40D histogram and shooting to the right

The 40D histogram has 4 faint lines dividing up the graph into 5 equal sections with black being extreme left and white being extreme right. More often than not, for me to get anything to show in the right most 1/5 section of the histogram, I need to use +1/3 to 2/3 EV. Does this mean my camera is underexposing by default and manufacture's design? In P mode or Full Auto with flash, it is still not quite all the way to the right, but close. In M mode, if I ajdust Tv and Av to get the pointer on the middle mark, the right 1/5 of the histogram is usually empty. Same thing if I set exposure to what a Sekonic meter indicates--the right part of the histogram is empty. The other day I was shooting some photos of buck rubs out in the woods and even with +1/3 EV, still got nothing on the right, but very little to the left. I did get a nice "bell" curve due to all the mid-tones in the woods, but the center of the top of the bell was left of center on the histogram--I thought it should have been in the midde more than it was. Is it just me, or are others experiencing this too? And yes, I do understand that not all images have to have info on the right side of the histogram, but since there is snow on the ground, you would think there would be some white represented on the right edge!

My 40D and previously my XT are always set to +1/3 EV.

I very often see the histogram being spread all over the entire range. Maybe I have a more dynamic surrounding than you have?

apersson850 wrote in post #4724437
I very often see the histogram being spread all over the entire range. Maybe I have a more dynamic surrounding than you have?

The spread on the histogram is due to contrast in the scene. Low contrast, no spread.

How do your images compare to the scene?

If I have -0- EV, normally an image seems to appear a bit on the underexposed side, sort of darker than I think it should be, on the LCD or on the computer. Me thinks I'd better do some bracketing off a tripod of several different scenes, then analyse them on the computer and LCD and see what I get in relation to the histogram. I do realize that some scenes will not have a lot of mid-tones, and some may not have any black to speak of (ski slopes on a foggy day!), and some images just happen to have a nice "bell" curve, or are evenly distributed all along the graph. But it seems that if there is no info on the right 1/5 of the histogram on say an image of a car in sunlight, then the image is underexposed. I think there should be some info there, whith maybe just a tad bit of high light blowout on something like a sparkle on chrome, or very close to it.

Here is a link to some ETTR info.

Rudy M. wrote in post #4723974
Is it just me, or are others experiencing this too? And yes, I do understand that not all images have to have info on the right side of the histogram, but since there is snow on the ground, you would think there would be some white represented on the right edge!

I have just started to notice the same thing working with hot lights and a grey card.

A simple experiment: Shoot a mono-colored object, a blank wall, a sheet of paper, whatever. Start at 0 EC. That shot should have a histogram spike slightly to the left of center, because the camera meters to 13% grey - not 18%, that's an urban myth ( http://www.bythom.com/​graycards.htm http://doug.kerr.home.​att.net …/Exposure_meter​ing_18.pdf ). Now add EC in 1/3 or 1/2 stop increments until at +2 EC the spike will be close to the right side and at +2.5 it will be bang up against it. Copy the images into an editing program like PS and compare the camera's histograms and the computer's.

tzalman wrote in post #4741346
A simple experiment: Shoot a mono-colored object, a blank wall, a sheet of paper, whatever. Start at 0 EC. That shot should have a histogram spike slightly to the left of center, because the camera meters to 13% grey - not 18%, that's an urban myth ( http://www.bythom.com/​graycards.htm http://doug.kerr.home.​att.net …/Exposure_meter​ing_18.pdf ). Now add EC in 1/3 or 1/2 stop increments until at +2 EC the spike will be close to the right side and at +2.5 it will be bang up against it. Copy the images into an editing program like PS and compare the camera's histograms and the computer's.

Thanks for the link. Very interesting. My grey card shots are around 1/3 stop underexposed.

Happens to me too. I just got my 40D three days ago and it's the first thing I noticed, under exposed shots when set to 0 Ev. I have had to use +1 to +1.67 to get what I got from 0 Ev on the 1D classic and my old 30D.

I'm still experimenting, but it might be the metering mode I am using and the fact that there is a lot of white snow in the shots. Not sure at this point.

Me too!
I am wondering if this is a issue with a small set of cameras or a 'feature' of the 40 D.
I got mine in late Dec 2007 from Best Buy.
The post about high contrast sounds correct, Pictures with direct sun suffer the most as there is always a super bright object somewhere in the picture, but too small to be significant, and seems to make the while histogram shift significantly to the low side. It is very annoying to have to adjust every picture I take with this expensive camera compares to my P&S before.

I started a post awhile back where I discussed a breakin period for the sensor. Of course, it got laughed at by the "pros" here, but it still makes sense to me. Whether the sensor needs a physical breakin or not, there was a definate change in my image quality when it rounded the 10,000 shots corner and it wasn't me. I saw the same thing with my 30D. Something similar happened with an old D30 I bought used from some people that had it from their sons stuff after he died in a car wreck. It sat in a closet for more than a year, and then when I got it and started using it, the sensor seemed all messed up for the first several hundred shots. Under exposing badly. Then by the second day of hard testing, something changed and it started working normally all of a sudden. I can't explain the reasons or the science, but thats what happened. And to tell the truth, I think my 40D is getting better as I use it, and I use it a lot, with over 25K on it since January.

What metering mode do you experience the underexposure in?
For me - shots with snow seem to dominate the exposure (evaluative) - so I either need to dial in ~1.5 to 2 EC, or spot meter & use manual.

I am set to Evaluative and use it exclusively. Once in a great while I will try Spot, but I don't really like it. It shouldn't really matter whether it's snow or black sand, if that's the main item in the frame, the metering will adjust for that with no compensation. Now if you have fresh snow as most of the frame, with a skunk walking through it, [don't laugh, this happened to me two winters ago] then you would need to dial in exposure compensation to allow for the black skunk.

But as I said above, the camera or sensor has now settled down, and normally, there is no under exposure at +/- 0 Ev.