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Nikon 5cm (50mm) f/2

© 2011 KenRockwell.com. All rights reserved.

Intro    Specifications    Performance   Compared   Recommendations

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Nikon 5cm f/2

Nikon 5cm (50mm) f/2 (40.5mm filters, 4.7 oz./134g, about $200). enlarge. This free website's biggest source of support is when you use any of these links, especially this link to this lens at eBay (see How to Win at eBay), or OC Camera. It helps me keep reviewing these oldies when you get yours through these links, thanks! Ken.


January 2011   Nikon Rangefinder System   Nikon SLR System   All Reviews

High-Resolution Sample Image (5MB)


Introduction       top

Intro    Specifications    Performance   Compared   Recommendations

Compatibility    History    Production    Pricing

The Nikon 5cm (50mm) f/2 was a very popular lens for Nikon's S series of rangefinder cameras, of which the Nikon SP is the best and most famous.

I'm very impressed at the 50mm f/2's performance, especially considering that it was first introduced in 1946!

Used properly, it's sharp and contrasty even wide-open.


Compatibility       intro     top

Gossen Digisix

5cm f/2 on a Nikon SP with Gossen Digisix. enlarge.

The Nikon S-mount 5cm f/2 works on all Nikon rangefinder cameras.

The Nikon S-mount is completely incompatible with any of Nikon's F-mount SLR cameras or lenses.


History        intro       top

Introduced in 1946 along with Nikon's first camera ever, the Nikon One, this 50mm f/2 saw several cosmetic variations, but used the same coated optics until Nikon forgot about the rangefinder system in 1962.


Production        intro       top

Nikon made about 100,000 of these 5cm (50mm) f/2 lenses.

Like most Nikon lenses, the same optics were sold in many shiny or matte chrome or black enamel cosmetic variations.


Pricing        intro       top

Catalog Price*
Selling Price*
$150-$300 used

* Corrected for inflation in 2010.


Nikon 5cm f/2

Nikon 5cm (50mm) f/2 . enlarge.


Specifications         top

Intro    Specifications    Performance   Compared   Recommendations


Nikon calls this the NIKKOR-H•C 5cm f/2.

NIKKOR is Nikon's trademark for its lenses.

H stands for "hex," meaning this lens has six elements.

C means coated, which was a competitive advantage for Nikon in the 1940s, but as all other brands of lenses were coated by 1957, Nikon dropped the C.

5cm means 50mm.


Optics            top

Nikon 5cm f/2

Nikon 5cm (50mm) f/2.

6 elements in 3 groups.

All are single-coated.

No, this diagram isn't supposed to be an asymmetrical aspheric design; it's how I drew the thing on a napkin while having sake out in Japan a little while ago.


Diaphragm            top

Nikon 5cm f/2

Nikon 5cm (50mm) f/2 at f/5.6. enlarge.

10 straight blades.

Stops down to f/16.


Aperture Ring            top



Full-stop clicks, uneven spacing.


Close Focus (set on camera)            top

3 feet.

0.9 meters.


Hard Infinity Focus Stop?            top

Yes, on camera.

This is great for astronomy; just turn to the stop and you have fixed laboratory-perfect focus all night.


Focus Scale            top

Yes, on camera.


Depth-of-Field Scale            top

Yes, on camera.


Infra-Red Focus Index            top

Sort of: Nikon says to use the f/2.8 index on the camera's depth-of-field scale.

Other Nikon 50mm lenses need different indices, so Nikon couldn't make one mark that would apply to all of their f/2, f/1.4 and f/1.1 lenses.


Filter Thread            top

40.5 x 0.5 mm, chromed brass.

Rotates with focus.

0.5mm is a finer thread pitch than larger filters. Luckily, unlike with 43mm filters, today's 40.5mm filters still use this finer pitch, so any Hoya, B+W or Tiffen filter today should work perfectly.


Hood            top

Nikon 5cm f/2 hood

Nikon 5cm f/2 hood.

The all-metal, enameled conical hood attaches with Nikon's standard split spring-loaded, 40.5mm attachment.

The markings are engraved and filled with paint.

See more under Hood, under performance.


Size            top

1.567" (39.80mm) overall length by 1.850" (46.99mm) diameter, measured.


Weight            top

4.715 oz. (133.7g), measured.

Different cosmetic versions may differ.


Introduced            top

Fall 1946.


Made in            top



Performance       top

Intro    Specifications    Performance   Compared   Recommendations

Overall   Focus  Bokeh   Bubbles   Color   Diaphragm Calibration

Distortion   Ergonomics   Falloff   Filters   Finder Blockage   Hood

Color Fringes   Mechanics   Sharpness   Spherochromatism  Sunstars


Overall      performance     top

The 5cm (50mm) f/2 is much better than I expected for a lens designed in 1946!

