Do some of the camera settings intimidate you? Do you want to learn how to develop your photography skills and learn how to use your camera effectively without always going back to the “auto” function? These challenges are for you!
These are designed for those experienced photographers to share their knowledge with others who are anxious to learn and improve their skills. This fortnight's challenge is ...
Metering Modes and Exposure Lock
Digital cameras, including most Point and Shoots, have three main ways to evaluate the light received and compute a recommended exposure. They are Matrix/Evaluative (Nikon/Canon terms, I’ll use the Nikon term to keep it short), Spot and Center Weighted.
You set the desired metering mode either from the menu system, or from a dedicated button and dial on the camera body in more advanced cameras. If a button, it will have a distinctive mark on it. You will need to consult your manual for your camera. If you can’t work it out, please ask us in a tagged comment below.
Matrix Metering
Matrix Metering is the usual default mode, and the one you probably already use. The metering system divides the sensor into many small rectangles (several thousand for a 24mp camera), considers the light at each site equally, computes the differences between different sites (the dynamic range) and comes up with a recommended “correct” Aperture and Shutter based upon the ISO you have set. Most cameras use extra smarts to evaluate the distribution of light and distances against a reference database and to make smart adjustments based upon the image type.
Since this mode concerns the whole frame, there is nothing for you to do other than point, focus and then shoot. The metering is handled “under the covers” with the last shutter half press before you fire it all the way.
Spot Metering
Sometimes instead of considering all areas equally, an exposure should be based on just one small piece of an image, ignoring the rest. A typical case is a light subject against a significantly darker background. Here’s an example where I did not want the dark background to influence the exposure.
If you have ever shot the moon on a dark night you will have encountered the same issue. If the dark/black background is included in the metering, the exposure chosen will be far too bright.
This requires us to use Spot Metering.
The “spot” in Spot Metering varies slightly from manufacturer to manufacturer. For Nikon Cameras it is the current active focus point. For Canon cameras, it is in the center of the viewfinder, independent of any focus point. For your camera, consult your manual. The spot is typically very small, usually less than 1% of the entire frame.
To use this mode, first set spot metering mode then activate the meter with a half press of the shutter which you can then release. Next point the camera to put the spot over what you want to meter. You can see the metered values in the viewfinder or on the LCD screen.
This point, however, will often not be where you want it in the final frame, so you try to move the camera to reframe. Oh dear, the metered values change based upon what is now under the spot! The metered exposure is, by default, not locked. We will have to do something to “lock” this exposure, like we “lock” the Auto Focus, before we re-frame and move off the spot. There are several ways to do this, depending on your camera, but a variant of at least one will be available to you.
Exposure Lock
The most accessible option on almost all cameras is a button labeled AE-L, or possibly AE-L/AF-L. By default, pressing and holding this button, with your right thumb is best, will lock in the current metered exposure. As long as you keep the button pressed, this exposure will be locked. You can move the camera and Auto Focus on yet another point if you wish. And with the Auto Focus locked (another half shutter press) and the Exposure locked (AE-L button still pressed) you can reframe again if you wish, then press the shutter all the way. You can then release your thumb.
Another way is available on some cameras, and that is to change the action of a half shutter press to lock not only the Auto Focus, but to also lock the exposure as well. This method will couple the AF Lock and the Exposure Lock onto the same point, unlike the method above where you have decoupled them, but it may serve you.
A final method allows you to decouple focus and exposure without keeping several buttons half pressed until you trip the shutter. It is to redefine the behavior of the AE-L button to Exposure-Lock-and-Hold (or something similar depending on your manufacturer). This will allow you to press and then release the AE-L button to keep the locked exposure until you press it again, or a stand-by timer (which you can also customize) expires.
If you are having trouble finding how to do this for your camera, please ask in a tagged comment below.
Center Weighted Metering
This third metering mode is something in between Matrix and Spot. It allows you to meter on a circle in the center of the frame, and have the camera use this as primary information, and information in the rest of the frame to a lesser extent. This is unlike Spot Metering where the rest of the frame outside the spot is ignored completely. This circle is larger than a “spot” and in most cameras can be resized to about 4% to about 12% of the frame. The exact options vary from manufacturer to manufacturer.
