Newb question about metering

J-see

Senior Member
It was never "meter using the blue sky" ...
The OP stated:



For me the pertinent part of the question is "how do you do both at the same time?"

Maybe I am just dumb


The only way I can think of is using spot metering on the sky to weigh it in the exposure, adjust the settings to that and then focus on whatever is needed.
 

grandpaw

Senior Member
On my camera I have the AE lock button on the back of the camera set to get and hold the exposure while the button is depressed. So if I wanted to meter the sky I would point the camera toward the sky , press and hold the AE lock button down with my thumb and while still holding the button down compose my picture, press my shutter half way down to focus and then I would press all the way down to take the picture. I usually use "Aperture priority" when shooting.
 

yauman

Senior Member
I am rather new but learning aggressively and seem to have hit a sticking point. I am shooting in manual and seem to grasp how to make a correct exposure. What I cant seem to grasp is metering. I am reading Bryan Petersons book and he constantly is referring to metering the sky and recomposing. I don't know how metering is indicated in the camera. How do you lock in a metering reading? If you are using single point focus and than recomposing, how do you do both at the same time? I'm sure I am just missing something obvious. Any help would be much appreciated. Thanks.

Ok, you are "over thinking" this. It really is quite simple so let me try. You are shooting in Manual mode - right. What it means is that you set the Aperture, the Shutter Speed and ISO - the camera does NOTHING for you. BUT you are using the camera's light meter to get the light level reading. This all has NOTHING to do with how or where you focus. So let's look at a concrete example.

In Manual mode, you are shooting a landscape scenery with the sky, hills and a lake in foreground and you want to focus on a boat tied to a tree in front of you. Now, you set your shutter speed at say 1/200 -it will stay that way - you are in manual mode. You set your ISO at 100 - you are in manual mode, it will stay that way. Now, you aim at the sky and using the light meter (in the view finder) you adjust your F-Stop to be correct pointing at the sky. Say, you set it at F16 - and the little bar in the light meter is correct at the center (0 ev point). You have the correct exposure - you are in manual mode - it will stay that way. There's no exposure to "lock in" - it will just stay that way - you are in Manual Mode - the camera will NOT change any settings for you!

Now, recompose, aim at the boat and now focus - doesn't matter what focus mode you use - the exposure you have set will NOT change -the sky will still be correctly exposed, the hill a bit darker and body of water probably correct. If you notice the light meter reading when you aim at the boat, it may indicate that you are not correctly expose - but it does nothing to the camera's setting - you set it to ISO 100, Shutter 200 and F16 - it will stay that way and you snap the picture with those parameters - regardless of what the light meter read - YOU ARE IN MANUAL Mode. In Manual Mode, the light meter tell YOU what you exposure is - over or under but it does NOTHING to change the camera's setting - so you can recompose, re-focus all you want and the image will be shot at whatever settings you have set. You set it based on light reading of the sky and it will be exposed as such.

Hope that makes sense.
 
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Lawrence

Senior Member
Ok, you are "over thinking" this. It really is quite simple so let me try. You are shooting in Manual mode - right. What it means is that you set the Aperture, the Shutter Speed and ISO - the camera does NOTHING for you. BUT you are using the camera's light meter to get the light level reading. This all has NOTHING to do with how or where you focus. So let's look at a concrete example.

In Manual mode, you are shooting a landscape scenery with the sky, hills and a lake in foreground and you want to focus on a boat tied to a tree in front of you. Now, you set your shutter speed at say 1/200 -it will stay that way - you are in manual mode. You set your ISO at 100 - you are in manual mode, it will stay that way. Now, you aim at the sky and using the light meter (in the view finder) you adjust your F-Stop to be correct pointing at the sky. Say, you set it at F16 - and the little bar in the light meter is correct at the center (0 ev point). You have the correct exposure - you are in manual mode - it will stay that way. There's now exposure to "lock in" - it will just stay that way - you are in Manual Mode - the camera will NOT change any settings for you!

Now, recompose, aim at the boat and now focus - doesn't matter what focus mode you use - the exposure you have set will NOT change -the sky will still be correctly exposed, the hill a bit darker and body of water probably correct. If you notice the light meter reading when you aim at the boat, it may indicate that you are not correctly expose - but it does nothing to the camera's setting - you set it to ISO 100, Shutter 200 and F16 - it will stay that way and you snap the picture with those parameters - regardless of what the light meter read - YOU ARE IN MANUAL Mode. In Manual Mode, the light meter tell YOU what you exposure is - over or under but it does NOTHING to change the camera's setting - so you can recompose, re-focus all you want and the image will be shot at whatever settings you have set. You set it based on light reading of the sky and it will be exposed as such.

Hope that makes sense.

Makes perfect sense - thank you. The answer I was looking for
 

grandpaw

Senior Member
Yauman, gave a good explanation of how you do this and I might add that I have not read Bryan Petterson's book but I would like to tell you what works for me.

