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Archive 2012 · Help please...Canon T1i overexposure problems
  
 
gusthecat
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p.1 #1 · p.1 #1 · Help please...Canon T1i overexposure problems


Hello, I'm having some issues with my T1i. Why is the auto ISO picking 800 for shots like this? This is pretty open shade in my back yard. Granted it was a bit backlit, but shot in P mode with I think centre weighted (Code #2 in the EXIF tag under Metering). Shot with the 18-55mm IS Kit lens with no hood.

https://picasaweb.google.com/lh/photo/Z5QZdVAEc0QlE-8j6w3cJelRBqR6uSYLd4D0jcBiB30?feat=directlink

I'm wondering why the shot has low contrast and saturation and why it the Auto ISO setting picked 800 for something like this? I can set the ISO to manually be fixed at 200 and think that would help. Normally I leave the ISO on Auto...that could be my problem.

I have a bunch of shots from a recent trip that are similar. I shoot jpeg mostly.

Thanks for any tips/advice you may have to help improve my shots.

Best Regards,

GusTheCat



Aug 21, 2012 at 01:17 AM
Monito
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p.1 #2 · p.1 #2 · Help please...Canon T1i overexposure problems


Please use the URL link tags automatically on left side of post box like this.

Or the img tags like this:

[img]https://lh5.googleusercontent.com/-GL6_B8nSnbw/UDLZ8lKscxI/AAAAAAAAEYw/4dw1vw0rLoo/s800/IMG_6047.JPG[/img]

will come out looking like this:



Edited on Aug 21, 2012 at 02:25 AM · View previous versions



Aug 21, 2012 at 01:32 AM
Monito
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p.1 #3 · p.1 #3 · Help please...Canon T1i overexposure problems


Solutions:

1) Set shutterspeed to something other than 1/40 second.

2) Learn how to shoot manually by centering the needle.

3) Use the Green box mode.

4) Use P mode and set the ISO to 400 or 800 and don't worry.

5) Get an Incident Light Meter and set the exposure that way.

6) Meter off a grey card and lock the exposure.

7) Use this Exposure Chart at ISO 200. Use 1/500 sec for ISO 400 and 1/1000 sec for ISO 800:







8) When in doubt, fiddle about. Make a shot on manual at ISO 400. Look at the histogram on the LCD. If there are blinkies use a faster shutter speed or a bigger f/number. If the histogram is too far to the left, use a slower shutter speed or a smaller f/number.


Edited on Aug 21, 2012 at 01:52 AM · View previous versions



Aug 21, 2012 at 01:34 AM
Jeff_Stapleton
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p.1 #4 · p.1 #4 · Help please...Canon T1i overexposure problems


my initial thought is that you are accidentally in Manual mode or you accidentally moved exposure compensation. I don't know how easy it is to do that on a T1i, but I do it on accident with my 7D quite often


Aug 21, 2012 at 01:51 AM
Monito
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p.1 #5 · p.1 #5 · Help please...Canon T1i overexposure problems


Date Aug 18, 2012 10:48:59 AM
Width 4752
Height 3168
File Size 6424710
Camera Canon
Model Canon EOS REBEL T1i
ISO 800
Exposure 1/40 sec
Aperture 4.0
Focal Length 27mm
Flash Used false
Orientation 1
White Balance 0
Metering Mode 2
Exposure Program 2
CCD Width 22.7076
Exposure Bias 0.0
Focal Plane X-Resolution 5315.436
Focal Plane Resolution Unit 2.0
Artist Ron Berdahl
Date and Time (Original) 2012:08:18 17:48:59
Copyright MemorySaver Photography
Color Space 1
X-Resolution 72.0
Y-Resolution 72.0
Resolution Unit 2
Date and Time 2012:08:18 17:48:59
YCbCr Positioning 2
Date and Time (Digitized) 2012:08:18 17:48:59
Subject Time 00
Sub Sec Time (Original) 00
Sub Sec Time (Digitized) 00
Custom Rendered 0
Exposure Mode 0
Focal Length (in 35mm film) 43
Scene Capture Type 0
Interoperability Index R98
Lens 18-55mm f/4-26



Aug 21, 2012 at 01:53 AM
Monito
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p.1 #6 · p.1 #6 · Help please...Canon T1i overexposure problems


The info Picassa gives has two fields that seem to overlap:

Exposure Program 2
Exposure Mode 0

The latter seems to indicate "Easy" mode. I'm not sure the meaning of the first in conjuction with the second. It could be Landscape mode (mountain symbol).

The metering mode 2 indicates Averaging metering.

Another possibility is that you were locking the exposure by half-press or other button press (depending on custom function settings) while pointing the camera at something very dark, perhaps grass at your feet or clothing.

