Canon EOD100D seems to be randomly overexposing images

[Leisa1977]

Hi all,

I'm fairly new here (and to DLSR photography in general) so I'm hoping someone can help. While taking pictures in Av mode recently my Canon EOS100D suddenly began doing something weird - seemingly overexposing some, but not all of the photos. It has happened while using 2 different lenses, and it doesn't seem to be due to me moving / pointing the camera anywhere different. So for example, I would be standing in the same spot clicking off photos one after the other (quickly), and then when I look at them some are overexposed and some aren't. Of course I could hear the shutter going slower / quicker at times too - but again this didn't seem to be due to anything I was doing.

It seems to have trouble focusing also as I'm taking some photos - the ones that turn out to be bad (even when the light is good) - I can tell when looking through the viewfinder that it isn't focusing properly.

Here is an example of 2 shots I took one after the other. Obviously my position changed slightly in this example but the light was the same:
103041103042
Settings: 1st pic f/3.5, 1/320, ISO400. 2nd pic: f/3.5, 1/100, ISO400

On another occasion I was taking multiple photos from the same position, and as I went on snapping the exposure got brighter and brighter until they ended up looking like this:
103043

Settings: f/4.5, 1/60, ISO100.
By this stage I was fiddling with settings trying to figure out what on earth was going on.

I've tried resetting the camera to factory default settings, taking battery / SD card in and out and turning on and off, looked up the manual for troubleshooting and looked online, and have no idea what to do next. The problem is still occurring, but it still seems quite random - i.e. in a series of 8 shots some will look overexposed to some degree, and some look normal. I've tried lots of different settings / light and it's the same problem regardless.

I'd appreciate anyone's ideas / help? Thanks for taking the time to read this, and for any advice or suggestions. Please let me know if you need more info - I read the guidelines and have tried to provide as much info as possible.

Thanks! Leisa :)

[arthurking83]

There doesn't appear to be any obvious user error going by the exif data.

If there was an issue with the camera, you could try using manual mode for a few shots and see how it reacts.

if there is an issue with the metering, then setting the camera to Manual mode will help to determine this. In Manual mode, the metering system is bypassed and the exposures should be consistent(to a degree).

If there was an issue with some mechanical component(eg. aperture) then you may still see random and obvious exposure differences again.

I noted that you have tried two different lenses so aperture shouldn't be the issue.

And in saying that:
In the top two images which appear to be similar, but still different, you have used spot metering for your metering mode.
From what I understand of Canon cameras, using spot metering relies on the central focus spot for the meter reading. If you have this spot area active over two different areas(say blue or white), then the metering is actually working correctly. In this instance it is user error (or misunderstanding) in how the metering system operates.
Where is the central meter spot located in the two images at the top?

As a quick test to appease your concerns, you would need to fire off some consecutive exposures of a scene that will not change at all.
In the lower image of the two kids, use the back fence as this static exposure scene. While it's boring, it will at least provide a consistent target to determine if you do indeed have a problematic camera.
Set the camera to spot metering, and Aperture priority and fire off about 5 images. Then do the same with matrix/evaluative metering too. To be sure that exposure is consistent make sure noting other than the grey fence is within the frame. For this test, 100% accurate focusing is not part of the issue, and if you have focusing troubles too, this may be part of the problem, or it may be a separate issue.
Try to work problems out one at a time.

[ricktas]

The issue is metering mode of SPOT. With SPOT metering you are letting the camera decide the exposure based on a 'spot' in the scene. When this spot happens to be a darker part of the scene, the camera is trying to get a good exposure for that spot, and thus the brighter parts end up over-exposed.

In the first photo, exposure looks good and focus looks to be on the face area, thus the spot metering has assessed the face and adjusted the shutter speed based on that. In the second photo, it appears focus was on the dark wood, thus the camera tried to expose the wood well, and over-exposed the lighter parts (skin and clothing).

In the third, metering was changed to multi, but I am unsure what your focus point was as everything appears to be blurred, so it is hard to tell what went on here.

Others might be able to see any other factors at play here.

[Leisa1977]

Thanks Ricktas and Arthurking - given that I'm a newbie I'll get my more experienced hubby to look through your replies and help me test these things out! I'll definitely try your suggestions.

Just for some extra info, I wasn't originally using spot metering when the problem started, we just changed it to spot metering as we were fiddling with settings trying to figure out what was wrong and try a few different things. When the problem started we were on evaluative metering - a setting recommended to me when I did a short course after first getting the camera. The camera has been on evaluative metering the whole time, until those last few pics where we changed it.

Glad to hear that perhaps it isn't a total user error on my part! Thanks again :-)

[ricktas]

OK., if you have been fiddling with settings it could be anything. Try doing a 'reset' of the camera back to factory defaults. It could be that you have set something inadvertently along the way. A reset will get you back to a starting point and then you can see how the camera performs.

[Warbler]

Is it possible that you have the camera's exposure bracketing feature on?

[Old Skool]

I know it's only a new camera, but from left field this can happen when the shutter starts to go or binds up - it stays open longer than it should sometimes. Could try shooting at the fastest shutter speed your camera can shoot at and see if any banding in present in the pic which also points to shutter issues.

[Mark L]

Since no one has addressed your focus problem, I'll have a guess.
Every lens has a closest (minimum) focusing distance. Go inside this and lens won't focus.
My 28-105 mm lens has a closest focusing distance of 0.48 meter. If I go a few cms closer than this, lens won't focus. Go to 0.5 mtr, auto-focus works every time.
So maybe move back a fraction. Crop the in focus photo later to get that little bit closer (if that's what you wanted).

[Leisa1977]

OK., if you have been fiddling with settings it could be anything. Try doing a 'reset' of the camera back to factory defaults. It could be that you have set something inadvertently along the way. A reset will get you back to a starting point and then you can see how the camera performs.

Thanks again Ricktas, but I tried that already and it was still happening afterwards.


Is it possible that you have the camera's exposure bracketing feature on?
Good suggestion Warbler thanks - I checked this setting and it is off. I had to look this up to understand what it meant - it certainly would have explained the problem had it been turned on!

- - - Updated - - -

Thanks to everyone for the testing suggestions too - I will try these out on the weekend when I have some time. I really hope there's nothing wrong with my new camera, which I otherwise love! Cheers :)

[hightone]

From your description, I too think it could be something to do with Bracketing. I agree that doing a reset back to original setting may help.

[bricat]

And have you had any luck yet? Camera faulty? Operator error? Would be interesting to find out. cheers Brian