metering

[Omer]

When photographing birds or small objects, its good to chose spot metering to get proper exposure of the bird using one focal point anywhere in the frame. This would work even if the bird is in one corner of the frame. Thats what I have heard.

But does a camera automatically chose one focal point for spot metering or do we have to chose which focal point to chose. It would be almost impossible to proper expose a bird using only one focal point. Which brings me to my question. I use a D5100. How can i photograph birds using one spot metering and a nikon 70-300mm lens.

[chauncey]

Quite often it's a crap shoot...you want your subject properly exposed but what about the background.
BTW, welcome aboard, ya might want to give us a heads-up on your skill level in PP software.

[Manfred M]

Both the metering point and the focus points are set independently, and your metering (even in spot metering mode) will not be the same as your focus point. I don't shoot the D5100, so am not familiar with the controls to set this. On my D90, these have to be set using menu options and on my D800, I can set the metering mode with a switch, but the options (for instance size of the metering point) have to be set via a menu. I suspect the D5100 is likley menu driven for the settings.

I am not a birder, so can't make specific recommendations, but I generally use single focus point and an averaging metering mode for exposure for the bulk of my shooting, and will use the exposure compensation control to tweak my exposure. You can certainly set one of the multi-focal points for focus and still use spot metering mode/ One thing to understand when you do spot meter, you are telling the camera to assume that your metering target is a mid-gray colour (that's the way all reflective in-camera light meters work), so if you shoot a bird that is predominatly black or very dark, it will be underexposed and if you shoot a white bird, you will find the opposite and get an overexposed shot.

[RichardTaylor]

I do shoot a few bird pics and as a Canon shooter use evaluative (or matrix metering for Nikon cameras) metering with exposure compensation dialed in if needed be. If you have time use the histogram as a guide. At the end of the day use what ever metering mode you are comfortable with. I shoot with centre focus ponit only active, focussed on the birds eye (if the bird is filling the frame) and try try to shoot a bit loose leaving room for compositional tidy up when cropping in PPing.

[ajohnw]

I suspect the set up will be similar to a D7000 so assuming it is.

Spot metering and centre weighted average need some thought to use. Especially spot. Both will meter to mid grey which may turn out ok or may not depending on what you point it at. Centre weighted will basically take some notice of the rest of the frame. Not so spot.

The matrix metering on the other hand will attempt to fit what it sees into a correct exposure so in general is the most reliable one to use as it leaves fewer problems. Mainly back lit subjects where you may need to apply up to maybe + 1 1/2 stops / EV exposure compensation. Perhaps even 2 at times. The converse can also happen if you are photographing a scene and want to capture every tone in the clouds rather than clipping them. Maybe - 1 stop/EV in that case. It really depends on the scene. No one can give you exact figures. It's a case of using your camera bearing these things in mind and finding out. No need to find out when you actually go out and shoot birds. Any old thing will do. Much can be learned by pointing a camera out of a window or trying various things in the garden.

Most cameras will favour the central AF point or you can set it up like that. Depth of field is controlled by the aperture the lens is set too. There are calculators on the web eg google dofmaster. Best play with that for a while to get a feel for it. This aspect is easy to practice by pointing the camera out of a window etc.

There are a couple of video's at the end of this thread that may help you control the camera. Not sure if this can be done on a D5100 but it allows the camera metering and focus to be locked when and where needed. 1/2 shutter button for exposure lock and release the assigned button to lock the focus. It saves messing around with focusing and metering points actually in the camera..

Single point auto focus vs manual focus

John
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[PhotomanJohn]

I would like to clarify earlier comments about spot metering. All the Nikon cameras that I am familiar with including the D5100, D7000, D7100 and D800 when in spot metering mode meter a fixed diameter spot around the current manually selected focus point. If the camera is set to automatically select the focus point then the camera meters around the center focus point no matter which point it has selected for focus. Refer to page 68 of the D5100 reference manual.

John

[Omer]

Thanks everyone for the great replies. Thanks for the video ajohnw. By PPing do you guys mean photoshopping? I am sorry I am a beginner and I thought that cameras use spot metering against a particular focal point facing the area that needs to be exposed.
If I want to photograph a bird that is in flight and far away so that it takes up only a small portion of the frame, then I have read that spot metering is best. If I do use spot metering, does the camera know what part of the image needs proper exposure, because it will only expose a spot. What if the bird ends up in a corner of the frame?
And Photoman John, your reply has hit the spot really. Thanks a lot.

[Omer]

I Posted this reply while reading photoman's post, so it has all been clarified now. Thanks for your help everyone.

[rpcrowe]

Another way to meter for a bird in flight is to use manual exposure and substitute metering. Meter the grass or a gray card which is in approximately the same light as the BIF will be. Then adjust your metering. Increase exposure for darker birds and decrease exposure for lighter birds; just the opposite from the way you would adjust your camera's built-in, reflected light meter. Using this manner to expose for BIF, your exposure will be correct for the bird and will not be impacted by the background against which the bird is flying.

The amount of exposure adjustment will be a matter of experience,,,

BTW: I have recently thought about using my incident light meter for measuring the exposure for BIF photography. I have not done so but, I strongly suspect that it would be virtually the same as using substitute metering. If you have a flash meter, most of them will also measure incident ambient light.

[ajohnw]

Another way to meter for a bird in flight is to use manual exposure and substitute metering. Meter the grass or a gray card which is in approximately the same light as the BIF will be. Then adjust your metering. Increase exposure for darker birds and decrease exposure for lighter birds; just the opposite from the way you would adjust your camera's built-in, reflected light meter. Using this manner to expose for BIF, your exposure will be correct for the bird and will not be impacted bt the background against which the bird is flying.

The amount of exposure adjustment will be a matter of experience,,,

BTW: I have recently thought about using my incident light meter for measuring the exposure for BIF photography. I have not done so but, I strongly suspect that it would be virtually the same as using substitute metering. If you have a flash meter, most of them will also measure incident ambient light.

Some people have substitute metered against their hand using average to grey metering usually centre weighted but in principle spot could be used. eg If bird is in sky hold hand up in a suitable position and meter. I suspect it needs a hand fiddle factor as it isn't mid grey and an assistant with many dslr set ups - especially the one Richard shows on his smugmug pages. Other have metered the ground - usually grass to obtain mid grey reflected metering.

It's also possible to use a camera as a spot meter. Set aperture priority and scan the scene counting stops for each time the shutter speed changes by a factor of 2. Sounds simple just set an exposure in the middle but one end or the other may be clipped. I believe there are some people about who would spot meter the highlight that they want to capture and then set compensation so that this is just captured in the camera's dynamic range. This page gives some idea what they are up to also an indication of what things may be around mid grey. I suspect as this was all laid out on film some mods may be needed for digital.

http://en.wikipedia.org/wiki/Zone_System

John
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[Omer]

How can I meter for grass and how can exposure be adjusted? Is there an article about that on this site?

[Manfred M]

I generally use matrix metering and then use my camera's histogram display to tweak the results. I'm not quite sure why you want to meter grass.

Once you understand how to read a histogram, you will find your exposures will be a lot better.

https://www.cambridgeincolour.com/tu...istograms1.htm

[RichardTaylor]

This may also be helpful.

https://www.cambridgeincolour.com/tu...a-metering.htm

[Colin Southern]

When photographing birds or small objects, its good to chose spot metering to get proper exposure of the bird using one focal point anywhere in the frame.

Hi Omer,

No. Your whole premise is wrong here. Spot metering doesn't give a "proper" exposure any more than any other metering mode does; what it will do is expose the subject as if it were a middle gray which may or (more likely) may not be correct. eg if you spot meter a black bird you'll get a middle gray bird, and if you spot meter a white bird you'll get a gray bird. No metering mode will necessarily give a "correct" exposure - it's simply a way to tell the camera which parts of the frame to consider when coming up with it's "starting point"; the difference is though that the bigger the area that the camera is told to consider, the greater the chance that this "starting point" will be correct - thus - spot metering more often than not gives INCORRECT initial results.

All metering works on a middle gray average, and if the subject isn't middle gray then we need to add what's called Exposure Compensation ("EC") to adjust the exposure from a middle gray to what it's actually supposed to be. eg if you spot meter a white bird then you need to add +2 EC and if it's a black bird then you'd need to add -2 EV.

