D750 exposure issues

dr. frets

New member
I am having exposure issues with my D750. I have a few months left on my warranty and would appreciate your advice if this is something I should send to Nikon for repair, or just adjust in the Menu setting.

When I shoot in either P, S or A modes.....I get the following results....from top to bottom...
Spot meter mode: 2 stops underexposed
Matrix meter mode: 1 stop underexposed
Center weighted mode: looks right to me.

Thanks for your advice and suggestions.

Roger
 

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Horoscope Fish

Senior Member
I am having exposure issues with my D750. I have a few months left on my warranty and would appreciate your advice if this is something I should send to Nikon for repair, or just adjust in the Menu setting.

When I shoot in either P, S or A modes.....I get the following results....from top to bottom...
Spot meter mode: 2 stops underexposed
Matrix meter mode: 1 stop underexposed
Center weighted mode: looks right to me.

Thanks for your advice and suggestions.

Roger
Based on those photos I don't think you have an exposure problem; all of those exposures look correct to me based on the metering mode you selected. The root of the problem, I think, is that you may not fully understand how your camera determines exposure.

This article explains it all in depth and better than I could: Camera Metering and Exposure

The quick fix for your situation is to simply correct the exposure during post-processing or use the Exposure Compensation function on your D750.
...
 
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pforsell

Senior Member
I am having exposure issues with my D750. I have a few months left on my warranty and would appreciate your advice if this is something I should send to Nikon for repair, or just adjust in the Menu setting.

When I shoot in either P, S or A modes.....I get the following results....from top to bottom...
Spot meter mode: 2 stops underexposed
Matrix meter mode: 1 stop underexposed
Center weighted mode: looks right to me.

Thanks for your advice and suggestions.

Roger

The camera looks fine to me and the results as expected. You need to familiarize yourself with the metering modes and the exposure meter. The matrix mode is kind of auto mode that gets the exposure close enough, and until you know how to get the maximum out of center or spot modes -- and why -- it's safest to use matrix.
 
Spot meter should only be used when you have exactly an 18% grey target. That is what it is set for. Matrix has its uses but rarely do I use it. I almost always use center weighted. Depending on the subject you might have to use exposure compensation.
 

pforsell

Senior Member
Spot meter should only be used when you have exactly an 18% grey target....

With all due respect and with most friendly kindness: that quoted sentence is so wrong that it's not easy to put it right.

Nikon exposure meters have been tuned since time immemorial in such a way, that the spot metered value is 2.7EV below saturation. It still is true with D5. The meter is actually tuned to 12.8 % reflection, exactly as the Kodak grey card packaging tells.

One counter example to the "... only be used when you have exactly an 18% grey ..." is like this: spot meter off the brightest highlights you want to preserve, set +2.7 EV exposure correction, and you're golden.

When you want white snow instead of grey, white wedding gown instead of gray, black tuxedo instead of gray and so forth, use spot metering and set appropriate EC.

The spot meter is the most useful metering mode. One can set the tones exactly like Ansel Adams' zone system. Nothing whatsoever to do with 18 % grey and in practice very little to do with 12.8 % grey either. It is powerful, but the user has to know what he/she is doing.

Dismissing spot meter as some exotic "only 18 % grey" mode which it isn't, is doing a disservice to those who want to learn.
 
With all due respect and with most friendly kindness: that quoted sentence is so wrong that it's not easy to put it right.

Nikon exposure meters have been tuned since time immemorial in such a way, that the spot metered value is 2.7EV below saturation. It still is true with D5. The meter is actually tuned to 12.8 % reflection, exactly as the Kodak grey card packaging tells.

One counter example to the "... only be used when you have exactly an 18% grey ..." is like this: spot meter off the brightest highlights you want to preserve, set +2.7 EV exposure correction, and you're golden.

When you want white snow instead of grey, white wedding gown instead of gray, black tuxedo instead of gray and so forth, use spot metering and set appropriate EC.

The spot meter is the most useful metering mode. One can set the tones exactly like Ansel Adams' zone system. Nothing whatsoever to do with 18 % grey and in practice very little to do with 12.8 % grey either. It is powerful, but the user has to know what he/she is doing.

Dismissing spot meter as some exotic "only 18 % grey" mode which it isn't, is doing a disservice to those who want to learn.


Everyone including you is entitled to his opinion but it is an opinion. Do not call anyone WRONG. That is just rude no matter how you state it.
 

hark

Administrator
Staff member
Super Mod
Contributor
I used to use Matrix metering for all my photos but found I was using the +/- exposure compensation button A LOT. When I switched to Center Weighted metering, the exposure seems to be much more accurate without having to override it like I did with Matrix metering. Most of the time I am in Aperture Priority with a D750. So what you are experiencing sounds about right.

And for the record, I agree with the explanation [MENTION=6277]Don Kuykendall[/MENTION] gave for spot metering. All of the metering types are supposed to meter for 18% gray. Matrix metering factors in the entire image. Center Weighted metering is predominately the center area, but if I remember correctly, I *think* you can adjust the size of the circle used for Center Weighted metering. And Spot metering takes in a very small area from which to meter. But they all meter for 18% gray.
 
I used to use Matrix metering for all my photos but found I was using the +/- exposure compensation button A LOT. When I switched to Center Weighted metering, the exposure seems to be much more accurate without having to override it like I did with Matrix metering. Most of the time I am in Aperture Priority with a D750. So what you are experiencing sounds about right.

And for the record, I agree with the explanation @Don Kuykendall gave for spot metering. All of the metering types are supposed to meter for 18% gray. Matrix metering factors in the entire image. Center Weighted metering is predominately the center area, but if I remember correctly, I *think* you can adjust the size of the circle used for Center Weighted metering. And Spot metering takes in a very small area from which to meter. But they all meter for 18% gray.

Yes, you can adjust the size of the area in center weighted. It is a great way to tailor the way your camera works to more suit your style of shooting.
 

Samo

Senior Member
Spot metering is a very effective tool in the kit if you know how to utilize it. Folks who are rooted in their method often dismiss such tools. Sort of like low light shooters who often present themselves as such only because they have no clue about flash.

Spot metering should be used when you understand it and know what you are doing. Mod your phrasing is, how to say without being rude, not very well stated.
 

Horoscope Fish

Senior Member
As I look at things the camera's exposure meter is there to give me consistent exposure, based on a Standard (of reflective light). 18% is what we used for a long time, thanks to Kodak, but what the exact nature of the Standard is, precisely, is really inconsequential since only the photographer can determine what is "proper" exposure for a particular shot. That being said, this is how the different metering modes work...
....
Center-Weighted metering biases the meter to a central portion of the frame, regardless of focus point(s) employed. Just how large an area that central portion of the frame used to determine exposure IS can be adjusted to a degree but a constant with Center-Weighted is that it is always the center of the frame that is biased at 75% in calculating exposure, with the remaining bits of the frame comprising the remaining 25%. This is how Nikon explains it:
Nikon said:
... the circular area in the middle of the frame averages everything it finds there, giving that calculation a 75% weight in the overall computation for exposure. Brightnesses [sic] outside the circle are still considered however their influence is minor. The size of the circular reading can be changed depending on which Nikon Camera you have.

....
Spot metering biases the exposure calculation to that very specific portion of the frame that falls under the focus-point, wherever that focus point happens to be in the frame. Put the focus-point on what it is in the frame you want exposed properly (as based on the Standard) and you're good to go. There's nothing particularly exotic about it, you simply need to understand how it works and it's not exactly rocket-science. In my mind I ask myself, "What, exactly, and too the exclusion of everything else in the frame, do I want to be "properly" exposed?" That's where I put the "spot" when using Spot metering. Here's what Nikon has to say about when to use Spot metering, it's a tad vague but the thing about the "exposure target" is what is important here, I think:
Nikon said:
When to use it? Using the Spot Meter takes practice and learning which areas of the frame make good exposure targets is something the camera will teach to you over time. Use the histogram feature in the Playback mode of your Nikon Camera to evaluate how well you are doing.

