Photography 101: Dynamic Range (Pt 1. General Concept)

Today's article is going to cover Dynamic Range

Let me kick this off by explaining that you own two of the best cameras in the world, not only are they vastly superior in every way to any camera in existence but they don't cost a cent (though they can be dang hard to replace).

I'm talking about your eyes of course.

The human eye can see a tremendous range between light and dark (in photographic terms this is called highlight and shadow). The total tones available between the highlight and shadow is called the dynamic range.

Unfortunately the best cameras money can buy can only see about 11 or 12 stops of light between the darkest point and the brightest point. This means your camera simply cannot reproduce the range of light and dark that you are seeing. If you are using a consumer point and shoot camera you'll get even less dynamic range. Trust me on this...you can drop $40K on a medium format digital back...but you'll still be stuck with 12 stops of dynamic range.

So, what's the big deal? 12 stops sounds pretty good, right? Hey, if most cameras are pretty much at the same place regarding their capability why do I care?

How you and your camera choose to manage the dynamic range (using exposure and other methods) is going to impact every single photo you take. It's definitely going to be a factor in architectural (real estate) photography.

I'm getting a little verbose here so let's take a look at a few examples.

1. 1. Because there is only so much dynamic range available to the camera I had to choose between the sky (which is very bright) or the subject (which is relatively dark).

Obviously I chose to expose for the sky.

1. My subject ends up very dark, but it works out ok because we get a fairly nice silhouette.
2. In this case you can say that the shadow detail is clipped. Clipping is the photographic term when shadow or highlight detail is lost due to limited dynamic range.
3. With me so far? You are doing great! :)

2.To capture this moment at a wedding rehearsal I needed to expose for the shadow detail. As a result the light coming in from the french doors get's over exposed or blown out.

How would we describe the highlight detail now?

Right! It's clipped.

You may also hear photographers describe the highlights as 'blown out'. Same thing.

So how specifically does all this apply to shooting homes? We'll get there in a second.

The Histogram:

For those of you who studied statistics in school, the histogram is the same good old visual data display you know and love (er, or hate). Only in this instance the histogram is describing tonal information from dark (left) to bright (right). A histogram will be available in any reasonably robust image editing package, and it will show you where your tone information lies, and whether you are clipping it or not (good for learning about dynamic range). Let's see some quick examples:

1. Histogram one shows us tonal information piled up on the left side. That means the shadow detail is being clipped (just like in the #1 image up top).
2. The second of the three shows us a fairly even distribution. This image has been exposed to capture detail from both light to dark.
3. The third histogram shows us an image that has the tonal information jammed up against the right side...that means we are losing highlight detail (just like in the #2 pic at the top).

Whew!

Ok, so now we have the general theory...how does this apply to snapping pics of homes?

Well, there's some bad news folks. Most of the time the lighting in the interior of the home will be much darker than 'competing' light from the windows / outside / sky.

This means if you accidentally expose for the highlights you are likely to get very dark images of the room itself. If you expose for the room, you are likely to get extremely bright windows.

Well, it's just the inside we have to worry about right? Unfortunately not. If the house is at all in shadow, or back-lit, or the sky is even reasonably bright you will have the same challenges with your external shot.

I'm going to cover some solutions very briefly here. My goal with this article was to introduce you to the concept, we'll cover solutions in a lot more depth later.

1. Think about the time of day you are shooting. Where is the sun coming from? Is the house in shadow? Will the natural light favor the interior?

2.Bring additional lights. Beef up the light in the room you are shooting. This could be on-board flash, strobes, or continuous lights.

3. Use a dusk shot (shown left). Twice a day the light outside matches artificial light. This is called civil twilight and usually last for around 20-30 minutes around dawn and dusk.

4. Use a fancy blending or HDR technique (note, you need to be pretty handy with post skills to do this).

5. Use a polarizer or neutral density filter for your outside shot.

Ok!

Can I be excused? My brain is full. :)

Cheers, -B

Architectural-Photographer