Me or My 800

Discussion in 'Nikon' started by mark_mandell, Nov 25, 2013.

  1. I've had several instances where, when taking an image in either full Program or a Preferred mode, the image is hugely overexposed to the point of being blown-out and useless. I have put ISO sensitivity control to "manual" but the issue still arises. It has happened with different lenses and different lighting situations (bright foreground or bright background).
    I can post examples if that would help.
    tia
     
  2. Yes when shooting a scene that has bright back lighting the matrix metering will overexpose. I was just photographing a burned forest with bright spots in the background and had to underexpose quite a bit. This type of situation is a good time to use spot metering - or just watch your histogram.
     
  3. I thought the specific idea of Matrix Metering was a whole-scene evaluation resulting in an idealised exposure for the whole scene. Centre Weighted specifically biases against anything outside the centre circle (of chosen diameter) and Spot ignores everything outside the much smaller circle diameter (of chosen diameter)?
    or just watch your histogram.​
    Yup, that's good advice. I thought the D800 had live histos?
    Oh, and yes could you post a couple of pics with EXIF intact?
     
  4. Sometimes overexposure results when the aperture of the lens is not closing reliably. Do the overexposed shots appear like they were shot with the lens wide open (when you intended the lens to be stopped down).
     
  5. pge

    pge

    Mark, you did not specifically mention in your post which metering you were using. Is it possible that you were spot metering rather than matrix metering?
     
  6. Example1: Spot metered, ISO selected was 400 in S @ 1/200. Shifted ISO to 800 and stopped to f/5. Lens: 70-200 VR-II
    00cBZ1-543781184.jpg
     
  7. Example 2: ISO set at 400 and shutter at 1/200. Spot-metered but the camera shifted to ISO1100 and opened up to f/2.8. Lens: 70-200 VR-II
    00cBZ8-543781284.jpg
     
  8. Example 3: ISO set at 500 in "P". Spot-metered. Lens. 24-85 @ 24, program went f/3.5 @ 1/50th.
    00cBZB-543781484.jpg
     
  9. You can use spot metering the same way you would use an incident meter, but you need to read off something of neutral luminance, such as green foliage. If the 'spot' is on the dark bear or dark jacket the camera will always over expose.
     
  10. Mark, the P mode did a good job in all three of those images. It preserved detail in the subject. The bear pictures would have been worthless if the bear was underexposed.
    I wanted to tell you to shoot manual or aperture priority to solve the program mode issues, but when your subject has such high dynamic range, there is only so much the camera can do. The best solution is to add some fill flash to reduce dynamic range. But that has issues too.
     
  11. I can play with No. 3 in Lightroom to get some of the "haze" out, but the first 2 are useless. Suggestions are welcome.
     
  12. Appears as though you are spot-metering on very dark areas--the black bear, for example--and thus causing overexposure.
     
  13. Hey, the bear is well exposed! Black subject, very bright background. You exceeded the dynamic range. Next time try popping on an SB-910 and using some fill.
    Kent in SD
     
  14. I agree with Kent and Dan, the bear is correctly exposed. The point is that the camera is doing what it's meant to do. As for suggestions; if you shoot raw you have considerable latitude for adjusting your exposure post hoc.
     
  15. Well spotted Phil! I'd taken Matrix from the second post...Doh!
    The problem here is the use of Spot Metering....and probably a pretty small spot as-well.
    Use of Centre Weighted or Matrix would have done OK. The predominantly dark tones beneath the Spot's area have 'made' the camera over exposure the scene by varying amounts. And the way it's done it is unfortunate as the higher the ISO selected, the less the Dynamic Range possible.
    Shot 1 is very hard on any camera, but the best image possible would be at the lowest ISO possible in RAW. This shot is perhaps 1.1/3 or 1.2/3 EV Over. Maybe use A @ 2.8 @ 200mm @ ISO 160?
    Shot 2 is OK'ish for the bear and tree, but the rest's gone too bright. Perhaps it's 1 EV Over?
    Shot 3 is nearly OK but has taken the exposure from the dark jacket and lightened the scene a little too much. Maybe 1/3 or 1/2 EV Over?
    It's easier to brighten shadows than darken blown highlights....but don't rely on doing too much of that or you quickly increase the noise in the shadows.
    I'm not sure fill-in-flash on a wild bear is a Good Idea? We don't have them in the UK, but I'm sure it might annoy it...:)
     
