"Alan Browne" wrote in message
...
leo6645 wrote:
Most of the messages in this group are spam - why is the moderator
allowing this? I invite the users to boycott the site until the spam
is gone..!
(Now I know I'm the next boycotted member.....)

Basic usenet has no moderators.

This NG is so quiet now that the spam hardly affects it.

The trick is to increase the signal/noise ratio by participation, but too
many MFers have gone DSLR (35mm).

The irony is that most DSLRs are not 35mm as far as sensor size is
concerned. The technology is there to make 35mm sized sensors (24mm x
36mm), but the manufacturers keep cranking out those less than 35mm sized
sensors...whence the 1.6 factor lenses. One quick consequence is the rarity
of DSLR lenses shorter than 20mm as per 35mm photography. At 1.6 factor, a
lens needs to be around 12mm in actuality to be equivalent to 20mm as per
35mm photography. Not too many DSLR lenses around with that focal length.

Another consequence is that because depth of field at any given f/stop of a
lens is dependent on actual focal length rather than on sensor/film size, a
DSLR lens equivalent to a 100mm focal length (35mm photography) is 62.5mm
and has the depth of field of a 62.5mm lens. So it is not feasible to have
a DSLR with a lens with focal length equivalent to a 35mm 100mm lens and a
depth of field of that same 35mm 100mm lens.

All these anomalies will go away once the DSLRs commonly have 35mm sized
sensors. But as long as the marketplace is receptive to this 1.6 factor,
don't hold your breath.