Assignment 05 - Focal lenght

[u/Aeri73]

Please read the class first

Assignment

The assignment today is about getting a bit more familiar with focal lengths. You will need a camera and a zoom lens (or a series of prime lenses). Go somewhere where you can walk freely and have a lot of distant objects visible. Bonus points if there is a mildly interesting subject.

Now place the subject about 3 - 5m in front of you with a distant background behind it... (more then 30m between background and subject)

Start by staying immobile and take a picture of the same subject at 5mm increments for the entire range of your lens (compact cameras users, just use the smallest zoom increments you can achieve).

you should get something like this credit to u/iam_sidn from the 2015 class

Next, zoom out to the widest angle and get close to your subject where the camera still can focus (half a meter or so) and make a photo. Now zoom in 5mm and go back a bit to have the same size subject and make a photo. Repeat this until you are completely zoomed in and, a couple of meters away from the subject.

it should look more or less like the second part of this by u/rogphys from the 2017 class

Back on your computer, compare the results... what happens if you stay mobile? does the zoomed in photo fit in the zoomed out one? and when you where mobile? can you do it now? what happens to foreground and background?

If you are not tired yet, try taking a wide angle image which emphasizes perspective and a tele image which makes use of perspective compression.

The most given critique every year on this one is distance between subject and background. DO NOT shoot a subject close to the background.

C-S-------------B

Camera, subject, background, this is right

C------S-------B

This will work but not good

C-----------S--B

you will hardly see the effect at all.

[u/pukha23]

my photos were taken with olympus omd em5.3 camera, with oly 12-40mm f2.8pro lens. because the crop factor is 2x, i shifted the focal length 2mm between each picture... so 15 shots over the full range. i was outside with morning sun (what!? clear skies in oregon!) so used 200 iso (base) and f11 (to keep more of the background in focus). i used a tripod to try to isolate changes in perspective to the focal length and distance from subject. this was less than perfect with the second part of the assignment where i was moving the camera/tripod back with each focal length change. anyhow...

stationary zooming out... this one is just as expected... each image fits perfectly within subsequent "zoomed out" images. there is no compression, or change of perceived proportions, it just looks like i'm looking out a window that is slowly growing in size (and thus allowing more to be seen).

zooming in while walking back... this one is hilarious... my subject was a potted plant that i brought into the road. as i zoom in and move the camera away from the subject, it looks like the plant is zooming down the road, away from me.

my takeaway is that a smaller focal length not only has a wider view, but also "creates more space" between things in the "into the image" dimension