Lens Spotlight: M50f1.7 - Jason Doss

Lens Spotlight

smc Pentax-M 50mm f/1.7

The Pentax SMC-M 50mm f/1.7 is another standard normal focal length lens that was sold as part of a kit with many of the M-mount film cameras. Like all lenses in my collection, this one is fully manual with an aperture ring and manual focus ring.  I obtained this one as part of a camera/lens kit from either eBay or KEH, and often you can get a setup like this for about the same price as the lens alone.


Normal focal length are officially described as anything between 43mm thru 58mm, or any focal length that produces a field of view that would be "natural" for the average observer. I guess it could have been called a "natural" focal length, but I guess they are all natural, aren't they? 55mm is at the upper end of what's considered "normal," but in use feels about as normal as a 50mm. There is, however, a distinct difference in feel between 40mm and 50mm, but that's for another day.


The lens is one of four pancake lenses I have, as defined arbitrarily as any lens bearing a length of one half or less than the width.  Pancakes were very popular in the film days, as 35mm was considered as the small format (even though there were 110s and APS-C units in those days), whereas medium format was preferred for high quality photos.  As interested as I am in medium format, I won't go there until Pentax whips out a mirrorless 645 which can accommodate K-mount lenses... but that has very little to do with today's topic, so on we go.


An extensive number of user reviews can be found here. The lens is 185g (0.4#) and, focused at infinity, 31mm long (1.2 inches) and has 6 aperture blades and 52mm filter threads. The fast aperture of f/1.8 is about average for normal lenses of the day, although some were considerably faster. The lens bears the usual aperture ring and has a rubberized grip for easy manual focusing. Minimum focus distance is 45cm (18in) producing 1:6.7 reproduction ratio (0.15x), which is pretty good unassisted. Of course, extension tubes and diopters can greatly increase the magnification.  My lens is in good condition, with the singular exception of the rubberized focal ring grip that seems to have loosened from the barrel.

So here we are.  Above, you'll see a photo I took at our friend's place.  They bought a new property, a hotel in Jasper called the Arkansas House.  We stayed there once a few years ago, and were shocked when we discovered it was sold to people we knew.  There is a multi-sleeper cabin in the back (background here) with a little pond and statue fountain water feature here.  I opted to use this statue to show the super-sharp detail possible with this lens when used wide open.  Again, this is f/1.7 and ambient light metering.


Below left is a scenic view taken on Highway 39 in southwest Missouri between Springfield and my place.  I did some work on the background of this shot focused at infinity and taken at f/11.


On the bottom right is a photo taken while driving (not recommended) of a roadsign that I found very very odd.  You see, I don't talk to my parents very much for a number of reasons.  However, just yesterday, I exchanged a few words with my mom, probably the first back/forth discussion in 2019.  It wasn't long, but it was longer than typical, and as usual, it ended badly.  So, as I drove unfamiliar roads hoping for photo ops after dropping my wife off at the Springfield Airport, I am surprised to see this sign bearing my parents' names, and nothing else.  Not Jerry & Cindy Smith, or Jerry & Cindy's Stop-n-Rob, but just Jerry & Cindy.  This is what is known in psychological and mystical realms as a synchronicity, coined by Carl Jung, and is at this time of unclear significance.  The mystical types I know say that when this kind of thing happens, it is the universe talking to you... so I share this here with you hoping something will come of it.


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


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