This is part of the initial research to create a dome projection. With no knowledge in photograph when it comes to lens math, my goal here is to understand what does “50mm f/1.8” mean.
Focal Length:
Focal length is measured in millimeters (mm) and it represents the distance from the optical center of a lens to the digital camera sensor when the subject of the photo is in focus.
- With a short focal length you have to be close to your subject for a close-up
- With a long focal length you can be far away and still get a close-up
- A zoom lens has a variable focal length
- A prim lens has a fixed focal length
- 50mm consider short, 200mm consider long
- entire focal range: 11mm to 600mm, lens covers all doesn’t exist.
- Landscapes — Wide Angle — 10 to 28mm
- Architecture — Wide Angle — 18 to 28mm
- Flowers — Standard — 75 to 100mm
- Portraits — Standard — 50 to 100mm
- Sports — Telephoto — 200 to 300mm
- Birds — Super-Telephoto — 400 to 600mm
Aperture:
- Smaller Aperture Number (2.8) = Wider Aperture = More Light
- Larger Aperture Number (22) = Narrower Aperture = Less Light
Maximum Aperture:
- The limit to how wide a lens can be opened is called the maximum aperture.
- All lens aperture can be narrowed as much as you want. All lens today regardless of manufacturer can be set to f/16. However, not all can be opened up to f1/1.4.