ISO - not the Classified Ads

The past few days, I've covered various technical basics. My goal is to explain how they can be useful for any camera, for any photographer. Today's topic is ISO.

A technical definition for ISO is "ISO sensitivity expresses the speed of photographic negative materials". I don't know about you, but I'd prefer the English explanation, which is:

Higher ISO -> better pictures in low light (because the image sensor is more sensitive)

Lower ISO -> higher image quality, but only in optimal light situations

ISO that is too high -> pictures with high amounts of noise, which may render them unusable

Examples:

Higher ISO speeds:



The first one was taken at ISO 800. I was using a macro lens, so this enabled me to take clean, precise pictures without worrying about camera shake. The second one, however, was taken with a wide-angle lens. The ISO was set at a very high 1600. The quality of this image is lower, but it's for effect - I wanted to show the drama of the storm that day.

Medium ISO speeds:

  

These were taken at ISO 400, with a wide-angle lens. In both cases, it was fairly dark inside, so I experimented with 800 and 400. I preferred these. I didn't want them to look artificially bright.

Low ISO speeds:



In both cases, I had good amounts of light and wanted the best pictures possible. They were taken at 100 and 200.

My advice:

1) Try different ISO settings so you can see the impact yourself

2) Do not go above 800, unless you're doing so for special effects

3) My default for a bright and sunny day is 100

I hope this helps! Till tomorrow!

Fun with Shutter Speed

Yesterday, I began this series with an explanation of aperture. I admit, it's not the easiest concept to explain, but applying it in practice is fairly straightforward. Shutter speed, however, is the opposite - easy to explain, a little more difficult to apply. What do I mean by that?

Well, let's start with what it is, and some examples. A technical definition is "the effective length of time a camera's shutter is open". It's expressed in seconds or fractions of a second.

Sounds reasonable. How do we apply this? I'll explain a few scenarios:

1) Fast shutter speed for definition and freezing moving objects (faster than 1/250 to 1/4000 and beyond):



This shutter speed (taken with a point-and-shoot) is 1/1000. If you look closely, the waves are highly defined - they're not blurred. It looks as though I froze time (or something like that). You would also use a similar speed for sports events or any situation where things are moving quickly and you want to capture everything.

2) Slow shutter speed for dramatic effect/strategic blurring (more than one second):



This is a 30 second shutter speed. The clouds and the reflections are very dramatic. At a faster shutter speed, the picture would have been frozen - like this:



The shutter speed here was a fraction of a second, so everything looks more crisp.

But wait, it gets more confusing:

3) On the slow side - better for low light (1/15 and slower):



It was dark out, and I was using my macro lens. I chose a setting of 1/15 to compensate for the low light. As I have mentioned in the past, I kept the ISO relatively high as well to avoid blurring.

4) On the fast side - good light for sharp landscape shots (1/80 to around 1/125):



I used 1/80. The light was good, and the detail is good, too.

And now, for the most confusing part:

Aperture and shutter speed are related to each other. If you select the wrong shutter speed, you can under- or over-expose your photos. I can only be so technical, so instead of addressing this manually (using the M setting), I decide what I want to control - one or the other - and I set my camera according to that. The camera adjusts based on my selection. This link provides a more technical treatment of the topic, but the best advice is:

1) Shoot with different settings to see for yourself, keeping the above guidelines in mind

or

2) Decide what you want to capture and how - and modify that setting. (lots of detail, fast shutter speed or high f-stop - blurring, low f-stop or slow speed, etc.) Use the above pictures as a general guide.

I'm in favor of 1), as it's really the best way to see this in action. Plus, multiple versions of the same shot can be equally interesting.

Tomorrow, I'll throw in another variable - ISO.

Till tomorrow!

Aperture - it's not just a Product

I was watching GMA in bed this morning (I've been sick), and a photographer came on. He talked about holiday photos and getting great shots. One key point he mentioned was "know your camera".

I struggled with this initially (years ago) - I'm not technical, and those details aren't really all that interesting to me. However, for the sake of my photography, I really did need to understand several key concepts. Therefore, I will be discussing the following over the next few days:

1) Aperture

2) Shutter speed

3) ISO

4) White balance

If you know how to adjust these on your camera (whether it be point-and-shoot, or otherwise), then you'll be in good shape.

I'll start with Aperture. A technical definition for it is "the diameter of the lens opening. The larger the diameter of the aperture, the more light reaches the film / image sensor. Aperture is expressed as F-stop, e.g. F2.8 or f/2.8. The smaller the F-stop number (or f/value), the larger the lens opening (aperture)."

Huh? I'm sure my engineering-educated customers could jump in and help us, but for the rest of us:

The smaller the aperture, the higher the F-stop. In English, this means that your picture will have more elements that are sharp and clear. Example:



This is a relatively high F-stop - around 10 and 11, respectively. I chose this picture to 1) Keep my mind off of this cold weather and 2) Because of the leaves. You'll notice that all of the elements are in equal focus, regardless of the distance. Compare this with other equally colorful pictures:



Notice that the butterfly and its surrounding flowers are in sharp focus. Everything else (especially the leaves) is strategically blurred. This is a relatively low F-stop of 2.8. The same points are valid for the second picture - the left side is in focus, to draw attention to the colorful details. The right side is blurred.

Some of your point-and-shoots give you the ability to adjust your aperture settings. You might not be able to by much, but even the smallest bit can make a difference for you. If you can, you'll want to take the same picture using different settings. This way, YOU can see the difference - and you won't have to just take my word for it. :)

So, to summarize - the higher the F-stop number on your camera, the more focused objects in your pictures.

Till tomorrow!