A question about lens design!

[art_karr]

This a question that I have wondered about for a number of

years. It is not a Leica question but deals with the philosophy of

lens design and marketing.

 

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According to their literature, Nikon makes 16 mm, 18 mm and 20

mm lenses in the AF mount. Is there some practical reason for

doing that? I use AI lenses in those focal lengths and can't think

of one.

 

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Maybe you can.

 

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Art

[kens]

1) Marketing.

2) Production consistency = lower production costs.

3) The D function - e.g. for flash and matrix metering control -

requires that the body know what distance the lens is set to. Does

this really require "auto-focus" or just focus feedback? The latter,

but then you're back to one-off production costs again.

[andrew_schank]

Nikon does not currently offer any AIS superwides that work with the

Matrix metering systems in any of the current AF cameras. Also, the

newest series of consumer AF cameras from Nikon (Like the N80, N65)

will not METER AT ALL with any of the AI lenses, so those users would

have to have the AF wides otherwise they'd have no in camera meter.

[z1x4y7]

Ken:

 

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<b> 1) Marketing. 2) Production consistency = lower production

costs.</b>

 

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I would guess that those make sense. Since, I mostly use an F2

with a non-metering prism, I hadn't considered the matrix

metering connection. I wouldn't have the courage to try a flash

set-up with a 16 mm lens on a regular basis.

 

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The question still remains: Is this a good way to design a lens?

It is certainly different than the way Leica has done it. [Let me add

that I am not a real fan of the Nikon lenses in AF mount. That is

just a personal impression].

 

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Thanks,,,

 

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Art

[kens]

I imagine Nikon has struggled with its design philosophy ever since

the Maxxum and EOS started eating substantially into Nikon's market

share. But I have no idea what's really going on in their closed-door

meetings, and I'm certainly in no position to discuss this with Nikon

engineers, let alone give them advice. I can only speak as a consumer.

 

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I started creeping away from Nikon and towards Leica when the F3 came

out. My creeping turned into a sprint when the N-series bodies and

plastic disposable lenses started appearing.

 

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Nikon has persisted with its ancient F mount as a marketing strategy,

at the expense of making great strides in lens design, all because

they were afraid to enlarge the mount. Ironically here we are now

with Nikon lenses being marketed without an aperature ring at all!

 

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It doesn't make sense to me. It's inconsistent, and it smells like an

in-house fight between elements of the Nikon company. Or maybe it's a

sign of the times - state of the art engineering versus the pervasive

global economy.

 

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Leica may be slow, ponderous, stubborn, and behind the curve, but at

least I can predict (for now anyway) their product design and its

compatibility with the rest of my Leica equipment. It's also top-

notch equipment. For me, right now, *THAT* is good lens design.

[art_karr]

Ken:

 

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Well at least you understand why I like my old M3. We have been

together forever.

 

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Art

[roberto_watson_garc_a]

I would think in diferent designs for diferent quality of image, not

just focal distance, and I belive those got to be diferent, I should

know them, but I haven´t try, well of course marqueting, after a wile

those become editor´s needs,

[jay3]

The exploitation of the enormous DOF of ultrawide lenses is not the

panacea. If you shoot ultrawides in the extreme close-up range or at

wider apertures, focusing can be more critical than you would

imagine. Manually-focusing them critically at mid-to-longer

distances is challenging on an SLR screen, especially without a split-

image rangefinder aid. AF can be a nice option. I have a Tamron SP

17/3.5 I use with an Adaptall on both Leica R8 and Nikon F5, and the

latter's electronic focus confirmation (otherwise an unused

annoyance) is a welcome feature.

[kens]

Jay's right. Autofocusing with an ultrwide is less distracting, not

having to strain to check the split-image or ground-glass image.

Easier to keep your mind on the image, as long as you are careful

with what you autofocus on and use the focus-lock feature habitually.

[Robin Smith]

Ken

 

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Is that not the advantage of AF in general? I don't see quite why it

is so vital for WA lenses, bearing in mind the large DOFs.

[kens]

Jay's point is that the assumed large DOF of ultra-wide angle lenses

can lull you into over-reliance on DOF alone. If that happens, a

person can get some unpleasant results. Manual focusing such a lens

on an SLR, however, is no picnic - error-prone and distracting at

best. So the bottom line is that while autofocusing seems, on a gut

level, to be particularly suited for longer lenses, in practice it's

helpful for ultra wides, too.