But all of that is moot because (a) spot metering birds is difficult, and (b) there's no need for it. In my opinion it's better to just use Evaluative / Matrix metering so the camera can work with the entire scene (which will more often than not be blue sky) and will thus get a very accurate reading; you just need to shift that reading up or down with EC to get the exposure where you want it. In reality it's usually a case of revealing detail of darker coloured birds in post processing; if you over-expose a shot to reveal detail in a dark bird then it'll also over-expose everything else as well, which doesn't make for a nice shot.

The BIGGEST mistake that people make is trying to capture a dark bird whilst shooting INTO the light; that'll end up giving a bad result EVERY time. Shoot with the sun/light behind you or illuminating the bird from an angle.

Hope this helps.

[ajohnw]

I generally use matrix metering and then use my camera's histogram display to tweak the results. I'm not quite sure why you want to meter grass.

Once you understand how to read a histogram, you will find your exposures will be a lot better.

https://www.cambridgeincolour.com/tu...istograms1.htm

Probably because I mentioned that as a substitute for mid grey as per the hand as well. Both in real terms are likely to need compensation anyway. I was just expanding on Robert's post - substitute metering. It wouldn't be of any use for birds in flight and I would hesitate to suggest either hand or grass to a new camera users.

John
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[Brownbear]

Hi Omer,

I hope you don't mind if I ask a question of Colin on your thread. I'm asking because I'm trying to learn more about the different types of metering modes when photographing birds, and hopefully my question will be helpful to you, too.

Colin,

Why is it that if one is photographing a white bird, say a swan or an egret (that doesn't fill the frame), if one switches to spot metering it seems easier to manage the exposure of the bird with nice detail (even if it means that the rest of the surrounding scenery goes black), and that this is also the case when photographing the moon.

I understand that I should also be able to do this with matrix metering but it seems quicker and easier to do with spot metering.

I have also read somewhere that spot metering produces truer to life colours. Is this true?

Thank you.

Hi Omer,

No. Your whole premise is wrong here. Spot metering doesn't give a "proper" exposure any more than any other metering mode does; what it will do is expose the subject as if it were a middle gray which may or (more likely) may not be correct. eg if you spot meter a black bird you'll get a middle gray bird, and if you spot meter a white bird you'll get a gray bird. No metering mode will necessarily give a "correct" exposure - it's simply a way to tell the camera which parts of the frame to consider when coming up with it's "starting point"; the difference is though that the bigger the area that the camera is told to consider, the greater the chance that this "starting point" will be correct - thus - spot metering more often than not gives INCORRECT initial results.

All metering works on a middle gray average, and if the subject isn't middle gray then we need to add what's called Exposure Compensation ("EC") to adjust the exposure from a middle gray to what it's actually supposed to be. eg if you spot meter a white bird then you need to add +2 EC and if it's a black bird then you'd need to add -2 EV.

But all of that is moot because (a) spot metering birds is difficult, and (b) there's no need for it. In my opinion it's better to just use Evaluative / Matrix metering so the camera can work with the entire scene (which will more often than not be blue sky) and will thus get a very accurate reading; you just need to shift that reading up or down with EC to get the exposure where you want it. In reality it's usually a case of revealing detail of darker coloured birds in post processing; if you over-expose a shot to reveal detail in a dark bird then it'll also over-expose everything else as well, which doesn't make for a nice shot.

The BIGGEST mistake that people make is trying to capture a dark bird whilst shooting INTO the light; that'll end up giving a bad result EVERY time. Shoot with the sun/light behind you or illuminating the bird from an angle.

Hope this helps.

[Colin Southern]

Why is it that if one is photographing a white bird, say a swan or an egret (that doesn't fill the frame), if one switches to spot metering it seems easier to manage the exposure of the bird with nice detail (even if it means that the rest of the surrounding scenery goes black), and that this is also the case when photographing the moon.

Hi Christina,

Because it's in essence under-exposing the shot by around 2 stops (you'll get a gray bird / moon), whereas at the "correct" exposure you'll get most of the detail crammed up in the highlights, which will result in loss of contrast (to human eyes -- the camera is still fine with it) and thus some tricky post-processing to recover it. I should add too though that spot metering things like the moon is still just an average of that (small) area; so you can't just blindly say "the moon is a highlight so add +2EC" - it'll already contain values that are middle gray - but also some that are higher and lower in value than middle gray. The moon is a bit of a special case though because it's surrounded by a "sea of black" which evaluative / matrix metering will try to compensate for resulting in an extremely slow shutterspeed and gross over-exposure of the moon).

