--- Gary Lim <[EMAIL PROTECTED]> wrote:
> Well, if you trust 1/focal_length rule and assume 1mm circle of
> confusion,
> you can yield a first order approximation using elementary physics:
>
> V = focal_length * angular velocity
> t = 1/focal_length (equivalent in second);
> d = x (I would assume 1mm at film base);
>
> Using V = d/t, this gives a hand-held angular velocity of 1 rad/sec
> (or
> 1/2pi Hz). You can also verify that this is focal length
> independent.
>
> I hope this helps,
>
> Gary
Thanks Gary.
In fact I did my own estimation in similar way assuming 1/focal lentgh
and acceptable circle of confision for 35mm are tied to each other.
however I assumed circle of confusion to be 0.03mm which is apparently
the common wisdom for 35mm (at least in film era).
Assuming 50mm lens focused atbinfinity (so that the actual focus plane
equals to focal lenght (i.e. 50mm) I obtained W=0.03 rad/sec which
yields near 2 degrees/sec.
All that of course, assuming constant or average angular velocity, i.e.
not taking to account angular acceleration that actually happens.
Now, if we would assume these 2 degree/sec, the problem would be
measuring this parameter by a micro-gyro. Usualy they have range of
+/-300 degrees/sec down to +/-75 degrees/sec with span of voltages
(around zero velocity) of about +/- 2 volts. That yealds about 20mV per
1 degree/sec and that before accounting for noise and drifts.
It seems a gyro with measurement range of +/-5-10 degrees/sec with
similar voltage span will suit my needs, however I couldn't figure such
yet.
Or probably measuring angular acceleration would be more approrpiate in
my case ? Will try to figure..
Best regards, Alex
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