Dumb 550D/Exposure Question

[atmenterprises]

I can't believe I'm asking this question as I should know the answer but I'm stumped.

While taking shots of the moon, let's say, if the moon is away from the center of the frame it's very overexposed but as it moves to the center it's correctly exposed. Then as it moves out of the center it's overexposed again. This happens regardless of whether or not I use a lens or connect it to a scope.

Any way to correct this so that the exposure settings are applied equally across the frame? I understand the moon is extremely bright compared to the blackness of the sky, but the camera seems to be automatically adjusting when I don't want it to do that.

[NigelCampbell]

That a not of the shutter speed and aperture (F-stop) that you get when the moon is in the centre. Then switch to manual mode and replicate those settings.

[ronin]

Check the manual, usually the exposure is centre weighed average, meaning that the centre provides the majority of the exposure setting but some of the left, right, top and bottom are taken into account. There should be an option for spot metering, this is usually the centre only and a small part of the centre, as in just 2% maybe 5%.

The get the right exposure you would have to set to spot metering, and select the centre spot as the one to be used, if there is an option to set more then the centre. Then aim at the moon and off you go.

There will be other sensor spots to use but not so "easy" to use. What normally occurs is that you set to centre spot, half press the exposure button and everything is measured and setup. You then move the camera to aim off centre WHILE still holding down the button, then go click. Not a feasible option if the lot is on a tripod.

Remember that if you use the camera for normal photography you may want or need to swap back to centre weighing exposure calculation by the camera.

[atmenterprises]

Thanks guys.

I did more research on this and found out that live view acts differently from looking through the viewfinder, but ronin I think going full manual and following your method will probably work. I just wish there was a way to turn off evaluative metering altogether but that doesn't seem to be an option for this camera body.