A200 - Nicely focussed darkness

[JimC]

JimC wrote:

Something probably changed in the images (something brighter in the images with faster shutter speeds and exposed to protect the highlights).

What metering mode are you using? If you're using something like spot, you're going to need to be careful what you're metering on.

In any even, I would set ISO speeds higher versus deliberately underexposing, since underexposing can lead to loss of dynamic range.

http://www.luminous-landscape.com/tu...se-right.shtml

Look at the images. The most likely cause is that something changed in them. For example, a lamp in one image and not in another.

Check your metering mode. If you're seeing a stop difference in exposure, something you're doing is probably causing it (for example spot metering, metering on darker and lighter areas between photos).

You're already a stop down to begin witth using a -1.0 EV setting, and another stop variance in exposure due to image content or metring settings would not be unusual.

I'd set meterng to matrix or center weighted unless you're good a judging something to meter from for correct exposure, and not use a -EV setting unless you need to protect the highlights.

Then, study the images to see what's different about them so you'll be more familiar with your camera's metering behavior.

[Bart150]

I'm sorry, Jim, but what we're talking about here is a camera automatically choosing ISO50 and producing a near-absolute black image as a result.

[JimC]

The most likely problem is that something is brighter in one image compared to the other.

Your images are already going to be a stop darker to begin with using a -1.0 EV setting, and if you meter on something lighter then it may underexpose another stop or so (the difference in two photos you mentioned was 1/20 versus 1/50 second).

Check your metering mode.

Your camera's metering is most likely leaning towards protecting the highlights to start out with as much as possible fighting dynamic range constraints (which can result in darker images). Then, you're deliberately darkening the images another stop using a -1.0 EV exposure compensation.

Set your ISO speed higher if the camera is keeping it set too low for the shutter speeds desired.