Nikkor 200 mm F2.0 AF-S VR - is NOT DX

[Joseph S Wisniewski]

I agree with what you are saying here, in fact I read somewhere
that a 300mm F2.8 (Nikon) lens circle of coverage will actually
cover some medium format film sizes.

True. It can run 6x6, as the "Bronica Nikkor".

http://www.nikon.co.jp/main/eng/society/nikkor/n11_e.htm

I also agree that trying to do
the "dx" thing on a telephoto doesn't give any design advantages,
but perhaps it could produce a cheaper lens. Producing lens
elements with smaller diameters may produce a much cheaper 300mm
"dx" lens.

It has the potential to be a little cheaper, but not "much cheaper".

Have a look at the optical design of the original Nikon 300mm f2.8.



Those massive front elements are what basically controls the cost of the lens. The rear elements, which could be reduced in size slightly in a DX version, are 1/2 the diameter, and therefore 1/8 the mass of the fromt elements. They account for less than 12% of the cost of the lens

I would bet that, if Nikon were to maintain two different 300mm f2.8 lenses in the line, and split the sales between them, the the price on both woudl end up rising because the volumes were smaller.

--
A cyberstalker told me not to post anymore...
So I'm posting even more!

Ciao!

Joe

http://www.swissarmyfork.com

 

[muskiemouth]

I agree with what you are saying here, in fact I read somewhere
that a 300mm F2.8 (Nikon) lens circle of coverage will actually
cover some medium format film sizes.

True. It can run 6x6, as the "Bronica Nikkor".

http://www.nikon.co.jp/main/eng/society/nikkor/n11_e.htm

Like I said I wouldn't be a proponent of this, but I don't see why the front element lens diameters couldn't also be reduced. They are pulling in light on the outer regions (of the lens circumference) that doesn't make it to the sensor (the crop). For instance I can put a much "narrower" lens hood on my 70-200VR when mounted on a D2H, and a film body I can't because it blocks the light that would strike the outer regions of the front element.

I also agree that trying to do
the "dx" thing on a telephoto doesn't give any design advantages,
but perhaps it could produce a cheaper lens. Producing lens
elements with smaller diameters may produce a much cheaper 300mm
"dx" lens.

It has the potential to be a little cheaper, but not "much cheaper".

Have a look at the optical design of the original Nikon 300mm f2.8.



Those massive front elements are what basically controls the cost
of the lens. The rear elements, which could be reduced in size
slightly in a DX version, are 1/2 the diameter, and therefore 1/8
the mass of the fromt elements. They account for less than 12% of
the cost of the lens

I would bet that, if Nikon were to maintain two different 300mm
f2.8 lenses in the line, and split the sales between them, the the
price on both woudl end up rising because the volumes were smaller.

--
A cyberstalker told me not to post anymore...
So I'm posting even more!

Ciao!

Joe

http://www.swissarmyfork.com

 

[Osku]

You have to admit, my Roman numeral definition of DC as D100 was
comedic genius.

There are so many no brainer around this forum, that even I have found much insight in your typical postings, I thaught you might be serious... Some people here even think they could make the photons multiply somehow in future, would be really nice for low light situations;-)

--
Osku

 

[Thomas Sapiano]

Like I said I wouldn't be a proponent of this, but I don't see why
the front element lens diameters couldn't also be reduced. They are
pulling in light on the outer regions (of the lens circumference)
that doesn't make it to the sensor (the crop). For instance I can
put a much "narrower" lens hood on my 70-200VR when mounted on a
D2H, and a film body I can't because it blocks the light that would
strike the outer regions of the front element.

Because on telephoto lenses the size of the front elements are primarilly governed by the size of the apperature. Any 300mm f2.8 lens (regardless of format) requires an apperature size of at least 107.1mm - the Nikkor has a 112mm front element, so there isn't much excess there to begin with. Near the effective apperature variables like the focal length, image circle, etc. don't have much effect - you only start to see that when you move down the lens into the smaller elements.

