Exposure problems with Canon 300D

[weedogt]

I have problems with uneven exposures when using my Canon 300D. When I take a series of images on the same object I can get really large differences (4 "steps").

Have a look at some examples:
http://www.fiberglassics.se/canon

The page in Swedish but the images (and data) is "international". :wink:

My analog camera (Minolta Dynax 8000i) and my other digital camera (Nikon Coolpix 990) expose a bit different from one image to the next but not even close to the differences with my Canon 300D.

Are these large differences really normal or are there some problems with my camera?

/anders

[Guillermo Freige]

I think there is something wrong with your camera.

I've been taking a lot of pictures of the same subject using the same lens and focal lenght at all the apertures in Av mode, using 4 different lenses, and all the exposures were consistent between them, even chaging ISO from 100 to 400. The larger difference between shoots because the slightly different frame (I shooted handheld) was around 1/3 stop, and between lenses using different focal lenghts (from 18 to 135) was around 1 stop., because the high contrast of the scene and the different framing

In fact, I've never seen a picture so underexposed as picture 4 or so overexposed as 1 or 3 from my camera. Picture 2 is almost right, and can be a typical "somewhat dark" drebel exposure.
Regarding flash ones, this can be typical too. You must wait 3-5 secs between flash shots to allow a full flash recharge. The pictures were taken 1 sec away only, so the darker second one can be normal, consequence of an only partially recharged flash.

[garethhhhh]

It is very difficult to tell with the first four pictures because they were shot using different shutter speeds & apetures, however, the last two were shot using the exact same settings and there does seem to be a very noticible difference between the two.

[weedogt]

It is very difficult to tell with the first four pictures because they were shot using different shutter speeds & apetures,

The camera is set to "P" (Program) and selects time and shutter automatically. The first image the data is 200/8 and for the second 400/11. This is half the time (-1 "step") AND -1 "step" in shutter. In total the camera has reduced the amount of light on the sensor -2 "steps".
If I had used "Tv" mode (automatic shutter mode) and set the camera to 1/200 sec the apperture would had changed from 8 to 16.

A small differnce is ok, the composure is, after all, not EXACTLY the same. But this large difference for such a small change in image content...?

however, the last two were shot using the exact same settings and there does seem to be a very noticible difference between the two.

The last two is shot with the built in flash. As the time/shutter is the same it seems like problem is that the flash does not fully recharge between the shots.

I think there is something wrong with your camera.

Yeah... I'm afraid so...

/anders

[garethhhhh]

Hear me out before you deem your camera to be malfunctioning.

With the first four shots you appear to have moved postion / composed differently between shots.
Program mode is the simplest of the Creative Zone modes, it will choose shutter speed and apeture for you.

If, for example, you were using the center AF point then:

In the first shot then it would have metered for the person's black jacket. It used a slower shutter speed and larger apeture so it could allow more light in so that the jacket would be exposed correctly (resulting in the rest of the scene being blown out).

Using the same AF point in shot #2 would have resulted in it metering for the second subject's face. The subject's face was much lighter than the jacket and so it stopped the apeture down and used a faster shutter speed to allow less light in and expose correctly for the subject's face (resulting in the rest of the scene being under-exposed)

You shot using Evaluative Metering, IMO Evaluative Metering doesn't always get it right. For strong back-lit subjects using partial metering is best. :wink:

[garethhhhh]

The last two is shot with the built in flash. As the time/shutter is the same it seems like problem is that the flash does not fully recharge between the shots.

I am not sure, but that sounds possible since you shot them one second apart

[scottbergerphoto]

All four pictures have strong backlighting. That's a difficult situation for any camera meter. You were using evaluative metering, which means that the camera was trying to get an average exposure. Small changes in where the camera is pointed can drastically affect exposure when you have backlighting. Try taking some similiar pictures using Center Weighted or Partial Metering. Kinda what Gareth said above.
Scott