....
Matrix metering is a bit of an odd duck. Matrix uses the entire frame to calculate exposure but with a degree of bias is given to the focus point. Further, Nikon's Matrix metering mode uses a built-in database of what I'm going to refer to as "stock shots" that are used by the camera to attempt to give you exposure you'll be happy with. This is how Nikon explains it:
Nikon said:
Matrix Meter is called the 3D RGB Color Matrix Meter.
This meter gathers information from 1005 red, green, and blue sensors and factors in distance information provided by the lens as it evaluates proper exposure calculation. This meter instantly analyzes a scene’s overall brightness, contrast, and other lighting characteristics, comparing what is sees against an onboard database of over 30,000 images for unsurpassed exposure accuracy, even in the most challenging photographic situations. By the time the 3D Matrix meter has made its considerations of colors by hue and saturation, tonal ranges by brightest and darkest, areas of similar tonality that are connected or separated, distance to the subject, and compared that to its database generated from photographic images, it’s got a very good idea of what the exposure should be.

....
Source: What is the difference between Spot, Center-Weighted and Matrix Metering?
 
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Samo

Senior Member
Good review of basics Paul.

For the op, with regard to the side track on spot metering, the manner in which I use spot metering is to always use it in manual only. I lock in the mid tone with the ael button because typically you have a recompose and shoot situation. If you are a bbf person this can make the metering mode difficult to use. I would be more concerned about shutter freeze. Just messing with you! ;)

There are many ways to skin a horse. Even dead horses! :)
 
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Blade Canyon

Senior Member
This post made me realize I had never changed the metering mode on my D800 since I bought it years ago. It has been set on Matrix since Day One. It was an even bigger surprise to discover that it's not something set on a menu or on an assigned top button, as it was on my D600, but after a few minutes of searching I discovered the rotating knob around the AE-L/AF-L button. I moved it to Center Weighted.

On my D600, I had the FX button assigned to spot-meter so I could grab a really quick spot reading without taking my eye away from the view finder. Yet I never did that on D800.
 

Samo

Senior Member
This post made me realize I had never changed the metering mode on my D800 since I bought it years ago. It has been set on Matrix since Day One. It was an even bigger surprise to discover that it's not something set on a menu or on an assigned top button, as it was on my D600, but after a few minutes of searching I discovered the rotating knob around the AE-L/AF-L button. I moved it to Center Weighted.

On my D600, I had the FX button assigned to spot-meter so I could grab a really quick spot reading without taking my eye away from the view finder. Yet I never did that on D800.

I do stuff like this all the time. LOL

Did I mention that I do not like getting new cameras?
 

