The Moose is probably still asleep.
Very interesting development on the Canon EOS in-focus indicator chip on
the UK ebay auction. I see there are a couple of sellers in the US as
well. I think I need one but it's a little too pricey at the moment.
Bet it will come down substantially as the number of ebay sellers grows
to 10,000 or so. :-)
As to your question about your Canon camera, yes the OM adapter will fit
the film camera as well as long as it's an EOS mount autofocus camera.
It will not fit the older FD mount manual focus cameras.
Now for stopping-down lenses.
OM's have an automatic diaphragm as do pretty much all cameras of that
era or later. On an OM when you set the aperture on the lens to, say,
f/8 the lens doesn't actually stop down. It stays wide open so you can
see to focus better. It doesn't' actually stop-down to your setting
until you press the shutter release.
But the stop-down mechanism is mechanical and part of the camera.
Putting the lens on another brand of camera leaves no means for the lens
to be stopped down. When adapting the lens to another camera the
adapter needs a pin that engages the stop-down lever on the OM lens.
When you attach the lens to the adapter that pin will engage. Now when
you change the aperture the lens will close down or open up immediately.
Also, when you meter the exposure the metering will take place at the
shooting aperture. Normally it would take place wide open and the
camera would adjust the reading for the expected actual shooting
aperture. Since the new body has no connection with the aperture of the
lens it can't know how it's set. But metering at the shooting aperture
is OK. It's just that the viewfinder is darker. If you focus wide open
to get a brighter image you need to remember to stop the lens down to
the shooting aperture before taking the shot if you haven't already done
that to get a meter reading. It's a habit that must be acquired. I
always forget.
I think Pentax claims the first fully automatic diaphragm in a
production camera in 1960. Prior to that photographers had to use
manual stop-down methods. Some lenses had what were called "pre-set"
diaphragms. You could set the aperture but the lens wouldn't actually
stop-down until you pushed the stop-down button or turned a lever. The
advantage was that, if you pre-set the aperture, you could do the actual
stop-down for the exposure very quickly without checking the setting on
the aperture ring.
Chuck Norcutt
Christos Stavrou wrote:
>
> Hi Moose,
>
> Sorry to ask something that might seem commonsensical but I'm not
> sure about it. What exactly does it mean 'they require a manual
> stop-down'? Could you explain the process please.
>
> And something else. I have a film C*non camera. Is it the same use,
> like with digital cameras if I attach OM lenses with the proper
> adapter? I mean in terms of the process but also the practical issues
> (i.e. no ability to view the shot)
>
> Christos
>
> Ps1: Have you seen this relevant piece:
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ih=009&item=190007617341&rd=1&sspagename=STRK%3AMEWA%3AIT&rd=1
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