelling diesel exhaust fumes and
stinking regular gas? Should be available in plenty in your area for free...

Ciao...