Chopped OVF for Sony A350

Focus wrote:


Thanks for clearing that up. Now, of course: how does it differ from say,
Canon and Nikon LV? I assume they don't have that CCD video sensor, because
the mirror is locked up, right?


They should take the exposure from the main sensor, though auto-gain can
influence that and I am unsure whether for example the Canon 450D really
does - as every shot always returns you to AF/mirror action.

I'm pretty sure the Nikon D300 and D3 get their exposure reading direct
from the sensor.

David

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In rec.photo.digital.slr-systems David Kilpatrick wrote:
Focus wrote:
"David Kilpatrick" wrote in message


And on the A350 you can always just switch to live view, viewfinder blind
comes over and you get 1200-zone evaluative metering read from the focus
screen - with alarming accuracy.

David

Can you elaborate on that? I don't quite understand.
Do you mean the metering in liveview is different than with the OVF?

And how is it alarming?

Yes, in evaulative (matrix) mode only. In centre weighted and spot, you
get the normal system. In matrix mode, the CCD video sensor does the
metering instead, and of course you never get overexposure (it's like a
bridge camera metering in that respect) and there is therefore no need
for the camera to underexpose slightly, which the A350 tends to do with
regular metering just to make best use of dynamic range (9.2 stops at
ISO 100 according to Anders Uschold in the BJP yesterday).

With Live View Matrix metering, you get 1200 colour sensitive points and
the live view image perfectly matches the final output in terms of the
live histogram, as well. with LV metering there really is no need ever
to think about bracketing, it's like using the KM A2 (which I still use
occasionally).

But surely even such comprehensive metering can only produce an
accurate exposure in cases where the image dynamic range is within the
dynamic range of the camera. Otherwise it's only going to get it right
if its algorithm takes the same decisions about what is the most
important detail to catch in this particular image as you do, e.g.,
blow out the highlights to catch all the shadow detail, or dump shadow
detail to preserve highlight detail, or only preserve highlight detail
up to the point of specular refletions, and so on.

I would have thought in those cases it could only get the exposure
"right" by good luck. So you would either do it it carefully manually
by examining the historgram, blown zebra stripes, etc., or do
bracketing to cover the range of uncertainty.

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"Chris Malcolm" wrote in message
...
But surely even such comprehensive metering can only produce an
accurate exposure in cases where the image dynamic range is within the
dynamic range of the camera. Otherwise it's only going to get it right
if its algorithm takes the same decisions about what is the most
important detail to catch in this particular image as you do, e.g.,
blow out the highlights to catch all the shadow detail, or dump shadow
detail to preserve highlight detail, or only preserve highlight detail
up to the point of specular refletions, and so on.

I would have thought in those cases it could only get the exposure
"right" by good luck. So you would either do it it carefully manually
by examining the historgram, blown zebra stripes, etc., or do
bracketing to cover the range of uncertainty.


Surely if the contrast range is greater than the camera can handle, and you
want both shadow detail and highlight detail, you have no option than to
take multiple exposures and use some form of HDR (auto or manual)

Otherwise it MUST be up to the photographer to choose what he wants to
sacrifice. Of course you can let the camera do it if you don't give a rats
what it chooses.

MrT.