  16. pge

    pge

    Yes Mark, problem solved, shoot in Matrix and you should be fine in most situations.
    But Mike, although you might think that a flash would bother an animal, I don't think they do in general. I shot a dog once under studio lighting and he didn't seem to mind at all. Not sure why.
     
  17. Thanks to all. I clearly have to get out and play more!
    Mike & Phil, I don't think I'll be doing the flashy-thingy with a 6+ foot tall - 500 lb. bear unless he's behind bars. Wife was going slightly nuts as I stepped outside to take the pix. Since this guy lives in the woods behind us, we do have an air horn to discourage him from getting too close. As you might expect, nobody in the neighborhood has bird feeders out any more.
     
  18. With spot metering and reflective metering in general, you should be aware that it assumes the area pointed to has roughly 18%
    reflectance. If the area pointed to is white, you should add about 2 stops to the indicated exposure to get it recorded as white. For black
    subjects you may want subtract correspondingly a few stops depending on how black you want it.

    With matrix metering the camera is using the data from the matrix sensor to determine how much to compensate from the center
    weighted meter reading which is used as baseline. It works reasonably in most common situations but sometimes only the user knows
    how to expose the scene, not the computer.
     
  19. A black object combined with extreme brightness such as sunlight on a light surface presents a contrast range that is challenging in both film and digital. Ansel Adams invented the zone system to address this problem. In this situation shooting film one would calculate the exposure needed to get some texture in the bear, which would overexpose the bright parts of the scene. Reducing film development would then greatly reduce the brightness of the highlights. With digital the above advice about shooting raw in matrix or center weighted is probably the best you can do, and then use the capabilities of the raw processing software to reduce the brightness to get some detail in the highlights and keep the bear exposed enough to reveal some texture.
     
  20. I'm an outlier, I still shoot film w/Nikon N90s, but it does have a spot meter, and when I use it, in sun, I usually meter my shadow or something close to fresh blacktop. Spot metering a black bear is like metering the mouth of a coal mine. Looks like in the last exposure the subjects aren't illuminated by the sun; if so, you could've use ambient, you would have nailed it. You're actually doing two things that highlight poor judgement; spot metering a black bear and coming within eating range of that thing. Good luck, grizzly man.
     
  21. Spot metering is counter-intuitive. The meter wants to make whites medium grey and it wants to make blacks medium grey. Hence, it'll underexpose whites and over expose blacks, exactly what you called for here when you put you spot meter on the darkest thing in the scene. In Matrix metering mode, the camera evaluates the scene and reaches a compromise setting, which is probably what you should be using until you get more instruction about exposure.
     
  22. It's nice to know it's me and not my rig.
    Guess I need to really step back and learn how to run this thing, eh?
    Appreciate all the help.
    M
     
  23. I'm not sure how anyone could think that the bear in the first picture was correctly exposed. I've taken the liberty of cropping the darkest part of the bear out and contrasting it against a truly black background. Without the distraction of the blown-out white background, it can be seen to be a mid grey colour - or it would be if the white balance was anywhere near correct as well.
    On the left is the original, and on the right I've lowered the black level by 30 and made an attempt at correcting the over blue WB. The level shift would probably be equivalent to reducing the camera exposure by around 3 stops. While the white balance shift appears similar to having used the Tungsten setting in daylight.
    Mark, I humbly suggest you leave Nikon's matrix metering to do its thing. It's not perfect, but it won't make quite such a hash of the exposure as using spot metering on the darkest part of the subject! If you turn on active D-lighting as well, the D800 will cope quite well with this kind of contrasty scene automatically. I also suggest you look at your selection of White Balance, which appears to have been set far too cool.
    00cBdS-543789884.jpg
     
  24. Spotmetering is more suitable for shooting in manual exposure where you set iso, aperture and shutter speed yourself.
    You would then spot meter something like the bear and then place that exposure at it's right place. Bear for instance showing up as -3 stops in the camera meter.
    But it's more common to spot meter something bright to make sure you are not blowing out the image. And then let the shadows fall where they might. For instance spot metering a cloud at +2 or +3 stops in the camera meter.
    Some people spot meter skin to set the exposure, around +1 for a caucasian.
    Another example when spotmetering skin could be when shooting a back lit portrait you might not care if the background turns white (it could even be that you want to blow out the background to white on purpose) but you want the person itself to be properly exposed.
    You could use spot metering in automatic modes as well but then you would have to dial in exposure compensation to get the proper tonality - unless you spot meter something that is mid gray all the time. For instance spotmetering skin in automatic you would set the exposure compensation to +1. If you spotmeter a white wall you would dial in +2 or +3 exposure compensation.
    Spotmetering in automatic modes could also be combined with autoexposure lock (ae-lock). For instance if you shoot a lot of portraits you could always spot meter off the skin and then press ae-lock. Now you get the same exposure for all shots until you release the ae-lock.
     
  25. You spot metered on a dark brown bear and a black jacket. The spot meter ignored the rest of the frame.
    or just watch your histogram​
    Watch it do what? Expose the sky without clipping while hiding the bear and the family in deep shadows? Backlit photos are about the WORST POSSIBLE case for depending on the histogram. Fill flash might have worked effectively if you set everything properly. Better yet, try to avoid shooting dark objects with bright light sources behind them.
     
  26. The easiest way to deal with a shot like that is with the histogram enabled and with the blinking highlight also enabled.

    Keeping in mind this is a D800 with a huge dynamic range, setting the lowest ISO possible while still getting good exposure, will provide the greatest possible dynamic range. That should have been the
    "base configuration" set up well before that particular scene presented itself.

    Then as circumstances unfold, If there is leeway above hose default settings, adjusting to blow out the brightest highlights (instead of blocking on the darkest shadows) is a change that can quickly be implemented without losing shots, and would result in the best possible data capture. Post processing can then be used to adjust the tone mapping as desired.
     
  27. Sorry if I am repeating yourselves. I did not read every word of your responses. Judging from the overall over all exposure of the photos provided, it could be that the Exposure Compensation has been set at +1 or more. Y0u might press the -/+ button and see what it reads.
     
  28. Lightroom has striped the EXIF data, but I'd guess there's no EC, just a 4mm sized Spot meter or whatever the D800 has as it's smallest or next to smallest spot size.
    Histograms are about the best way ever of determining the correct exposure, they give direct feed from the actual scene as viewed through the camera. Once you can take the time to learn how to interpret them correctly, they are invaluable.
    With the first frame of Blown Bear, I'd suspect there's no single exposure that would work. I high speed 3 shot auto-bracket burst* with Matrix Metering set of -2 EV.....0.....+2EV, all in RAW, would give you a good chance at a composite or HDR frame. Depending on how fast the bear's moving, you may need to rely on a bit of careful alignment and/or ghost removal.
    The actual bracket increment is more tricky to determine and will depend in whether you can get away with, say, a 5 frame burst if time allows. The more shots the better the odds of a convincing composite, but equally the chances of major movement within the shooting timeframe go up too.
    Go into the woods and have a play. Get someone to wear a black duffel coat and hide, growling under a tree... but keep a lookout for the real thing!
    *.....or even 2 frames; keep using Spot Metering and set 0 and -3EV.
     
  29. Spot metering is a great tool, but it's all about how you use it. In the case of a black bear, I might spot meter the bear and exposure comp for -2 stops.
    I agree with the suggestion to practice. Find a black stuffed animal? Black bear in a bright woods is a tough subject.
    Finally, if in doubt, I suggest matrix metering.
     

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