Spring 2012

Spring 2012
by ani

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Refers to lenses in which focus is changed by moving internal lenses only. In contrast to "block focus" designs which focus by changing the distance of lens groups, or the entire lens, from the sensor.

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2answers
59 views

Macro lens: IF or Extending Barrel?

I'm an aspiring photographer of fish. So the implication is that, I have a segemented working distance: 1st Between me and the aquarium, that I can adjust 2nd The breadth of my aquarium The 2nd is ...
16
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2answers
4k views

What is the benefit of an internal focus lens?

The "IF" in Pentax DA★ 200mm f/2.8 ED (IF) SDM stands for "Internal Focus". I know what this means: the lens doesn't change in size as I focus. (And it's true; it doesn't.) What's the point of this, ...
3
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2answers
127 views

How to check if Nikkor lens has IF feature?

The specification for the lens says that the Nikkor 18-105mm ED VR has the IF feature. However, the local market product label doesn't advertise this feature. How can I make sure that the IF feature ...