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Author Topic: Why higher end camera underexposes images?  (Read 7066 times)

duydaniel

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Why higher end camera underexposes images?
« on: September 16, 2013, 01:09:10 PM »
Hey folks

I have done some homework with high ends CaNikon cameras.
And I found that higher end cameras often "under expose" their images.

If you google "D4 under exposure" or "1Dx under exposure", you will find that quite a bit.
Someone even commented
Quote
I was told by NPS (Nikon Pro Service) that this is by design. All “pro” cameras of the Nikon lineup underexpose by -1/3EV.

src: http://www.luminescentphoto.com/blog/2012/03/29/testing-the-nikon-d4-metering-comparison-with-d700/

I understand that people have different tastes on how they would adjust exposures differently. There is theory about ETTR etc. However, it is interesting to see manufactures set exposure to the left on their professional line up of cameras.

Any thoughts?

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Why higher end camera underexposes images?
« on: September 16, 2013, 01:09:10 PM »

neuroanatomist

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Re: Why higher end camera underexposes images?
« Reply #1 on: September 16, 2013, 01:25:17 PM »
Well, what is 'underexpose'?  We could also say that non-pro cameras tend to overexpose, much in the same way that in-camera jpgs tend to be fairly saturated and contrasty, because 'most people' (whoever they are) then to prefer bright, colorful images (same reason most computer monitors are saturated and contrasty at the default calibration, and a proper color calibration with a spectrophotometer tends to make them what some would call 'dull').

Why the exposure difference?  Perhaps for highlight preservation - you can lift shadows, but can't recover truly blown highlights.  However, it's worth noting that on the Canon 1-series bodies you can adjust the set point of the metering with AE Microadjustment, up to a full stop darker or lighter in 1/8-stop increments (and I suspect Nikon pro bodies have a similar feature, but I don't know for sure).
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Mt Spokane Photography

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Re: Why higher end camera underexposes images?
« Reply #2 on: September 16, 2013, 01:34:01 PM »
Many people use the AFMA feature in their Canon or the Fine tuning Feature in their Nikon bodies.
 
The manual warns you that use of the feature will affect the exposure and that you should use EC to correct it.  I suspect that some never read their manual ;)

 
I read the manual, but my brain read AF Microadjustment   where the manual was talking AE Microadjustment.
 
As a result, my post was nonsense.
« Last Edit: September 16, 2013, 03:22:08 PM by Mt Spokane Photography »

neuroanatomist

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Re: Why higher end camera underexposes images?
« Reply #3 on: September 16, 2013, 01:46:54 PM »
Many people use the AFMA feature in their Canon or the Fine tuning Feature in their Nikon bodies.
 
The manual warns you that use of the feature will affect the exposure and that you should use EC to correct it.  I suspect that some never read their manual ;)

Where does it say that?  I don't see anything to that effect in the 7D, 5DII, 5DIII, 1D IV or 1D X manuals, at least not in the AFMA sections.
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duydaniel

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Re: Why higher end camera underexposes images?
« Reply #4 on: September 16, 2013, 02:01:06 PM »
Well, I am more interested in knowing their reasoning behind this as Dr John said.
Probably highlight preservation is what the manufactures want to set their pro/consumer lines apart.

Or maybe -1/3 EV make the photo more attractive?
So what is the deal with shooters who do Exposure to the right?

P.S.
Yes Nikon D4 has a similar adjustment as in the 1DX AE Microadjustment
« Last Edit: September 16, 2013, 02:02:59 PM by duydaniel »

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Re: Why higher end camera underexposes images?
« Reply #5 on: September 16, 2013, 02:55:09 PM »
Well, what is 'underexpose'?  We could also say that non-pro cameras tend to overexpose, much in the same way that in-camera jpgs tend to be fairly saturated and contrasty, because 'most people' (whoever they are) then to prefer bright, colorful images (same reason most computer monitors are saturated and contrasty at the default calibration, and a proper color calibration with a spectrophotometer tends to make them what some would call 'dull').

Why the exposure difference?  Perhaps for highlight preservation - you can lift shadows, but can't recover truly blown highlights.  However, it's worth noting that on the Canon 1-series bodies you can adjust the set point of the metering with AE Microadjustment, up to a full stop darker or lighter in 1/8-stop increments (and I suspect Nikon pro bodies have a similar feature, but I don't know for sure).