You activate this mode exactly as you do Spot. The circle is always in the center of the frame, not tied to a focus point specifically, and on many cameras is not marked. You can lock the exposure after you have captured it and then reframe as required, just as we did for Spot.
For me, I find it is not as “severe” as spot, and if I am metering on strong highlights, it can give me a little detail in the shadow outside the circle that I wouldn’t get with Spot. Here is a fairly typical use of Center Weighted metering. Rather than take space here, you can read the "tech facts" by just clicking on the image.
One Scene, Three Metering Modes
Below are three images of a window with the bright sun and blue sky shot from inside a building with artificial light sources. The composition is not much to write home about, but I hope it shows you the result of the three metering modes. Matrix blows out the window highlights, Spot (on the window and sky) “correctly” exposes the blue sky to a “12% gray” on my Nikon and consequently renders almost no detail on the inside walls and window frame, and Center Weighted (on the window and sky) has the sky exposed stronger than with “spot” (but not blown out) and so shows a little detail on the inside frame and wall, missing from spot.
Tone is SOOC, whereas in reality for “production” I would probably accept the “center weighted” and adjust the tone further in something like Lightroom or Camera Raw of Photoshop.
Matrix Mode f/5.6, 1/200, ISO 100
Spot Mode f/5.6, 1/1250, ISO 100
Center Weighted Mode f/5.6, 1/640, ISO 100
Conclusion
Next week, the second of the fortnight for metering modes, we’ll try and move on a little more and talk about mixing the Metering Modes with Exposure Compensation, which was the subject of the last two weeks here at CSC. Yes, they do go together, and we’ll show you how and why you should consider doing so.
Challenge for This Week
Of course, if you now understand the principles, please show us what you have achieved, and perhaps give us a little commentary about how you achieved it. You may not need any further direction from us, but a “moon” shot or a portrait on a very dark background would be ideal for “spot.”
However, if you need a little practice pressing all those buttons, try to find a situation similar to my “window,” one with very bright highlights and dark shadows. Put your camera into A/Av, select a comfortable aperture between f/5.6 and f/8. Take at least three shots of the same scene with each of the three metering modes.
For “basic” credit, shoot the first with Matrix metering and for the next two, meter from the strong highlights for Spot and Center Weighted.
For “extra” credit, take two more shots, metering from a darker source. If you do all five, you should have five distinct exposure interpretations of the same scene. See if you can explain the results seen in each shot.
Good shooting, and we hope you find at least some of this interesting and useful. As always, please post your results here, along with any comments, suggestions or questions. If we don't know the answers, we will certainly find out for you. If you want to use a separate tag, please use "csc-metering"
In this one, the spot metering seems to overexpose the flower, which is slightly out of focus (the wind I think). i was thinking that the spot metering might help get good exposure for a flower taken against a brighter background like the sky. It's possible that it didn't work because the flower takes up so much of the frame?
@camerasavvy Superb explanations. I am enjoying this series. Here's a shot where I used spot metering on the sunlit grass to bring out the contrast and the rim lighting highlights around the toddler.
@jasperc That's the idea. The composition problem here in my mind is the highlight on the top right on the leaves. Since it is brighter than the grass, it appears to be quite blown out and to me pulls the eye up and to the right. Perhaps crop it out, or move a little to your right so it's not in the frame? Also note how the hair edges/light is brighter than the grass too, but that you want I think...
@francoise The flower spot metered is very nice. I am sure you noted it, but see how the background stays much darker and less obtrusive; the background is the darkest of the three, and as expected, center weighted is next and lastly matrix/pattern has the lightest background, the camera including the "dark" information fully. Great illustration.
@jasperc You certainly could clone it out, but there is a lot of it, and you might want some hint of it still there. Best to step a little and get it right as you shoot. Or as right as you can.
So today, I finally had some time to try the three metering modes. I only posted the shot I liked best. In this shot (f 5.6, 1/350 M mode) I used the center weighted metering. I liked this one best because of exposure. It highlighted the blossom without blowing out the whites (spot metering) or making the background really dark (matrix). I hope to find time to try it with a moon shot. Also, I forgot to try metering on different places, only metered the blossom. Ah....next time! I do want to keep playing with this as I''m not really feeling confident with which one to pick for different situations but I definitely feel more knowledgable! Thanks again for these challenges!! I really appreciate them!
@dianen You've got the idea for sure. Nice clear and clean exposure. While I personally use spot and center weighted metering for certain types of "difficult" image, I do trust matrix much of the time with modern digital cameras. Others don't however, spot metering as a general rule.
For my Camera Savvy Metering Challenge I set up a little 'Still Life' Shot in front of the Dining Room Window with the curtain half drawn.
I tested Partial Metering & Centre Weighted Metering on the Right Eye of the Bear, the Belly of the Bear, the Left Foot of the Bear & on the Hat.
All images were shot @ f8., 400 ISO. The image on the left is the Base Evaluative Metering Shot @ 1/13. In this shot the Left side of the Bear is a bit dark & lacking in detail.
The other shots varied in the level of brightness & detail Some were way too bright & others way too dark.
The image on the right is Centre Weighted Metering on the Left Foot of the Bear @ 1/6 - this shot is the best compromise. You can see all the detail in the Bear & both it's eyes. While the front of the chair & the window are blown out, I find that is acceptable because the Bear is the Subject of the Shot.
I enjoyed learning this & love the Exposure Lock Button, much simpler than what I was doing
I wanted to capture (photographically) one of the bees feasting in the garden. Since I don't have a good macro or telephoto I knew I would have to make a major crop so I used centre-weighted metering. I set the camera to manual: 1/1000, f11 for good DOF close-up and ISO to auto. Interested to know what settings camerasavvy would use for a shot like this...
@jasperc I think your settings worked well. As you said capturing a bee is difficult and the metering you used makes sense for this type of shot. I like the fact that the black on the bee doesn't look like it's too much in the shadow and you can see some details of the "fur" on the bee. You should "bee" proud of this.
@jasperc Hi Jasper. Re the bee. Just wondered, did you get those exposure settings from the camera meter and then dialed them in with "M?" And if you had a huge frame where you wanted the exposure yo ignore that, Center Weighted or Spot is a good choice. Puling up the shadows some ion the be would work in post pretty well since I am sure there is detail there, another reason not to use matrix, to make sure there is enough detail where you want it even if still in some shadows.
@jennymallett Hi Jenny. Yes, you have the idea. Cute bear! Center weighted is certainly a good choice for this shot. "Spot" would have blown the highlights even more.
@frankhymus Thanks Frank. I hit on those exposure settings going by first principles: a fast shutter speed to capture the moving bee; a high f number for DOF (but not so high diffraction would set in) and I then left it to auto iso to strike the balance. Thanks for the suggestion to pull up the shadows - is this a question of using a dodge brush over the bee?
I have been having a go at changing the metering mode, something I have not tried before. I do struggle to see the point of this as I use manual and live view all the time. If my subject, such as a flower is not the correct exposure using live view then I would just change it in manual before shooting. I am never relying on the camera to choose the exposure only to get me roughly there. If there are more advantages than I am seeing to changing the metering mode rather than adjusting exposure in manual please will you let me know
@helenhelen It will allow you to determine an exposure from which to work much faster than a "hunt and peck" or "trial and error" method based on exactly what you want to include to contribute to the light decision, useful if the scene is transient and you don't have time to experiment.
Also, it's for those of us who "shoot raw for the editor," especially in high contrast situations with strong highlights and deep shadow, where we don't want to blow the highlights away completely but yet expose as strongly as we can to get as much (editor recoverable) detail in the shadows. This so-called "Expose to the Right" ("right" being on the histogram, you'll see the acronym ETTR sometimes) strategy can much more accurately be controlled with selective metering, exposure compensation thrown in on top, besides getting you to the "right" exposure usually with a single effort. New Nikon full-frame cameras even have a new metering mode "highlight weighted metering" that will do this automatically without having to point at those highlights, very useful.
Your Live View strategy can certainly be an extra plus quickly judging and changing exposure settings. With your Olympus, have you thought of using the electronic viewfinder? That would give you the advantages of seeing the exposure right off the sensor as well as the advantages of the firmer grip and control that a classic shooting position will give you hand held. For many classic DSLRs though, the Live View/sensor-based strategy will not perform as well as "through the viewfinder," auto-focus and focus tracking being just one. Plus they are usually heavier than mirrorless-system cameras and so Live View grip problems are exaggerated.
I applaud your perseverance and tenacity using "M" solely. There is, of course, nothing you can't shoot in "M" that you can in "A" and "S," and of course visa versa, it comes down to personal preference ultimately.
@frankhymus Thanks for your reply. Yes I can see that it may be quicker at times to use a different metering system, as long as I wasn't changing it per shot and in a fast moving situation this would help. Most of the time I am now sure it doesn't actually matter to me because of the camera I have and the way I use it. I always shoot in RAW and I use live view through the electronic viewfinder not across the screen because as you say tis gives me better camera stabilisation when I shoot. I suppose I am always changing my exposure dependent on my live view image which is very accurate on this camera. However I think I must be more aware that the electronic image is a JPG version of what I am shooting so what I am seeing may not be accurate and yes maybe I should shoot to the right a little more and maybe trust the camera a little more.
I use M mostly but do occasionally use A and S when the action is fast such as wildlife shooting. If I have time I always us M because I can then be in control.
This exercise has been really good because it all comes together to help me understand and improve on what I am doing and it is certainly doing that. Thanks so much for your reply which gives me loads to think about, now for some more experimentation.
@helenhelen Cool Helen. Actually, what you see in the EVF and in Live View is technically not processed jpeg, that's for stills, but "processed" video nevertheless, MPEG4 perhaps, just as in a standard camcorder. But glad this latest csc and perhaps my further thoughts gave you something to think about. All the best...
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So today, I finally had some time to try the three metering modes. I only posted the shot I liked best. In this shot (f 5.6, 1/350 M mode) I used the center weighted metering. I liked this one best because of exposure. It highlighted the blossom without blowing out the whites (spot metering) or making the background really dark (matrix). I hope to find time to try it with a moon shot. Also, I forgot to try metering on different places, only metered the blossom. Ah....next time! I do want to keep playing with this as I''m not really feeling confident with which one to pick for different situations but I definitely feel more knowledgable! Thanks again for these challenges!! I really appreciate them!
For my Camera Savvy Metering Challenge I set up a little 'Still Life' Shot in front of the Dining Room Window with the curtain half drawn.
I tested Partial Metering & Centre Weighted Metering on the Right Eye of the Bear, the Belly of the Bear, the Left Foot of the Bear & on the Hat.
All images were shot @ f8., 400 ISO. The image on the left is the Base Evaluative Metering Shot @ 1/13. In this shot the Left side of the Bear is a bit dark & lacking in detail.
The other shots varied in the level of brightness & detail Some were way too bright & others way too dark.
The image on the right is Centre Weighted Metering on the Left Foot of the Bear @ 1/6 - this shot is the best compromise. You can see all the detail in the Bear & both it's eyes. While the front of the chair & the window are blown out, I find that is acceptable because the Bear is the Subject of the Shot.
I enjoyed learning this & love the Exposure Lock Button, much simpler than what I was doing
Also, it's for those of us who "shoot raw for the editor," especially in high contrast situations with strong highlights and deep shadow, where we don't want to blow the highlights away completely but yet expose as strongly as we can to get as much (editor recoverable) detail in the shadows. This so-called "Expose to the Right" ("right" being on the histogram, you'll see the acronym ETTR sometimes) strategy can much more accurately be controlled with selective metering, exposure compensation thrown in on top, besides getting you to the "right" exposure usually with a single effort. New Nikon full-frame cameras even have a new metering mode "highlight weighted metering" that will do this automatically without having to point at those highlights, very useful.
Your Live View strategy can certainly be an extra plus quickly judging and changing exposure settings. With your Olympus, have you thought of using the electronic viewfinder? That would give you the advantages of seeing the exposure right off the sensor as well as the advantages of the firmer grip and control that a classic shooting position will give you hand held. For many classic DSLRs though, the Live View/sensor-based strategy will not perform as well as "through the viewfinder," auto-focus and focus tracking being just one. Plus they are usually heavier than mirrorless-system cameras and so Live View grip problems are exaggerated.
I applaud your perseverance and tenacity using "M" solely. There is, of course, nothing you can't shoot in "M" that you can in "A" and "S," and of course visa versa, it comes down to personal preference ultimately.
I use M mostly but do occasionally use A and S when the action is fast such as wildlife shooting. If I have time I always us M because I can then be in control.
This exercise has been really good because it all comes together to help me understand and improve on what I am doing and it is certainly doing that. Thanks so much for your reply which gives me loads to think about, now for some more experimentation.