Another possibility is that you had +2 Exposure Compensation. The Picassa recorded EXIF does not report that setting, unless it is the setting "Exposure Bias 0.0". Try other tools like Opanda and DPP and PhotoMe to see what the exposure compensation was.

Definitely a bit of a mystery. Operator error has not been eliminated.



Aug 21, 2012 at 02:16 AM
BrianO
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p.1 #7 · p.1 #7 · Help please...Canon T1i overexposure problems


gusthecat wrote:
...I'm wondering why the shot has low contrast and saturation...


Because it is way over-exposed.

gusthecat wrote:
...and why it the Auto ISO setting picked 800 for something like this?


That is the question.

I don't know much about the T1i, but I do know that I use auto-anything as little as possible. If I set things myself I find it easier to trouble-shoot when something goes wrong.

I'd suggest not using auto-ISO and P mode together. (In fact, I wouldn't use P-mode at all; I'd use Av, Tv, or -- often -- M.)

You may be able to save your over-exposed images with some post-processing, but they won't be perfect.








Aug 21, 2012 at 03:29 AM
BrianO
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p.1 #8 · p.1 #8 · Help please...Canon T1i overexposure problems


BTW, Canon Digital Photo Professional confirms that you were in Program mode with Center-weighted Average metering and zero exposure compensation. The camera chose ISO 800 and 1/40-second shutter at f/4.0.

There may be a problem with the camera's meter, or a firmware glitch in the Auto-ISO function.



Aug 21, 2012 at 03:45 AM
goosemang
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p.1 #9 · p.1 #9 · Help please...Canon T1i overexposure problems


can you see if perhaps he accidentally locked the exposure before composing the shot?


Aug 21, 2012 at 03:53 AM
BrianO
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p.1 #10 · p.1 #10 · Help please...Canon T1i overexposure problems


goosemang wrote:
can you see if perhaps he accidentally locked the exposure before composing the shot?


DPP doesn't indicate that, however since he says several shots came out this way I suspect that wasn't the problem.

DPP also shows Highlight tone priority "Enabled," Auto Lighting Optimizer "Standard," and Peripheral Illumination Correction "Enabled." I have no idea how those functions might combine, and if they could be part of the problem, since I never use them.



Aug 21, 2012 at 03:59 AM
 

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goosemang
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p.1 #11 · p.1 #11 · Help please...Canon T1i overexposure problems


seems like it should be a pretty standard exposure.... nothing really tricky in the fame either.

op: is this happening frequently or is this a one off?



Aug 21, 2012 at 04:04 AM
gusthecat
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p.1 #12 · p.1 #12 · Help please...Canon T1i overexposure problems


Hello Forum Friends,

Thanks for the constructive feedback and questions.

I was recently on vacation for a week and a half and have 1300 shots. About 1/3rd of them are overexposed. When I got home, I was quite disappointed as I liked the shots from my little point/shoot better. Anyways, the majority of the overexposed shots from my vacation were in open shade or on the water (in a boat in direct sun).

I came home and was not looking forward to trying to edit all the shots to save them. So I started experimenting with camera settings. I first did a reset to factory defaults. Then I turned on "Highlight Tone Priority" via the Custom Function setting. I prefer shooting in P mode as it seems to decide faster than the Green Box mode. I also like to focus and recompose while shooting so I usually half press, frame and then shoot. I have in the past used Av mode on my other camera bodies with great success (Pentax and Olympus). I think it could be operator error but I am a bit suspicious that it could be something else (metering issue?).

Anyways, I really appreciate the tips and suggestions. I want to figure out how to turn on the histogram preview on the back LCD so it shows the exposure right after the shot.

In the sample pic, a friend took the shot. That's me in the middle with the ball cap. Haa haa.

Thanks for loading it in the Canon Software. I have that too and can play around with it.

GusTheCat

PS: My Canon SX230HS seems to take great shots in similar light. Example:
Point and Shoot Sample



Aug 21, 2012 at 04:53 AM
Monito
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p.1 #13 · p.1 #13 · Help please...Canon T1i overexposure problems


gusthecat wrote:
I prefer shooting in P mode as it seems to decide faster than the Green Box mode. I also like to focus and recompose while shooting so I usually half press, frame and then shoot. I have in the past used Av mode on my other camera bodies with great success (Pentax and Olympus). I think it could be operator error but I am a bit suspicious that it could be something else (metering issue?).


For Focus-Recompose, you need to do what I do and many others do including many pros. Separate the AF away from the shutter button and to the * (star) button on the back of the camera, top right (left one of the two buttons). That way you can focus with your thumb, recompose and then press the shutter button gently. You will get the exposure from the actual scene as shot.

You set it by Custom Function 10, option 1. It's on page 188 of your manual. There is a lot of good stuff in your manual.

