ISO?

Discussion in 'Sports' started by carol_lee|2, May 2, 2011.

  1. What ISO should I use for sunny outdoor sports photography? This is for my science fair, which is The Effect of Shutter Speed on Sports Photography Photo Clarity Rating and Brightness. Thanks!
    Carol
     
  2. Depends on the camera. For modern DSLRs, ISO 400 produces clean results and should provide a fast enough shutter speed. ISO 800 would probably be clean enough, but you probably won't need to go that high unless its cloudy. If you're using a point and shoot, the noise will be less tolerable and ISO 100 or 200 would be preferable, but may not provide the shutter speed needed. Just remember that a sharp image is first priority, sometimes noise is a necessary evil, but not usually with outdoor sports.
     
  3. Thanks! I'm using a DSLR, and it probably wont be cloudy. so I'll try ISO 400.
     
  4. Always try use the base ISO for the camera in all conditions. The sensor works best at that setting. Only use higher ISO settings if they are required to get an exposure at a reasonable shutter speed for the picture you are attempting to take.
    A higher ISO setting can affect the clarity of the photo.
     
  5. Sounds interesting. As an experiment, I would start at base, as suggested, then take shots at higher and higher ISO settings to show the effect as you describe. Stop motion is great to show. See the blur of the background as you follow the subject.
     
  6. Since this is a science fair project, you'll want to try to keep everything the same EXCEPT your shutter speed.
    I'd suggest shooting at the camera's base ISO, usually either 100 or 200. Make sure any Auto-ISO settings are OFF.
    RS
     
  7. So basically, I'm keeping the F-stop at 4.0 and the ISO at 200 for the whole all of my trials. The only thing I'm changing is the shutter speed. I'm testing 1/4000, 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, and 1/15.
     
  8. It'll be interesting...
    This trial will not only show you the difference when it comes to stopping motion, but also the amount of light hitting the sensor.
    You could also do a second set of trials where you change the shutter speed and allow the camera to dictate the correct aperture so that all of your shots will be properly exposed and you only get the effect of stopping motion.
    RS
     
  9. Carol, the three factors which determine exposure are shutter speed, aperture and ISO. You can't hold two of them constant and change the third...as you imply, your exposure will be wrong for all but one of the shutter speeds.
    If you are doing a study on the effect of shutter speed, when attempting to capture motion, you can hold the ISO constant, and allow the camera to determine the aperture, for the shutter speed that you are testing.....OR, you can hold the aperture constant, and allow your camera (if it's capable) of choosing the ISO.
    What you will learn with your science project is exactly what many of us who shoot sports continually learn, and that is, there are tradeoffs in aperture and ISO which are necessary to achieve the shutter speed required for sports photography.
    Best of luck to you, and please share some of your work when done.
     
  10. So what you're saying is that I keep either the ISO or aperture constant and let the camera determine one of them and change the shutter speed?
    I think I'm going to set the ISO, and let the camera decide the aperture. This would be the Tv on a canon correct?
    Do you think that I should set the ISO on 200?
    Thanks for the help!
     
  11. Carol, Tv in canon lingo is shutter priority...which as you know, means YOU set the shutter speed, camera determines the aperture based on the ISO setting, and the lighting conditions.
    It would seem that 400 is becoming somewhat of a "native" ISO for digital SLRs, I would start there. The actual shooting wouldn't seem to take all that long, once you've designed your experiement...you may consider duplicating the experiment at ISOs 100, 200, 800. You can then determine if your conclusions are consistent across the range of ISOs.
    Either way, you're going to learn more about photography, and that is a good thing.
     
  12. William Michael

    William Michael Moderator Staff Member

    I'm testing 1/4000, 1/2000, 1/1000, 1/500, 1/250, 1/125, 1/60, 1/30, and 1/15.​
    If you want to test all those shutter speeds and you are ONLY testing for the effect of Shutter Speed on the Blurriness of the action (i.e. you want the EXPOSURE to be correct for each image), then it is very likely that you will have difficulties with the experiment
    What lens will you be using?
    The reason you will have difficulties is because it is very likely that the lens you use will not have enough Aperture Stops to allow that range of Shutter speeds to be tested if you keep the SAME lighting situation.
    For example, if it is a sunny day and you are using shooting a runner lit by front on sunlight and you choose ISO100, for a correctly exposed image you will pull the shot at approximately: F/16 @ 1/125s @ ISO100.
    So as you want to test the other shutter speeds you will have (using the same ISO):
    F/11 @ 1/250s @ ISO100
    F/8 @ 1/500s @ ISO100
    F/5.6 @ 1/1000s @ ISO100
    F/4 @ 1/2000s @ ISO100
    F/2.8 @ 1/4000s @ ISO100
    AND:
    F/22 @ 1/60s @ ISO 100
    F/32 @ 1/30s @ ISO 100
    F/45 @ 1/15s @ ISO 100
    BUT it is highly unlikely that your lens has any aperture stop smaller than F/22. AND you might not have a lens which has F/2.8, anyway.
    If you (can) choose to use ISO50 (and it is a sunny day) then you will need a lens that has about F/2 AND also F/32 – that’s also unlikely you have a lens like that.
    If you want to test the slower shutter (in full sunlight) you have the option of using a Neutral Density Filter – but I think, it might be easier to break the experiment into two parts and use full direct sunlight for the faster shutter speeds and use a shaded area for the slower shutter speeds.
    WW
     
  13. Look up the Sunny 16 rule. Explaining that in itself is a science project. P.S.: It works for digital as well as film.
     

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