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Friday, 18 October 2013


It is approximately 0.47393118833241233283316097108315 stops faster...

I realize that is isn't an SLR lens, but, for what it is worth, the Leica 50/1.2 Noctilux aspherical came out in 1966.

> (Ctein could tell us what the fraction is—it's not half)

Actually, it's very nearly half. Exactly half would be f/1.189; a third stop down from f/1.4 would be f/1.26, two thirds f/1.122. The case of f/1.2 is a little confusing because manufacturers usually round both the half-stop and the two-thirds-stop increment to /f1.2.

Generally, f-numbers are simply multiples of the square root of 2 (which is why f/1.4 is actually f/1.414).

To add a bit to the "Why isn't the new 58mm a f/1.2?" question : there is also the fact that digital sensors don't benefit much from very oblique incident light rays, and the supplementary rays going from f/1.4 to f/1.2 are generally very oblique in the corners.
See http://www.dxomark.com/Reviews/F-stop-blues : in short, digital sensors don't benefit that much from large aperture lenses.

I'm tired of all these endless "upgrades". I will not get excited until either Nikon, Canon or even Sony produces a pro level SLR with an upgradeable sensor and firmware to go along with it. My D700 is built like a brick shit house. Heck it will probably outlast me! But according to pundits it's a dinosaur. No matter it does everything I want it to.

What does this have to do with a useless focal length lens that's not fast enough and costs $1800CAD? Nothing really, I'm just venting.

It seems that once digital took over all the major camera manufacturers lost their minds.

I say we name this new 58mm lens the "Edsel".

Here is an interesting review of the Canon 55mm from the May 1978 issue of SLR Camera magazine.

Best thing about the review Jeff points to is that the body the lens is mounted on is an AT1 - my first in a long line of camera bodies.

Lots of good memories - probably the only body I've replaced 'cause I wore it out.

The Leica Noctilux 1:1.2/50 mm (1966) was the first 35mm camera with an aspherical element.

[Hi Esa, The subject here is SLR lenses. --Mike]

There's a very simple reason why it isn't an F1.2 lens, and that is that the rear element would be too large for the throat of the mount on a CPU-equipped lens. The tab that holds the lens contacts on modern Nikon lenses limits the size of the rear element to smaller than what was possible with mechanically coupled lenses, including all 3 of the f1.2 lenses made in F mount (the 50, 55 and 58mm)

Mike, have you taken a look at the MTFs compared to the Noct-Nikkor? The closeness of the sagittal and tangential lines is astounding, and they are also surprisingly flat until well out in the field. I am guessing that this lens will have stunning boke... Yes, I use the pre-h spelling by preference :)

P.S. I see I am not the only FMer here: Adam even wrote what I wanted to write before I got there :)

Dear Sebastian,

As a matter of fact, our semi-innumerate [g] editor DID ask me... and I told him one half.

No one ever talks about this stuff closer than 1/12th stop (i.e., is something closer to 1/2 than 1/3 or 2/3).

pax / Ctein

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