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AE and AF Lock function

Discussion in 'Panasonic Cameras' started by rossi46, Mar 16, 2012.

  1. rossi46

    rossi46 Mu-43 Regular

    141
    Mar 1, 2012
    Hallo everybody.....

    I am just pondering and checking on this fucntion,...I was wondering why do we still need to use it?

    With the GX1, we are able to adjust the size area of focus on the touch screen easily, and the spot where we want to focus quite easily.

    When we are doing this on screen focus, does the GX1 already automatically calculate the focus area information to preset the shutter speed and so on?


    I can only imagine the only reason we want to lock AE and AF is to capture the light info, set the aperture and ISO based on a subject,...and keep this settings throughout the time when we are moving around in the area we are capturing and so on.
    Is my understanding correct?
     
  2. Kiwi Paul

    Kiwi Paul Mu-43 Top Veteran

    729
    Aug 15, 2011
    Aberdeen Scotland
    The main purpose of AF lock is so you can focus on an object then recompose the picture and the camera will set to exposure to the new composition but retain the focus from the initial composition. I use it a lot, although it's not so user friendly on the G3, Olympus cameras are much better.
    AE lock is similar but you lock the exposure and set the focus when you take the picture, I don't use it much if at all.
    You are correct in that a touch screen allows you to focus on any part of the shot so AF and AE lock become less useful, but when using a camera with a viewfinder it's very useful.

    Paul
     
  3. Kevin

    Kevin Mu-43 Regular

    62
    Aug 25, 2011
    Vancouver, Canada
    How is it not user friendly? You press the shutter half way and then recompose the picture. How does Olympus do it?
     
  4. FastCorner

    FastCorner Mu-43 Veteran

    310
    May 28, 2011
    In difficult lighting conditions, I use AE Lock to set a baseline and use EV compensation to adjust the histogram. If you set the EV compensation without locking AE, there's a good chance in "dynamic" situations that the exposure comes out wrong.

    IMO AF Lock is great when you're holding the camera with a large lens one hand. Really tough to keep the shutter half-pressed sometimes.

    On my G2, however, the lock goes away when I chimp into Playback mode. Bummer.
     
  5. rossi46

    rossi46 Mu-43 Regular

    141
    Mar 1, 2012

    Hallo FastCorner,....

    Talking about AE lock with EV compensation, I am just trying to figure out -

    We AE lock so that we can get the spot on the LCD screen where we want the exposure level to be metered,....
    But with the LCD screen display, can't we just have Aperture Priority or Shutter Speed priority at the low light conditions,..then view the brightness on the screen, and adjust the exposure from there?

    Rather than having to focus on the area of preferred light, lock the AE then adjust the composition.


    I am sorry, I am a newbie and just want to know more.
     
  6. napilopez

    napilopez Contributing Editor

    826
    Feb 21, 2012
    NYC Area
    Napier Lopez
    This triggers a mini rant about the G3, a camera which I love but has some annoying quibbles which mostly apply to panny cams in general.

    That on the G3 even though exposure is locked for the resulting image, there is nothing in the preview to tell you you are locking exposure when you half-shutter-press. I spent many an hour trying to figure out why I couldn't lock exposure on the G3 until I realized I was; it's just that live-view doesn't show it. Basically, if I set exposure on a shadowy region of my display, continue to half hold the shutter, and pan the camera to a brighter area, the preview will darken to compensate. Once I fully press the shutter, it will be exposed based on the shadowy area I originally metered with.

    However, if you assign a dedicated button to exposure lock, then the preview actually will show the locked exposure, and not change as you point at area of different brightness. It's kind of bizarre and unecessary behavior really. I see no benefit whatsoever to the G3(and all panasonics AFAIK) behaving like this, so that half-shutter pressing and having a dedicated AE lock button function differently.

