2 Lenses, General

2.1 Fittings

As a broad generality, all lenses will fit all bodies. But early bodies will not have focus, parallax, and exposure compensation scales for the focal lengths introduced later. The original 1/400th Seikosha-MX shuttered lenses and some Seikosha-S shuttered 180mm lenses will not fit C33 and later auto-cocking bodies. The problem with the MX series is that the lens cocking arm is located higher than on the later lenses, and the auto-cocking lever will not engage. It also fouls the lens lever for manual cocking..

Some lenses are known to fail to cock properly on later bodies. This appears to be due to the auto-cocking lever not moving the lens cocking lever quite far enough. At least one case has been recorded of the body cocking arm needing more travel than the lens shutter arm permits.

Lenses of different focal length have different back focus distances. In practice this means that the bellows extension required for infinity focus is different. This is common with bellows focusing systems, and does have the benefit of giving the optical designer more freedom.

2.2 Lens hoods

The lens hood diameter refers to the square clamp-fit Mamiya hoods. They will only fit over slimline filters. Conventional screw-fit hoods of suitable dimensions may be used in the filter thread. The Mamiya hoods are of two basic designs. The first design, used for the 55mm, 65mm, 180mm, and 250mm were square with the upper flap hinged at the front. This permitted the angle of the top flap to be set so that glare from the top of the hood was invisible in the finder. The hoods for the 80mm, 105mm, and 135mm lenses were of a circular changing to square aperture rigid type. The 80mm and 105mm chrome lenses used 42mm hoods, the 80mm and 105mm black, and both 135mm lenses used the 48mm hood. All the 180mm and the 250mm lenses used the same hood. These hoods are generally metal. There is also a telephoto lens hood for the chrome series that consists of two rigid square shades in a single plastic unit. (Compiler's Note: This item is huge!)

2.3 Optical design

There was a change in physical and optical design between the chrome and black series lenses. One known effect is that the 105mm D and DS lenses have a different back focus from the 105mm chrome and the early 105mm black. This means that the scale on the C330 and earlier bodies is incorrect for the later lenses. The C330s (and probably most C330f) have scales for both 105mm lenses. It should also be noted that earlier bodies do not have scales for the focal lengths introduced later. The lenses will function, however. The 180mm (black) and 180mm Super (black) are different optical designs, but appear to share the same back focus.

2.4 Lens coating

This is a contentious issue, probably stemming from a lack of understanding of lens coating in general. Lens coating has been common since the Second World War, initially as general single coating, then as single coating tailored to individual lens performance, and most recently coating of internal elements and multiple coating for optimum corrections. Coating is used to reduce reflection from the surface that contributes to flare and lack of contrast. It also helps compensate for minor variations in glass batches, and in multi-coating the performance over a range of wavelengths is made more consistent.

The chrome lenses were single coated, and the black series had single coatings which may have extended to various lens elements. Some late black series lenses have had multi-coating, but there is a lack of substantive evidence as to when it was introduced, and on which lenses. The 55mm, 80mm S, 105mm DS, and 180mm Super are the most likely candidates, as these were later or more extreme designs.

Even the best of these lenses won't have the class of coatings that appeared in the 1990's.

2.5 Shutters and flash synchronisation

The original chrome lenses were fitted with shutters having a maximum speed of 1/400 second (Seikosha-MX). Later chrome lenses were improved to a 1/500 second top speed, giving a conventional range from 1 second to 1/500, plus B (Seikosha-S). The changeover seems to have occurred during the production life of the C2. The final black series lenses used a Seiko shutter with 1 second to 1/500th second plus B settings. Some shutters exhibit a leaf with a raised tip. This `anti-crash' feature is intended to reduce the chance of the shutter blades locking when closing. It usually indicates a newer shutter, often with a blue insert in the shutter cocking arm. The 80mm f3.7 black lens had a Copal shutter. At least one Seikosha-MX shuttered 80mm lens was labelled `f=8cm'.

The lenses all have integral leaf shutters, providing X and M synchronisation at all speeds. Connection is via a standard 3mm co-axial PC cord on each lens. Lenses which have been in professional hands sometimes have the flash synchronisation levers fixed in the 'X' setting. This is usually achieved by cementing a small stop to the lens barrel. Obviously the inadvertent shift to 'M' with electronic flash had happened once too often! There is around 200 milliseconds delay between releasing the shutter (and closing the flash contacts) and the shutter opening on the 'M' setting. This delay was to allow flash bulbs time to reach full illumination. Since the delay is a mechanical process, and the M setting is rarely used, longer delays are quite common and the shutter may stick.

The PC connection on most lenses consists of a hollow stud. The centre hole is one side of the flash contact, and connects to a wire running to the shutter assembly. The outer portion of the stud is the other contact, and connects to the lens mounting through its mounting screws. Intermittent flash problems may be caused by the mounting or wire becoming loose. This can be tested using a resistance (Ohm) meter. [A resistance meter applies a negligible current and voltage across its probes. Higher voltages or currents may result in damage.] Set the lens to a slow speed (say 1 second), and cock it. Insert the PC cord, and hold the resistance meter probes to the terminals at the other end of the cord. When the shutter is fired, the meter will register if the flash circuit is made. A slow speed is necessary to be sure the meter has time to react.

Some later lenses, such as the 105mm DS, have a shrouded PC socket that appears less vulnerable to accidental damage or loosening.

At the risk of stating the obvious, these shutters work in fixed steps. Intermediate speeds should not be set. Intermediate apertures can be set.

The most frequent sign of damage with lenses is a dented filter ring. The lens locking wire can scratch the top of the viewing lens barrel.

Weights, where quoted, may include front and rear caps.

2.6 Dating lenses (and bodies and accessories)

Mamiya claim not to have any dating information based on serial numbers.

It has been suggested that lenses can be dated (for black models at least) by the gold two-letter stickers that sometimes survive. These are not the `JCxxx' series stickers that are found on all new Japanese exported equipment. The two-letter stickers do not appear to have been used on chrome series lenses. New information suggests that letter code series apply to individual items. So code `AA' would mean a different year/month on a C330 and a C220, for example. Since this equipment isn't new, the amount of wear and tear is probably more important than chronological age so far as practical use is concerned. For the curious:

Example two-letter codes carried by black series lenses, cameras, and accessories

The Chrome series lenses do not appear to have carried two letter codes.

The BG C330 and the BF 80mm are believed to be the pairing as originally sold.

The FA in the C33 is known to be no later than May 1966.

The DI C22 is 1966 or later.

Using the barrel focal length marking and aperture click stop as a guide (see section 4) gives the `Early', `Middle' (1970's), and `Late' (1980's) production groupings for the black lenses.

The current known ranges are: First letter A - L, Second letter A - L.

For comparison: An early Mamiya 6 rangefinder has a body tag of `II'.

Tabulation of example serial numbers

Although there are some exceptions, which may be due to inaccurate or sparse data, it appears that serial number sequences were issued by item type. It is reasonable to expect that numbers were issued sequentially within a block, though there is no evidence to support this supposition. There are 5, 6, and 7 digit numbers, as well as letter prefixes for bodies. Since the letter prefix used on the C33 was `H', even those are not in chronological sequence.

Tabulation of known letter codes and equipment (all lenses cited are black series)