topic Re: Canon 5D Mark III - underexposes in EOS DSLR & Mirrorless Cameras

Canon 5D Mark III - underexposes

suntcatalin — Mon, 20 Jan 2014 18:39:31 GMT

Hello,

I've noticed that my Canon 5D Mark III underexposes somewhere between 2/3 stops and one stop.

I've taken a test photo and I've attached the histogram and the exif. I photographed a white sheet of paper

Is this behaviour normal or is there a problem in the camera's metering system?

Thanks,

Catalin

Histogram

Test photo

I have also attached the full exif:

[Image]
Make = Canon
Model = Canon EOS 5D Mark III
Orientation = top/left
X Resolution = 72
Y Resolution = 72
Resolution Unit = inch
Date Time = 2014-01-20 21:16:29
Artist = Catalin Fuioaga
YCbCr Positioning = co-sited
Copyright = Catalin Fuioaga
Exif IFD Pointer = Offset: 360
GPS Info IFD Pointer = Offset: 9554

[Camera]
Exposure Time = 1/200"
F Number = F5.6
Exposure Program = Normal program
ISO Speed Ratings = 2000
8830 = 2
8832 = 2000
Exif Version = 30, 32, 33, 30
Date Time Original = 2014-01-20 21:16:29
Date Time Digitized = 2014-01-20 21:16:29
Components Configuration = YCbcr
Shutter Speed Value = 7.63 TV
Aperture Value = 5 AV
Exposure Bias Value = ±0EV
Metering Mode = Partial
Flash = Flash did not fire, compulsory flash mode
Focal Length = 105mm
Maker Note = 8152 Byte
User Comment =
Subsec Time =
Subsec Time Original =
Subsec Time Digitized =
Flashpix Version = Version 1.0
Color Space = sRGB
Exif Image Width = 2880
Exif Image Height = 1920
Interoperability IFD Pointer = Offset: 9326
Focal Plane X Resolution = 1971.253
Focal Plane Y Resolution = 1975.309
Focal Plane Resolution Unit = inch
Custom Rendered = Normal process
Exposure Mode = Auto exposure
White Balance = Manual white balance
Scene Capture Type = Normal
A430 =
A431 = 073024017512
A432 = 24/1, 105/1, 0/1, 0/1
A434 = EF24-105mm f/4L IS USM
A435 = 00001bcf3a

[GPS]
GPS Version ID = 2, 3, 0, 0

[Interoperability]
Interoperability Index = ExifR98
Interoperability Version = Version 1.0

[Thumbnail Info]
Compression = JPEG Compressed (Thumbnail)
X Resolution = 72
Y Resolution = 72
Resolution Unit = inch
JPEG Interchange Format = Offset: 11444
JPEG Interchange Format Length = Length: 3320

[Thumbnail]
Thumbnail = 160 x 120

Re: Canon 5D Mark III - underexposes

hsbn — Mon, 20 Jan 2014 19:35:16 GMT

That's how any camera meter work. Use gray card to test instead of white paper. Also, do you have Lighting Optimizer or High Tone priority turn on?

Re: Canon 5D Mark III - underexposes

suntcatalin — Mon, 20 Jan 2014 19:54:04 GMT

Thanks for the reply.

Obviously, I did not expect to meter the exposure to the right of the histogram :). But I expected to see it in the middle of the histogram, not to the left.

If I would compensate +2/3 the histogram would have become perfectly centered.

ALO OFF

HTP OFF

Re: Canon 5D Mark III - underexposes

hsbn — Mon, 20 Jan 2014 20:10:00 GMT

Canon is a little conservative in term of "middle gray". I think they're trying to avoid blowing out the high light. Depend on the company, middle gray can vary greatly and Canon seems to go a little on the "dark side". 🙂

Re: Canon 5D Mark III - underexposes

TCampbell — Mon, 20 Jan 2014 20:11:27 GMT

The camera is calibrated for 12% gray. If you were to obtain a "12% gray card" then the metered exposure would put the histram spike right in the middle.

I have an 18% card -- but really I use this for white balance. When I'm _really_ worried about exposure, I grab my hand-held incident light meter. But when you're _really_ worried about exposure, don't take a single meter reading.

When I use my hand-held meter, I can hold my meter in high-light area and take a reading, then put it in a shadow area and take a reading, and the meter will tell me the middle exposure (the one that would be best if I want to grab the greatest range of tonality while avoiding clipping off or blowing out my shadows and highlights.

You can do this with your camera by switching to spot metering mode... then center the camera on the darkest area you see in the scene, take a meter reading, then do the same with the brightest area and take another reading. With those two readings, find the middle exposure.

Re: Canon 5D Mark III - underexposes

suntcatalin — Mon, 20 Jan 2014 21:45:42 GMT

Thanks for your help!

Re: Canon 5D Mark III - underexposes

diverhank — Mon, 20 Jan 2014 22:47:29 GMT

I think evaluative metering does essentially what Tim C. said to average the darkest and lightest. I shoot entirely using evaluative metering...I find it to be incredibly good, even for subjects against the sun.

Re: Canon 5D Mark III - underexposes

amfoto1 — Tue, 21 Jan 2014 02:00:06 GMT

"....Exposure Bias Value = ±0EV
Metering Mode = Partial
Flash = Flash did not fire, compulsory flash mode
Focal Length = 105mm..."

You are in partial metering mode, which is fine if you are shooting a plain white piece of paper. However most of the time I'd recommend either Evaluative instead, or if you are more accustomed to it, Center Weighted. Or use Spot Metering in some cases. Partial is sort of like a "Large Spot Metering" mode.

Evaluative has the advantage of putting extra emphasis on the area right around the active AF point, i.e. presumably around your subject. The rest of the image area is considered, too, but more weight is given to the active AF point. Center Weighted metering doesn't do this (it's sort of an "old fashioned" method of metering, but some people are accustomed to it from using older cameras.)

Do a Google search on Expose To The Right (ETTR), which is a common technique used by Canon shooters. Like hsbn mentioned above, I think Canon is a bit conservative about their metering, erring a little toward underexposure to "protect the highlights". This was a good practice back in the days of slide film, but is just the opposite of what you want to do with digital. To minimize noise in images, it's better to slightly overexpose and pull the exposure back down a little in post processing. Not a lot... just +1/3 to +2/3 stop. Here is a link to one of the better descriptions of ETTR I've seen. There are other tutorials and discussions about it other places online, so do a search if you wish.

Oh, and there was an exposure issue with the 5D III early on. The problem was a light leak near the top LCD, that would cause underexposure from additional light reaching the metering array in the viewfinder. Canon did a recall made some changes to fix the problem. Yours would have to be a very early production camera that was never fixed under the recall, to have this problem. The problem would vary, depending upon how strong light was striking the top of the camera whle shooting. Outside on a bright sunny day would cause more error than shooting indoors in low light.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM

Re: Canon 5D Mark III - underexposes

TCampbell — Tue, 21 Jan 2014 03:06:20 GMT

@diverhank wrote:
I think evaluative metering does essentially what Tim C. said to average the darkest and lightest. I shoot entirely using evaluative metering...I find it to be incredibly good, even for subjects against the sun.

My understanding (and this would be a great topic for a Canon USA's YouTube page https://www.youtube.com/user/CanonNorthAmerica/ ) is that "evaluative" uses the multi-zone metering... except it then compares the metering to a database of "patterns" in the camera in an attempt to determine what type of shot you are likely taking and then biases the exposure based on the needs of that type of shot.

I've never seen an example of what these "patterns" are.

What I was mentioning was a bit more primative... find the darkest and brightest point... and use that to find the middle exposure so that (hopefully) nothing is blown or clipped.

Re: Canon 5D Mark III - underexposes

marcosphoto — Fri, 01 Aug 2014 13:31:00 GMT

Did you ever get satisfaction from this thread? Many people have the same concerns with the 5D3 as do I. I have even had my camera in and they do nothing about it, claim it's normal. However searching through these forums I found this thread and some very interesting information that had worked for two people following the thread. It was written by Canon personel. Try this:

Dgtl_nm8r,

There was a serivce advisory for the EOS 5D Mark III, but it was not related to the issue you are experiencing. As a first step towards resolving this issue, we suggest that you restore the camera's default settings. You can reset to the factory settings by following the procedure below:

Press the MENU button.
Select the [Tools #4] tab.
Select [Clear All Camera Settings].
Press the SET button.
Select [OK].
Press the SET button.

Re: Canon 5D Mark III - underexposes

jondaddio — Wed, 14 Jan 2015 12:51:20 GMT

Somehow, my EOS 5D Mark III got into a mode where it was creating very dark images. I was using normal camera automatic settings (at least I did nothing to change any settings). The "Clear All Camera Settings" did the trick for me as stated by @marcosphoto. Now they look normal again.

Re: Canon 5D Mark III - underexposes

marcosphoto — Wed, 14 Jan 2015 15:49:01 GMT

Hey thats good news and interesting too - now you've proven that the info I came across actually does something. I have run into a period where I have used my camera very little, so I've had little need to run any controlled testing on mine yet. I did a wedding a couple months ago and it was behaving.