Why Nikon Chooses f1.4 & Canon Chooses f1.2?

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Simple question that I have never thought to ask. Why does Canon build f1.2 pro lenses while Nikon builds predominantly f1.4 pro lenses?
 
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IIRC from an article on the 58/1.2, the maximum aperture for a lot of focal lengths is constrained by the physical diameter of the lens mount...
 
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That's what I understand too Al. I learned about this in a post (where?) that compared the Nikon 85mm D to the Canon 85mm f/1.2 L (and to the 85mm f/1.8 D for comparison.) The Canon won, but just by a hair over the 1.4 Nikon. Now that the Nikon D has been superseded by the G, I wonder if parity has been achieved?

Aperture controls DoF, which is related but not exactly proportional to, bokey. Other factors influencing that mysterious quality of blur, include optical design, diaphragm design, distance and choice of background. So it is possible for a lens with a slightly slower aperture to meet the bokey of the faster lens. The Canon 85 L is one sweet lens though. I'll bet it can still edge out the Nikon, but as I can afford neither, the point is moot for me.

Search for that comparison - I used it to help decide on a lens and system. I went with the 85 f/1.8, then replaced that with the 105 f/2.
 
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Aperture controls DoF, which is related but not exactly proportional to, bokey. Other factors influencing that mysterious quality of blur, include optical design, diaphragm design, distance and choice of background. So it is possible for a lens with a slightly slower aperture to meet the bokey of the faster lens.

And don't forget the T stop.
 
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Also Nikon made 1.2 lenses with the f-mount before. I think with the advent of the Nikon 1 32mm 1.2 lens, we might start seeing 1.2 FX lenses.

At least a 50mm 1.2 would be nice since the 1.4 version isn't all that great.
 
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Okay so I'll ask the dumb question here....
How does Voigtlander make an ƒ0.95 lens for Micro Four Thirds :confused:

Leica does as well and its mount is bigger. :wink:

Neither are SLRs - the distance between lens mount and sensor/film plane is also a factor in the design.

As is focal length - the 200/2 doesn't need a 100mm diameter mount...
 
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Neither are SLRs - the distance between lens mount and sensor/film plane is also a factor in the design.

As is focal length - the 200/2 doesn't need a 100mm diameter mount...

I'm not an expert in optics. The aperture is measure at the entrance pupil which has a certain distance from the projection plane (sensor/film). While that distance might not be exactly equal to the focal length I'm pretty sure there's some kind of relation between the two.

For a 200mm lens that distance is far away from the lens mount. For lenses in the 20-85mm range that distance is close enough to the lens mount that the lens mount diameter starts to interfere.
 
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I'm not an expert in optics. The aperture is measure at the entrance pupil which has a certain distance from the projection plane (sensor/film). While that distance might not be exactly equal to the focal length I'm pretty sure there's some kind of relation between the two.

For a 200mm lens that distance is far away from the lens mount. For lenses in the 20-85mm range that distance is close enough to the lens mount that the lens mount diameter starts to interfere.

Pretty much what I thought :biggrin:
 
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Simple question that I have never thought to ask. Why does Canon build f1.2 pro lenses while Nikon builds predominantly f1.4 pro lenses?

I don't know why, but I will have to say that it really doesn't matter as you would be hard pressed to tell the difference between both lenses on the same camera. Both are great with good bokeh. I'll stick with my lame and obsolete f/1.4 Nikkors!!!:biggrin::biggrin::biggrin:
 

fks

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Physical diameter of the lens mount....I'll take that as the answer.

Joe Wisniewski on dpreview said several times that the F-mount geometry was not a constraint to making an 85mm f/1.2 lens. I couldn't find any of those threads (this was way back in the day), but here's one from a review of the Canon 85mm f/1.2 on photo.net (scroll down to the comments section). In this thread someone claims to have adapted a 98mm f/1 lens to F-mount.

http://photo.net/equipment/canon/85L/
 
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Wikipedia (at Lens Mount) says the Nikon F and Leica bayonet mount is 44mm diameter, which is the diagonal of 35mm film. But the Leica screw mount is 39mm. Yet Leica has f/1.2 lenses, even a 50mm f/1.

A 50mm f/1 implies 50mm aperture, but that is not at the lens mount, or at the physical aperture, or even at the smaller film plane. It is the entrance pupil at the front element.

My notions are this:

Any lens has an angular field of view, X degrees diagonal view. This angle of view coming in the front entrance pupil establishes the point of the front node of the lens.

The same necessary angular view exiting the rear covers the film (or sensor) diagonal. That size and angle establishes the point of the rear node (basically and obviously, defines the point that is the focal length).

These nodes can be placed about anywhere by the design, and internal elements relay the signal between them, between input and output. For example, telephotos have the rear node in front of the front element (by definition of telephoto). Wide angles have the rear node well behind the rear element (moving the lens forward so the mirror has room to rise - otherwise a 24mm mirror could never rise behind a 12mm lens).

An f/1 lens could also move the rear node back, so its view was not blocked by the lens mount (of any diameter).

I think the issue is just that it is substantially harder to make a lens be sharp overall at f/1.2. That wider expanse of glass has to be tamed. Same reason why f/2.8 lenses are more expensive than f/4 lenses.



Fearing no one gets it, edited to add a picture: (from an ancient Nikon F Handbook, back when details were discussed):

mike1.jpg
Subscribe to see EXIF info for this image (if available)


Note the front and rear nodes H and H'. These can be placed about anywhere by the design. There is no reason the lens mount diameter needs to block the large diameter lens. But I think a f/1.2 is a bear to design and manufacture with any optical quality.
 
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fks

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Bingo. Limited resources are better spent on products that bring more ROI.

Perhaps Nikon simply decided not to make such lenses. They might not expect a lot of sales for it, or they wanted to focus their design team on something else.
 
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It should be remembered that, although a manual focus lens, the 50mm f/1.2 is still in the current Nikon lens lineup.

http://www.bhphotovideo.com/c/product/36976-USA/Nikon_1435_NIKKOR_Normal_50mm_f_1_2.html

Exactly.

I wish someone would go to all the trouble to take this lens apart, and rig up the elements inside of a different screw drive AF housing so it would be possible to build a DIY 50mm 1.2 AF. :biggrin:
 
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I recall reading elsewhere it's definitely possible to manufacture a super-speed lens with the F-Mount, but from a business perspective it just doesn't make sense. It'd require some real resources and they probably wouldn't turn very many units given how expensive I'd imagine the lens would cost given a wide-angle or tele 1.4 is ~$1,700 and a 50/1.4 is $440, in each case a multiple of what their comparable f/2.8 sister lenses cost.
 

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