With wide angle lenses, there are other concerns that force the front elements to be much larger than the apperature. For example, the 17-35f2.8 only needs a 12.5mm apperature - yet the front element is 77mm in diameter. Going to a smaller projected circle allows you to push that down in this case because there is plenty of extra room designers can trim off. However, regardless of how small you made your sensors, a 35mm f2.8 lens could never have a front element smaller than 12.5mm.

 

[muskiemouth]

Like I said I wouldn't be a proponent of this, but I don't see why
the front element lens diameters couldn't also be reduced. They are
pulling in light on the outer regions (of the lens circumference)
that doesn't make it to the sensor (the crop). For instance I can
put a much "narrower" lens hood on my 70-200VR when mounted on a
D2H, and a film body I can't because it blocks the light that would
strike the outer regions of the front element.

Because on telephoto lenses the size of the front elements are
primarilly governed by the size of the apperature. Any 300mm f2.8
lens (regardless of format) requires an apperature size of at least
107.1mm - the Nikkor has a 112mm front element, so there isn't much
excess there to begin with. Near the effective apperature
variables like the focal length, image circle, etc. don't have much
effect - you only start to see that when you move down the lens
into the smaller elements.

With wide angle lenses, there are other concerns that force the
front elements to be much larger than the apperature. For example,
the 17-35f2.8 only needs a 12.5mm apperature - yet the front
element is 77mm in diameter.

The opening is 77mm so that at the 17mm end the wide angle "light can make it to the front element. The front lens is not 77mm though, it's much smaller.

Going to a smaller projected circle
allows you to push that down in this case because there is plenty
of extra room designers can trim off. However, regardless of how
small you made your sensors, a 35mm f2.8 lens could never have a
front element smaller than 12.5mm.

I think I see what you mean; it has to do with the "35mm" aspect. In reality (I think) what I'm thinking of is a "dx mm" lens whose signature would actually be a 200mm F2.8 and would have smaller front elements etc, and whose FOV would appear like a 300mm F2.8 on a film body. Right?

 

[Leon Obers]

With wide angle lenses, there are other concerns that force the
front elements to be much larger than the apperature.

Yes, all wide angle lenses to a SLR are forced to have a more long "retrofocus" design to give distance for the mirror within a SLR camera.

For example,
the 17-35f2.8 only needs a 12.5mm apperature - yet the front
element is 77mm in diameter. Going to a smaller projected circle
allows you to push that down in this case because there is plenty
of extra room designers can trim off.

No, still limited to the fact of the needed distance from front bayonet to sensor or film plane distance. You only can have a nice small wide angle lens when the design is not taking account to the distance as fixed within the camera mirror box.

E.g. that is the difference between a normal Hasselblad using 40 mm wide angle lens, and the Hasselblad wide camera (without a mirror box) using a "real" non retrofocus 38 mm wide angle lens design.

However, regardless of how
small you made your sensors, a 35mm f2.8 lens could never have a
front element smaller than 12.5mm.

Yes, agree.

And bigger and bigger related to the distance from bayonet to sensor / film by the retrofocus design.

The distance bayonet to sensor / film is about 46 mm (not checked).

A real non retrofocus design 17 mm wide angle lens should have a distance from the "center" of the lens to the sensor/film plane of 17 mm when focused at infinity.

Using SLR, the design has to overcome about 3x the distance of this 17 mm focus (at least 46 mm --> the size from bayonet to sensor/film plane).

So the size of a front element of a 17 mm wide angle is at least about 3x the size of your early calculated "12.5" mm. Still the front element is even more big, because the front element is not situated just at the bayonet place of the camera but even far more in front.

The other factor of lens size is how big the image circle should be under these strange "retrofocus" design rules.

That's why special DX lenses are designed for. Not needed an image circle for full frame, but limited to the more small APS sensor size.

With the above story in mind, everyone can understand that lenses that do have a more long focus than about 46 mm (the size from bayonet to sensor/film plane), it is not needed to have have a retrofocus design. Okay, in practice just a bit more, because the lens itself still is in front of the camera bayonet. Maybe about 85 mm and up.

That's why there is totally no advantage to design a 200 mm lens as a "DX" lens.

In practice lenses with a more long focus, often are designed in a way they are even more short than the real "natural" focus should be. The opposite of "retrofocus" as needed at wide angle lenses.