It's softer at f/2, but cleans right up by f/2.8. It's sharper at most apertures than the 5cm f/1.4, which is as expected in this era. Back in the 1950s, people knew that faster lenses sacrificed optical quality for speed, and thus slower lenses were sharper.


Focus      performance     top

On a Nikon SP, I found focus to be right-on at all distances at f/2.


Bokeh      performance     top

Bokeh, the character of out of focus backgrounds, not simply how far out of focus they are, is mediocre.

It's better than the funky organic bokeh of the 5cm f/1.4, but still tends to be more distracting than neutral.

Blur circles have soft edges, but the edges are slightly brighter than their centers.


Bubbles    back to performance    back to top

Nikon 5cm f/2 bubbles

Specks of internal dust? enlarge.


Nikon 5cm f/2 bubbles

Close-up of upper left: tiny bubbles!

Back in the good old days, making glass was even more of a pain than it is today.

The bubbles are leftover from when the sand and other materials were melted and stirred to make glass. Today we heat the mix electrically (liquid glass is a good enough conductor) and under a vacuum to remove the air bubbles.

Some special kinds of optical glass used back then were especially susceptible to these microscopic bubbles. This is why instruction sheets of the era always said something like "tiny bubbles are a sign of high-quality glass and are in no way a defect or will they affect picture quality," to try to prevent weenies from returning perfectly good lenses.

Bubbled lenses are especially prized by collectors. This lens still has original 1950s air in it, forever!

These bubbles are invisible to the eye. To the eye, these are completely invisible unless magnified, and even when magnified, usually just look like dust. These are visible as bubbles only under high magnification as shown above.


Color Rendition      performance     top

The color rendition of this Nikon 50mm f/2 matches my other Nikon S-mount lenses, except for the 35mm f/1.8, which is much warmer than the other lenses.


Diaphragm Calibration      performance     top

My slides matched perfectly as I shot at each stop from f/2 to f/16; bravo!


Distortion      performance     top

The Nikon 5cm (50mm) f/2 has minor to moderate pincushion distortion. You won't see it unless you are deliberately looking for it.

It can be corrected by plugging these figures into Photoshop CS2's lens distortion filter. These aren't facts or specifications, they are the results of my research that requires hours of photography and calculations on the resulting data.

Correction Factor
10' (3m)
3' (1m)

© 2010 KenRockwell.com. All rights reserved.


Ergonomics      performance     top

Nikon 5cm f/2

Nikon 5cm (50mm) f/2. enlarge.


Nikon 5cm f/2

Nikon 5cm (50mm) f/2, actual size at 106 DPI. enlarge.

The Nikon 5cm (50mm) f/2's ergonomics are a little better than the f/1.4 because there is a little more spacing between the smaller apertures.

Except for setting the aperture, this lens is about as passive as a golf ball; it doesn't even have its own focus mechanism! It's simply an optical tube that mounts into the Nikon rangefinder camera bodies.

The aperture ring of this particular cosmetic variation is matte chrome, which is easy to read in any light, however the black index dot is on bright chrome, and therefore usually invisible in any light.


Falloff (darkened corners)          performance     top

Falloff is moderate at f/2, almost invisible at f/2.8, and gone by f/4.


Filters, Use with      performance     top

There is no problem with vignetting.


Finder Blockage          performance     top

There is no finder blockage at any distance, unless you use a hood.

If you use the hood, there is a good deal of blockage:

Nikon SP finder blockage at infiity

Nikon SP finder blockage at infiity


Hood      performance     top

As a conical hood, it is designed well so that it offers the best shielding it can for its size without blocking any of the on-film image, however it blocks a lot of the viewfinder.

A proper reverse conical design, like the LEICA 12 585, would have given the same protection from flare without blocking the finder as does this NIKKOR hood. (The two hoods are not interchangeable.) Oh well, this is one of the many reasons that LEICA outsold Nikon by ten times in the 1950s, and why Nikon rangefinders died a fast death, and LEICA lives strong to this day.

Nikon 5cm f/2 with hood on a Nikon SP

Nikon 5cm (50mm) f/2, with hood deployed, on a Nikon SP. enlarge.

The all-metal hood attaches, removes and reverses by pushing the two spring-loaded metal tits. These compress the split, threaded spring ring that attached to the 40.5 x 0.5mm threads of the 50/2 lens.

The threaded split ring has threads on both sides, so the hood also mounts in reverse for stowage.

When reversed, the standard 40.5mm cap will attach to the front of the reversed hood, improving survivability when stowed.