    It's especially annoying on the G3 since panny cams already have an issue where what you see isn't always what you get, particularly in dark situations. If you aren't spot metering, I find the G3 will underexpose almost ever dimly lit scene with any amount of dynamic range, even though your image preview shows you a perfectly exposed scene. It's honestly tremendously annoying as I shoot indoors or at night half the time. This makes me also need to set a button to AE preview, which will shot how the final image will be exposed. Only thing is, you don't have many buttons to program on the G3.

    On the Oly cams, if you half press the shutter, the preview image will reflect the lock. In other words, it functions exactly like the dedicated AE button does on a panny. Probably the thing I miss the most from my E-PL1, besides IBIS.
     
    • Like Like x 1
  7. bryan

    bryan Mu-43 Regular

    34
    Feb 27, 2012
    That's not quite correct. With automatic exposure, the camera is constantly adjusting the exposure level based on the scene. The purpose of AE Lock is to freeze the camera's exposure settings, so that if the scene changes, the AE system won't change aperture or shutter speed values.

    I find AF/AE Lock a lot more useful with the "AF/AE Lock Hold" option enabled (located in the Custom menu of Panasonic Lumix G cameras).
     
  8. fredlong

    fredlong Just this guy...

    Apr 18, 2011
    Massachusetts USA
    Fred
    It's often quicker to lock the focus and recompose than to move the focus area around. Another thing I do is lock focus on something in the frame while waiting for a moving subject to enter the frame.

    Holding the shutter release half way for more than a few seconds is annoying and for me not reliable. I just let go and the camera has to go through it's whole auto focus routine again.

    Fred
     
  9. Kevin

    Kevin Mu-43 Regular

    62
    Aug 25, 2011
    Vancouver, Canada
    Until your mini rant I never even realized a shutter half press on the G3 locks the exposure too! I had always thought it was AF lock only and programmed the Fn1 button as AF/AE lock. Just played around in the settings and, unless I'm mistaken, the only way to get AF lock without AE lock is to program one of the function buttons for it.
     
  10. Kiwi Paul

    Kiwi Paul Mu-43 Top Veteran

    729
    Aug 15, 2011
    Aberdeen Scotland
    That's it, that's why it's a bit of a cack handed affair to use AE or AF lock on the G3. You either have to hold the FCN button in while recomposing or configure it so it locks the focus or exposure until you press it again to reset it.
    With Oly cameras you only need to press the shutter half way to lock and all the way to set the exposure and take the picture.

    Paul
     
  11. ill_dawg

    ill_dawg Mu-43 Veteran

    201
    Aug 26, 2010
    Yesterday, I was taking a picture of a mostly black dog on a grey blanket with white walls and a whitish floor. My e-pl1 couldn't get the exposure quite right on full or center-weighted metering. I have my ael set to spot metering, so I took a reading off of the grey blanket and was good to go. I'm not sure how panny does it, but I love the ability to lock metering off of any point, regardless of where I want to focus. I didn't want to focus on the blanket, but neutral grey is the best target for metering in even light. Is the metering systems on the panny bodies so different? Do you never need to meter on the sky or on the sand when full frame or center weighted doesn't do the trick?

    Sent from my HTC Vision using Tapatalk
     
  12. rparmar

    rparmar Mu-43 Top Veteran

    639
    Jun 14, 2011
    Limerick, Ireland
    Sorry I misread the post. Useless info deleted!
     
  13. Kevin

    Kevin Mu-43 Regular

    62
    Aug 25, 2011
    Vancouver, Canada
    Ya, for some reason I had always thought the G3 was the same but after taking some test shots and playing around with the camera this morning I was obviously wrong! Much prefer the Olympus (and virtually every other camera maker) method of a half shutter press for AF lock only.
     
  14. josh

    josh Mu-43 Regular

    52
    Sep 17, 2010
    i think i'm missing something, pressing the af lock doesn't seem to do anything. I just want to keep my focus after I've fine tuned it for multiple exposures of the same subject without having to refocus for every shot.
     
