[Recovered Thread: 34029]

[JimC]

Kalypso wrote:

I vote that Jim change his last name to "Google" ;-)

Actually,I do use Google a lot. It helps to find things like guide numbers, specs, etc., when trying to respond to posts from users having problems. Even though I may not own their camera, I can at least find out some information to hopefully help them out. Most problems are common between models anyway -- so the solutions are often similar. Of course, some problems are stranger than others (like this one).

Chances are, something is simply set wrong, impacting the camera's metering and/or autoexposure algorithms, causing underexposed shots regardless of mode or ISO speed. It almostsounds like it's got -EV Compensation set the way he describes his results. If it's a setting problem, resetting it back to factory defaults should fix it. If the camera or lens is defective, then he'll have to work around the problem for tonights game, until he can getthem replaced.

[SSD]

HI

Most of the pictures came out very dark last night. I tried several different things with the camera with not a lot of luck. I had 30-45 minutes of good daylight and the pics were still dark. I am thinking there is something wrong with the camera

Jim

I can't tell you how much I appreciate your help and information, being a newbie I need all the help I can get!

I was using a Sigma 28-135

http://www.wolfcamera.com/webapp/wcs...ductId=7465726

I am on a major budget and already had this lens which worked great with my film Rebel.

I ended up taking most of my pictures with my Fuji S602 and most of them came out great until it got dark.

Thanks!

Sally

[JimC]

I doubt it's lens causing underexposure (but stranger things have happened).

The pic you posted the first time showed the camera picking a smaller aperture (i.e., f/11), yet it still showed f/5.6 as being the largest aperture supported. So, the camera should be aware that it can select a larger aperture.

According to what you told us, the photos are still underexposed, even if you use higher ISO speeds. So, something is throwing off the camera's exposure algorithms. To be frank, it sounds like the camera is set to use -EV Compensation. So, if the flash sync speed is 1/200; and you had -EV Compensation set; it may be using a smaller aperture instead of varying the shutter speed -- even in sports mode.

Did you try resetting the camera back to factory defaults as suggested?

Did you try using Aperture Priority Mode and selecting a larger aperture (smaller f/stop number) to see if the problem still occurs?

Does the underexposure problem only occur when using flash?

Did you try taking the pics last night without flash, using higher ISO speeds as suggested?

[SSD]

Hi

I did forget to reset the camera to default settings, but I am fixing to do that right now. I did use the aperature priority mode and used the largest aperature possible on several shots.

The underexposure occured without and with the flash, I tried both ways.

Do you mind to explain the Ev compensation to me?

I attached one of the pics, though I can't remember the settings I used on this one.

Thanks!

Sally

[JimC]

SSD wrote:

Hi

I did forget to reset the camera to default settings, but I am fixing to do that right now. I did use the aperature priority mode and used the largest aperature possible on several shots.

The underexposure occured without and with the flash, I tried both ways.

Do you mind to explain the Ev compensation to me?

I attached one of the pics, though I can't remember the settings I used on this one.

Thanks!

Sally

Sally:

Your last photo was taken at ISO 400, 1/400 second, using the maximum aperture available for the 70mm focal length you were at (f/4). Flash was off.

This is exactly what I would expect if the camera was set to use -EV Exposure Compensation without flash. It picked the largest available aperture, yet selected a faster shutter speed than it normally would have (which resulted in an underexposed photo).

EV stands for Exposure Value, and is how light is measured. For any given lighting condition, aperture and ISO speed, the camera must keep the shutter open long enough to properly expose the image.

When the camera measures the light level with it's built in metering, it then selects the appropriate aperture and shutter speed combination to insure proper exposure.

However, under some circumstances, you may wantto override the metering. So, the camera gives you a way to do this caused Exposure Compensation (a.k.a., EV Compensation).

Most models allow you to either underexpose or overexpose an image as desired.

You have a limited dynamic range with a camera (the ability to capture both very bright and very dark areas in the same image). So, sometimes you need to make a choice of which areas are properly exposed, and which ones may be left either underexposed or overexposed; if the scene is not evenly lit.

An example of when you may want to use +EV with Exposure Compensation is for a backlit subject.If you use the default matrix (multi-segment) metering, the camera takes the entire image frame into consideration when determining the best aperture/shutter speed combination to use.

