REVIEWS - Mamiya 645M 300mm F2.8 APO Telephoto Lens

OVERVIEW

The Mamiya 645M 300mm F2.8 APO was a halo product to showcase Mamiya's optical prowess and the brand's boldness. Released during film's pinnacle, the 300mm APO was designed to showcase resolution and best in class chromatic aberration management / performance. I recently came across a nice Mamiya 300mm F2.8 APO. Having fond memories of the lens from many years ago, I decided to give it a try again.

The Mamiya 645M 300mm F2.8 APO's Competition

In this review the Mamiya 645M 300mm F2.8 APO is loosely compared to the Leica 280mm F4 Telyt-R APO and Leica 280mm F2.8 Telyt-R APO Modular because the they were on hand. And the cameras include the Leica M10 Monochrom, Leica M10-R and Sony A7rIV. I have previously used it with the Leica S2 as well.

PRODUCTION HISTORY

The Mamiya 645M 300mm F2.8 APO was introduced in 1992 based on this reference in Popular Photography in October 1992. Beyond that, not much else is known, so I compiled some serial numbers -

Source: Ebay 2021 and Google Images

It looks like there may have been two batches, 100000-100500 and 101000-1001250. 750 units? Or, maybe serial numbers were continuous, thus a production run of ~1250 units. Both hypotheticals are 100% speculation on my part.

Stumbled across this web page which explains Mamiya's production date codes. For the Mamiya 645M 300mm F2.8 APO, if the little gold sticker is still on lens foot, the first letter denotes the year with A = 1981. The second letter denotes the month with A = January. That schema works except for the one lens which had a "IN" sticker. But the table provides an indication of when a specific serial number was likely manufactured.

And another mystery... what was list price? Again, no idea. Reading through past magazines that Google scanned into their library, I have seen numbers range from $9,900 to $18,845. But the most reliable piece of information was looking through the old retailer advertisements in the back of the magazines, which put the lens at ~$7700 USD in the mid 90's.

Source: Mamiya 645M 300mm F2.8 APO Street Price - October 1992

BUILD QUALITY AND HANDLING

The machining of the Mamiya's lens barrel, knobs and other controls remind me of the Canon EF 200mm F1.8 L's build quality and other telephoto lenses of that era. After 25'ish years of use, there is nothing about this particular Mamiya M645 300mm APO's cosmetics or physical performance that gives me pause. The focus ring has a light, pleasingly smooth throughout its focus range. Making small focus adjustments is easy because there is no play or slop. The aperture rings clicks cleanly from stop to stop. The lens hood extends smoothly. The drop-in filters slide in and out easily. There is no flex or wobble in the lens barrel, nor any rattles or weird sounds.

The rubber edge on the lens hood tends to stretch out if the lens was stored in a standing position (resting on the lens hood). Unfortunately the rubber does not "snap" back to its original size or shape. Replacement parts are not available, so I designed a replacement part made of Thermoplastic Elastomer (TPE) and had it printed by Shapeways. Their TPE is white, so I dyed the print black. It is not a factory looking result, but meets my criteria for "good enough". It provides plenty of support for storing the lens vertically.

3D Print - Prototyping a Replacement Rubber Ring

The Mamiya M645 300mm is heavy and not a lens I would attempt to shoot hand-held. Once the lens is locked down on the tripod, using it is no more difficult than any other moderately sized telephoto lens. Some things that could be better -

• Lens Hood Cover:  A front lens cap would be simpler. The slip-on lens cover grabs the front rubber ring - which is already loose - and makes the situation worse.
• Tripod Foot:  Much of the lens' weight is forward of the lens foot, thus I use a long lens plate to help keep the lens' weight balanced 50/50 when mounted on the tripod. The tripod foot only has one screw for the lens plate; two would be better.
• Lens Hood Extension:  The Mamiya lens hood is two stages. The first stage simple slides forward and then turns to lock into the extended position. Then a second piece screws into that. I do not use the hood extension.

Those are minor annoyances. A custom designed 3D printed front lens / hood cap replaced the leather cap -

Mamiya 645M 300mm F2.8 APO Custom Designed Front Lens / Hood Cap

A heavy lens needs a correspondingly capable tripod. I use it with a Gitzo GT5533S Systematic Series 5 Carbon Fiber Tripod and Arca-Swiss C1 Cube Geared Head. A 5-series Gitzo is overkill for a 300mm F2.8 lens, but I appreciate the additional stability provided with a 5-series.

