Thoughts On High ISO Outside When There Is Plenty Of Light

I've been thinking lately about how to best achieve a good exposure and the sharpest image possible while hand holding the camera. On a tripod when everything is locked down I'll use ISO 100 or 200 and take it from there. That's all fine and dandy if everything is static but it things are moving around or you are hand held and you want tack sharp, well you need to increase your shutter speed. A lot. The rule is 1 over the focal length you are using for example if you are using 100 mm then you would keep your shutter speed at 1/100th second or faster. Sometimes though that is just hard to do if you don't have enough light so you either sacrifice your shutter speed and risk motion blur or you open up your aperture and lose the depth of field you wanted. But, you could increase your ISO setting and maintain that shutter speed and aperture setting.

I did some tests outside during lunch today just to see how the ISO effected the image when there is plenty of light and all you are trying to do is keep your shutter speed up there. 


ISO 100 f/8 @ 1/200 sec.


ISO 200 f/8 @ 1/400 sec.


ISO 400 f/8 @ 1/800 sec.


ISO 800 f/8 @ 1/1600 sec.


ISO 1600 f/8 @ 1/3200 sec.


ISO 3200 f/8 @ 1/6400 sec.

Now, you may notice that there is not really much of a difference in these photos. That's the point really. The higher ISO values didn't significantly increase the noise in the images. Not even at ISO 3200! That's because there was plenty of light and no really dark shadows in the scene. Believe me ISO 3200 in my house is a much different look.

So what then is the point of this post? Well, Look at the shutter speeds. For ISO 100 I was at 1/200 sec which for my zoom of 270mm is a bit low. I should be at 1/400 sec at least given that 270mm is like 432mm on a crop sensor camera like my 50D. I didn't get that shutter speed until ISO 200. That's going to give me a pretty good sharp image if everything is still. But it wasn't it was a bit breezy out and this weed was swaying a little in the breeze. Still the ISO 200 image looks pretty good.

What's got me excited is the fact that even at ISO3200 the image is still fairly clean and sharp. With this new information in my head I will be more inclined to up the ISO when shooting the kids playing around jumping off things, water skiing, etc. Sporting events will be sharper and cleaner for me now too. I've heard that you should keep the ISO as low as you can to get the cleanest possible image and I agree but if you need to increase your shutter speed to stop that action or stop that coffee you had from introducing unwanted camera shake don't be afraid to push up the ISO. Most of today's DSLR's are more than capable of producing a clean image at ISO 1600 and up.

One thing I noticed with my 50D is that ISO 400 to ISO 1600 look the best but would not be afraid of ISO 3200 outside if I needed it. Next I'm going to test the expanded ISO settings of 6400 and 12800. I'm not holding my breath on those.

Chris.