Is my camera faulty?

So I notice that some low light images seemed a little dark around the edges. I took a bunch of pics (the two below for examples)..

The following images were taken in low tungsten lighting pointed at a wall (I realize its way underexposed, I used manual shutter for conformity). I first held the camera as you normally would then turned it upside down and took the same exact picture. What I see is each image having dark areas around the edges and turning the camera upside down show the pattern following, indicating to me that the darker areas stay in the same places on the sensor. Is this normal or do I have a defective camera?

*Edit - Indoor lighting was even.

right side up:

Byte size: ZERO | Content warning: NOT AN IMAGE

Byte size: ZERO | Content warning: NOT AN IMAGE

I guess that what you are seeing is called "light fall-off", it is caused by the lens mostly. Try to shoot at smaller apertures and / or to zoom in a little bit - the darker corners will change or even dissapear.

Like Olegis says, this is most likely caused by the lens and it is called vignetting.

Your test was probably also not very exact. Was the wall really exactly evenly lit? Try this by shooting the blue sky, which is very evenly lit.

Ok. I just wanted to see if anyone has done this sort of test with the same camera/lens. As far as the sky goes, I hadn't noticed this before as I've only seen it in low light conditions.

I'm a worry freak, so I was more concerened about having to send it back before return policy.

Do you use any filters (UV, polarizing, sky...) on your lens?

If so, that might also be the reason for vignetting.

Best regards,
Andy

no, I did not use any filters during testing..

**edit - as suggested earlier, I did take several pictures of the blue sky to make sure I had even lighting. I tested at full wide, middle and full telephoto positions of the lens. ALL test photos showed the same thing: darker around the edges and brighter in the middle (no filters).

I went to my local Best Buy to test against their display camera. I took an image with my camera and lens, then put a non-wide angle lens on mine that they had on display, and then tested their display rebel using it's own 18-55 lens. I then compared them on a computer in the store. My camera had signifigant darkening around the edges and brighter center than the store rebel and using a longer lens on mine yielded less outer darkening but still did not get rid of it.

So, Although I do see an improvement on my camera getting out of wide angle a bit, it still doesn't look as even as compared to another rebel at it's widest setting.

I'll be calling Beachcamera in a few.... God I hate having to return a thousand dollar piece of equipment..

BTW, I called canon and told them exactly what was going on and how I tested, they told me to send to canon for repair or to the vendor for defective replacement.