SMC Pentax-M 200mm f/4

by Johan J Ingles-Le Nobel
Last updated May 13, 2017


Like all Pentax-M series lenses, the 200mm f/4 is sharp, small and beautifully constructed.

expect to achieve 10:1 using this lens

This is a good, inexpensive telephoto prime lens that works just fine as a tube lens with an infinite objective.

SMC Pentax-M 200mm f/4

SMC Pentax-M 200mm f/4, which gives me 10:1 as a tube lens using a Nikon CFI BE 10X NA 0.25 infinite objective. A good, inexpensive telephoto prime lens that works just fine as a tube lens with an infinite objective.

200mm Magnification

Nikon, Mitutoyo and Leica Infinite objectives all achieve their rated magnification using a 200mm tube lens.

Therefore with a 10x infinite objective, expect to achieve 10:1 using this lens, which in the case of APSC means a view of 2.37 by 1.57 mm.

The filter diameter of the SMC Pentax-M 200mm f/4 is 52mm which is a little annoying as the rest of my Pentax stuff is 49mm. The lens is constructed with 6 elements in 5 groups.

SMC Pentax-M 200mm f/4 Performance

a very marked depth to shots

The colour rendering is superb, especially for blues, and the image quality is uniform across the whole APSC frame. It has a very marked depth to shots - almost a 3D type of look.

The 8 aperture blades are a nice touch, chromatic aberration is under control one stop down and at f/5.6.the SMC Pentax-M 200mm f/4 seems to have great uniformity across the frame and no feeble zoom-type centring issues.

no feeble zoom-type centring issues

The lens also seems to give better than expected results when coupled with a moderate teleconverter, for example a 1.5x. This potentially makes it usable to push a 10x up to 15:1.

Pentax-M Series Lenses

The SMC Pentax-M series of lenses were launched in the very late 1970s, a compact successor range of lenses to the first multicoated plain SMC series. This was the second series using the then revolutionary K mount. Being -M series there is no auto aperture with this lens series, which differentiates it from the successor SMC-A series of Pentax lenses. It is thought that the -M designation maybe a nod to the then Asahi factory in Mashiko. Optically they benefit from the SMC coating and perform significantly better on today's colour cameras than the earliest Pentax lenses which were designed for black and white, and can therefore show aberration with colours not being corrected for colour use.

Comments (7)

Article: Pentax-M 200mm
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Paul says...
It would be awesome if you could provide example and comparison pictures on all the different lens setups on your site.
I should do that, yes. But I barely have enough time to do anything as it is, let alone take on more =(
18th February 2017 10:14pm
Jorge Torres says...
Another set of questions is regarding the SMC Pentax m200 f/4: do you think the image quality would be better using this lens rather that my canon zoom? If so And if got this prime lens I would need similar converter but this type adapting the nikon objective to a 52 mm filter size rather than 58, I am correct? I ordered this one just in case My question is I would need an adapter that attaches the rear end of the pentax lens to my canon camera and this is what I came up with: a pentax k PK to canon EOS EF camera adapter ring, again do I need anything else to make it work? Thank you very much in advance for your invaluable help Johan - respectfully, Jorge
12th June 2015 4:01am
Johan says...
Wish I knew the answer but honestly I don't. from what I do know though a prime does tend to have better IQ than a zoom, but beyond that I'd hesitate to speculate without some evidence to base it off =/
17th June 2015 9:43pm
Jorge Torres says...
Hi Johan, A complete newbie here. Excellent website and article! If you don't mind me asking you a few specific questions, I saw your recommendations about the Nikon 10x objective and I just ordered it. I have a canon T31 cropped sensor camera and a full frame canon 6D. Reading here and there, My understanding is that I need an adapter to connect the rear end of the nikon objective to the front end of a 200 mm prime lens (or a zoom lens) to make it work. I have a canon 70-300 zoom lens which has a 58 mm filter size, so I order Nikon CFI M25 microscope objective to M58 58mm adapter ( the questions are: Is my logic correct? Do you think this adapter will work? Is there anything else I should place in between the objective and the front of my Telephoto zoom lens to make it work?.

Another set of of questions would be regarding the SMC pentax m200 f/4
12th June 2015 3:47am
Johan says...
Should work if you have the right CFI adapter. You don't need anything between them =).
17th June 2015 9:45pm
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