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Seeking advice: New lens: Nikon 105 f2 DC or Fuji 90 f2

Started Feb 22, 2018 | Questions thread
SpacemanUA
SpacemanUA Senior Member • Posts: 1,773
Re: Seeking advice: New lens: Nikon 105 f2 DC or Fuji 90 f2
2

MisterHairy wrote:

135/2 > 90/2. The 135 has an aperture which is 2.25 x as large by area.

Lets more light in.

Is faster.

You're messing up DoF with light transmission. And the "aperture area" is a nonsense.

f/2 means that a lens transmits 1/2 of incoming light through itself, and it doesn't matter, if its made for m4/3 or FF or MF or how big is that lens is. If its f/2, its always f/2. F-number always and only means the amount of light transmitted. 90/2 and 135/2 lenses transmit 1/2 of incoming light through themselves hence they're have same "speed". As for lens diameter (not aperture diameter or area) - F-number depends on it too, so if you're counting it twice, you're obviously wrong.

As for DoF - 135/2 will have harrower DoF than 90/2 obviously.

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