The Photography Tip of the Week #042

Posted by Philip in Podcast

042 Photography Tip of the Week (audio)

(Over?) Compensating for sensor inadequacies

What a difference a year makes.  I must confess I haven’t taken a lot of photos in the snow.  Even though I used to live quite a bit north of where I do now, we were surrounded on three sides by water so snow was very infrequent.  Early last year we had several days of snow and like a kid on a snow day off from school I rushed out of the house with my camera in hand and no thought of  what I was actually doing.  Your eyes are capable of seeing about 20 times the dynamic range better than a digital sensor or film.  So when you go out into the white covered landscape, your eyes automatically adjust.  Unless there’s a whiteout you can see depth and shadow within all the fluffy white.  But the sensor can get confused as easily a kid in a round room with a toy in the corner.
This first image was one of the first I took in the snow.  As you can see it’s white… very white.  It wasn’t that bright out at the time since I took the photos right after sunrise.  But as you can see everything looks really washed out.  I did look at the LCD on the back of my camera after many of the shots, but it was deceptively bright out and difficult to see what was going on.  Normally the bulk of the photos you take have a nice average of colors and shades, so when you have a lot of white, the camera tries to average the white so there’s a “normal ” distribution of shade and gets it all wrong.
What you need to do is to compensate for the inadequacies of the sensor using exposure compensation.  This photo was taken a few weeks ago.  This time I realized it was bright out and darkened the the scene by taking the exposure compensation down by 2 stops.  This gave the scene greater dynamic range and made it easy to pull out the color in the sky a building.
For the observant, you will notice that not only were those photos taken at drastically different times, they were also taken of different places.  This means that I’ve done a better job of taking the photo altogether, but not showing how much better exposure compensation helps in this situation.  For that I took two photos of basically the same scene one after the other.  The first is without exposure compensation which looks a bit washed out.
This second one is with minus two stops.  When it imports to your machine, it looks much darker than the first.  Almost to the point where it lacks the brightness you would expect for this type of image.  Don’t be deceived.  The first image is missing depth to the data.  So there are very few subtle shades to the rolling snow, it’s just all full out white.  The second can be easily adjusted by using a white balance correction tool which will pull out all of those subtle differences.  I’ll show you how to do that later this week on my blog.