450 - Under Exposing in P Mode ( Yes its a user issue )

ccsnet

ccsnet

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Terran
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Hi - I've took quite a few images in P mode which looked fine at the time but when I got them on the PC where really under exposed....

Pretty sure its some thing I'm doing although iirc I have the speed set at 1/125 and on auto ISO ( was trying to stop this happerning as I was running at 100 ISO as a rule ) but the apature is set automatically in this mode which is my first thought of where I'm going wrong...

Any thoughts ?

T

PS I'll see if I can get the exif info - Just checked - F5.6 is the appature....
 
Terran, what metering mode are you set for, and what are you shooting ? Do you have any examples ?
 
Terran, without seeing an unedited example of what you are pointing the camera at it is not much help to know your shutter speed, aperture and ISO. What kind of subject and scene do you have - generally light, generally dark, about in the middle? Do you have the sun or a large expanse of sky in the frame? Do you have exposure compensation set, and to what value?

The easiest thing to do is to post an example picture, unedited except for resizing, and leave all the EXIF data intact within the image. Also, please find an example where you did not focus and recompose. If that is what you did then please let us know. What sort of lighting conditions do you have? The settings you have mentioned would be plenty bright enough for most daytime shooting outdoors.

So far there is insufficient information upon which to draw any conclusion whatsoever.
 
tdodd said:
Terran, without seeing an unedited example of what you are pointing the camera at it is not much help to know your shutter speed, aperture and ISO. What kind of subject and scene do you have - generally light, generally dark, about in the middle? Do you have the sun or a large expanse of sky in the frame? Do you have exposure compensation set, and to what value?

The easiest thing to do is to post an example picture, unedited except for resizing, and leave all the EXIF data intact within the image. Also, please find an example where you did not focus and recompose. If that is what you did then please let us know. What sort of lighting conditions do you have? The settings you have mentioned would be plenty bright enough for most daytime shooting outdoors.

So far there is insufficient information upon which to draw any conclusion whatsoever.
Click to expand...
NP I've got a couple here I'll share later.... as for metering, tried both spot and adverage....

Terran
 
ccsnet said:
NP I've got a couple here I'll share later.... as for metering, tried both spot and adverage....

Terran
Click to expand...

Spot and average are all well and good but the exposure you obtain is influenced strongly by the tones at which you aim the metered area. If you spot meter off a pale target - a white shirt, for example, you will get a radically different exposure than you would be metering from a dark shirt. Same with skin colours, paint or anything else.

Default metering works when you aim at a "mid tone" and set the exposure from that. If you are metering from something other than a mid tone then you need to let the camera know. If you are using any autoexposure mode, including P mode, you may need to adjust your exposure compensation. It might also be the case that you have accidentally adjusted exposure compensation and not realised. Seeing the full EXIF data, not just the bits you choose to show us, will help us see the full picture. Hah! Hah!
 
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For user error, I would double check that no exposure compensation has been dialled in at some time and not cancelled.
 
Thanks both...

Heres the image... let me know if you can get to the exif info ok - if not I'll host it omy own web site.

http://picasaweb.google.co.uk/lh/photo/OpAyXCTPQCAF75FMiKIXiA?feat=directlink

T

Photo information
Loading…
4 Aug 2010
1600×1067 pixels – 169KB
Filename: IMG_0508 BAD.jpg
Camera: Canon
Model: Canon EOS 450D
ISO: 200
Exposure: 1/800 sec
Aperture: 18.0
Focal Length: 18mm
Flash Used: No
Latitude: n/a
Longitude: n/a
less info
Click to expand...
 
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Terran, you were SPOT metering off a part of the scene that is predominantly quite a bright part of the sky, and with exposure compensation set to 0 the camera rightly tried to render that bright part as a middle tone. The rest is history.

20100804_215857_.JPG
20100804_222337_.JPG


Of course, if you used exposure lock when metering off some element of the foreground then I am wrong, but the evidence suggests I'm right. :)

The exposure settings you ended up with would be about right for lighting conditions over four times brighter than full sunshine, yet it is an overcast day.

My approach to this shot would be to spot meter off the brightest part of the sky at +3, not 0, and then I'd have a fighting chance of saving the foreground, but not without some PP to pull out the details. You can certainly do something to save this shot, but it would be better to have started with a brighter exposure to begin with. I recommend you get into the practice of checking your histogram to confirm that your exposures are OK.

20100804_223949_.JPG
 
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your camera is in spot metering mode.

what has happened here is that your camera has perfectly exposed the sky, at the cost of everything else.

i'd wager that if you simply went out again and took the picture with the metering set as evaluative you'd get a much better result, at the expense of the sky, which would probably be blown (it would look completely white or have large amounts of clipping).

without getting too technical, the camera can't capture all the range of tones in the image, so you have to expose for one specific area. you can use trickery such as HDR or multiple exposures to get the final result you're after.

in many ways, spot metering is *the* mode to use in such difficult high contrast situations, what you need to do is point the focus point at a neutral colour (ideally a mid-grey) in the area you want to expose correctly and press the '*' button on your camera, re-compose your shot and press the shutter.
 
I agree with Tim... but then he knows a lot more about this than I do... in P mode, the camera does a best guess on a correct exposure for what you're pointing at. Spot mode is worse for this than average, but I've had all that with my 450d, and it was after reading a number of posts that Tim made in a thread on bird photography, that the reason I was getting what I thought were odd exposures became clear. Now I only use manual and the tricks that Tim mentioned... metering for the grass, palm of the hand and over expose by a little etc. Although, it looks like that was always gonna be a real tough shot to get in a single exposure.
 
Guys.... thanks for the advice.... ill have a really good read at it in the morning as its been one of those days. Quickly reading it about spot it sort of makes sense. I've managed to rescue it in lr3 my self but my real aim is to get to a point where I don't need to do that and get it right first time.

Thanks again for your time and advice.... it really is appreciated.

Terran
 
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