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photo:low_light_photography

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low light and action photography

Introduction:

  • photography in low light presents technical problems for the photographer as it tends to push the limits of the ability of the camera for the required purpose.
  • in general, assuming we don't resort to assisted lighting such as electronic flash, we need to ensure our shutter speed is fast enough to handle camera shake and subject motion, while our aperture is small enough to give adequate depth of field and out film/sensor sensitivity (ISO) is low enough to give the most dynamic range and least noise.
  • thus, how we select our tools and the settings will result in different compromises in each of these areas as we no longer have the luxury of shooting ISO 100, 1/400th sec at f/8 for bright sunlit shots.
  • what I have not discussed below are a few other potentially important functions for action photography:
    • ability to rapidly auto-focus on a continuously moving subject
    • ability to take rapid sequence shots:
      • most can take 2.5-3 fps, some pro models go faster:
        • Canon 1D Mark III/IV/X - 10fps
        • Nikon D2H - 8fps
        • Nikon D2X and D200 - 5fps
        • Canon 1Ds Mark II - 4fps
        • Olympus OM-D E-M5 camera - 9fps
    • fastest shutter speed:
      • most digitals can take 1/4000th sec, some models go faster:
        • Nikon D1x - 1/16000th
        • Nikon D2X, Nikon D70s, Canon 1Ds Mark II, Canon 1Ds Mark II, Canon 5D - 1/8000th 
    • camera responsiveness - shutter release delay, viewfinder blackout duration, time to next photo ready, etc.
  • there are 4 main scenarios, each with different solutions:
    1. the stationary or near-stationary subject eg. portrait, still-life, landscapes, paintings in an art gallery, etc.
    2. a moving subject but where we don't mind motion blur eg. movement of water in a stream, waterfall, etc.
    3. a moving subject where we can pan the camera to reduce motion blur of subject and give motion blur to surroundings
    4. a moving subject where we desire an adequate shutter speed to “stop” the action eg. sports

The stationary or near-stationary subject:

  • in this scenario, the shutter speed can be slower as long as it is fast enough to adequately “stop” the action (eg. perhaps 1/10th sec for a portrait, and as long as you like for a stationary inanimate subject) and fast enough to control camera shake if not using a sufficiently sturdy tripod.
  • in general, for these situations, best results will be had using a sturdy tripod if the situation allows and you have one as it then frees you to choose a lower ISO and in some situations the aperture of choice. 
  • If you cannot use a tripod, then an image stabiliser will help significantly in this situation to reduce camera shake but not subject movement.
  • an image stabiliser is of no use when using a tripod and may make it worse so you generally must turn it off when using a tripod.
  • let's assume you don't have a tripod or monopod and you are going to try to hand hold the camera as steady as possible to get your shot of a portrait with available light:
    • in general, the slowest shutter speed you can get away with for a 35mm camera is approx. 1/(effective focal length in mm) secs, thus for a short telephoto 100mm focal length, the longest shutter speed should be ~1/100th sec.
    • using an image stabiliser you could get away with 2-3 stops less, ie. 1/25th sec which means you can shoot in darker conditions, or make the aperture smaller to increase DOF, or reduce the ISO to reduce noise and increase dynamic range.
      • I managed to shoot above my head hand held at night with my Olympus E510 with its IS and 7mm lens (14mm equiv.) at 0.5 sec with good results! - see night
    • how much ISO do we have to play with before noise becomes a nuisance?
      • my preferred maximum ISO for low noise though from what I have seen would be:
        • Canon 1D Mark III - 1600-2000 ISO although 3200-6400 is very usable for sports and night
        • other Canon, Nikon dSLRs - 800-1200 ISO
        • Olympus dSLRs - 400-800 ISO (640 max. with E330 and older)
        • smaller sensors (ie. most point and shoot cameras) - 100-200 ISO
      • if you are desperate you can double these ISO's but noise will be obvious and you will lose dynamic range.
    • the 3rd element is aperture, the wider the aperture the better, as long as you do not need a lot of DOF.
    • so the best results will be from a camera with a larger, lower noise sensor with image stabiliser and a fast lens:
      • an IS-equipped Canon, Nikon, or Sony dSLR will have a ~1 stop advantage over the current CCD-IS Olympus dSLRs (E510) due to their reduced noise at higher ISO (2 stops for the Canon 1D Mark III).
      • BUT this isn't the end of the story, what about the lens?
        • well, here is where the Olympus buys back a little ground as it can produce wider aperture lenses at lower price and size as it has a smaller sensor, and what's more you get more DOF for a given aperture and effective focal length (although sometimes you want even less DOF).
        • let's compare a Canon 400D with EF-S 17-85mm IS lens which has max. aperture of f/5.6 at this focal length, with an Olympus E510 with similarly priced 14-54mm lens which has max. aperture of f/3.5 at the equivalent focal length:
          • the Olympus lens has ~1.5 stops more aperture which easily makes up for the noise at high ISO and gives a DOF at 2m of 17cm compared with 21cm for the Canon.
      • thus the new models of IS-equipped Olympus bodies will have an edge in value for money as IS will be available for any of its lenses, including manual focus ones, and furthermore, Olympus and fellow 4/3rds members are making a range of fast aperture lenses which are either not available, too expensive and too big in the Canon, Nikon, Sony or Pentax mounts.
        • eg. for bushwalkers who need a fast, relatively light super-telephoto zoom:
          • Olympus 50-200mm f/2.8-3.5 (=100-400mm effective) 1.07kg ~$A1400
          • Canon 70-200mm f/2.8 IS L (112-320mm) 1.57kg ~$A3395
          • Nikon 70-200 VR f/2.8 (= 105-300mm) 1.47kg ~$A3400 ie. almost 50% heavier and 2.5x the price!
    • and what about ambient lit portraits from window light?
      • see portrait lenses
      • depending on the amount of light outside and how far the subject is from the window, an EV of 11-12 is usually needed, which equates to ~1/125th sec, f/2.8 at 400ISO
      • fortunately, for most portrait photography, a wide aperture is desirable for shallow DOF and blurring out distracting backgrounds along with a 100mm lens in 35mm terms, so let's look at a few examples:
        • Olympus E510 with 50mm macro at f/2.0:
          • we could easily get by with 100ISO, f/2, 1/30th sec with its IS, and could manage even if light levels dropped by 2-3EV but increasing ISO to 400 and shutter speed to 1/15th sec.
        • Canon 400D with EF-S 17-85mm IS lens which has max. aperture of f/5.6:
          • f/5.6 at 1/30th sec with IS allows ISO 800
        • Canon 1D Mark III with EF 85mm f/1.2 lens but no IS:
          • 100ISO, f/1.2 at 1/100th sec, although one could easily use a faster shutter and use ISO 800 with excellent results.
        • Canon 1D Mark III with EF 100mm f/2.8 macro lens but no IS:
          • 800ISO, f/2.8 at 1/100th sec, although one could use 1/200th sec at ISO 1600 with still very good results.
    • now what about hand held low light wide angle and macro options - maybe best to use an Olympus solution for these:
      • Olympus E510 with ZD 7-14mm f/4 + ZD 50mm f/2.0 macro = $A4950
        • this gives image stabilised 14-28mm wide angle at usable ISO 400 f/4, 1/4 sec ⇒ LV down to -1
          • at 7mm, you can even get great pics at ISO 800, f/4, 1/2 sec ⇒ LV down to -3 - see night
        • and usable macro ISO 400  f/2, 1/15th sec ⇒ LV down to -1
      • Canon 1D Mark III with EF 100mm f/2.8 macro + EF 16-35mm f/2.8L II = $A10,600
        • this gives 21-46mm wide angle at usable ISO 1600 f/2.8, 1/30th sec ⇒ LV down to +1 only
        • and usable macro ISO 1600, f/2.8, 1/125th sec ⇒ LV down to +3 only (4 stops worse than Olympus !!)
      • debatable points:
        • how does the Olympus image quality at ISO 400 really compare with Canon at ISO 1600? Even if Canon were better here, you really need to bump the Canon to 6400ISO to match the Olympus LV level and I am very sure the Olympus noise at 400ISO would easily beat Canon at 6400ISO.
        • will the Olympus IS really allow shutter speed to be reduced to 1/4 sec for wide angle?
        • of course, the Canon is MUCH better at astrophotography and sports photography, but then these are not usually with wide angle or macro lenses, so what I am suggesting is that you need BOTH cameras if you want to push boundaries.
        • the forthcoming Canon full frames will have similar ISO noise as the 1D but allow wider angle albeit with barrel distortion at the edges, but unless they add sensor IS, it still won't be as good hand held in low light as the Olympus.
        • the Nikons + VR Micro-Nikkor 105mm f/2.8G actually gives a comparable macro performance to the Olympus (it's one stop slower lens balances the one stop ISO noise difference, but perhaps Nikon's IS is better than Olympus and optical IS should help AF in low light), however, Nikon do not have live preview for manual focus macros & don't have an IS super wide angle, although there are rumours the next Nikon near-full frame dSR will have a Sony IS sensor - but then you would have to throw out your DX lenses.