+ 1 for me
Thanks you sir , Dear Teacher, Mr. Neuroanatomist  , for very clear understanding for me.
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meli

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Re: Why higher end camera underexposes images?
« Reply #6 on: September 16, 2013, 02:57:25 PM »
P.S.
Yes Nikon D4 has a similar adjustment as in the 1DX AE Microadjustment

I think every nikon from d7k on has it, separate for each mode too (spot /matrix /cw).

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Re: Why higher end camera underexposes images?
« Reply #6 on: September 16, 2013, 02:57:25 PM »

gbchriste

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Re: Why higher end camera underexposes images?
« Reply #7 on: September 16, 2013, 03:18:16 PM »
Under (or over) exposed based on what standard reference point? The odds of any given scene in the real world having exactly the right blend of highlights, midtowns and shadows to render a prefectly exposted image with the meter needle centered are very, very low.  If the scene is a little heavy on shadows, the meter behavior will tend to pull to the right.  If the scene is a little heavy on highlights, the meter behavior will tend to pull to the left.

So the only way to know whether the camera - by design - is under or overexposing is to meter off a known reference.

Now as it happens, I am a devoted fan of the Lastolite EZBalance.  The "normal" model is 18% gray.  I shoot almost exclusively outdoor, natural light portraits with a 5D3. I have my subject hold the EZBalance right up to their face and I spot meter off of it.

And my experience has been that when I spot meter and center the needle on the very accurate 18% gray EZBalance, I do infact tend to get an image that is a little underexposed....about 1/3 stop, actually.  So I now habitually kick the meter needle over to the right 1/3 step when metering off the 18% grey target.

And understanding that there is some variability in the market place for exposure/metering practices and equipment behavior, Lastolite also makes a 12% gray model.  Since it is slightly darker, the meter needle behavior will be to pull to the right when compared to a reading taken off the 18% gray model under the same lighting.  As it so happens, that difference is...you guessed it...about 1/3 step.

At the end of the day though, the camera doesn't underexpose or overexpose.  It is up to you as the photographer to know and understand your equipment, and the theoretical and practical underpinnings of how it works and why it works that way.  You ultimately are in control (unless you are shooting on full auto) and if an image is under or over exposed, it's because you under or over exposed it (equiment malfunctions not withstanding).

Mt Spokane Photography

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Re: Why higher end camera underexposes images?
« Reply #8 on: September 16, 2013, 03:19:51 PM »
Many people use the AFMA feature in their Canon or the Fine tuning Feature in their Nikon bodies.
 
The manual warns you that use of the feature will affect the exposure and that you should use EC to correct it.  I suspect that some never read their manual ;)

Where does it say that?  I don't see anything to that effect in the 7D, 5DII, 5DIII, 1D IV or 1D X manuals, at least not in the AFMA sections.

I'm not having a good week!  I was reading the manual yesterday and read AE microadjustment as AF Microadjustment.  Its something completely different, of course.
 
At least I read the manual, now I need to comprehend it better :)

duydaniel

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Re: Why higher end camera underexposes images?
« Reply #9 on: September 16, 2013, 03:54:23 PM »
The point of this thread is not about how you expose your images.
There is no standard. Some prefer darker/lighter... etc. we can talk about this for 100 years
without conclusion.

I just wanted to theorizing some reasons why manufactures adjust the cameras the way they do.
By high end cameras, I meant D4 and 1Dx.
It seems like both NiCanon slightly under exposed the image a bit when the light metering at the middle.
Maybe I am too old school but I enjoy technical stuff

Skulker

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Re: Why higher end camera underexposes images?
« Reply #10 on: September 16, 2013, 04:14:57 PM »
The point of this thread is not about how you expose your images.
There is no standard. Some prefer darker/lighter... etc. we can talk about this for 100 years
without conclusion.

I just wanted to theorizing some reasons why manufactures adjust the cameras the way they do.
By high end cameras, I meant D4 and 1Dx.
It seems like both NiCanon slightly under exposed the image a bit when the light metering at the middle.
Maybe I am too old school but I enjoy technical stuff

I think that the old "standard" exposure was to aim for 18% grey. That was just an arbitory choice, as I understand it.  ;D

If Canon and or Nikon now think 20% grey would be better it could be for all sorts of reasons. But all sorts of possible ideas are possible, and many people will be convinced they know why. To my mind I can't think of anything more likely than preserving highlights, and I like to do that. But many people like to ETTR, so I guess they don't worry so much about their highlights.

