Anyone got a rational explanation why Canon underexposes?

Set your camera in auto mode and fire away. Set the flash with zero FEC and fire away. The camera underexposes. Underexposes by a fair bit.

I spent some time this weekend reading a lot of Canon literature and couldn't really pin anytihng down other than "be on the safe side" and don't blow stuff out.

I have found the M mode getting a hell of a lot more uage from me lately since I and growing discouraged with the interpretation of the metering modes that the Av, Tv modes do.

My FEC is ALWAYS cranked up +1 or more in ETTL. Once the sun goes down the exposure comp goes way up.

Now I've not used any high end Nikon stuff, just a D100 that was literally garbage and awkward to use. Does Nikon have as much as a tendency to expose to the left as well?

Considering Canon views the megapixel wars over and they are on top, can we see more advances in metering technology along the rush to ISO 10000000?

my XTi is generally kept at +2/3 sometimes +1/3 or 0 for nice sunny days.

i don't know about this... my xt seems to do a fairly accurate metering unless my subjects are abnormally light or dark (or both, a lot of teams like white and black on their uniforms..). when i tell it to overexpose by 2/3rd-1stop in indoor things, it often overexposes even more, around 1 stop to 5/3rd stop more...

I'm sure you've already thought about this, but since no one has mentioned it yet...

The Auto features on the camera do tend to underexpose - usually somewhere in the -.5 to 1 stop range. However, on your particular camera and with your particular shooting situation, the image could be even more underexposed.

For example, if you have the camera set on 100 ISO at say... 1/250 and F11... there is no way you would get a properly lit image. It would be underexposed by several stops, especially if you were relying on an on-camera flash or a "small" flash head, such as 420EX.

The AV and TV modes work the same way as the Auto mode - a slight underexposure, which would vary greatly depending on your camera settings and the type of flash you were using.

I am just hoping Canon provide some sort of firmware fairly soon to rectify this.

I have an xti by the way and I have now learnt to increase FEC when required I also shoot in RAW so I can recover pictures post shooting.

Are you sure it's not something you're doing? It's easy to blame the equipment!

my 30D gets iso setting of 160 by underxposing iso 100 iso settings like 160 and the rest are the result of in camera processing - sounds like **** to me! But I still love my camera

There is some infernal logic that Canon has employed particularly with flash. Might have something to do with the fact that the flash at the camera will be reflected off some shiny object in the scene and be misread by the ETTL system. But since it happens even if there are not shiny surfaces, it might simply have to do with deliberately keeping exposure down so as to not blow out highlights. But like you, I wonder why Auto mode ambient lighting and flash mode ETTL cannot result in a shot of the same relative brightness, and relate it to the twisted logic of the Canon engineers!

In 40+ years of photographic experience, I had come to rely upon the absolute predictability of TTL flash in film cameras, and was blown away with the perversity of the Canon flash system. First adjustment was learning about Av mode ideosyncracies (I avoid it with flash as main source of light), then was learning about dialing in FEC all of the time when flash is the main source of light. Now that my mind has been warped to 'the Canon way of flash', I now only shake my head in puzzlement whenever some new behavior of Canon flash goes counter to all of the collective experience accumulated by my own shooting and by other POTN experts in Canon flash. Learning Canon flash is like learning English grammar and spelling...all the exceptions to the rule!

John T wrote in post #2384425
Are you sure it's not something you're doing? It's easy to blame the equipment!

I'm talking about auto modes. Pressing the shutter is pretty hard to screw up bud. And I'm talking easily exposed stuff, not like two people in the ocean or a building in the shadow with the clear sunny sky behind it.

I do have to take a bit back on this. I notice that only certain lenses do it with my cameras. My new 70-200 F/4 L IS seems to NOT do it. My non-L lenses always need exposure comp. The non IS 70-200 I have seems ok. This may be a contrast thing Canon is totally aware of and sets cameras middle ground for.

I find this is only the case when the light is not hard midday sunlight.

As we've all experienced Canon and other DSLRs have extremely tight highlight tolerance. So it's actually not a bad idea for the camera to build in a -1/3 or -2/3 EV into the auto modes so snapshooters aren't blowing all their skies. I never shoot in auto, but I'm often dialing down the exposure to protect highlight detail.

Wilt wrote in post #2384503
There is some infernal logic that Canon has employed particularly with flash. Might have something to do with the fact that the flash at the camera will be reflected off some shiny object in the scene and be misread by the ETTL system. But since it happens even if there are not shiny surfaces, it might simply have to do with deliberately keeping exposure down so as to not blow out highlights. But like you, I wonder why Auto mode ambient lighting and flash mode ETTL cannot result in a shot of the same relative brightness, and relate it to the twisted logic of the Canon engineers!

In 40+ years of photographic experience, I had come to rely upon the absolute predictability of TTL flash in film cameras, and was blown away with the perversity of the Canon flash system. First adjustment was learning about Av mode ideosyncracies (I avoid it with flash as main source of light), then was learning about dialing in FEC all of the time when flash is the main source of light. Now that my mind has been warped to 'the Canon way of flash', I now only shake my head in puzzlement whenever some new behavior of Canon flash goes counter to all of the collective experience accumulated by my own shooting and by other POTN experts in Canon flash. Learning Canon flash is like learning English grammar and spelling...all the exceptions to the rule!

I had a Noink with an Sb flash. It was a certain pain to use coming from Canon gear. It made me appreciate the idiosyncrasies and manage my shooting around them.

I guess we all ask for a perfect system and we still all forget digital imaging is still in its infancy.

cosworth wrote in post #2384505
My new 70-200 F/4 L IS seems to NOT do it.

It made it? WHOOOT!

I have not seen this problem cosworth, i am mostly in spot metering. I'll have to check it out. Glad the lens made it!!!!!

cosworth wrote in post #2384226
Set your camera in auto mode and fire away. Set the flash with zero FEC and fire away. The camera underexposes. Underexposes by a fair bit.

I spent some time this weekend reading a lot of Canon literature and couldn't really pin anytihng down other than "be on the safe side" and don't blow stuff out.

I have found the M mode getting a hell of a lot more uage from me lately since I and growing discouraged with the interpretation of the metering modes that the Av, Tv modes do.

My FEC is ALWAYS cranked up +1 or more in ETTL. Once the sun goes down the exposure comp goes way up.

Now I've not used any high end Nikon stuff, just a D100 that was literally garbage and awkward to use. Does Nikon have as much as a tendency to expose to the left as well?

Considering Canon views the megapixel wars over and they are on top, can we see more advances in metering technology along the rush to ISO 10000000?

samples???

DrPablo wrote in post #2384528
As we've all experienced Canon and other DSLRs have extremely tight highlight tolerance. So it's actually not a bad idea for the camera to build in a -1/3 or -2/3 EV into the auto modes so snapshooters aren't blowing all their skies. I never shoot in auto, but I'm often dialing down the exposure to protect highlight detail.

This is interesting becauase IMexperience the 5D (which is what I use) OVERexposes a little generally but I have very very limited experience using it with flash.

I'll wait for the burning ball of hellfire in the sky to wane a bit and I'll take some lenses out and try it.

I notice my 17-40 has to get cranked when shooting volleyball with a polarizer.

Hmm... maybe the metering system has a bit of trouble with polarizers.