--
Leon Obers

In cases of e-mail sending messages, exchange 'invalid.cc' domain name within the profile e-mail adress by 'fotograaf.cc' (detour to avoid SPAM).

 

[Joseph S Wisniewski]

With wide angle lenses, there are other concerns that force the
front elements to be much larger than the apperature.

Yes, all wide angle lenses to a SLR are forced to have a more long
"retrofocus" design to give distance for the mirror within a SLR
camera.

Quite true. But that's not really what forces them to have such large diameters.

For example,
the 17-35f2.8 only needs a 12.5mm apperature - yet the front
element is 77mm in diameter. Going to a smaller projected circle
allows you to push that down in this case because there is plenty
of extra room designers can trim off.

No, still limited to the fact of the needed distance from front
bayonet to sensor or film plane distance. You only can have a nice
small wide angle lens when the design is not taking account to the
distance as fixed within the camera mirror box.

E.g. that is the difference between a normal Hasselblad using 40 mm
wide angle lens, and the Hasselblad wide camera (without a mirror
box) using a "real" non retrofocus 38 mm wide angle lens design.

And that "real" non-retrofocus lens suffers from great light falloff at the periphery of the image, due to the infamous cos^4 law. That's why you have to throw a lot of light away with a center filter, to dim the center down to resemble the edges. That's where most of the enormous bulk in the front sections of wide angles comes from, an attempt to even out illumination.

However, regardless of how
small you made your sensors, a 35mm f2.8 lens could never have a
front element smaller than 12.5mm.

Yes, agree.
And bigger and bigger related to the distance from bayonet to
sensor / film by the retrofocus design.

The distance bayonet to sensor / film is about 46 mm (not checked).
A real non retrofocus design 17 mm wide angle lens should have a
distance from the "center" of the lens to the sensor/film plane of
17 mm when focused at infinity.

And a rear element that would almost touch the film plane, as the read node is likely to be well within the lens, and three thick elements will be between lens center and the film.

Using SLR, the design has to overcome about 3x the distance of this
17 mm focus (at least 46 mm --> the size from bayonet to
sensor/film plane).
So the size of a front element of a 17 mm wide angle is at least
about 3x the size of your early calculated "12.5" mm.

That's not how it works. You can move the rear node entirely with optics behind the lens. Relay the image at the focal plane through an optical system with nodes much farther from the film plane. the lens gets longer, not wider.

The other factor of lens size is how big the image circle should be
under these strange "retrofocus" design rules.
That's why special DX lenses are designed for. Not needed an image
circle for full frame, but limited to the more small APS sensor
size.

Actually, the DX lenses get even worse. Aside from the retrofocus aspect of rear nodes outside the lens, they also have exit pupils very far forward of the film plane. In the case of the Nikon 17-35, for example, teh exit pupil is actually in front of the lens.

With the above story in mind, everyone can understand that lenses
that do have a more long focus than about 46 mm (the size from
bayonet to sensor/film plane), it is not needed to have have a
retrofocus design. Okay, in practice just a bit more, because the
lens itself still is in front of the camera bayonet. Maybe about 85
mm and up.

Exactly.

That's why there is totally no advantage to design a 200 mm lens as
a "DX" lens.

And right on, here.

In practice lenses with a more long focus, often are designed in a
way they are even more short than the real "natural" focus should
be. The opposite of "retrofocus" as needed at wide angle lenses.

Quite right, again.

--
A cyberstalker told me not to post anymore...
So I'm posting even more!

Ciao!

Joe

http://www.swissarmyfork.com

 

[Leon Obers]

Yes, all wide angle lenses to a SLR are forced to have a more long
"retrofocus" design to give distance for the mirror within a SLR
camera.

Quite true. But that's not really what forces them to have such
large diameters.

Can you explane why?

I never have seen lenses with a retrofocus design without a more than normal sized front lens. Always bigger. (See also explanation below).

And that "real" non-retrofocus lens suffers from great light
falloff at the periphery of the image, due to the infamous cos^4
law. That's why you have to throw a lot of light away with a center
filter, to dim the center down to resemble the edges.