A moving subject but where we don't mind motion blur:

  • this is a lot easier in low light, just use a tripod, or the slowest shutter speed for camera shake taking into account image stabiliser if available as above.
  • in brighter light, the smallest aperture and lowest ISO may not allow a slow enough shutter so a ND filter or polariser filter may be required to reduce the amount of light coming in.

A moving subject where we can pan the camera:

  • this usually requires the subject to move in a reasonably predictable manner and the photographer to have some skill in panning the camera at the correct rate to match the subject movement.
  • shutter speeds used during panning tend to be 1/15th sec to 1/250th sec, although longer exposures can be achieved with good results by using a panning tripod head to minimise vertical camera movement. 
  • here IS is not as effective although newer versions of IS can be set to accommodate horizontal panning.
  • perhaps more important is the problem of viewfinder blackout during exposure although one can still keep panning at a constant rate during the exposure.
  • often it is best to pre-focus the camera so you don't need to rely on accurate AF, and likewise, you may wish to preset the exposure to avoid changing backgrounds giving false light metering readings (eg. bright sky becoming your background producing under-exposure). Where the subject is at a distance and backlit, a spot meter is useful.
  • the blurring of the background will impart a truer impression of speed and add greater tension to the photograph.
  • being aware of peak-action to time your shutter release when subject is at peak of a jump, etc is another useful technique.

A moving subject where we desire an adequate shutter speed to "stop" the action:

  • in this situation, image stabiliser is of little benefit as the shutter speed required to freeze the action is almost certainly sufficient to deal with camera shake although it is still wise to use a tripod or monopod whenever possible, especially if using a super telephoto.
  • the shutter speed required is dependent on how fast the subject is moving in relation to the camera (ie. its relative angular velocity) and this is determined by:
    • speed of movement
    • direction of movement
      • coming towards or away from the camera requires less “stopping” than does perpendicular motion
      • movement 45deg to camera allows shutter speed 1/3rd slower than movement at 90deg.
      • movement toward or away from you allows shutter speed 1/2 slower than movement at 90deg. BUT creates problems with accurate focusing.
    • magnification factor of subject - the closer the subject or the greater the focal length, the greater the apparent motion.
  • shutter speed usually needs to be 1/500th - 1/4000th sec depending on the above.
  • the fastest shutter speed (T) you can use if dependent upon:
    • amount of light hitting the subject (LV)
    • the widest aperture on your lens (A) - most professional sports photographers use f/2.8-f/4 lenses
    • the highest ISO that gives acceptable degree of noise (S)
    • (see light values)
    • ie. you will probably be best to set the ISO at the highest you can tolerate and choose a relatively wide aperture (as long as it gives enough DOF) so you can then use the fastest shutter speed (eg. 1/2500th sec, f/8, 640ISO on a partly overcast day)
    • NB. faster shutter speeds are possible using very brief electronic flash to light the subject (eg. objects dropping into water or insects flying) but that's another story.
  • in this situation, the 1-2 stop loss in ISO with an Olympus may be an issue unless you use a lens with 1-2 stop more aperture, which fortunately is possible: eg. the Olympus 150mm f2.0 compares with the Nikon/Canon 300mm f2.8
  • currently, the Canon 1D Mark III is THE BEST camera for action photography as:
    • lowest noise at high ISO - a critical requirement to allow fast shutter speeds
    • fast burst rate of up to 10fps (if shutter speed is 1/500th sec or shorter)
      • next is the Nikon D2Xs which is 5fps or 8fps with 30% cropping
      • most other digital SLRs average at 2.5 to 3fps burst rate
    • fast AF on moving subjects
    • fast shutter speed as short as 1/8000th sec
    • weather-proofed
  • examples of sports photography:
    • most sports - many use wide open aperture, manual metering for indoor & aperture priority for outdoor
    • shoot tight, crop tight as usual aim is to show facial expressions, ball, action & contact
    • avoid cropping limbs at or below the elbow or knee
    • in high contrast situations such as bright sunlight, shoot in RAW mode.
    • use a monopod where possible
    • a sharp noisy image is usually better than a clean blurry one.
    • 1/400th is usually the slowest shutter speed that will stop action, usually aim for 1/1000th-1/3200th sec, the faster the better if you are a bit sloppy with you camera work 
    • indoor ice skating:
      • custom WB on the side boards not the ice, and regularly check it if lighting is part daylight
      • meter the ice at f/2.8 and adjust shutter speed by 1.5EV to avoid underexposure
      • many use ISO 1600, f/2.8, 1/640th
    • football:
      • wide open aperture (or at least f/4-5.6), 1/400th sec to freeze players but add a little blur on the ball, ISO accordingly.
      • indoor AFL football under lights (ideally need a 35mm effective focal length of 300-400mm):
        • see AFL football
        • using a Canon 1D Mark III with 300mm f/2.8 lens:
          • ISO 3200, f/2.8, 1/1600th sec
          • big advantage of 10fps and usable option of ISO 6400
          • NB. the 70-200mm f/2.8L lens is a bit too short unless used on a APS-C Canon with 1.6x crop.
        • using an Olympus with ZD 150mm f/2.0:
          • ISO 800, f/2.0, 1/800th sec
          • only just adequate, and at only 3fps and too much noise at ISO 1600, you have limited options, but the benefit of a much smaller and lighter outfit.
          • NB. other great Olympus lenses such as ZD 90-250mm f/2.8 or the much cheaper ZD 50-200mm f/2.8-3.5 would require you to drop shutter speed to about 1/400th sec which is really pushing things, but if your camera work is great then it may just work well.
        • using a Nikon D2Xs with Nikkor AF-S VR 300mm f/2.8 lens:
          • ISO 1600, f/2.8, 1/800th sec
          • 5fps or 8fps if cropped.
          • NB. using the nice Nikon AF-S VR 200-400mm f/4G IF-ED lens means dropping shutter speed to 1/400th sec, which as in the Olympus case is pushing things and the f/4 means less background blurring which reduces the impact of the photo.
    • baseball:
      • usually need 1/2000th sec to adequately stop the ball.
  • Canon 1D III autofocus for sports:
  • bird photographers often use:
    • 400-500mm lens at f/5.6-7.1 and 1/1000th - 1/2000th sec, and given the sky background need exposure compensation
photo/low_light_photography.txt · Last modified: 2013/02/20 10:13 by gary1
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