Reasons why no Nikon 85mm f1.2?

Started Apr 11, 2013 | Discussions thread
whoosh1
Senior MemberPosts: 1,041
Like?
Still not very convincing :-)
In reply to Grevture, Apr 12, 2013

Grevture wrote:

Some actually have an idea

>> Some think they have an idea

Look, this "why is there no Nikon 85/1.2 discussion" has a tendency to pop up here at least every six months or so, and has done so for many years. The issue has been discussed in length many times, and some very knowledgeable people has been involved from time to time. And yes, the rear diameter of extremely fast lenses really is an issue. A big issue (pun intended).

To be very exact, it very likely can be done - technically speaking. But from a "what makes sense" perspective, it cannot without getting and extremely expensive design. What is meant by the statement "Nikon can't make a 85/1.2 for the F mount" more precisely means "Nikon can't make a 85/1.2 for the F mount that any customer outside military entities and well funded science organisations could afford". Technically you can build almost any optical design, but what is the point of building something so horribly expensive nobody could buy it?

It is not just an internet myth.

The bigger choice to me from Nikon's perspective is not if Nikon can make or not make 85mm f/1.2 at a reasonable price (may be it is possible - may be it is not possible and neither of us know) - but the following:

A) Canon can only charge $2200 for 85mm f/1.2 lens (which is also relatively new - 2006 release) - so Nikon cannot charge much different for their version of an 85mm f/1.2 lens.

B) Nikon makes an 85mm f/1.4 lens and charge $1650 and people buy it in reasonably good numbers - and possibly cheaper/easier to make than 85mm f/1.2 and probably selling more quantity (due to slightly lower price) than if it was f/1.2.

So option B makes financial sense from Nikon's perspective - especially if their customers are not screaming for the f/1.2 - instead being content & offering explanation that F-mount is too small to make a quality f/1.2.

Not wanting to be rude, but I think you might want to read a little about lens design

>> Sure - but what you have explained below is not much more convincing proof either - till then its a speculation.

To make an over-simplistic explanation: When you calculate the aperture size, it is the diameter looking from the front end that matters (where the opening indeed is about 150 mm in a 600/4). This is what is often referred to as the "entrance pupil" in optical discussions. But after the aperture you can quite easily shrink the optical path using the built in teleconverter already in place to keep the size down (or also the other way around, like with the Metabones Speedboaster).

The irony is that it probably could be easier to build a very fast longer lens then a 85 without getting a overly complex lens design - because by virtue of the longer focal length you have more optical path to play with.

From the picture (linked by Grevture) I would think that Canon took advantage of the larger mount size for their 85mm f/1.2 design - but if Nikon were to design it they would design differently taking their own mount size into consideration. I have not checked side-by-side but from the dpreview review of Nikon 70-200 f/2.8 VR II where they show the Nikon next to the Canon - it seems to me that the Canon 70-200 f/2.8 rear element is wider but the Nikon lens is longer. May be that is related to the mount size or may be it is just a different design - but definitely different dimensions (longer/narrower vs wider/shorter). I fail to understand why similar difference in dimensions cannot be present for 85mm f/1.2 if Nikon were to decide to make one.

The real clue in that image is the fact that Canon had to put their electrical contacts inside the rearmost lens element - they would not have done that unless they really, really, desperately needed that large diameter to make it work optically. So even the wider EF mount is problematic for a 85/1.2 lens. The F narrower mount is even more problematic.

Again that does not mean Nikon will have to have the same design where they really really desparately need as large diameter as possible of the rear element. The problem will have to be solved with a different approach - and I doubt there is likely to be a will at Nikon to find a way while Nikon 85mm f/1.4g sells sufficiently good numbers. After that source of buyers is exhausted (slowed down at least) I would not be surprised if Nikon comes out with a Nikon 85mm f/1.2 - till then folks will continue to post on internet fora (forums) assertions why it is not possible in an F-mount (similar to the way folks used to post why its not possible for Nikon to do a digital full frame SLR before 2006).

And the bigger issue here - for what reason? That 1/3 extra stop has almost no meaningful photographic purpose which make such a lens a bit of a non-starter anyway. Canon did it for marketing purposes and bragging rights. Nikon has wisely stayed out of that.

Agree on that point.

Look at the re-occurring 85/1.8 vs 85/1.4 discussions - where many point out the f1.8 version in practical terms deliver something like 90-95% of the usable performance of the f1.4 version at a fraction of the price. For some, the difference still is worth the money. But considering how expensive (and cumbersome, and slow focusing) a f1.2 version would be, and that it probably would deliver almost no discernible practical image quality advantage at all - it is practically pointless commercially speaking.

Agree on this as well - there would be no point of releasing such a lens (as I said before while there are plenty of willing buyers for 85mm f/1.4g.

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