Common DSLR Myths – Always Use The Lowest ISO
In the first of our Mythbusting series we are going to look at a common myth that you should always use the lowest ISO number possible to get the best results This is based on the knowledge that the higher the ISO number you use, the more noise (digital artifacts) will be created in your image While this is certainly true, what we are going to examine in this article is wether or not you should always shoot in the lowest ISO number your camera can handle in order to get the best images Will this myth be confirmed or busted? Continue reading to find out
Understanding ISO
The different ISO settings will control the light sensitivity of the camera, the problem is that the higher you crank the ISO setting, you will introduce more noise effects In a dim room with no other lighting available, you can increase your ISO setting in order to make the camera more sensitive to light New cameras actually perform quite well at ISO 1600 which was unheard of only a few years ago Upcoming cameras will be able to shoot very usable images at ISO 6400. If we don’t want to add any unneeded noise or digital artifacts if possible if we want the cleanest images we can possible get
Myth Expectations
According to the myth, if our camera will go down to ISO 100, then so long as we can have the aperture that we want to use and a fast enough shutter speed, then we should shoot at ISO 100 whenever possible. To test this we will take a series of images of the same scene at different ISO resolutions and compare the results. If this myth is true, than our images at the lowest resolution will be the ones to keep.
The caveat here is every camera does behave differently and the results may vary slightly between different makes and models, but the overall result should apply to pretty much any camera.
Testing the myth
We setup a shot in mid-day that could easily be handheld since the shutter speed will be plenty fast enough. By zooming in we can see the differences between the different images.
At these resolutions the differences between these images is very subtle and you really need to look closely at the leaf you will see some color noise. While this at first appears to be the only real difference, we should be able to see even more when we zoom in even closer.
Now you can see the noise that is present in the ISO 1600 image a little better but you can also see an odd effect in the ISO 100 image, note that the ISO 100 image is not as sharp at the ISO 400 image.
This is actually a phenomenom we noticed when shooting a lot of wedding photos. While we always believed that shooting at the lowest ISO setting would give us the best image, it actually was a sacrifice between noise and sharpness. The higher the ISO image the more noise you get, but the lower the ISO setting the less sharp the pictures were. The sweet spot for different cameras may vary but with many other settings, you will not get the best results from either of the two extremes. With our Olympus E-500, the sweet spot for ISO was between 200-400 ISO and with our Canon cameras the sweet spot is between 400-800.
Results
While it may sound intuitive that the lower the ISO the better the image but the results do speak for themselves and show that this is not actually true, the best shots will result in a setting that is not at the extreme of the available ISO levels.
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About the Author: Kerry Garrison is a wedding, portrait, and product photographer living in southern California. With 10 years of experience shooting products and 3 years of experience in the wedding industry, Kerry brings a good deal of technical know-how and can explain topics in easy-to-understand terms. Kerry's work can be found at http://kerrygarrison.com and on Facebook at http://facebook.com/KerryGarrison