I was advised, by a professional that I respect, to over expose bright scenes and to under expose dark ones. This was to compensate for the "standard" exposure and to make the image more life like.
If you debate with a fool onlookers can find it VERY difficult to tell the difference.

lintoni

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Re: Why higher end camera underexposes images?
« Reply #11 on: September 16, 2013, 05:32:08 PM »
Possibly this a hangover from the days when 'pro' cameras were more likely to be used with slide film as opposed to 'consumer' cameras that were more likely to be used with print film?
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cliffwang

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Re: Why higher end camera underexposes images?
« Reply #12 on: September 16, 2013, 07:18:11 PM »
Well, what is 'underexpose'?  We could also say that non-pro cameras tend to overexpose, much in the same way that in-camera jpgs tend to be fairly saturated and contrasty, because 'most people' (whoever they are) then to prefer bright, colorful images (same reason most computer monitors are saturated and contrasty at the default calibration, and a proper color calibration with a spectrophotometer tends to make them what some would call 'dull').

Why the exposure difference?  Perhaps for highlight preservation - you can lift shadows, but can't recover truly blown highlights.  However, it's worth noting that on the Canon 1-series bodies you can adjust the set point of the metering with AE Microadjustment, up to a full stop darker or lighter in 1/8-stop increments (and I suspect Nikon pro bodies have a similar feature, but I don't know for sure).

+1.  Most PS cameras are overexposed.
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Re: Why higher end camera underexposes images?
« Reply #12 on: September 16, 2013, 07:18:11 PM »

dave

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Re: Why higher end camera underexposes images?
« Reply #13 on: September 16, 2013, 07:43:37 PM »
Well, they have got to pick a spot somewhere along the range. Like others I think that our perception of what is underxposed and overexposed (outside of extreme variation) differs depending on what you want for your shot.

I almost never shoot without exposure compensation shifted away from centre. More often this is in the + range but there are plenty of occasions where I go south (-) as well. I think in the real world it is a basically redundant question given that the ability to adjust to taste is simple to do and available to owners of all those bodies.

As long as is within a tolerance of 2/3 of a stop I don't think it really matters that much - you just adjust depending on your preference.

Martin

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Re: Why higher end camera underexposes images?
« Reply #14 on: September 16, 2013, 09:39:08 PM »
  Some time ago, when I switched from Nikon to Canon (D300 to 5d2) I was sure that there is a problem with my new camera (5d2) as all images were underexposed in comparison to what I was used to in Nikon in terms of exposure.
  I tried to convinced myself that maybe its my mistake etc. I am and was aware of mattering and its options however the underexposed images were kind of standard with my new 5d2 and especially indoors.
  I run some tests with "gray card" or any other equally lit surface (white board or wall), I've checked exposure with Nikon D300 as well as with Sekonic meter, and of course with 5d2. Checked it in different environments.
 The well calibrated light meter should give an exposure with histogram with peak in the center. This is standard exposure. It does not matter if u check it on completely black surface, white or gray. The histogram should be the same.
Test results was a little shock to me as Nikon and Sekonic gave me exactly the same exposure, and perfectly centered histogram. Canon 5d2 gave a histogram with off-centered peak (to the left), so it was underexposing obviously by (-2/3 EV or -1/2EV). The 5d2 has an exposure correction up to _+2EV so if u make standard exposure corrected with +2/3 there is not as much room for further correction  (it is but not so much)
Sent it to Canon, they've checked-all in line with standards. Another shock. I've checked another 5d2 and the result was the same.  Now I own a 5d3 and it is underexposing like his older brother.

I have completely no idea why canons are metering  out off the standards. A lot of users just dial +2/3 all the time. Also, have no idea why no one in canon correct this, this looks like kinda design fault, made years ago.
What is more important, canon sensors are bad for pushing shadows as there is much banding or very poor information if any, so there shouldn't be any tendency to underexpose.
« Last Edit: September 16, 2013, 09:47:36 PM by Martin »
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Re: Why higher end camera underexposes images?
« Reply #14 on: September 16, 2013, 09:39:08 PM »