CONTAX CLUB Carl Zeiss 討論區

有無兄台知道zf100的Selective focus 是甚麼? 同電影鏡頭的設計有何分別?

謝謝

有沒有兄台買了? 可以放放例子嗎?

Selective focus is a term used to define shooting technique, not a feature of a particular lens , and of course its far easier to do so with tele and fast lens

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那麼和用Tele或大光圈時的淺景深有何分別? ZEISS 只有zf100 和 zm85 提及過, 而這兩只鏡頭有運用其電影鏡頭的設計. 那麼 selective focus 的技巧, 如何能在 zf 100 上發揮? 請 FR 兄台指教, 謝謝.

"Selective focus " used by Carl Zeiss to describe the two tele ZF lens is referring to the lens feature, not shooting technique.

It is just a general term to describe the very narrow depth of field features of these two lens ... so that only a very narrow range of object (more narrow than other lens design at the same aperture) will appear clear in the image.

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Contax : RTS, RTSII(50Y), RTSIII, Aria D, Aria(70Y), N1, ND, T3D(70Y), G2D
Nikon : FM3A, FM3AB
Leica : M9, X1
Fuji : X100
OM : EP2

Well, that can hardly be called a feature, really its more a marketing term. The funny thing about good lens as regard to DOF is that the better corrected the lens, the more likely the lens will exhibit a typical DOF. To get a deeper DOF, ( as in Deep field lens ) a lens can employ several technique regarding optical design, but no particular trick on optical design can give you narrower DOF as lens in real world is always worse than theoretical, but by that, the DOF increase, not decrease.

What do happen is the change of acuteness and defining / resolving power when shift from the focusing plane to defocussing plane. Not the actual quantitative, but how it exhibit in image.

Selective focsuing in a typical fast lens or tele really mean the capability to place the focus at a specific plane. This can be achived with any lens, but usually in lens term that mean the lens exhibit a fairly high contrast and acuteness when in focus. This term had been and is used by Zeiss in such manner ( and many other Mfr too ) but again one must note that this is just a by product of how the lens can be employed, in a word a technique to employ the high contrast and acuteness, not by itself a specific feature. One can do the same with any other lens that do not exhibit such contrast and acuteness, just that it would be harder to judge the focus when viewing.

My wager on the matter is this is just marketing jargon to tell that this lens is good for such and easily employed for such.

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