XTi Underexposure Question

[rixhobbies]

As most people now know, the XTi has a tendency to underexpose about 1/3 to 2/3 of a stop in certain lighting conditions. The work-around, of course, is to set exposure compensation to, well, compensate!

Many XTi users leave exposure compensation set to +1/3 all the time and some use +2/3.

The question I have is that, assuming the light meter is correct, aren't we losing some low-light performance when comparing to a camera like the 30D that doesn't require a constant bump up in exposure compensation?

If you happen to have an XTi (like mine) that works best at +2/3 exposure compensation, it would seem that if you were using an f2.8 lens, you would get the full benefit from that lens' low light performance than if you used the same lens on a camera that didn't need the exposure compensation.

Am I on the right track here in understanding this? Or is it just that the XTi's light meter is slight off and you're just adjusting it to compensate, meaning that +2/3 is actually "0".

I am just trying to understand this a bit more so your feedback would be great!

Regards,

Rick

[Texsrt4]

i actually get great exposers at 0EC. every once in a while i have to bump it in bad light conditions, but even then its only +1/3...maybe i got lucky...thats a first

[ofdphoto]

This is the first I've heard of this problem with the 400D/XTi (though I don't own one).

I suspect that a good understanding of 18% grey will turn it into a non-issue, though ... ;-) (search here or on google)

As for your concern about losing fast lens performance, a good exposure of a scene at a particular ISO will require the same combination of aperture and shutter speed, regardless of how you may meter the scene. If it really is true that the XTi meter is calibrated badly, the weak link is the meter, not the sensor, so you won't be losing any lens performance.

[Kevin034]

If for any reason the XTi would lose speed performance, it'd be it's poor ISO performance. My 2 cents.

[evandavies]

Rixhobbies, yes, by increasing EC you would be loosing a bit of speed unless you bump up ISO to compensate.

I also have the 400D/XTi and most of my shots come out OK though a few times they do need a bit of luma boost in editing. I almost never use EC.

Try using CenterWeighted Averaged. I like it more than Evaluative.

[gjl711]

I shoot RAW+Jpeg and I have noticed that in certain conditions that the jpeg looks dark. If I go to the raw, the exposure looks spot on.

[Kevin034]

I shoot RAW+Jpeg and I have noticed that in certain conditions that the jpeg looks dark. If I go to the raw, the exposure looks spot on.
w/ that said ... has anyone ever just tried increasing the brightness of the LCD display?

[ofdphoto]

Hmm.

Getting accurate exposures requires a good understand of what your meter is doing.

I generally find the best way is to use partial metering and set my exposure off something neutral (like the sky or some concrete), or failing that, off something bright (which I'll over-expose) or something dark (which I'll under-expose). Otherwise you are at the mercy of your subject's tones and the intelligence of your metering mode.

I'm sure the XTi's noise handling is inferior to the 30D's, but accurate exposures, even at high ISO's, should yield very acceptable results.

[ofdphoto]

Oh, one more thing ... the histogram is your friend ;-)

[kumicho]

have had zero problems with this, but never used the kit lens (first the nifty then the 17-50mm). usually do center-weighted average, as the last thing I want is some dark (or light) corner screwing up the exposure.

[mntbikejack]

I have never had an underexposure problem the XTi. I also shoot in RAW exclusively.

[Bob_A]

Can you post some examples of images that you are having problems with so we can help you determine if your camera has a fault or if you may be doing something wrong?

Until you post some images it is impossible to give you any real help.

[xpsentity]

I shoot +2/3 on my XTi (Raw, Center Weighted) for my "average" settings. If I go down to 0EC every shot is far left walled on the histogram and underexposed.

You are not alone. (http://www.google.com/search?hl=en&q=xti+underexposure&btnG=Google+Search)

[Olyst]

To those of you having exposure 'problems', please read what linarms said in this thread. Understanding of 18% grey, your camera meter system and histogram are crutial components to master in order to get the best exposure results. Also note that Shuter Speed, ISO and aperture are closely related and work in conjuction with the meter system. Please research, take lessons and get a good understanding of these concepts and you'll get better results! You camera meter system can be easily fooled by some situations, and I believe that is what happening to some of you.

If there is a exposure problem on your camera, try the sunny 16 rule. ;-)

[Bodog]

As most people now know, the XTi has a tendency to underexpose about 1/3 to 2/3 of a stop in certain lighting conditions. The work-around, of course, is to set exposure compensation to, well, compensate!


Wasn't this "common knowledge"about the 300d and the 10d also???:rolleyes:

[Mr. Clean]

Different cameras meter differently too. Two of the same model side my side would meter slightly differently (at least,back in the film days). I notice my 1D meters differently than my 30D. Knowing how your camera meters and how to correct that on the fly in certain lighting conditions is a huge tool in the field.

[rixhobbies]

Thanks to everyone who has posted. As some of you have noted, slight underexposure in some situations is something that a lot of people have experienced. But, it should also be noted that those of you who express that getting to know your camera, technique and workflow is the key to taking great pictures. Every camera has a personality to it and getting to know it is important. Underexposure compensation is not a big deal and is easily dealt with. I certainly never meant to imply that I was dealing with a "problem", because I am not. My XTi's pictures are wonderful and once I learned to use the histogram and what I needed to do to get things where I wanted them, it was a cakewalk.

Also, one thing I have learned is that one person's opinion of over and under exposure, or sharpness, or color saturation and fidelity, etc, may not match that of someone else and that's OK. Sometimes there are real problems with our gear that prevent us from taking good pictures no matter how good we are. There are some great posts and responses on this forum helping people with those, but this wasn't meant to be one of them. It was more to help me better understand something and I think many of you helped me with that, so thanks!

The XTi is a great camera and I certainly enjoy mine! Having said that, I am going for the 30D but that's more for personal preference on ergonomics than anything else.

R