Olympus G_Zuiko 50mm f1.4 lens — Blimey it’s a silver nose!

A little while ago I got a new to me camera (more about that in a later entry) and it came with an Olympus OM Zuiko 50mm f1.4. Initially I wasn’t really interested in the lens at all as I already had a copy. However, on arrival I noticed that the front filter ring and the edge of the aperture ring were silver chrome and I realised that it was an Olympus “Silver Nose” lens. This realisation sent me down a rabbit hole looking at all the variations of Olympus lenses and the effects of lens coatings and trying to see which lens is better.

Get online and look at the many forums that talk about classic film cameras and lenses you can find “Olympusphiles” (or should it be “Zuikoholics”) discussing/arguing about the merits of silver nose lenses and whether they are better than black nosed lenses. So what is a silver nose exactly? Well when Olympus launched its 35mm OM camera system at Photokina in 1972 the lenses all had the chromed filter rings and they were single coated, I think there were a couple of exceptions, but, I’ve not managed to confirm this one way or the other. These lenses stayed in production until roughly 1983/4 and were replaced by multi-coated lenses. The situation is not entirely clear cut as between 1972 and 2002, when production of OM Zuiko lenses ceased there were four generations where each iteration brought some improvement in either the optical performance, or manufacturing efficiency. The table below goes through the various changes each generation brought.

1st generation	The original lenses released in 1972 and they have the characteristic silver nose. They also have a prefix letter in front of the Zuiko label that indicates the number of lens elements. My 50mm f1.4 is G.Zuiko which shows it has seven elements. The lens elements are single coated.
2nd generation	This was largely just a cosmetic change where the silver nose was dropped in favour of the so-called black nose.
3rd generation	The letter prefix is dropped and replaced with Zuiko. MC which indicates the lens is multi coated which makes the lens appear sharper.
4th generation	The MC designation ceases and construction was changed to cementing the lens elements in place.

To further aid in identification Olympus OM lenses have a code indicating place and date of manufacture. Pre 1983 this code is found underneath the rubber focusing ring and accessing it is a destructive process. After 1983 the code was printed on the light baffle retaining ring in the lens mount. Having said this I have a 1984 35-105mm f3.5-4.5 that doesn’t have this. An example of this code can be found on my 21mm f3.5 which has the code TNMA. The first two letters are the factory where the lens was made, in this case Tatsuno-Machi. The third letter is the year 1993, and the fourth letter is October. If you would like more information about these codes then I would suggest looking at Konrad Beck’s entry on photo.net.

To further understand what a silver nosed lens is we need to talk a little about lens coatings. This is going to be very brief as it is such a complicated subject. Simply put lens coatings are thin layers of minerals applied to a lens surface to improve optical performance by reducing reflections and improving the transmission of light through the glass element. The effects of lens coatings was discovered by accident in 1886 by John William Strutt, 3rd Baron Rayleigh. He observed that a new lens he had acquired didn’t transmit as much light as an older version he had which was a bit tarnished. It was found that by controlling the material used, examples being magnesium fluoride and calcium fluoride amongst others and its thickness meant you could fine tune the characteristics of a lens. Initially this was done in a single coating. Zeiss pioneered multi-coating in 1935, but it wasn’t until a collaboration with Pentax in the early 1970’s until the process bore fruition with the launch of Pentax’s Super Multi Coating, or SMC and Zeiss’ T* coating. The first multi-coated lens for an SLR was the Pentax 50mm f1.4 Takumar in 1972. These multiple layers of minerals increase the amount of light transmitted through the lens, cut down on flare, and improves the contrast which all adds to the apparent sharpness of the lens. The need for multi-coated was accentuated by the increased take up colour film.

A little known fact about the silver nose 50mm f1.4 is that it is mildly radioactive. Most people attribute this to the lens coating which is incorrect. There is no thorium in the coating, it is in the glass used in the lens elements. This was done to increase the refractive index of the glass so as to reduce chromatic aberration. With age the thorium glass discolours and developes a yellowish tinge. People often mistake the yellow hue of lens coatings for this but the only way to find out is to hold your lens up to a plane white illuminated background and look through it. If the image has a yellowish brown tint then the thorium has started to degrade. This can be reversed by exposure to UV light. Is thorium glass dangerous? Well only if you grind up the glass and either inhale it or digest it. To put this into context you are exposed to more radiation when you eat a banana. Having said that for the sake of my love spuds I’m not going to walk around all day with this in my trouser pocket. The use of radioactive materials in glass was phased out by the 1980’s mainly as a health and safety precaution for the people who made the lens elements – they came into contact with a lot of thorium glass dust when grinding and polishing the lens elements. Another reason was that lens manufacturers had discovered they could get better results by using magnesium fluoride and calcium fluoride.

In the end it is all very bewildering. So I decided to take a more practical approach and compare my first generation Olympus OM G.Zuiko 50mm f1.4 to my third generation Olympus OM Zuiko MC 50mm f1.4 and see which one I thought was better.

Physical Properties

Irrespective of the version the Olympus 50mm f1.4 has seven elements in six groups.