However I stand by what I said originally about using matrix / evaluative even in situations like this (ie BIF, not moon shots!) for 2 reasons;

1. If the correct EC is set then matrix / evaluative will give you EXACTLY the same shutterspeed as spot metering anyway, and

2. It's a darn site easier (and thus more repeatable) to "matrix meter" an entire sky (with a bird in it) than it is to spot-meter a bird in flight.

The paradox/irony is that spot-metering a white bird is giving "better" results because people don't know how to use spot metering correctly (ie adding/subtracting exposure compensation) and as a result they're under-exposing by 2 stops in this situation which is giving lots of protection to highlight detail.

As a rule of thumb in this situation I'd probably dial in around -1EC, but primarily I'm guided by the blinkies; (if I have blinkies in any important area then I'm going to dial in some -EC)

I understand that I should also be able to do this with matrix metering but it seems quicker and easier to do with spot metering.

EC is EC - it's exactly the same to do in any metering mode. The net result of any metering mode is a shutterspeed / aperture / ISO calculation that's use for the entire shot. Once one has the ideal combination it affects the entire frame and it doesn't matter how it was derived. Coming up with 1/2000th @ F2.8 @ ISO 200 from spot metering is no different in exposure to coming up with 1/2000th @ F2.8 @ ISO 200 from evaluative metering - the difference is in how easy it is to obtain that reading -- and I maintain that it's easier to hit the side of a barn with a shotgun than it is to hit a fast moving target with a rifle!

The difference is though that for normal photography, the narrower the metering area the greater the chance one will need to apply EC - because most scenes average out to middle gray anyway - so no EC is required. BIF is a bit different though in that often we have a problem where folks are saying "matrix / evaluative always under-exposes my BIF shots", but they're not stopping to think about it from the cameras perspective. Point a camera on matrix / evaluative at a bright sky and it's going to expose that bright sky (and everything in it) as a middle gray. So folks just need to understand that if they don't understand metering nor EC then evaluative /matrix metering isn't doing to work well for them with dark birds and bright skies. In my opinion it's better to delve a little deeper (like you're doing - well done) - understand what's happening and why - and then gain a far better understanding of how to handle any exposure situation with ease!

I have also read somewhere that spot metering produces truer to life colours. Is this true?

I really don't know where people come up with these things!

No - not true in the slightest. Correct exposure will influence colours (over-exposure will wash out a sky for example, and under-exposure will increase saturation (to a point -- after than it just goes black)), but how that exposure was derived is irrelevant. Folks really need to disassociate "spot metering" with "correct exposure". The ONLY time spot metering is technically correct is when the subject being metered is an exact middle gray (or equivalent gray value for a colour object). At ALL other times - in theory - a correction is required to compensate. In PRACTICE though a correction may or may not be desired, depending on things like artistic choice and how much safety margin is available and how much safety margin is desired to cut into (eg spot metering and shooting a black cat without EC will give around a 2 stop over exposure, but a 2 stop over-exposure at base ISO will essentially just be ETTR and will most likely be completely recoverable (just)).

Hope this helps!

[Brownbear]

Thank you Colin! It seems that I asked the million dollar question today, and I think I finally get it.

Thank you for answering my question so thoroughly, and explaining it so well with a great example.

I think what happens is that when one is eager to learn, you read up on things, and try them out without a thorough understanding of the subject, which includes understanding why it is working or not... Thank you!

Hi Christina,

Because it's in essence under-exposing the shot by around 2 stops (you'll get a gray bird / moon), whereas at the "correct" exposure you'll get most of the detail crammed up in the highlights, which will result in loss of contrast (to human eyes -- the camera is still fine with it) and thus some tricky post-processing to recover it. I should add too though that spot metering things like the moon is still just an average of that (small) area; so you can't just blindly say "the moon is a highlight so add +2EC" - it'll already contain values that are middle gray - but also some that are higher and lower in value than middle gray.