spb_stan

Senior Member
Metering is a tool set, not some absolute, but Matrix does a pretty good job of balancing a lot of factors to guess what you intended. That also makes it less desirable when you know just what you want and know what the meter is actually telling you. In studio work or in difficult lighting, like stage or theater work, spot can be your friend. In the sample photos about, each seemed right bases on what the meter was seeing, which is not what the photographer sees of the overall scene.Spot is the most "accurate" for what it does, but what it does is not how a photographer expects unless he thinks like the meter. Visualize how the meter sees it and it becomes a very valuable tool and realizing spot means spot, not a scene, and its value reported is in proportion between full black and saturated white, middle grey which turns out to be 18% of full well white mixed with dead black is right in the middle of our perception of brightness. Take a can of white paint and dribble in and mix black until it looks half as bright, and note that you added black with 18% of the volume of the white paint. This is a crude thought experiment that describes what the spot meter is telling you.
So naturally, the meter will run you astray when the subject is supposed to be bright, like a sunny day brides white dress. If you went by the meter, it would tell you to lower exposure because it thinks the dress is too bright. So the image comes out dull grey. Next, take a photo of the groom in his deep black suit or tux. The meter tells you and the camera that it is way too dark so suggests/sets a few stops higher exposure. The image shows the suit a dull grey instead of rich deep black. The camera is not wrong, based on the simple instructions the meter goes by. That is where the photographer enters the picture, he knows the meter is showing a mid point so he knows he has to adjust exposure to compensate for the difference between middle grey and the intended brightness in an photo. So he dials in a couple stops higher exposure in the Triad, for the wedding dress and a few stops less exposure for the dark suit. Same with snow photos, always look grey unless compensated because you know the meter is telling the truth about what it sees, assuming it thinks middle grey is optimum. So you dial in more exposure by the amount you thing the scene is brighter than middle grey. Grey is not a color, it is an energy level of light.
There is an old classic book on exposure that explains it all in an easy to understand style called "Understanding Exposure" by Bryan Peterson It was written for film back in the day but has been updated to a 4th edition. Armed with an understanding of this essential element of photography makes everything seem simple.....it is. Once you understand exposure, any camera will do exactly as you intend. Every confusion has a foundation in not really understanding this core concept.
 

pforsell

Senior Member
... All of the metering types are supposed to meter for 18% gray. Matrix metering factors in the entire image. Center Weighted metering is predominately the center area, but if I remember correctly ... But they all meter for 18% gray.

With all due respect, and for what it's worth, you might want to read my summary, or the referenced ISO standards, or the link below. No hearsay, no opinions, just the actual facts.

The exposure meter is finely engineered piece of equipment and the user's opinion about it doesn't change the actual operation.


You'll see that ISO 2240, 2721 and 12232:2006 (and related ANSI equivalent) imply:


"The adequate average exposure Hm is regarded as 1/7.8 of the exposure level at the saturation point "

1/7.8 = (1/2 stop below 18% Middle-Gray) = 12.8% = -2.7 stops from saturation.

Kodak Grey Card user Manual states, that "take a reading from the card and open half a stop" and since the meaning of "open" in this case might be archaic to some, it means add 1/2 stop of positive EC. And that's just what the ISO standards point out: 1/2 stop up from 12.8% is 18%.

If you prefer a longer explanation, see here:
Meters Don't See 18% Gray by Thom Hogan

I'll leave this now. I don't like shouting contests where the loudest person wants to have his/her way regardless of the actual facts. I am only interested in discussing the facts with other interested parties. Thanks.
 
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hark

Administrator
Staff member
Super Mod
Contributor
With all due respect, and for what it's worth, you might want to read my summary, or the referenced ISO standards, or the link below. No hearsay, no opinions, just the actual facts.

The exposure meter is finely engineered piece of equipment and the user's opinion about it doesn't change the actual operation.


You'll see that ISO 2240, 2721 and 12232:2006 (and related ANSI equivalent) imply:


"The adequate average exposure Hm is regarded as 1/7.8 of the exposure level at the saturation point "

1/7.8 = (1/2 stop below 18% Middle-Gray) = 12.8% = -2.7 stops from saturation.

Kodak Grey Card user Manual states, that "take a reading from the card and open half a stop" and since the meaning of "open" in this case might be archaic to some, it means add 1/2 stop of positive EC. And that's just what the ISO standards point out: 1/2 stop up from 12.8% is 18%.

If you prefer a longer explanation, see here:
Meters Don't See 18% Gray by Thom Hogan

I'll leave this now. I don't like shouting contests where the loudest person wants to have his/her way regardless of the actual facts. I am only interested in discussing the facts with other interested parties. Thanks.

I am not the only one who doesn't always agree with Thom Hogan. He is quite good, but no one is always right in every instance.
 
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