Metering... confused...

Discussion in 'Olympus Cameras' started by Adobres, Dec 25, 2011.

  1. Adobres

    Adobres Mu-43 Regular

    Nov 25, 2011
    Quick question on metering, I think I understand everything on my EPM1, exept for the metering part. Do you just use the all around metering option, or when do you use the spot metering, or the other options? thanks!

  2. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Matrix metering is good for scenic shots with no defined subject. However, if you have a particular subject in your photo, you should avoid Matrix and choose either Center Weighted or Spot. I prefer Center Weighted for general-purpose use because it uses a larger area to meter off of and isn't so easily thrown off by landing on a small shadow or highlight. Spot meter can throw your exposure way off like that, while Center Weighted is more consistent.

    As a classic example, say you have a person standing in front of an outdoor sky. The sky will usually be a lot brighter, and your person will be shadowed in comparison. If you use Center Weighted meter on the subject, then it will be properly expose the person while the sky will be left alone and may be blown out if necessary. If you use Matrix Metering instead, the camera will try to retain the highlights in the sky without blowing them out. In so doing, it's going to leave your subject in shadow. What's more important, the subject of your photo or the background? I would say the subject, lol. That's why using center weighted (or spot) gives you full control of how you want your photo to come out, allowing you to properly expose the things that you want properly exposed.

    When you have no particular subject in the scene and just want an average of the entire frame, that's where Matrix Metering comes in. I rarely ever shoot those kind of photos, so I don't even touch Matrix.
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  3. ean10775

    ean10775 Mu-43 All-Pro

    Jan 31, 2011
    Cleveland, Ohio
    In general you can just use the evaluative metering option - it does a good job in most situations. The center-weighted metering can be used in situations where your subject is backlit and in the center of the frame (or you can just use evaluative and apply positive exposure compensation because you know that camera is likely to underexpose your subject.

    Spot metering can be used if you want to ensure a certain portion of your image is properly exposed - for example: you're taking a photo of a person standing inside a doorway of a dark building and want to properly expose their face, but you are standing outside in bright light. By spot metering on an area on their face you can obtain the exposure you are looking for. However, there is much more to effectively using spot metering, which can be read about here: What is spot Metering - Spot Metering Examples

    With m43 cameras with a live view of the image you intend to capture, using evaluative metering + exposure compensation or fully manual control makes the other metering options all but unnecessary in my opinion because you can see what your exposure is going to look like prior to capturing it - the same can't be said for traditional DSLR photography making the other metering modes much more useful with those cameras.
  4. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Just to be clear on this, your subject doesn't have to be in the center of the frame to use Center Weighted metering. If you focus and re-compose the AE lock will apply along with the AF lock on the default AEL/AFL modes. If you use back-button AF to separate your AutoFocus and AutoExposure functions, then you have even more control by allowing you to pick one AF spot and a different AE spot. In other words, you can chose the subject for exposure metering just like with Autofocus, anywhere you want.
  5. ean10775

    ean10775 Mu-43 All-Pro

    Jan 31, 2011
    Cleveland, Ohio
    Ned, agreed. I just wanted the OP to understand where the camera was going to calculate the exposure from for center-weighted metering.
  6. dhazeghi

    dhazeghi Mu-43 Hall of Famer Subscribing Member

    Aug 6, 2010
    San Jose, CA
    Evaluative metering (ESP) works great for most things. If you are finding images consistently under- or over- exposed in certain situations, you can always dial in exposure compensation.

  7. Adobres

    Adobres Mu-43 Regular

    Nov 25, 2011
    Thanks guys that clears up a lot. Just wondering NEd if you could clarify a bit on when you talk about:

    "If you focus and re-compose the AE lock will apply along with the AF lock on the default AEL/AFL modes. If you use back-button AF to separate your AutoFocus and AutoExposure functions, then you have even more control by allowing you to pick one AF spot and a different AE spot"

    Where do I find the settings for this?

    and also to add to al this, do you keep your focus "square" locked in the middle? I can't ever see a reason to use the option where it trys and finds where it thinks you want to focus atomatically? seems poointless?