However I stand by what I said originally about using matrix / evaluative even in situations like this (ie BIF, not moon shots!) for 2 reasons;

1. If the correct EC is set then matrix / evaluative will give you EXACTLY the same shutterspeed as spot metering anyway, and

2. It's a darn site easier (and this more repeatable) to "matrix meter" an entire sky (with a bird in it) than it is to spot-meter a bird in flight.

The paradox/irony is that spot-metering a white bird is giving "better" results because people don't know how to use spot metering correctly (ie adding/subtracting exposure compensation) and as a result they're under-exposing by 2 stops in this situation which is giving lots of protection to highlight detail.

As a rule of thumb in this situation I'd probably dial in around -1EC, but primarily I'm guided by the blinkies; (if I have blinkies in any important area then I'm going to dial in some -EC)



EC is EC - it's exactly the same to do in any metering mode. The net result of any metering mode is a shutterspeed / aperture / ISO calculation that's use for the entire shot. Once one has the ideal combination it affects the entire frame and it doesn't matter how it was derived. Coming up with 1/2000th @ F2.8 @ ISO 200 from spot metering is no different in exposure to coming up with 1/2000th @ F2.8 @ ISO 200 from evaluative metering - the difference is in how easy it is to obtain that reading -- and I maintain that it's easier to hit the side of a barn with a shotgun than it is to hit a fast moving target with a rifle!

The difference is though that for normal photography, the narrower the metering area the greater the chance one will need to apply EC - because most scenes average out to middle gray anyway - so no EC is required. BIF is a bit different though in that often we have a problem where folks are saying "matrix / evaluative always under-exposes my BIF shots", but they're not stopping to think about it from the cameras perspective. Point a camera on matrix / evaluative at a bright sky and it's going to expose that bright sky (and everything in it) as a middle gray. So folks just need to understand that if they don't understand metering nor EC then evaluative /matrix metering isn't doing to work well for them with dark birds and bright skies. In my opinion it's better to delve a little deeper (like you're doing - well done) - understand what's happening and why - and then gain a far better understanding of how to handle any exposure situation with ease!



I really don't know where people come up with these things!

No - not true in the slightest. Correct exposure will influence colours (over-exposure will wash out a sky for example, and under-exposure will increase saturation (to a point -- after than it just goes black)), but how that exposure was derived is irrelevant. Folks really need to disassociate "spot metering" with "correct exposure". The ONLY time spot metering is technically correct is when the subject being metered is an exact middle gray (or equivalent gray value for a colour object). At ALL other times - in theory - a correction is required to compensate. In PRACTICE though a correction may or may not be desired, depending on things like artistic choice and how much safety margin is available and how much safety margin is desired to cut into (eg spot metering and shooting a black cat without EC will give around a 2 stop over exposure, but a 2 stop over-exposure at base ISO will essentially just be ETTR and will most likely be completely recoverable (just)).

Hope this helps!

[Colin Southern]

Thank you Colin! It seems that I asked the million dollar question today, and I think I finally get it.

Thank you for answering my question so thoroughly, and explaining it so well with a great example.

I think what happens is that when one is eager to learn, you read up on things, and try them out without a thorough understanding of the subject, which includes understanding why it is working or not... Thank you!

You're welcome Christina.

Sorry that it turned into a bit of an epic post, but I felt that if I didn't address some of the peripheral areas then people wouldn't understand why what I'm saying didn't work for them. Plus it's one of the most important and yet not thoroughly understood areas of photography, and it's really not that hard to grasp once people grasp the concept that cameras can only meter light levels -- the only knowledge they have of a particular level is in how it compares to other levels in the scene (eg "zones"); for many scenes this works very well, but for other specialist scenes (small bird in a big sky, or small moon in black sky) mean that the way metering works doesn't necessarily mean that that's what the photographer wanted.

As a case-in-point, for moon shots, I'd probably just spot meter it - then chuck those values in - shoot manual - and refine from there.

In summary, I think folks probably need to just get out and shoot - pay attention to where the light source is - ride the EC - and take advantage of the feedback that digital offers and reshoot immediately after fine tuning things. The reason I push evaluative over spot is purely for consistency; BIF photography is likely to always be a case of "spray and pray" - and exposures are the last thing we want to be worrying about.

[IzzieK]

Omer....I was watching if someone will answer your question about "PPing" --it means Post Processing.-- done via an editing program, whatever you are using, not necessarily Photoshop...