Lower Right of Image is Under Exposed

[jjranieri]

I have a Canon Rebel 350D and I'm using the kit lens 18-55mm. In low light conditions in full auto mode many of my shots are very under exposed in the lower right of the image. The dark area is triangular. Has anyone experienced this and can you explain why this happens?

[hsbn]

can you upload sample image? You said it only happens in low light situation? Did you use flash? We can tell more if we see some photos.

[jjranieri]

Hello -

Thanks for the reply. I believe that for each shot the flash popped up. In many cases it just blinked a couple of times. I will try to attach some examples of phots that show the problem.

[diverhank]

Without seeing an image, I can only hazard a guess...in full auto, the flash pops up and the light from the flash is partially blocked by the lens or lens hood, creating a dark area. Try removing the hood.

[jjranieri]

Hello

thanks for the reply. I will enclose some exampes of the problem. I believe that when I took the shots the flash did pop up and it blinked a few times before the shutter snaped. I was not using a hood for any of the shots. I hope that you can see that a triangular region - always in the bottiom right is under exposed. any insights would be appreciated.

Regards

Joe Ranieri

Point of Rocks, MD USA

[MikeSowsun]

According to the EXIF data embedded in the photo file, the flash was fired in each of those shots.  That shadow is very pronounced and should not be there. Even with a lens hood on. 

I suspect two possible problems:

1) The shutter curtain is malfunctioning and may need to be replaced

2) The flash is somehow malfunctioning and not providing even flash coverage

Can you take a photo without the flash being fired so we can narrow it down?  

[diverhank]

I actually have seen much more pronounced shadows created by a lens hood.  The shadow is odd shaped and consistent...I still think that it's the result of the flash being partially blocked by something, like a lens or a finger.  Of course we cannot rule out something more serious.

[TCampbell]

Well... the good news is it's not the camera sensor and it's not the lens hood.

The shadow actually shows up in a different position in every shot and one image doesn't have any shadow at all (but the EXIF data tells me the flash did fire.)

I'm going to hazard a guess that you're holding your hand around the lens in such a way that your hand is creating the shadow.

When holding the camera try to learn to support the camera from below.    At no point should your hand or any fingers of your left hand be above the lens.

Position your left hand with palm facing up.  Your left elbow should be in so that your forearm is basically bracing from your stomach or ribs up to the camera.  Now you have excellent support -- but also in this position your fingers and hand cannot block the pop-up flash.  

Here's a video or two to demonstrate:

This first one is Rudy Winston of Canon USA.

That was a bit brief, so here's another by Brent Mail -- he goes into a bit more detail.

Try to be especially conceous of making sure nothing blocks your flash.  You'lll ultimately get better light with an external flash -- and these position the flash farther away from the lens and have the advantage of being able to point the flash to the ceiling or walls to "bounce" the flash for even softter light.  But the built-in pop-up flash is very close to the lens and especially sensitive to shadows from theings like lens hoods or hands partially blocking it's path.

[ScottyP]

I think I agree with TCampbell. Something seems to be blocking the flash. Either his hand is on top of the lens or on top of the camera instead of under it, or maybe he has the neck strap wrapped around the lens or something.

It actually COULD be a lens hood, but only IF it is one of those un-symmetrical hoods, where the top petals are bigger, but only IF he has not got it snapped into the correct position, with the long petals exactly on top. (I learned this the first time I shot a new lens once, and I had the hood screwed in about 45 degrees short of the right position). I sort of doubt it though.

I would still like to see some shots with NO flash to be 100% sure they come out clean, though.

[jjranieri]

Hello:

I will try to get some photos that exhibit the problem WITHOUT flash and will post them. To my recolection the problem only occurs when the camera decides to pop up the flash. I do NOT own a lens hood so that can be ruled out. Also I virtually cetain that I am not blocking the flash or the lens with my hand. Again thanks to all of you that have replied.

regards