So, here I am back again after a break from photo-blogging (and photography in general). I was bored today, without my camera or laptop with WoW on it OR a car to go to the barn, so I decided to take a look at some of my Alaska photos and see if I could find a common theme for entering them into the World Nomads 2009 photo scholarship contest. I’ve been feeling pretty strongly about water lately and I just so happen to have a number of water-related photos from Seward, Alaska. I also noticed a few things about my images…the ISO.
I figured I’d like to make a post about ISO since, like everyone else, I usually use the auto ISO setting on my camera when I should be really using it as a tool that is directly linked to aperture and exposure.
ISO is pretty advanced these days.
ISO 3200 anyone? What about ISO 12,800? Yes, really it does go that high! Quite the change from ISO 10 back with the first cameras. Such is technology!
What do you do with it?
People normally think it is just ISO 100…you don’t do much else with it. Really, it is another way of controlling an image with varying light or depth-of-field.
Light
Nice sunny day and outside photography with still or slow moving objects, grab ISO 100. This is because you’re free to adjust your aperture and exposure as you please and you’ll still get the light you need without ramping up ISO to allow you more options.
Exposure: 0.067 (1/15), Aperture: f/5.6, ISO: 100
Low light tunnel with lots of people walking around and you want a clear photo, grab ISO 800+. This is because you’re going to want as much light entering that lens as possible AND you want a fast shutter speed so those people do not look like blurs AND you want to use the natural light and no flash. This is great for weddings…
Photo by: Andreas Helike from flickr.
Exposure: 0.008 (1/125), Aperture: f/8, ISO: 800
Yeah speaking of weddings this was what I took at my friends wedding…sigh. You can see here that there is a blur of some of the people as they just didn’t stand still for that 3 seconds it took to take the photo sans-flash. The ISO could have helped dramatically with this photo…at least I know now.
Exposure: 2.59 sec, Aperture: f/4, ISO: 100
Depth-of-Field
Now this is neat. First take a look at this butterfly and notice the back wing is blurred. This could have all been fixed if I had had the ISO up higher, adjusted the aperture to f/11-ish and adjusted the exposure to the appropriate level so that I would have gained a depth-of-field.
Exposure: 0.004 (1/250), Aperture: f/5.6, ISO: 400
Now take a look at this photo (a bit blurred but still shows the idea I’m getting at here). Notice that the back wing is fully in focus—meaning there is a great depth-of-field because the ISO was higher, therefore allowing the photographer to apply a smaller aperture (smaller means that the number is actually larger: f/11 is smaller than f/5.6) so there is greater depth-of-field.
Photo by: Slightly Foxed from flickr.
Exposure: 0.001 (1/1000), Aperture: f/8, ISO: 800
This is not just limited to butterflies either. Having greater depth-of-field can dramatically help in any sort of image where you want more of the subject in focus. This could also mean a landscape where you want the background just as sharp as the foreground or if there are subjects close to the camera and some set back but you want them all in focus.
Be warned.
Yes, ISO is pretty awesome and you’ll more than likely get a great shot up to about ISO 3200 (maybe even higher with some of the camera technology today, just depends on your particular camera) but as you increase the ISO you’ll start to get a bit of ‘noise’ in the image—meaning it wont be as clear as it was at the lower ISO.
Most of the Canon DSLRs today have some form of High ISO speed noise reduction settings so be sure to check out your camera’s booklet. However, noise reduction only applies to JPEG formatted images not RAW and it only helps with chrominance noise (off coloured speckles) and not luminance noise (dot noise, pixilated look)
As always, go out and try it for yourself and see the difference!
