Understanding Focal Length

 18 mm
ISO- 400
F/stop- 22.0
Shutter Speed- 1/6

 24 mm
ISO- 400
F/stop- 22.0
Shutter Speed- 0.3

 35 mm
ISO- 400
F/stop- 22.0
Shutter Speed- 0.5

55 mm
ISO- 400
F/stop- 22.0
Shutter Speed- 0.3

I learned that there are 4 "primary" focal lengths that I can and will use on this particular lens, 18mm, 24mm, 35 mm, and 55 mm. I also learned the actual formal definition of focal length which is "the calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor."