There is a difference in how a dSLR camera meters. In live-view, the actual camera sensor is used for metering, while outside the live-view, a separate metering sensor is used. Please see attached image. The location of the components might be different for your camera, but the exact same principle applies.
When not in live live, light enters the lens and hits the main mirror. From there, some of it passes though (the mirror is not completely opaque) and hits a secondary mirror and then the phase detect autofocus sensor. What gets reflected by the main mirror hits the pentaprism which in turn directs it to the optical view finder and the metering sensor.
Below the pentaprism there is a tiny display. This is used to provide the info you see in the viewfinder. The light needs to pass though this transmissive display too.
This is the reason why the viewfinder is dark when there is no battery in the camera body (even if the camera is turned off, power is still delivered to this tiny display).
If this display is faulty then exactly what you mentioned happens. The OVF is darker and, because less light hits the matering sensor, the metering will be off as well.
Hi
There is a difference in how a dSLR camera meters. In live-view, the actual camera sensor is used for metering, while outside the live-view, a separate metering sensor is used. Please see attached image. The location of the components might be different for your camera, but the exact same principle applies.
When not in live live, light enters the lens and hits the main mirror. From there, some of it passes though (the mirror is not completely opaque) and hits a secondary mirror and then the phase detect autofocus sensor. What gets reflected by the main mirror hits the pentaprism which in turn directs it to the optical view finder and the metering sensor.
Below the pentaprism there is a tiny display. This is used to provide the info you see in the viewfinder. The light needs to pass though this transmissive display too.
This is the reason why the viewfinder is dark when there is no battery in the camera body (even if the camera is turned off, power is still delivered to this tiny display).
If this display is faulty then exactly what you mentioned happens. The OVF is darker and, because less light hits the matering sensor, the metering will be off as well.
Cheers!
Bogdan