Gitzo GT5533S Systematic Tripod and Arca-Swiss C1 Cube Geared Head

I am probably the only idiot using the Mamiya 645M 300mm APO with a Leica M10 Monochrom. I like to stack a dark red filter with a polarizer for a high contrast result with the Leica M10 Monochrom. Mamiya never made a drop-in polarizer, but I did manage the dark red filter by sacrificing a B+W 46mm dark red filter, placing the liberated glass in the Mamiya gelatin filter holder. Also "updated" clear drop-in filter with a modern UV filter held in place with a 3D printed part and a bit of Gorilla glue.

Re-worked Drop-in Filters with New Glass

The biggest challenge with the Mamiya 645M 300mm F2.8 APO is nailing focus. Atmospheric conditions can make seeing the plane of focus challenging. At night, focus is decidedly more challenging as the EVF is heavily degraded with pixel noise. Toss in a 2X teleconverter and things just get harder. An EVF camera with in-body image stabilization (IBIS) helps to smooth out viewfinder while focusing. Focusing on the Sony A7rIV is easier vs the Leica M10 Monochrom's EVF.

PERFORMANCE

I have been thoroughly impressed with resolution and detail from the Mamiya 645M 300mm F2.8 APO -

• Sharpness:  The Mamiya 645M 300mm F2.8 APO is sharp with plenty of resolving power. Even at F2.8 the Mamiya is sharp, but in bright conditions it will exhibit a slight purplish haze or glow on bright edges. The glow is gone at F4. Sharpness is so-so when stacking Mamiya's 2X. With some aggressive sharpening in post, the 2X's results can look deceivingly good.
• Chromatic Aberrations:  With a busy background of tree branches, the 300mm APO will show some LoCA (Longitudinal Chromatic Aberration) in the bokeh. Otherwise, in the plane of focus I am not seeing any color fringing.
• Bokeh:  In terms of colors, contrast, the bokeh character - the Mamiya 300mm F2.8 APO is similar to its little brother, the Mamiya 645M 200mm F2.8 APO. My only niggle is the nervous-looking bokeh in settings with busy backgrounds. Stopping down to F4 or F5.6 reduces or eliminates the "nervous" bokeh. To be fair, the Leica 280mm F2.8 Telyt-R APO Modular's bokeh can be guilty of the same nervous look too.
• Flare:  The Mamiya 300mm was designed to cover a 645 film negative, so when using the Mamiya 300mm F2.8 APO on a 35mm sized negative / sensor, light sources which are just outside of the OVF's or EVF's view are likely shining directly into the lens (due to its large image circle). I used to think 645 lenses flared too easily, but the issue is a case of large image circle vs tiny sensor.
• Focus Shift:  I have noticed some focus shift as the lens is stopped down when using the dark red filter and Mamiya 2X.

Here are Mamiya's published MTF charts for the Mamiya 300mm F2.8 APO (scanned from the original brochure). Bear in mind these are based on a 645 negative (56x41.5mm) -

Source: Mamiya 645M 300mm F2.8 APO MTF Charts

And for a blast from the past when we read printed magazines, here is Popular Photography's summary. Pardon their many typos in the specifications table -

Source: Popular Photography Review - November 2000

CONCLUSION

Whether there is value in the Mamiya 300mm APO's rarity and its place in history as the fastest medium format 300mm lens ever made, that is in the eye of the beholder. If you share an affinity for such lenses and appreciate their old-school mechanicalness, then there is an undeniable charm to be found in the Mamiya 645M 300mm F2.8 APO.

I obviously like the Mamiya 300mm APO, but I am cognizant that most readers are looking for a 300mm F2.8 to pair with their Sony A7rIV or similar. Adapting a legacy auto-focus Canon or Nikon SLR lens to the Sony makes infinitely more sense. But if you find yourself needing manual focus and manual aperture, possibly wanting to cover a large sensor, then the Mamiya 645M 300mm F2.8 APO is pretty darn hard to beat.