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4 Days Ago   #1
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Pentax 67 200mm f4 with 2x rear converter minimum focusing distance

Hi all,

Iím wondering about the minimum focusing distance when using the P67 200mm f4 with the 2x rear converter.

4 Days Ago   #2
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AFAIK, the same as without the converter.
4 Days Ago   #3
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It should be the same as the lens minimum distance without the converter.

Neat things about teleconverters; they increase the magnification, lose some light, but don't change the focusing.
4 Days Ago   #4
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QuoteOriginally posted by Ontarian50 Quote
lose some light
Technically, not quite right - they spread the same amount of light out over a larger area, so each pixel gets less light than it would have otherwise.

The effect though is they do seem to lose some light.

4 Days Ago   #5
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Great! Thanks indeed! Appreciated!
3 Days Ago   #6
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They double the focal length but don't change the diameter of the front element which changes the f/stop two stops. A 100mm lens with a 50mm front element is an 100/50=2, an f/2 lens. A 200mm lens that has a 50mm front element is 200/50=4. An f/4 lens.
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