  8. phigmov

    phigmov Mu-43 Hall of Famer Subscribing Member

    Apr 4, 2010
    A good example of wanting to focus on more than one thing (multi-point) or moving focus is a group photo - face-detect will sharpen the picture up (closing the aperture until all the faces are in focus).

    Alternatively, if you have a group of people in a line and you want to focus on the first person and get everyone else in host then you'll want to be able to move the focus point to the side.

    Having said that - I usually just use center-focus & metering too.
  9. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    Hey Adobres, just as a heads-up, there is a lot more to metering than modes. Learning how the light meter work is one of those steps to improving ones photography and increase your consistency rate for keepers.

    Two Basic Meter Notes:

    1) A reflective meter is a guide not a 100% accurate tool; and

    2) A meter typically provides a determination/read-out for 18% gray. 18% gray is a medium gray, twice as dark than the palm of one's hand, slightly lighter than grass.

    So what does this all mean? Well, set your camera to B&W (just easier in B&W) and using any metering mode (in manual center the meter for 'proper' exposure), fill the frame with a white wall and release the shutter. The resulting image should look medium gray. Do the same exercise again with a black wall ... the image again should look medium gray.

    So what does this mean? It means that the no matter what you point your meter at, it will turn that object into 18% gray. The different meter modes don't really change how the meter works but places more or less emphasis on different areas in the frame. Example- Center-Weight uses a greater percentage from the center of the frame in determining 18% gray than from the outer edges.

    The best way to understand and improve upon your metering skills is to use Manual Mode with spot metering. You select a specific light zone and then adjust accordingly.

    (Disclaimer: There are many ways to meter and adjust and just as many 'metering systems', [i.e. Adams Zone System just to name one], to help facilitate the photographer in attaining not just a 'proper' exposure but the exposure that will best capture the desired image.

    I was trained as a photojournalist, so I will explain how I expose which is much different than, say, a landscape photographer.)

    As an example:
    I was taught that in a fast moving environment to expose for the principal subject and not worry about anything else ... just let the rest fall in the exposure zones as it may. So typically I'd use a spot meter and read off the face of my principal subject and then open it up a stop if it was a white person, or close it down half a stop to one stop if it was a person of color.

    What I did was use the meter as a guide and dialed in the exposure I wanted, more shutter speed for a shallow DOF or vice versa for greater DOF. Then I'd open the aperture or lowered my shutter speed by one stop (for a light complected person) or close the aperture a stop or raised my shutter speed (for a darker complected person).

    Over time you'll be able to see the light and make the adjustments to optimized your photography.

    I have just provided you with a little information from the top of the exposure barrel, grab a good photography/exposure book and read more and experiment. There are many tool available to help with exposure some are cheap (gray card) and others are expensive (handheld meters).

    Good Luck and Good Shooting,
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  10. Ned

    Ned Mu-43 Legend

    Jul 18, 2010
    Alberta, Canada
    Yes, listen to Gary's advice! It is spot on (no, that wasn't a pun, lol!) and very concise.

    By default, when you half-press the shutter button it will set both your Autofocus and your Exposure based on what is in the frame at that particular moment, and lock it there.

    To change this behavior, go to Setup => Sprockets => Button/Dial => AFL/AEL. From there, find the AF mode you wish to work in (ie, S-AF, C-AF, MF), keeping in mind that setting back-button AF to the MF mode will allow you to use both Manual Focus and S-AF together. I never use S-AF as that turns off Manual Focus... why would anybody want to do that?

    Default mode is 1 on most, I think 2 or something for C-AF. Set any of these modes to "Mode 3", and you will have back-button focus. What that does is it will send AF capabilities to whatever button you assign as the AEL/AFL button, while leaving the half-press of the shutter to determine your Auto Exposure Lock. Depending on your camera, this may be a dedicated button already or you may have to assign one for yourself. To assign a button, go to Setup => Sprockets => Button/Dial => Button Function, and set the button you want to use for AF to "AEL/AFL".

