Lens Spotlight: M85 - Jason Doss

Lens Spotlight

smc Pentax-M 85mm f/2

The SMC-M Pentax 85mm f/2 is the smallest 85mm lens Pentax made, and also the slowest. Portrait lenses tend to have fast apertures of f/2 or less, and all other Pentax 85mm lenses have max apertures of f/1.8 or f/1.4. The reason for this is to generate shallow depth of field, and with multiple aperture blades for smooth bokeh transitions.


This is a lens that was purchased accidentally. Yes, I did intend to add the M85 to my collection, but not on the day that I did. KEH is a well known and reputable used camera gear dealer, and quite a few of my children used to live there. However, their mobile website used to be so poor, that I managed to purchase the lens while I was checking the inventory without knowing it. I didn't even know the purchase went thru until the net day, when I got a confirmation email that the lens had shipped. Luckily, I had the funds to cover it, and couldn't reverse course since the box was already in the mail.  By the way, the KEH website and the mobile version is worlds better now, and I highly recommend them (and always did).


What showed up was a very good quality lens, except it had significant amounts of internal haze.  Old lenses have a small number of issues that can arise over time, including haze, delamination, fungal growth, and internal pollutants (ie, dust). Haze is generally thought to be due to evaporation of volatile chemicals used in lubrication for the focusing helicoid, and is easily cleanable but requires servicing (unless you know how to disassemble and reassemble yourself, which I do not).  Before (top) and after (bottom) photos are shown above.

  • Pentax-M 85/
  • Pentax KX and M85

I can't stand defects like this, so I shipped the lens off to a skilled individual who I knew from Pentax Forums. This guy does exemplary work in vintage lens restoration, and has mastered the skill of reanodizing the external surfaces of these lenses to remove the original black, and to replace with silver.  He had a few other colors in his repertoire, and there are options to add flair, like a red colored aperture ring.  I stuck with "standard silver" this time, along with standard cleaning, lubrication, and adjustment (CLA) and what returned was a stunning, lens which looked brand new.  I don't know if he still does custom service (although he did tell me once he was willing to accommodate my collection, whenever I get around to it), but he has items available on eBay as seller silvervintagephoto.


The lens is 251g (0.55#), 46mm long (1.8 inches), has 6 aperture blades, and 49mm filter threads. The lens bears the usual aperture ring and has a rubberized grip for easy manual focusing. Mine has a silver barrel, silver aperture ring, ad colored lettering on the ring that I chose.  Minimum focus distance is 85cm (33.5 inches) producing 1:7.7 reproduction ratio (0.13x).

Here we see a set of photos from a recent walkabout to the River Market area in Kansas City.  It was a sunny and warm late October day, punctuated on both sides by cold rain.  So we jumped out with the boys and went for our usual Sunday coffee and a trip to the Blue Line Sports Bar, where we had some lunch.  Above, are a couple of shots of strangers on scooters.  Where they were going, I don't know, but they did go.  Bottom, we see Kawai anticipating a treat that never came, at least not till we got home.  He tries real hard to please his mother.


All photos were taken at f/4 and the scooters were pre-focused before they entered the frame.  The crosswalk striping made for a good target, and I think success was achieved.  As are most M-series lenses, this one was easy to use, and the f/2 max aperture was adequate for achieving accurate focus even when time was short.  A few other shots were taken this day which will be shown in another article, but these, and especially the bottom one, were my favorites.


That's all I have for now... See you next time.

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