I tried Alex Tweedly's stack before recommending it. On some images it only returned -2. Apparently those did not have EXIF information. On other images, e.g. from my Canon Ixus it reported a lot of stuff. Also for images from another Canon camera. This is on an Mac.
EXIF seems to be a bit complictated, since it is not uniformly handled by different sources.
took 26
Image ,Make,Canon,ASCII,122
Image ,Model,Canon DIGITAL IXUS 50,ASCII,128
Image ,Orientation,1,Short,42
Image ,XResolution,180/1,Ratio,150
Image ,YResolution,180/1,Ratio,158
Image ,ResolutionUnit,Pixels/Inch,Short,78
Image ,Software,Adobe Photoshop CS Macintosh,ASCII,166
Image ,DateTime,2007:08:09 13:22:44,ASCII,196
Image ,ExifOffset,216,Long,114
EXIF ,ExposureTime,1/640,Ratio,534
EXIF ,FNumber,28/5,Ratio,542
EXIF ,ExifVersion,0220,String,250
EXIF ,DateTimeOriginal,2007:07:24 15:34:06,ASCII,550
EXIF ,DateTimeDigitized,2007:07:24 15:34:06,ASCII,570
EXIF ,CompressedBitsPerPixel,5/1,Ratio,590
EXIF ,ShutterSpeedValue,149/16,Signed Ratio,598
EXIF ,ApertureValue,159/32,Ratio,606
EXIF ,ExposureBiasValue,0/1,Signed Ratio,614
EXIF ,MaxApertureValue,95/32,Ratio,622
EXIF ,MeteringMode,CenterWeightedAverage,Short,346
EXIF ,Flash,Off,Short,358
EXIF ,FocalLength,29/5,Ratio,630
EXIF ,FlashPixVersion,0100,String,382
EXIF ,ColorSpace,1,Short,394
EXIF ,ExifImageWidth,259,Long,406
EXIF ,ExifImageLength,195,Long,418
EXIF ,FocalPlaneXResolution,11520/1,Ratio,638
EXIF ,FocalPlaneYResolution,81000/7,Ratio,646
EXIF ,FocalPlaneResolutionUnit,2,Short,454
EXIF ,SensingMethod,2,Short,466
Skipping EXIF ,Tag a401
Skipping EXIF ,Tag a402
Skipping EXIF ,Tag a403
Skipping EXIF ,Tag a404
Skipping EXIF ,Tag a406
I could retrieve above EXIF data from the image here when I drag-dropped it to my desktop and ran libEXIF 0.9 on it.