I teach the aperture formula to my students because it’s worth knowing why we use inverse, seemingly counterintuitive, numbers to express aperture values: big numbers = small apertures, and small numbers = large apertures. We get this by the formula: focal length divided by lens diameter (at the front opening) equals aperture value. Example: a 50mm lens with a 36mm diameter … 50 ÷ 36 ≈ 1.4. The 50 mm lens in this example has an f/1.4 maximum aperture.
I thought of this recently at Open Mic Nyte, where I have become a regular, and where I like to bring a different lens every time as my “featured lens.” Last Monday, I lugged along my heavy, beautifully-made Nikkor 200mm f/2.0 ED-IF, a lens which dates back to the late 1970s, and which I acquired in the late 1990s.
If you do the aperture math like in the first paragraph, you find that to get to f2, a 200mm lens needs a 100mm (almost four inches) diameter front element.
To say that this lens is rare is an understatement, since I not only do I seldom use mine, I have never seen another one in the field.
Made of steel and brass, with 11 very large optical glass elements, it weighs 5.3 pounds, and is even heavier than it looks in-hand. It is as smooth to operate as any device I have ever held. Its optics, however, lag behind today’s modern computer-drafted lenses, so it can be a bit quirky to shoot well.
As I researched this post, I discovered several vloggers who asserted that lenses like this, and it’s insanely expensive modern autofocus version, are “hubris” lenses, created by the company and purchased by the customer in the milieu of “the best money can buy,” and not very useful.
One vlogger went as far as to say this lens is for “bokeh sluts.”
Shooting at f/2.0 with this lens makes a very difficult challenge to get the focus where you want it. Since depth of field is a matter of millimeters, moving the focus ring a tiny amount can result of a uselessly out-of-focus image. Of course, you could stop down to f/2.8 or f/4.0, but that defeats the entire idea of carrying and shooting a 200mm f/2. In fact, I have no idea how this lens performs stopped down because I never shoot it stopped down.
I always feel good when I make a point to get this lens out and use it. It certainly creates a unique look with its razor-thin depth of field and deep, deep selective focus. But I think for me, it is a combination of having something no one else can wield and my love of how finely crafted old Nikkor lenses were before the autofocus era.