sharing my journey in photography & Photoshop CS3 every week for a year
what makes it hard(er) - my girls have to be the subject because we're making a book
Front Entry September 13, 2010 3:55 pm Nikon D90, 35mm Manual, No Flash, ISO 250, SS 1/50, f/2.8 RAW, Spot Metering, AF-S, WB in Auto
When I started this journey 37 weeks ago I only knew that I wanted to try and learn as much about my camera as possible and try to take a good picture of my girls once a week with something "new" in mind.
It's getting hard. I'm not as joyful about this project as I was when I started and so this week I'm posting a picture that is joyful but where I didn't try or learn anything new and did a great job of chopping some hands - but its OK, because look at those smiles!!! They were testing out some potential Christmas photo tops and were "striking a pose" using either a dance move or something they've seen on Project Runway - I'm not for sure which.
post-processing did a quick mask of their face and did a slight midtones contrast adjustment...just a touch.
Backyard
September 05, 2010 2:28 pm
Nikon D90, 70-300 4.5-5.6 VR @ 300mm
Manual, No Flash, ISO 250, SS 1/200, f/5.6
RAW, Spot Metering, AF-S, WB in Auto
Compositionally, I didn't get the best shot of Alena with the board running up the back of her head, I should have been moving my own feet a bit more. Working with the telephoto lens zoomed all the way out reminds me of using binoculars to go birding (this is easier of course), you have to search a bit sometimes with your lens to get your subjects in the frame. The sun was also going in & out of the clouds, and while they were in the shade and it metered the same it changed the tone of the photos between Iva & Alena. Alena's is just a bit soft too, one of us moved or I snapped the shot before the camera focused.
One aspect that creates a nice effect for portraits is depth of field - the ability to separate the subject from the background by having a sharply focused subject and a soft, blurry background.
The easiest way for portrait photographers to do this is use a fixed aperture lens, usually a prime lens - 50mm 1.4 (or 1.8) - is a popular starter lens for a lot of photographers.
I have tried a couple times to explain this to some photography pals of mine and I haven't done a very good job because first of all I don't understand the mechanics of why using a lens with the widest aperture creates the softest effect and smallest depth of field (smallest plane that is focused).
Then to complicate matters, the farther away you are from your subject the deeper your plane of focus will be. For example if I am taking a photo with my 50mm set at f/1.8 from 5 feet away the focused plane depth is only 2.5 inches. If I step back to 8 feet away now the focused plane depth jumps to 6.5 inches, but of course I'm including a lot more of the environment around my subject as well.
When you learn about the exposure triangle you learn that each change in f/stop results in a double or halving of the amount of light entering the sensor. But why on earth is 2.0 half of 1.4? It is because to allow double the light to hit the sensor you have to make the aperture twice as big - and you do that by doubling the radius and then hence the area of the lens opening.
So taking a 50mm lens you divide the focal length (50) by the aperture (1.4) to get the lens opening diameter (35.7) which using some math from school long ago results in an area of 1002 mm^2. For 2.0 the result is 491 mm^2 - pretty darn close to half - so hence f/2.0 is half is f/1.4.
So even though I took these photos with a variable aperture lens which only allows me a maximum aperture of f/5.6 at 300mm, the lens opening is the same if I had used f/1.0 on a 50mm lens (which doesn't exist) or used a 70-200 f/2.8 at f/2.8 at 150mm (which I don't have the budget for that lens).
So does that mean you can get the exact same results using f/2.8 @ 150mm vs. f/5.6 at 300mm? Not exactly because the DOF is also affected by the distance to your subject and you would move closer to fill the frame if you were at 150mm vs. 300mm and so that also changes your distance to the background...but in my few experiments its pretty close.
I did a little quick experiment with this back in April when I had the chance to rent a 28-70 f/2.8 and the 70-200 f/2.8. My experiment wasn't all the scientific because I was in a bit of a rush, but if you look at the rose bushes you will see how the blur really doesn't change much even though the aperture is increased because the focal length is also increased. But you can also see the blur created when the longest focal length in combination with the widest aperture was used.
Did I confuse everyone again?
post-processing
Iva's photo was left alone - the focus and colors were beautiful with the sun coming out behind the clouds. For Alena I warmed the photo in ACR, but then also added a warming photo filter masked to her, then a cooling photo filter where she was masked out, and then a green photo filter to the foliage to brighten it and make it appear closer to the foliage in Iva's photo.