I have found that if I have two very different areas in the same shot that if my subject is in the darker area and I expose for it, the sky gets blown out and if I point towards the sky and take the reading the sky is correct but the subject is very dark. What I have found to work much better is to use matrix metering and point at an area that contains about half of the bright area and about half of the darker area and set my exposure setting, then I re compose focus and shoot. This usually give me skies that are not blown out and a subject that comes out reasonably well. In my experience pointing just at the sky only gives me a nice sky and the subject is too dark and if you take a reading just on the dark area the sky is blown out. To me what you are trying to accomplish in setting the exposure is NOT to get one or the other areas right but to have both come out reasonably good and by including both while setting your exposure you have a much better chance at getting the whole scene correct.

This is just my opinion and it works the best for me. It doesn't matter if you are shooting in aperture priority like I do or manual, if you have the exposure lock button set to hold the exposure setting and you re compose, focus and shoot it will work.
 

J-see

Senior Member
It's always best to maximise exposure without clipping the highlights. For me, in the majority of cases, the sky is much brighter than anything else which implies if I let that weigh on my exposure, the rest becomes underexposed with an inevitable quality loss as a direct result of that. It is better to expose to the darker parts in a shot while controlling the highlights.

I don't know the theory behind sky-exposure and there might be an advantage to it I not yet understand.
 

WayneF

Senior Member
I don't know the theory behind sky-exposure and there might be an advantage to it I not yet understand.


It is just coincidence. A little like metering at the subjects feet to exclude the sky or bright window behind, it can work out.

Of course, we are introducing a new picture situation, and hoping we can make it work out,
instead of working with the real picture, and hoping we can make it work out.
 

J-see

Senior Member
Thanks, I'll check it out. It's not that I use metering much, or at least not as intended, but a little more knowledge won't harm.
 

yauman

Senior Member
One more important point about manual mode and using the camera's light meter which I left out - the exposure mode. Even in Manual Mode, the 3 exposure mode - Matrix, Center-Weigh and Spot will affect how the Light Meter read the scene. It will NOT affect how the camera sets anything - you are in manual mode (nag.. nag ..nag.. :) ) So, in the scene I described above, ie a landscape, the proper mode to use would be Matrix - the light meter will give you reading a based on the evaluation of the whole scene. I shoot models and when I'm not using strobes, I always use spot metering - meter the flesh tone or a grey card to determine the exposure setting. Once I set it, it will stay that way (I'm in Manual mode) then I recompose and using spot focusing, focus on the eye (eye closest to the camera - always.) Voila!
 

Jaysmark

Senior Member
Thank you guys so much for all your effort. What I actually learned is that metering is not something separate from exposure but really the cameras best guess, which is not always correct. I now understand what is meant by metering off different light sources. Now to go out and practice. How do you guys choose where to meter in certain situations? A portrait or a sunset for example. Oh one other question. Is it impossible to not get flashing highlights on my LCD under any exposure? I always have something flashing and have tested certain situations taking a array of exposures and I could not get rid of the blinking. Do you then underexpose a little and try to clean it up in edit? How the hell do you get detail from a window inside a low light room. They just blowout no matter where I meter. I cant thank you guys enough as you continue you to be generous and push my learning forward.
 

J-see

Senior Member
I hardly ever use the light meter to get correct exposure. Let me first tell you; I'm the strange duck so it's up to you to make up your mind about what I say.

Correct exposure is great if you shoot JPEG but if you shoot RAW, it's no longer about getting the correct exposure but about maximising the data you gather. A light meter is only good to warn you about potential clipping.

I try to gather as much "light" as possible while trying to remain in control of any sacrifice to be made. It doesn't matter if the shot is incorrectly exposed when shot since I can always correctly expose it in post.
 

Eyelight

Senior Member
If the range of light in the scene is wider than the range the sensor can capture in one shot (bright window in an otherwise unlit room), you will not be able to expose both the room and the window properly. You can get it close and then adjust part of the single image in post, or you could take two (or more) exposures and merge the parts in post.
 

Horoscope Fish

Senior Member
What I actually learned is that metering is not something separate from exposure but really the cameras best guess, which is not always correct.
Well hold on a minute here... Your camera's meter does not "guess", nor it is ever really "wrong" (unless it's broken). What it does is EVALUATE and then suggests, or sets, exposure based on that evaluation. You may not LIKE what it's doing but you can't expect it to understand what you want. Further, what the meter is doing but is entirely predicable once you understand how the meter does what it does. The Absolutely Crucial Point is this: The light meter in your camera exposes every shot for middle grey. EVERY SHOT, ALL THE TIME. No matter what you're photographing, no matter how you're metering the camera's light meter exposes for middle grey every... single... time. You can over-ride the meter by using the Exposure Compensation button of course, but you're still basing the adjustment off of the meter's initial reading which will always be based on middle grey. Stop thinking of it as an Exposure Meter and start thinking of it as a "Middle Grey Meter", because really... That's what it is and that's how it operates.

