Understanding ISOs

I have been working on Photo composition for years, that is what sparked my interest in photography. Then about two years ago when I signed up for this Photography Diploma program I decided it was time to learn all the technicalities of Photography - something I wasn't too interested in but knew I had to learn if I ever wanted to take better photos. Now here I am, two years later, and on a learning scale of 1-10, beginning at 0 when I started, I'd say I've probably gone up about 3 notches. Not too impressive, but it's better than nothing! For the longest time I could not grasp the correlation of aperture and shutter speeds, no matter how many times my husband tried to explain it to me, no matter how many times I read about it in my textbooks, no matter how many websites I looked at on the subject... it just did not click (no pun intended...haha)

As for the ISO - I've known about the ISO (International Organization of Standardization) for years. Ever since I was in my early teens and began taking photos with Film. I also learned about the ISO in my photography schooling, but with my lack of understanding of aperture (f-stops) and shutter speeds it all wasn't quite fitting together for me. It wasn't until about two months ago that I began to understand the correlation between the three settings. I didn't know that I could change the ISO settings on my camera until about 6 months ago! I am amazed that you can record images with different ISO settings all on the same memory card! Back in the days of Film, you would have to physically change the roll of film if you wanted to use a different ISO, now with digital cameras you can change it with just a couple buttons.

Ever since I was about 14 or 15 years old, my basic understanding of the ISO was this: 400 is good and should be used for pretty much everything, 800 is better for photos with a lot of movement. I figured that meant that anything lower than ISO 400 was lower quality. I remember seeing some ISO 100 Film in the store and thinking, "Why would anyone want to buy that?" Now I understand what the ISO is and I'm looking forward to experimenting with the different speeds.

Basic Info about the ISO:

• ISO sensitivity expresses the speed of the photographic negative materials. Since Digial cameras are built with ISO equivalent using image sensors rather than film. My Nikon D40 has the following ISO settings: Auto (100), 200, 400, 800, 1600, and H1.
• You obtain the highest quality photo by using the lowest ISO setting possible on your camera.

ISO 50 and lower - Best used for very bright scenes such as a sunny day on a white sandy beach.

ISO 100, ISO 200 - The Standard ISO used for clean, clear, colorful images for most situations and subjects.

ISO 400 - This is actually considered to be a high ISO and it should normally be used when indoors or in poor lighting. The lower the light, the higher ISO you should use.

ISO 800 and higher - Used for low lighting. The higher the ISO the more sensitive the sensor/film will be to the light, which means you are more likely to have a grainy picture.


Our Wedding Pictures - After our Wedding I took one look at the pictures and all I saw was...darkness. Each and every photo was dark, some were so dark you couldn't even make out who was in the photo. I had to go through and fix each one in Photoshop (over 300!) Up until this week I didn't know that every digital picture stores EXIF information that tells you what all the settings were on the camera for that particular exposure. I just went to see what ISO my photographer used in the very low lit church and just as I suspected... ISO 100. :) The shutter speeds and apertures were also a little odd. If you are ever in search of a good deal on Wedding photos, make sure your photographer has at least some knowledge of ISO, shutter speeds, and aperture.