Up for sale is an excellent CLAed and RECEMENTED example of the SMC Pentax-M 100mm f/4 macro lens.
Between its fantastic image quality, long 100mm reach, and gorgeous Pentax build, this lens developed a reputation as a classic film-era macro. Unfortunately, the cemented doublet lens in the front group used an unstable optical adhesive that degrades over time, leading to some degree of hazing, in virtually all unserviced examples of this lens, even ones described as "mint."
This lens, however, has had the original doublet solvent separated and recemented using Norland Optical Adhesive 61, an ultra-tough modern cement so reliable, it is the one preferred by the United States Military for mission critical applications! As such, it is one of the few examples you will find that delivers the imaging clarity that a new example from the 1980's would have!
In addition to being recemented, this lens has also been disassembled with full mechanical tuning and relube, including replacement of the original helical grease with modern lubricants for ultimate performance!
Lens physical condition is excellent, with minor handling wear only, excellent mechanics, and glass free of scratches/haze/fungus.
Includes caps
This lens features the original version Pentax K mount, which can be used natively on all Pentax K mount SLRs and DSLRs, with mechanically coupled aperture on K mount film cameras. It also can easily be adapted for use on most popular DSLR, and mirrorless formats with an inexpensive adapter ring (sold separately, see chart below for digital compatibility).
If you have any questions about whether this lens is adaptable to your camera system, please contact me before purchase.
Digital mount compatibility chart
Mount |
Adaptable? |
Glassless Infinity? |
Notes |
Canon EF DSLR |
Y |
Y* |
* Some lenses require minor modification for use with Full Frame Canon cameras. |
Nikon F DSLR |
Y |
N |
|
Pentax K DSLR |
NATIVE |
NATIVE |
Green button/manual operation on DSLR |
Sony A DSLR |
Y |
N |
|
Sony E Mirrorless |
Y |
Y |
|
Panasonic/Olympus 4/3 DSLR |
Y |
Y |
|
Canon EOS M Mirrorless |
Y |
Y |
|
Canon EOS R Mirrorless |
Y |
Y |
|
Fuji X Mirrorless |
Y |
Y |
|
Leica/Panasonic/Sigma L |
Y |
Y |
|
Panasonic/Olympus m4/3 |
Y |
Y |
|
Nikon 1 Mirrorless |
Y |
Y |
|
Nikon Z Mirrrorless |
Y |
Y |
|
Pentax Q Mirrorless |
Y |
Y |
|
CLA FAQs
This lens has been completely disassembled and CLAed (Cleaned/Lubed/Adjusted), with cleaning of individual components aperture cleaning and total helical cleaning/relube for like-new performance!
Q: Why buy a CLAed lens?
Put quite simply, lenses get dirty over time. Many used vintage sold lenses here on eBay are described as “mint condition,” typically meaning they are free of obvious optical flaws like haze or fungus and have a clean-appearing exterior. However, opening them up tells a quite different story. While these lenses may appear tightly built, they nearly all use open designs, which allows substantial amounts of dust, dirt, and grit to enter the lens, where it settles into delicate precision components, adversely affecting the mechanical properties of the lens and leading to increased wear. Furthermore, even in unused samples, lubricants tend to degrade over time, leading to degraded focus action as grease dries out, or slow blades and soiled optics as oil migrates within the lens.
Q: What services do you perform on the lens before sale?
With the lens disassembled, I perform a full CLA (Clean Lube Adjust). This entails cleaning out any internal and external soiling, cleaning aperture blades of grease that can slowing, re-lubing the focus helical, and adjusting all components for tightness and accuracy. Where there is extensive dust or internal lens soiling, I will disassemble lens cells and clean off surfaces; however, it is my general philosophy to keep lens elements in their factory positions in assembled cells when at all possible to ensure optimum performance.
Q: DUST? What do you mean DUST?
A: All
vintage
lenses have dust in them. In fact, they had dust in them when they
were brand new from the factory! This is because prior
to the advent of very modern sealed designs, lenses were not put
together in a clean room environment, and the natural static charge
of the glass tends to attract dust particles. Coupled with the open
designs used in these lenses, it is virtually impossible to find any
vintage lens without some degree of dust particles visible when you
look closely through the lens. All of my CLA lenses have at minimum
the exterior and internal cell surfaces wiped with a dust-free,
lab-grade optical tissue and then blown off with an air bulb prior to
reassembly and thus have a significantly below average amount of dust
for a vintage lens.
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