.....
How do you guys choose where to meter in certain situations? A portrait or a sunset for example.
I usually use Matrix metering because most of the time it's very, very good. I use my histograms and Exposure Compensation button to adjust when necessary. When I'm not using Matrix I'm typically using "Spot" metering to ensure that the subject is correctly exposed, everything else be damned. What might help you a lot is reading this article: Understanding Histograms. It will teach you how to better work with your camera's meter and how to nail proper exposure every time. Where perfect exposure is not possible, you have to make a choice but understanding your camera's histogram will help you make those decisions so you wind up getting what you want.

.....
Oh one other question. Is it impossible to not get flashing highlights on my LCD under any exposure?
Yes, see the link above regarding understanding and using histograms.
 

WayneF

Senior Member
Thank you guys so much for all your effort. What I actually learned is that metering is not something separate from exposure but really the cameras best guess, which is not always correct. I now understand what is meant by metering off different light sources. Now to go out and practice. How do you guys choose where to meter in certain situations? A portrait or a sunset for example. Oh one other question. Is it impossible to not get flashing highlights on my LCD under any exposure? I always have something flashing and have tested certain situations taking a array of exposures and I could not get rid of the blinking. Do you then underexpose a little and try to clean it up in edit? How the hell do you get detail from a window inside a low light room. They just blowout no matter where I meter. I cant thank you guys enough as you continue you to be generous and push my learning forward.

Are you asking about turning blinking off, or preventing the blinking? You don't want to turn it off. First thing to learn is to look only at the three RGB histograms, and to totally ignore the one single gray histogram ( Two types of Histograms ). See the page, D750 manual page 249. It is not uncommon for one channel to blink, and the way you prevent blinking is to reduce exposure so that it is not overexposing there. Just barely not blinking is NOT underexposure (however, sometimes we can accept some overexposure, it just depends on scene and goals).

To get detail in a room window, expose for the window, and use flash for the indoors.
 

Jaysmark

Senior Member
Wow, you guys rule. I again cant thank you enough for your direct and comprehensive answers. I am definitely a nikonite for life now. I have gotten more from this one post than three books. I just exposed my first room properly and finally grasp metering and manual mode. I'm still working on grasping 18% grey though.
 

Horoscope Fish

Senior Member
Wow, you guys rule. I again cant thank you enough for your direct and comprehensive answers. I am definitely a nikonite for life now. I have gotten more from this one post than three books. I just exposed my first room properly and finally grasp metering and manual mode. I'm still working on grasping 18% grey though.
If it helps, just forget about the "18%" part. I don't use it and prefer to say, "middle grey" instead. We could get needlessly technical on this point about the actual percentages and so forth but there's really not much point in it. Suffice it to say middle grey is a tone that is pretty much halfway between absolute black and absolute white on a lightness scale as seen by the human eye. It's right down the middle, if you will. Average. This what the camera's meter uses... The "average". Get it?

If you're not, don't worry... It'll sink in eventually. :D

....
 

yauman

Senior Member
Wow, you guys rule. I again cant thank you enough for your direct and comprehensive answers. I am definitely a nikonite for life now. I have gotten more from this one post than three books. I just exposed my first room properly and finally grasp metering and manual mode. I'm still working on grasping 18% grey though.

See my White and Black Cat examples here in this post in the other thread about perceived over/under exposed image - keep the cat image in mind when you use exposure meters of any species!
 

Al Gentile

Senior Member
"I'm still working on grasping 18% grey though."

Back in the early 1900s, Kodak engineers determined that if, in a 'typical' scene, you averaged all the colors and brightnesses, you'd end up with the color grey that reflected 18% of all the light that fell on it. Thus, light meters were calibrated to assume that they were always pointed at an 'average' scene, and would recommend the proper combination of aperture and shutter speed (for the given ASA [ISO]) that would correctly render the proper exposure. Although that's clearly sometimes a mistaken assumption, it makes more sense than to assume the scene was always brighter or darker than normal.

Nowadays your camera's meter is still based on the same assumption - that the scene in front of it is 'average'. If the scene is brighter or darker than average, then the meter will recommend the wrong exposure. Matrix metering is less likely to be confused than the other metering modes (e.g. spot, center-weighted), but it can still be confused in some tricky situations.

Luckily, the BLUE sky (away from the sun, no clouds) is about as bright as a 'grey card' which reflects 18% of the light falling on it. Thus, if you 'zero' your meter when pointed at the blue sky, you'll be setting the proper exposure for anything else in the same light. If you then recompose & focus, you can ignore your meter, which may have subsequently varied from the 'blue sky' recommendation when you recomposed.

Hope that helps.

Al
 
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