	Olympus OM G.Zuiko 50mm f1.4	Olympus OM Zuiko MC 50mm f1.4
Focal length	50mm	50mm
Angle of view	43º	43º
Minimum focusing distance	45cm	45cm
Maximum magnification	0.15x	0.15x
Lens construction	7 elements in 6 groups	7 elements in 6 groups
Lens coatings	Single coated	Multi-coated
Maximum aperture	f1.4	f1.4
Minimum aperture	f16	f16
Diaphragm	8 curved blades	8 curved blades
Focusing	Manual focus with a straight helicoid	Manual focus with a straight helicoid
Filter size	49mm	49mm
Dimensions	36mm (h) x 60mm ⌀	40mm (h) x 60mm ⌀
Weight	227g	229g

Apart from the cosmetics the only differences are the lens coatings, the length and the weight. Both lenses have that loverly dense feel with glass inside the metal barrel. The focusing is beautifully buttery smooth with a throw of 180º and the aperture ring is click stopped in one whole stop intervals. They are wonderfully tactile – I just can’t help fondle them.

Optical Performance

Wide open both lenses were very noticeably soft in the centre and at the corners with the MC version having a bit more contrast. The silver nose had very pronounced chromatic aberration while on the MC version it was more controlled. By f2.8 the MC version’s chromatic aberration has cleared up completely. In the centre of the frame both lenses have improved sharpness and contrast. In the corners the MC has improved sharpness and contrast while the silver nose shows no improvement in sharpness but the contrast is slightly better. At f4 the silver nose is now equal in performance to the MC version in all areas except for chromatic aberration where it is still present. At f8 both lenses have reached their best optical performance and the CA has cleared up in the silver nose. By f11 both lenses are starting to show the effect of diffraction and at f16both lenses are quite soft and CA has returned.

You don’t buy an f1.4 lens and not be concerned about the quality of the bokeh. Well given both lens have the same lens construction and aperture configuration they are all but identical. Misshapen cat eye bokeh at f1.4 throughout the frame. Polygonal bokeh balls as you stop down. More importantly the transitions from in focus to out of focus are nice and smooth.

In terms of optical aberration both lenses exhibit mild barrel distortion and produce vignetting. Stop down to f4 and the vignetting disappears.

Olympus OM Zuiko MC 50mm f1.4 — At f2.8 with a specular light source in the frame the OM Zuiko MC 50mm f1.4 is also prone to flare.The MC handles the flare better than the earlier silver nose. What is interesting is the change in colour of the rflections, from yellow orange to green. This is the change in colour of the lens coatings.

That leaves us with flare resistance. Well it should come as no surprise that the later multi-coated version is better than the single coated, but the difference isn’t as marked as you’d expect. Both lenses are prone to veiling glare which which reduces contrast and dynamic range. Lens flare and reflective glare is also present in both lenses – this is where light is reflected off the lens elements and bounces around the lens internals until it hits the film/sensor. The colourful polygons that are often seen is light reflected off of the rear of the lens diaphragm. The more you stop down the worse they become. Changing your composition so specular highlights aren’t visible in the frame and/or using a lens hood can fix the problem. On the subject of lens flares we should also talk about diffraction spikes or sun stars – well they aren’t very special being poorly defined. This all sounds pretty damming, but we shouldn’t compare these lenses to their modern counterparts. A lot has happened in lens design and manufacture in the last 40-50 years. You buy these old lenses if you are looking for character.

Olympus OM Zuiko 50mm 1.4 test — Olympus OM Zuiko MC 50mm 1.4 shooting into the sun at f16. Note the ghosting, the veiled flare and lack lustre diffraction spikes.

Conclusion

Which one of these lenses would I recommend? Well I didn’t buy either of these lenses intentionally. Both of them came bundled with a camera body that I bought – the Olympus OM Zuiko MC 50mm f1.4 came with an OM4 that I bought in 1986 and the Olympus OM G.Zuiko 50mm f1.4 came with a camera body I bought last month. Now if you were to ask me which Olympus OM Zuiko 50mm f1.4 is the best I’d have to say neither of these. It is generally acknowledged that the best version is a 4th generation one with a serial number higher than 1,100,000.

The argument that single coated lenses are inferior to multi coated lenses doesn’t take into account what the photographer actually wants from a lens. Generally single coated lenses are favoured for black and white film photography as the lack of contrast and flatter look suit the medium especially if you do your own printing in a darkroom. Multi-coated lenses give stronger colours, more contrast, and reduced flare which makes them more suitable for coloured photography. But it’s not that hard and fast. Some colour photographers like a more muted palate, lower contrast and lens flare as they think it adds character so favour the use of single coated lenses, indeed they are also popular with cinematographers for the same reason. If you like punchy high contrast black and white look at multi-coated lenses.

Oh and if someone offers to sell you silver nose 50mm f1.4 and says they are rare, well Olympus churned these lenses out by the barrel load. To give some perspective my silver nose has a serial number of 347876 and my MC version is 800260 – that’s a difference of 452, 384 lenses.