  15. jloden

    jloden Mu-43 Hall of Famer

    May 15, 2012
    Hunterdon County, NJ
    Jay
    With regards to the first part above, it depends on what metering mode you're using. Center-weighed or multi-metering will take meter readings around the scene and average them (biased towards the center of the frame in center-weighted). In those cases, selecting a focus point doesn't necessarily mean your exposure will be correct for the area you selected.

    AE lock is useful in certain situations, particularly ones with a high amount of dynamic range. For example, if your subject is backlit, it allows you to spot meter off the subject instead of the overall scene, and expose properly for the subject. Otherwise the light meter tries to balance out everything to 18% gray and you'll likely get a silhouette effect instead of a properly exposed subject with a bright background. Conversely, if you *wanted* a silhouette effect, you can use AE lock to expose for the background, while focusing on the backlit subject.

    Another common reason to use AE lock would be as you noted, to lock settings when working repeated in an area that has the same exposure values. If you're moving around and want your exposure to stay the same even if the light changes, it's invaluable. Lastly, as others mentioned, touch screen focus isn't always the fastest way to work (especially with a viewfinder), and you may wish to lock exposure while recomposing a shot.

    Josh - usually default behavior is for the lock button to only apply while it is held down, so you would need to keep it held in while recomposing. I don't have my GX1 handy but I believe you can set it in the menu to "hold" lock, so that it retains the focus/exposure lock until the button is pressed a second time. That's how I have mine set up for AE lock, so that I don't have to hold it down while recomposing.
     
  16. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    SoCal
    AEL is useful if you understand how the light meter works. The light meter spits out settings for medium gray (generally 18% gray). If you fill your frame with a white wall, the resulting setting will underexpose the wall rendering it a medium gray. If you fill your frame with a black wall, the light meter will over expose making the black wall, once again, the same medium gray. There are many meter modes that are useful to compensate for how the meter works. But knowing what is considered by the light meter as medium gray and lock one's exposure for that medium gray subject, is very useful and fast when shooting a dynamic scene. Metering in Manual is similar to using the AEL.

    AFL is very useful for shooting in a dynamic scene and not having time to move the focus box/point around the frame. One just focuses on the subject, recomposes and release the shutter. All of which can be done very, very quickly. Moving the focus to a back button increases the ease and speed of AFL.

    Gary
     
    • Like Like x 1
  17. vtsteevo

    vtsteevo Mu-43 Regular

    96
    Nov 20, 2012
    jloden, I have a GX1 and I use AEL the exact same way. My only confusion is why this button is called AF/AE lock, and not just AE lock. Sure, it locks both AF and AE, but as soon as you start pressing the shutter button, it changes the AF while keeping AE locked.

    To use AFL the way GaryAyla described it I would just half press the shutter. Is there any other way to lock AF but not AE?
     
  18. GaryAyala

    GaryAyala Mu-43 Legend

    Jan 2, 2011
    SoCal
    Move the focus to a back button. I had my GF1 setup that way, I'm sure the GX1 can accomodate this setup as well. It takes a while to adjust to back button focus, but most who use it find it worthwhile.

    Gary
     
  19. jloden

    jloden Mu-43 Hall of Famer

    May 15, 2012
    Hunterdon County, NJ
    Jay
    You can configure AF/AE lock on the Panasonic to lock both focus & exposure, or just one of the two. Hence why it's labeled AF/AE lock since it can be either or both things.

    You can also decouple the focus from the shutter so that pressing the shutter halfway does not re-focus the shot. However, that requires you to use the AFL button to focus every shot.

    Personally I prefer to pair focus with the shutter button and use AEL only for that reason, since I can still lock for either focus (hold shutter halfway) or exposure (AEL button) and recompose.
     
  20. josh

    josh Mu-43 Regular

    52
    Sep 17, 2010
    Alright this is great.

    In the "CUSTOM" menu on the second page I set the AF/AE LOCK to "AF" and the AF/AE LOCK HOLD to "ON", that mixed with MF+AF set to on I have this set up exactly how I want. I can auto focus on my subject, manually fine tune it, and leave it there between shots.
     
    • Like Like x 1