Optical Zoom/Focal Length

[HankScorpio]

Optical Zoom - what's it all about...?

OZ is derived from dividing the widest FL by the Zoomiest FL.
e.g. Sony DSCW7, widest is 38, zoomiest is 114 so OZ is x3
Epson 500V is 34-102 also x3 but the sensor is a different size so no direct comparison of output.

So...
as far as I can decipher, that would render the comparison of OZ in any situation pretty pointless as the final output would depend on sensor size and the starting point.

I have a 24-20 (OZ = 5)
and a 80-400 (OZ = 5)

Either of these fitted gives me an Optical zoom of 5 but very different output.

When manufactures report size should they use something that's common across everything?

Or am I missing the point somewhere?

[simpo two]

It's just a ratio of short end to long end.

However, having been browsing compacts recently, one thing does puzzle me. They all seem to have focal lengths expressed in 35mm 'equivalents'. For example the Ricoh Caplio R3 has a '28mm-200mm' optical zoom - but I can't believe it has a sensor that big.

My Olympus Mju300 is more honest. Whilst it may be a '35mm-105mm' optical zoom, the lens actually states '5.8mm-17.4mm' - which just shows you the diference sensor size makes!