Canon Patents 45mm f/2.8, 40mm f/2.8, 35mm f/2.8, 28mm f/2.8 Pancake Lenses

Canon filed new pancake lens patens. The new patent details include 45mm f/2.8, 40mm f/2.8, 35mm f/2.8, 28mm f/2.8 pancake lenses.

Currently Canon has two pancake lenses in their line-up, they are the EF 40mm f/2.8 STM and the EF-M 22mm f/2 STM. Egami discovered the new patent filed by Canon and all are for f/2.8 pancake lenses with a focal length of 45mm, 40mm, 35mm, 28mm.

Below are the patent details of the 45mm f/2.8, 40mm f/2.8, 35mm f/2.8, 28mm f/2.8 pancake lenses.

Canon 45mm f/2.8, 40mm f/2.8, 35mm f/2.8, 28mm f/2.8 Pancake Lenses

• Patent Publication No. 2013-137411
  • Publication date 2013.7.11
  • Filing date 2011.12.28
• Example
  

  embodiment

  	Focal length	Fno.	Half angle	Configuration length	Total length	BF
  One	45.00	2.80	25.68	20.00	57.99	37.99
  Two	39.00	2.80	29.02	23.50	62.50	39.00
  Three	35.00	2.80	31.72	25.00	63.01	38.01
  Four	28.00	2.80	37.69	27.00	65.00	38.00

  Image height = 21.64mm

• Canon patent
  • The longer the focus back a Gaussian type, field curvature occurs
  • 2-group configuration positive positive, Gauss type

via Eg