    You now have separate and distinct control of all three functions which used to be mixed into one - Focus point, Exposure point, and Shutter release. Point the camera where you want to set the focus, press the back button. Point your camera at the frame you want properly exposed, half-press the shutter button. Frame your composition, then fully release the shutter button. That's full "manual" control of all the Auto features (I know it's an oxymoron, lol).

    Unfortunately, the default camera settings are always geared towards the Point-and-Shoot mentality, such as the turning off of Manual Focus by default (default AF mode is S-AF with no MF). This also relates to the default AEL/AFL function of tying it all into the shutter release. You point the camera at what you want to frame, release the shutter, and the camera calculates everything together at once for you. Obviously, any serious photographer will want individual control of each function to choose how WE want the photo to be made... not to have the camera decide for us how to take a picture! That also ties into your next question...

    Pointless, yes. An exercise in frustration, yes. One of the hottest selling marketing features which many consumers buy their cameras for but which experienced photographers don't even use? Yes. :) 

    Disclaimer: This WAS a huge selling feature at one time, when many people were buying cameras based on the "number of AF points". Thankfully this is falling more by the wayside... but I wouldn't be surprised if it doesn't come back - after all, the megapixel race is once again taking the forefront in consumer buying decisions now.

    As you say... why would you want the camera to choose what YOU want to focus on? Doesn't make sense. You're supposed to be the photographer.

    A single AF point is the most accurate. A diamond pattern will allow you a little bit faster control with a little less accuracy if you need (ie, some might use it for action). If you have time to, you can move that single AF point around to avoid having to "focus-then-recompose". Recomposing does throw your AF point off slightly... however, if you don't have time to play around with the focus point, then focus/recompose is the next best thing. It still lets YOU choose, which is the important thing. For instance, maybe you're shooting a series of portraits, all in portrait orientation and focused on the eyes. In that case, you would pick a focus point that's more to the "right" of the frame (which will end up at the top portion of the photo) to avoid having to move much to compose the frame. You'll still be using a Single Point, but not the center one.
  11. WT21

    WT21 Mu-43 Legend Subscribing Member

    Feb 19, 2010
    Reading Gary and Ned's responses, you might think "this isn't an easy answer." Well, it isn't! Metering is really at the heart of using photography to meet your vision. For a couple of years, I used matrix and average metering, and then did a light of dodging and burning in post. Since moving to spot, I can achieve my vision much more directly with OOC shots. Less post-work, but it took, and is still taking, a lot of practice.
  12. Adobres

    Adobres Mu-43 Regular

    Nov 25, 2011
    Awesome! thanks so much guys, I feel lik eI should be paying a tuition here :) 

    I can post this another day but if you do check this, I have developed on my own to use shutter priority when in low light and program mode in daylight/more light. I did this becuase I like keeping the ISO down around 600-800 in low light and the camera when set to auto ISO seems to always favour the max ISO when in program mode. Anyways, does this sound kinda accurate, or I guess its depending on the scenario. Anyways, thanks again for all your help!

  13. MajorMagee

    MajorMagee Mu-43 All-Pro

    Feb 24, 2011
    Dayton, OH
    In P, A, or S mode the camera is always doing the same calculation of the exposure requirements based on the readings it's taking in from the internal light meter. You can get a feel for the rules that it tries to follow from the Program Line Diagram in the manual. As you can see there's a fairly narrow range of conditions where it's not at an extreme, and in that zone it follows just a few even steps to go from one to the other extreme. The Auto ISO function tracks right along with this logic and it will be driven to the extremes over much of the possible range of light readings unless you tell it to do otherwise.
  14. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    Hey Adam, I'd never use auto ISO under any circumstance. Go Manual, extend your hand out and position your palm to reflect light similar as your subject, meter off your palm, center the meter for an 18% reflective exposure then over-expose by one stop. Compose, focus and shoot.
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