under exposure another dumb question

[amimaija]

why does the camera underexpose photos when all seems to be set right..what am I doing wrong....I will tell you what happens at times. I will be shooting this time in P (sometimes I shoot in AV) ..And a group of photo's will be underexposed and others will be fine. I need help again..I know you guys are so helpful. It was a horribly sunny day..that is the time they picked not I. I had reflectors on them to try and ease the shadows. It makes me want to shoot in raw..

File Name IMG_3650.JPG
Camera Model Canon EOS DIGITAL REBEL XSi
Shooting Date/Time 5/3/2008 11:09:23 AM
Shooting Mode Program AE
Tv( Shutter Speed ) 1/60
Av( Aperture Value ) 5.6
Metering Mode Evaluative Metering
Exposure Compensation 0
ISO Speed 100
Lens EF-S55-250mm f/4-5.6 IS
Focal Length 250.0 mm
Image Size 2848x4272
Image Quality Fine
Flash Off
White Balance Mode Cloudy
AF Mode AI Focus AF
Parameters Settings Tone Curve Standard
Sharpness 3
Contrast 0
Noise Reduction Off
File Size 2490 KB
Drive Mode Continuous shooting
Camera Body No. 0320110716

[michaelb]

Wow, I think you mean overexposed. A SS of 1/60, f/5.6 under such sunny skies sounds like way too slow of a shutter speed for such sunnny conditions.

I don't know why your camera chose these settings, but....

Here's my advice....

Shoot in P or Av mode, take the shot and then look at your histogram - you'll quickly see with a photo like this that the shot is waaaay overexposed. Then you can adjust EC accordingly.

OR...

Shoot in full manual, and follow the same above steps, except this way if the shot is overexposed then increase the shutter speed some - if the lighting is fairly constant this will give you the best control.

The beauty of digital is being able to check the histogram, retake the shot and get the exposure right the second time. (unless your a wedding photog!! ;))

AND...

I would shoot RAW, not only because its easier to fix errors like this, but mostly so you can get WB correct - so easy to fix in DPP, which came with your Xsi.

I hope this helps.

[24Peter]

Hmmm... not good. Something's not right here. It's like the camera's metering system is off. Your settings look OK but like Michael said, the camera should have selected a shutter speed much faster for this scene - 1/250th or more I would think.

There's no reason you should have to shoot RAW or full manual mode to try to compensate for a camera that clearly isn't metering properly.

All I can say is keep shooting and if the problem persists, send your camera in for service.

[Mark_48]

How's this sound....

Just prior to taking the picture you accidently hit the AE Lock button * while the camera is pointed at something dark like the ground or something. You take your shot and as in the example above is overexposed since it was already locked for a shot in the dark.

Not sure if AE lock shows up in the EXIF or not...

Edit: Just tried a test shot to see if the EXIF showed any evidence of AE lock and it didn't appear to.

Mark.....

[amimaija]

ok guys thanx ..It happened to the powershot s5 Is, once in a while also...I thought it maybe the metering mode...kinda scary when you are a gun for hire...(: I will shoot in raw for sure and check the histogram.. I also got some random dark photos, maybe it is because of the brightness...??


File Name IMG_4056.JPG
Camera Model Canon EOS DIGITAL REBEL XSi
Shooting Date/Time 5/3/2008 12:00:40 PM
Shooting Mode Program AE
Tv( Shutter Speed ) 1/250
Av( Aperture Value ) 8.0
Metering Mode Evaluative Metering
Exposure Compensation 0
ISO Speed 100
Lens EF-S55-250mm f/4-5.6 IS
Focal Length 55.0 mm
Image Size 2848x4272
Image Quality Fine
Flash Off
White Balance Mode Cloudy
AF Mode AI Focus AF
Parameters Settings Tone Curve Standard
Sharpness 3
Contrast 0
Noise Reduction Off
File Size 3540 KB
Drive Mode Continuous shooting
Camera Body No. 0320110716

[24Peter]

Couple of other things: your WB is off. It lookis like you have it set to "cloudy". I'd move it back to auto WB. Also, EXIF data says AI auto focus. Both shots you've posted look soft. I would use "one shot" (or whatever the equivalent is on the XSi) for the AF setting. And then maybe play with the metering modes to see if you get better exposures. I don't think you want to use spot metering, but maybe center-weighted?

[adam75south]

looks like it's time to learn to use M mode. i shoot almost 100% of the time in M.

if you don't have a light meter, then just set your ISO and aperture you want to use, put it on spot meter, point it at the subjects face, keeping it steady on their face as you adjust your shutter speed until the little camera exposure meter balances up in the middle. i usually leave mine about a 1/3 stop overexposed since that is usually what it takes to get a correct exposure on my 30d, take a picture, check histogram, adjust. then you won't have to change settings again until you change up location or light direction.

i will say that in those conditions in those pictures, even if exposed right, they would have had some very harsh shadows. i'd either shoot later in the day, use fill flash, or try repositioning your reflectors closer to them.

[amimaija]

ok i will change the settings .. i noticed the softness i'll check the lens to keep it cleen maybe i should get lens cleaner on it..yes i should go to M and spot meter i will

[FLiPMaRC]

Amimaija ... I noticed the same exact issues on my XSi on Av mode. I usually shoot on Av or M modes on my S3 IS.

While attending a friend's wedding last Friday, I tried Av mode on the XSi. IIRC, my settings were iso400, f/4 (EF 28mm f/2.8), and partial metering. For some odd reason, the camera decided 15" was the correct shutter speed :confused: I checked the settings and fired off a second shot and it did the same thing. I'm not sure if I need to be on Evaluative or Center Weight metering for Av to be effective. I didn't think about it at that moment so I just kept shooting on M mode the rest of the night.

[amimaija]

that would not be good at a wedding..i am a little worried about it..the s3 is and s5 is did the same thing for me i thought it was the safety shift..

I need to start using M

Amimaija ... I noticed the same exact issues on my XSi on Av mode. I usually shoot on Av or M modes on my S3 IS.

While attending a friend's wedding last Friday, I tried Av mode on the XSi. IIRC, my settings were iso400, f/4 (EF 28mm f/2.8), and partial metering. For some odd reason, the camera decided 15" was the correct shutter speed :confused: I checked the settings and fired off a second shot and it did the same thing. I'm not sure if I need to be on Evaluative or Center Weight metering for Av to be effective. I didn't think about it at that moment so I just kept shooting on M mode the rest of the night.

[amimaija]

could be.. i will be careful

How's this sound....

Just prior to taking the picture you accidently hit the AE Lock button * while the camera is pointed at something dark like the ground or something. You take your shot and as in the example above is overexposed since it was already locked for a shot in the dark.

Not sure if AE lock shows up in the EXIF or not...

Edit: Just tried a test shot to see if the EXIF showed any evidence of AE lock and it didn't appear to.

Mark.....

[amimaija]

I think I figured it out...

A flickr guy said to clear my settings so I did and now it works..yeah...I had the auto focus points set to the center one maybe that's what messed it up..it was static.. now the red light point focus on objects differently depending on the scene....

[amimaija]

if I use auto lighting optimizer and the highlight tone priority I get consistent photos not random over and under exposed pics is this normal?

[Nickcanada]

Is it normal to get consistent results in an auto mode? NO! Is it a good thing? YES! :D