Since the backlit subject is much darker than the rest of the frame, you can use +EV Compensation to make the image brighter (so that your subject is properly exposed). This can have the effect of overexposing the rest of the image; but the camera gives you the choice. Using +EV Compensation usually forces the camera to use a slower shutter speed (although it may also use a larger aperture, depending on the conditions, focal length, etc.).

An example of when you may want to use -EV Compensation is when your subject is much brighter than the rest of the scene. So, if the camera tried to properly expose the entire scene (to make sure shadow areas are brighter), your subject could be overexposed. When -EV Compensation is used, the camera normally picks a faster shutter speed than it would normally use (as it did in the last problem photo you posted today). It may also select a smaller aperture than it would normally select (as it did in the first photo you posted).

That's why I wanted you to reset your camera back to factory defaults in my post yesterday -- in case you accidently changed a setting that is impacting the camera's autoexposure algorithms -- like EV Compensation (Exposure Compensation) would do. That's also why I wanted you to post an unmodified example (straight from the camera, not touched by PSCS) on a web site like pbase.com. Image editors usually strip the "maker notes" from the EXIF (so you can't tell if some settings were modified).

Try resetting your camera to factory defaults under Setup page 2 (the menu choice will be "clear all settings"), and see if this fixes the problem. You'll see where the menu is on this page in Steve's review:

http://www.steves-digicams.com/2003_reviews/300d_pg4.html

[JimC]

Sally:

See my previous post on how Exposure Compensation works. Chances are, you've got it set to the -2 EV side of the scale, causing your underexposure.

I'd still reset your camera back to camera defaults (as suggested andexplained in my previous posts) -- just in case you've got something else set wrong, too. Here is how to set Exposure Compensation on your model (copied from your manual). You'll see the scale in your viewfinder when you half press the shutter button. If the pointer is on the negative side of the scale,put itback in the middle of the scale (but resetting your camera back to defaultsshould also reset this):

[SSD]

JimC

Thanks again for the help! I have reset the camera. I realize what the exposure compensation meter is now (thanks to your explanation) and it was set right in the middle the whole time.

I just noticed you are in Marietta, I am just 1 1/2 hours up I-75 from you!

Thanks!

[JimC]

Actually, we recently moved to Savannah (I just haven't updated my profile)... I'll do thatnow.

Sally, have you tested the camera since the reset ("clear all settings" menu choice), to see if that fixed it?

If you still have the same symptoms after a reset, then the camera is probably defective (perhaps something wrong with the sensor used for metering), since thereset shouldalso reset metering modes, etc. back to factory defaults. From all appearances (especially from your last photo), it's simply underexposing the images (it should have used a slower shutter speed for the last one to properly expose it).

If it's still underexposing that much with and without a flash, I'd try a different lens on it just to make sure it's not a compatiblity problem with the lens (a local store would probably let you take some test shots with different one). If the camera is defective, you don't want to wait too long (or a vendor may not take it back).

Let us know if the reset fixed it or not.

[Jedi]

data from the exif... i toke it from the first pic.

EXIF
Camera
Make Canon
Model Canon EOS DIGITAL REBEL
Orientation upper left
X resolution 180
Y resolution 180
Resolution unit 2
Software Adobe Photoshop CS Windows
Date/time 02/09/2004 10:11:45 p.m.
YCbCr positioning centered
Image
Image description
Artist
Copyright
Exposure time 1/200 s
F-number 11
ISO speed ratings 100
Date/time original 02/09/2004 07:17:17 p.m.
Date/time digitized 02/09/2004 07:17:17 p.m.
Component config YCbCr
Compressed BPP 3
Shutter speed value 0.005000 s
Aperture value 6.918870
Exposure bias value 0.000000
Max. aperture value 4.970860
Metering mode Pattern
Flash Flash fired [on][red-eye]
Focal length 135 mm
User comment
Colorspace sRGB
Pixel X dimension 700
Pixel Y dimension 467
Focal plane X res. 3443.950000
Focal plane Y res. 3442.020000
Focal plane res. unit inch
Sensing method One-chip color area sensor
Custom Rendered Normal process
Exposure mode Auto exposure
Scene capture type Standard
Miscellaneous
Exif version (30,32,32,31)
FlashPix version (30,31,30,30)
File source DSC

JimC wrote:

Actually, we recently moved to Savannah (I just haven't updated my profile)... I'll do that now.

Hey...that's cool! I think all of us in the SE USA should head over to Jim's for a cookout...I'll bring 2 models & some studio lighting! Who else is in?