It takes a little getting used to, but quickly becomes second nature. Once you use it you will never go back to the default way. But you have to remember about it if you hand the camera to anyone else.




Aug 21, 2012 at 08:17 AM
Monito
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p.1 #14 · p.1 #14 · Help please...Canon T1i overexposure problems


Histograms are on page 161 and 162. You can switch them on by using the DISP button while playing back images to switch to the most detailed display. It shows some sample histograms.

The manual can be downloaded from Support at the US Canon site T1i Instruction Manual and I think the Canada site.



Aug 21, 2012 at 08:24 AM
melcat
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p.1 #15 · p.1 #15 · Help please...Canon T1i overexposure problems


Monito wrote:
For Focus-Recompose, you need to do what I do and many others do including many pros. Separate the AF away from the shutter button and to the * (star) button on the back of the camera, top right (left one of the two buttons). That way you can focus with your thumb, recompose and then press the shutter button gently. You will get the exposure from the actual scene as shot.


If dpreview have listed the custom functions correctly

http://www.dpreview.com/reviews/canoneos500d/12

it looks to me like you would with the shipped setup of the camera too: shutter half-press just starts AF and by default doesn't lock AE.

By the way, on many of the Canon bodies AE lock on shutter half-press is disabled with the metering set to evaluative. This can cause the behaviour to unexpectedly change if you change to centre-weighted.

I guess it's possible the meter looked at the black pants and made them grey, but it's hard to see how it metered on them.

BrianO wrote:
Canon Digital Photo Professional confirms that you were in Program mode with Center-weighted Average metering and zero exposure compensation. The camera chose ISO 800 and 1/40-second shutter at f/4.0.


f/4 is approximately wide open so it's not a sticky aperture mechanism. I suspect this is a faulty camera body.


Edited on Aug 21, 2012 at 11:11 AM · View previous versions



Aug 21, 2012 at 08:50 AM
Gochugogi
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p.1 #16 · p.1 #16 · Help please...Canon T1i overexposure problems


If you lock AF on a dark area and recompose, metering is also locked at the moment of focus and thus it renders the dark area it as a medium tone resulting in overexposure. Depending on your preference, you could do one of two things: 1. anticipate that the dark area will fool metering and dial in appropriate EC or 2., use the AE lock button (*) to lock metering from a medium toned area, recompose and focus as you please. I prefer to dial in EC as I can guess very accurately. In olden times I used to lock the spot meter on a medium tone in the same light as my subject to get my metering and recompose/focus. However, estimating EC is much faster for me.

And, finally, although we all wanna love autoISO, it pretty much sucks and often causes more harm than good. I'm amazed whenever I want fill flash in Av mode, whether in blazing sun or a candle lit room, autoISO only sets ISO400...



Aug 21, 2012 at 08:52 AM
Monito
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p.1 #17 · p.1 #17 · Help please...Canon T1i overexposure problems


melcat wrote:
By the way, on many of the Canon bodies AE lock on shutter half-press is disabled with the metering set to matrix pattern.


Canons don't set "matrix pattern".



Aug 21, 2012 at 09:27 AM
melcat
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p.1 #18 · p.1 #18 · Help please...Canon T1i overexposure problems


Gochugogi wrote:
If you lock AF on a dark area and recompose, metering is also locked at the moment of focus and thus it renders the dark area it as a medium tone resulting in overexposure.


This is very surprising behaviour and the opposite of a 5D, but sure enough you are right, and according to page 64 of the manual it's what it does with evaluative metering - not with centre-weighted, though. Anyway it's hard to see AE lock on focus acquisition as a cause of the problem here as the camera is unlikely to have locked focus on the black pants.

Monito wrote:
Canons don't set "matrix pattern".

Fixed above now.

I think a test of this camera's meter is in order. I like to do this by taking the camera outside on a clear sunny day and shooting blue sky at various f-stops. This will avoid wide-open vignetting from giving a misleading result, while also showing up a faulty lens diaphragm (aperture, iris). I know from experience the "kind of blue" I should be seeing, slightly darker than in real life.



Aug 21, 2012 at 10:10 AM
Monito
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p.1 #19 · p.1 #19 · Help please...Canon T1i overexposure problems


"Matrix" metering is a Nikon term. It does not apply to Canons. If you want to be understood in a technical field like photography, then take care on technical terminology. We only have your written words to go on, not any telepathy. Perhaps you will talk about Canon lens 'VR' next.

The OP needs to get out of the box, out of the "Easy" Full Auto mode.



Aug 21, 2012 at 10:42 AM
melcat
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p.1 #20 · p.1 #20 · Help please...Canon T1i overexposure problems


Monito wrote:
The OP needs to get out of the box, out of the "Easy" Full Auto mode.


OP claims it was shot in "P".



Aug 21, 2012 at 11:01 AM
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