Nikon 5cm f/2 with hood on a Nikon SP

Nikon 5cm (50mm) f/2, with hood stowed, on a Nikon SP. enlarge.


Lateral Color Fringes      performance     top

I can't see any on Velvia 50, either at 22x magnification optically, or scanned at 3,600 DPI.


Mechanics      performance     top

Nikon 5cm f/2

Nikon 5cm (50mm) f/2 . enlarge.

This Nikon NIKKOR 5cm (50mm) f/2 is an optical tube with a diaphragm. It doesn't even have focus helicoids.


Barrel Exterior

Chromed brass.


Filter Threads

Chromed brass.



All metal.


Aperture Ring

Machined chromed brass, or black-enameled (depending on cosmetic variation).

Engraved markings filled with paint.



Chromed brass.



Engraved and filled with paint.


Identity and Serial Number

On front of lens inside filter ring, engraved into the metal and filled with paint.


Ass-Gasket (dust seal at mount)



Noises When Shaken

Almost silent clicking from the diaphragm blades.


Made in



Sharpness      performance     top

Warning 1: Image sharpness depends more on you than your lens.

Warning 2: Lens sharpness doesn't mean much to good photographers.

Manhole 06 Sept 2010

Manhole Cover: f/6.3 at 1/60 at 3.6 feet. 3600 DPI scan.

This is sharp, and this is hand-held at a low shutter speed at close distance!

The 5cm (50mm) f/2 is better than expected for a lens that was designed in 1946.

For normal subjects with normal contrast, this Nikon 50mm f/2 is sharp and contrasty even at f/2 in the center. If you don't have a lot of subject contrast, the slight veiling at f/2 is invisible, and this lens gives a very sharp image throughout most of the image field, even at f/2.

It's actually very sharp at anything other than f/2. My observations below are looking at film at 3,600 DPI (36x); for actual photography, f/2 is a tiny bit hazy if you have a contrasty subject, and this lens is super-sharp from f/2.8 on.


At f/2

Contrast and sharpness are down a bit, with a light veiling flare from spherical aberration.

It's still more than sufficient for use in the low light under which you'd shoot at f/2.


At f/2.8

All the veiling flare is gone by f/2.8.

The center is super-sharp, while the sides better than f/2, but still blurrier than the center.


At f/4

The sides are much better than at f/2.8, but still slightly blurry compared to the ultra-sharp center.


At f/5.6

The sides are just about perfect.


At f/8

Everything is super-sharp at f/8. f/8 is optimum, but only because the corners are ever so slightly less sharp at f/5.6 and f/4.


Spherochromatism      performance     top

I saw no spherochromatism, meaning that out-of-focus highlights don't take on color fringes.


Sunstars      performance     top

With its 10-bladed diaphragm, the 5cm (50mm) f/2 should make 10 -pointed sunstars on bright points of light.


Compared        top

Intro    Specifications    Performance   Compared   Recommendations

I prefer the sharpness of this slower f/2 lens to the 5cm f/1.4.

Distortion and falloff at the same aperture seem to be the very similar, with possibly less falloff at smaller apertures in this f/2 lens.

Forget comparing it to a 1956-1968 LEICA SUMMICRON 50mm f/2, which is far superior optically and mechanically. It's both much sharper and has far less distortion. This is also why these SUMMICRONS sell for about five times as much in 2010.

The original 1953-1960 LEICA SUMMICRON 50mm f/2 was probably about as good; I haven't shot them off directly against each other.


Recommendations       top

Intro    Specifications    Performance   Compared   Recommendations

This is my favorite 50mm lens for the Nikon rangefinders. I find it sharper than the equally popular 50mm f/1.4.

Stop down to f/2.8 for the best results with contrasty subjects if you're making huge enlargements, and to f/5.6 if you're looking too closely in the corners. Guess what: this advice applies even today with Nikon's newest 50mm f/1.4 AF-S!

You may want to try to find a 40.5mm to 43mm filter adapter ring so it takes the same filter size as other common Nikon S-mount lenses, but it's unlikely that the thread pitches will match what you need.


Help me help you         top

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The biggest help is when you use any of these links to Adorama, Amazon, eBay, Ritz, Calumet, J&R and ScanCafe when you get anything, regardless of the country in which you live. It costs you nothing, and is this site's, and thus my family's, biggest source of support. These places have the best prices and service, which is why I've used them since before this website existed. I recommend them all personally.

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Thanks for reading!



Mr. & Mrs. Ken Rockwell, Ryan and Katie.


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End of review originaly 09 Sep 2010


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Test daten roll 0628, 02-06 Sep 2010, filed under the lens.