Rebel T2i shooting questions

[Buzzaro]

Hey Guys,

I've been taking quite a few photos since getting my camera. Most of them are still indoors of the new little tyke. This past weekend I had a strange issue come up. Well, it was strange to me but perhaps it is normal. I normally shoot in AV mode. No real reason, I've just learned to use it and how to access all the controls from that mode so I haven't ventured into shutter priority or full manual too often.
What happened is this: Shooting the same subjects from the same location with the same settings and in the same light the pictures would come out dramatically darker or lighter.
A little pressed for time at the moment, so I can't figure out how to show you the photo properties but if you could explain how to do that I will update the thread. The camera would change the ISO and shutter speed by quite a bit. Here are a couple examples:

[OldClicker]

It's there in the EXIF data. I use a program called Opanda to see it.

Top image:

[Image]
Make = Canon
Model = Canon EOS REBEL T2i
Orientation = top/left
Software = Adobe Photoshop Elements 6.0 Windows
Date Time = 2011-05-04 05:09:16

[Camera]
Exposure Time = 1/40"
F Number = F5
Exposure Program = Aperture priority
ISO Speed Ratings = 6400
Exif Version = Version 2.21
Date Time Original = 2011-04-30 16:01:54
Date Time Digitized = 2011-04-30 16:01:54
Shutter Speed Value = 5.38 TV
Aperture Value = 4.63 AV
Exposure Bias Value = ±0EV
Metering Mode = Pattern
Flash = Flash did not fire, compulsory flash mode
Focal Length = 42mm
User Comment =
Subsec Time = 0.29"
Flashpix Version = Version 1.0
Color Space = sRGB
Exif Image Width = 800
Exif Image Height = 533
Custom Rendered = Normal process
Exposure Mode = Auto exposure
White Balance = Auto white balance
Scene Capture Type = Normal

[Thumbnail]
Thumbnail = 160 x 107


Bottom Image:

[Image]
Make = Canon
Model = Canon EOS REBEL T2i
Orientation = top/left
Software = Adobe Photoshop Elements 6.0 Windows
Date Time = 2011-05-04 05:09:16

[Camera]
Exposure Time = 1/60"
F Number = F5
Exposure Program = Aperture priority
ISO Speed Ratings = 2500
Exif Version = Version 2.21
Date Time Original = 2011-04-30 23:01:44
Date Time Digitized = 2011-04-30 23:01:44
Shutter Speed Value = 6 TV
Aperture Value = 4.63 AV
Exposure Bias Value = ±0EV
Metering Mode = Pattern
Flash = Flash did not fire, compulsory flash mode
Focal Length = 46mm
Flashpix Version = Version 1.0
Color Space = sRGB
Exif Image Width = 800
Exif Image Height = 533
Custom Rendered = Normal process
Exposure Mode = Auto exposure
White Balance = Auto white balance
Scene Capture Type = Normal

[Thumbnail]
Thumbnail = 160 x 107

The bottom image with 1/60 sec, f/5 and ISO 2500 is going to be darker than the first with 1/40 sec, f/5 and ISO 6400. Why the camera chose these values is not evident to me.

Terry

[Grandpaw]

The biggest difference that I can see is that the one that came out good was taken around 4:00 in the afternoon and the dark one was taken around 11:00 PM. I suspect that you may have had more light in the room at the earlier hour than at 11:00 at night. It is strange that in the later hour the camera choose a slower ISO, Jeff

[Buzzaro]

The biggest difference that I can see is that the one that came out good was taken around 4:00 in the afternoon and the dark one was taken around 11:00 PM. I suspect that you may have had more light in the room at the earlier hour than at 11:00 at night. It is strange that in the later hour the camera choose a slower ISO, Jeff

I will have to doublecheck, but I these were both shot in the same session around noon. I know for sure no shots were taken at 11pm. I am not sure why the data shows a time discrepancy.

Edit: I had it mixed up, the photosession was after the bike ride and not before. So these shots were taken around 4pm within a couple minutes of each other. When I "show properties" in photoshop, the "date time original" are both 4:01pm

[flyinion]

You might try turning off auto ISO, at least then it should be more consistent in the shutter speed values. I never use the auto setting, mostly because I'm trying to use the lowest ISO I can get away with the reduce noise.

[Buzzaro]

You might try turning off auto ISO, at least then it should be more consistent in the shutter speed values. I never use the auto setting, mostly because I'm trying to use the lowest ISO I can get away with the reduce noise.

I started messing with full manual to get the fastest shutter speed and lowest ISO i could use for that lighting but I am still a little too slow and miss shots. The light in the room was quite a bit better than many other times the camera has taken good shots. I guess my real question is "why is the camera choosing these settings with this light?" I don't know if there's a particular metering mode I should be using, if someone here noticed some conditions in the pictures that would cause the camera to do what it did, or if there is some setting in the metadata that I have set wonky, or if there is something else entirely that I am missing.