Xti possible underexposure? pics.

[bisdakr]

Finally able to take some pics with my xti, however the pictures look dark to me under P mode, I need your help on this one I have taken couple of pics of the same subject in AWB in P and M mode M mode is taken with +1E. In P mode the pictures look dark and in M mode with +1 overexposure the pictures look just right. Could I have an underexposure problem?
here are the pictures:

1. P mode

2.M mode +1 on the bar

1. P mode

2. M mode +1 on the bar

all pictures are taken in auto white ballance for full exif click on the link:http://bisdakr.phanfare.com/album/195777

 

[bisdakr]

does this mean I will have to overexpose my pictures or are there any settings to fix this, other people use my cam without knowledge and I have it set to P mode but pics come out dark.

 

[John_05]

i looked at the 2 cat pictures, and the EXIF says the underexposed one was shot with a shutter speed of 1/60, and the other was 1/25, and both were shot with the same aperture.

im no pro, but that would explain why the 2nd shot is brighter. thats 4 stops slower than the first.

 

[bisdakr]

yeah I overexposed the 2nd shot to get it brighter the 1st shot is on P mode which is 0 on the scale, however its too dark. My problem is P mode is taking dark pictures and on the scale it says 0.

 

[Big Mike]

It has little to do with the mode you are in. The image would be the same if you shot in P with +1 EC...or if you shot in M with the scale at +1.

You have to understand what the camera's meter is trying to do. It always wants to make the image as close to middle grey as it can. So when your subject is white, as in both of these images...the meter will think it's bright and give you less exposure...so you need to add exposure. If it was a black cat/dog...then the meter would think it's too dark and it would overexpose the subject...so you would need to subtract exposure. This is how reflective metering works.

The catch with digital is that you have to be a little more aware of this than if you were shooting negative film...which a lot of us have been doing for the last 30 years. Negative film is more tolerant of under/over exposure...and then the lab would make small corrections...so that we didn't even know the shot was off.

 

[bisdakr]

can I automatically set P to have +1? my gf uses the camera and the pictures she takes are dark under P mode, pretty much everything not just whit subjects, is there a way to set P so the its +1?

 

[Sw1tchFX]

I don't know if canon's do this, but with my D70, if i set EV comp and turn my body off, it will still be in effect when I turn it back on. So if your rebel can do that, just keep it on +1.

 

[Big Mike]

I don't know the control on that camera...but with my 20D, I have it set so that once I activate the meter (half press the button)...I just turn the thumb wheel on the back and that will adjust the EC. I'm sure your camera has an EC function which allow you to set the EC to where you want it...and it will stay that way until you change it back. If you feel that it's always underexposing...then you can just set a positive EC.

Check your manual.

 

[bisdakr]

how should I set my meetering mode?

 

[Big Mike]

If you have a good idea of what the meter is trying to do...then it may be best to use centre or centre weighted metering. Then you can have more control over what the meter is seeing...which should help you when you decide what EC you want to use.

Matrix metering would be good if you don't quite understand what the camera/meter is doing. Sometimes it makes it easier...but it can be fooled as well.

 

[bisdakr]

i've been reading the threads and now learning about RAW. Loaded the pictures up and opened the RAW images on the provided software, is the brightness the same thing as exposure? In editing the RAW images do you basically adjust the levels to get the picture they way you want it(brightnes, White ballance, Saturation and RGB? or is it more to that? So it's basically better to shoot in RAW so that you can get the effect you want? No overexposure or underexposure problem.

 

[Big Mike]

RAW allows you more leeway that JPEG...which is one reason that RAW is better. I guess you could call exposure, 'brightness'. The more exposure, the brighter it gets.

You can adjust the exposure of a RAW files but you can't really compensate for a poorly exposed image. Try it yourself...open a RAW file and change the exposure by 2 stops or more...the image probably won't look too good. The more you change it...the worse it will look...so it's best to get the exposure as good as possible from the start.

White balance is different...it's not actually applied to the RAW image until you convert it...so you can change it substantially without hurting the image.

 

[MACollum]

To change the EC on the Digital Rebel XTi in P mode, hold the button to the right of the viewfinder down while scrolling the wheel behind the shutter button to the left to decrease and to the right to increase exposure. My pictures come out underexposed a lot too but I think I'm metering wrong. I've been playing with the EC more lately and it's much easier to change the exposure than to edit the picture after the fact. I know I have as much to learn in the editing department as the photography department.

 

[fmw]

The reason the cat is underexposed is that the metering system, for whatever reason, saw it as the important part of the frame and then went about exposing it for medium gray. Since the cat is white, it is underexposed. If it had been a medium gray cat, the exposure would likely have been just fine and a black cat would likely have been overexposed.

Exposure meters aren't very smart. They need a photographer to interpret what they do and adjust as necessary. View what a meter does as a recommendation and not necessarily a correct answer. I would think an exposure compensation of +1 1/2 stops would probably expose the white cat properly.

You have a couple of good tools with the digital camera. One is the LCD screen that gives you an idea of what the subject looks like after exposure. The other is the histogram. I would expect the histogram to look something like a snowboarding chute with the two ends high and the middle part low. If I got that histogram, I would know I nailed the exposure.

 

[MACollum]

I would expect the histogram to look something like a snowboarding chute with the two ends high and the middle part low. If I got that histogram, I would know I nailed the exposure.

I always try to get my histogram to look like that. Sometimes the lines skipe up high, say, in the middle. I think that means that a lot of the picture has a dark color (tone?). Is that ok as long as the graph stays somewhere in between the dark (left) and light (right), meaning the exposure is good?