Okay, a "real" non-retrofocus lens do have disadvantages too.

That's where
most of the enormous bulk in the front sections of wide angles
comes from, an attempt to even out illumination.

No, IMHO has nothing to do with it. Even out illumination is coming by the retrofocus design. Because the distance to the film plane is more big, the infamous cos^4 has less influence to the lighting at the corners of the filmplane. The more big the distance is, the less light fall-off to corners.

Wide angle lenses for technical camera's also have big front (and rear) lens elements, in spite it most are no retrofocus lenses. The big size in this case is needed to have a large image circel c.q. a wide angle of view (about 100 degrees). Light fall off is big.

A retrofocus design as used for a technical camera in combination to use a digital SLR camera body as "back", the design also comes to a big front size in relation to the short focal length.
E.g. Schneider Kreuznach Digitar 28 mm / 2.8
http://www.schneider-kreuznach.com/pdf/foto/digitare_e.pdf

As found at the Schneider PDF-file, you can see there is no center filter available for the Digitar 28 mm / 2.8. Not needed by the great distance from back of the shutter "box" (mounting to a lens plate) to film plane of about 70 mm at infinity.

Using SLR, the design has to overcome about 3x the distance of this
17 mm focus (at least 46 mm --> the size from bayonet to
sensor/film plane).
So the size of a front element of a 17 mm wide angle is at least
about 3x the size of your early calculated "12.5" mm.

That's not how it works. You can move the rear node entirely with
optics behind the lens. Relay the image at the focal plane through
an optical system with nodes much farther from the film plane. the
lens gets longer, not wider.

Okay, I think not entirely.

If you are using thick lens elements, you can subtract the distance of the thickness of the lens element itself as far if you can "cut" a parallel slice out of the lens element from the middle part. E.g. if a minimum thickness of a lens element is 5 mm, a lens element with the same "fastness" and focus that has a thickness of 25 mm, you can cut a slice from 20 mm.

This 20 mm you can substract from the total length of the build lens "system". Parallel conduction / direction of the light by the "air" parts between lenses I think likely is not used as it brings bigger dimensions for a lens system as needed. The distance from rear lens element to film plane never is a parallel light direction, otherwise an image never can be made to the film / sensor.

If you have other insite information. Nice to exchange.

--
Leon Obers

In cases of e-mail sending messages, exchange 'invalid.cc' domain name within the profile e-mail adress by 'fotograaf.cc' (detour to avoid SPAM).

 

[v_]

Yes, I have seen many indications that this lense will be all over the Olympics in Athens.

The timing was perfect!

Viktor

The anouncement of the 200 VR lens really targeting on DX sensor,
especially sport shooter with D2H, D1H etc........Personally I
perfer FF as I got 17-35 & 28-70 AFS, 70-200 VR etc.........they
are the ideal 3 lens for FF.........I also got TC-14E......but I
always feel 200 x 1.4 =280 is a bit not long enough for sport when
I was still using my F5, but I don't want to get the TC-20E to slow
down the focusing speed...............Now I have been using D1x for
1.5 years, I am very happen with the long end.....I really hope
Nikon will release FF in D2X to solve my wide end problem as I am
not willing to sell my 17-35 and replace my 12-24 since I still
want to keep my F5 ........Since Nikon also anounce TC-17E.......it
make me feel adding the TC-17E will solve my long end problem in
FF.......I am happy with 340mm in f4.7 if Nikon can make a FF D2x
with 10MP, 4fps and under $5000 street price........If that is the
case, you will see my D1x and TC-14E in ebay very soon.

Derrick

 

[v_]

One day, when I'll have the cash..... I'll have one also! ;-)

Viktor

What do you guys think about that? Is this means that FF DSLR is on
the way?

My theory.......
If Nikon was so dedicated to the current CCD size, than all new
lenses would be DX labeled to make them cheaper. It is known that
DX lenses are cheaper to develop, since the image circle is
smaller, so the engineers don't have to worry about such a big
image area. That causes the street prices to be lower as well.

Am I right?

Viktor

I've already had my name on the wait list.

Chris L

--
FM..FM2..F3..F5..F100..D1X..D2H......and the saga continue