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SMC Pentax-A 50mm F1.7

Reviews Views Date of last review
130 441,101 Tue September 4, 2018
Recommended By Average Price Average User Rating
98% of reviewers $60.75 8.95
SMC Pentax-A 50mm F1.7

SMC Pentax-A 50mm F1.7
SMC Pentax-A 50mm F1.7
SMC Pentax-A 50mm F1.7

The SMC Pentax-A 50mm F1.7 is a fast standard lens shipped with many 1980's Pentax bodies. It supports all exposure modes.

SMC Pentax-A 50mm F1.7
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (A setting)
Automatic, 6 blades
6 elements, 5 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
45 cm
Max. Magnification
Filter Size
49 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 32 ° / 27 °
Full frame: 47 ° / 40 °
Various types
Hard case HA-90B
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
63 x 31 mm
165 g
Production Years
1984 to 1989
Engraved Name
smc PENTAX-A 1:1.7 50mm
Product Code
User reviews
Lens was sold without hood. Several hoods will fit like PH-S49 (50mm) and screw-in type metal and folding rubber hoods
Manual FocusAperture RingAutomatic ApertureFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax-A 50mm F1.7
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-15 of 130
Senior Member

Registered: February, 2017
Posts: 117
Lens Review Date: September 4, 2018 I can recommend this lens: Yes | Price: $35.00 | Rating: N/A 

Pros: Super cheap, super sharp images from f2.2, nice looking bokeh, small and light, ok CA resistance, smooth focus ring, full frame coverage
Cons: Not as sharp wide open? Can focus far but not to infinity.
Sharpness: 8    Aberrations: 8    Bokeh: 8    Handling: 10    Value: 10    Camera Used: Pentax K-70   

This is a surprisingly good old lens that is very affordable and produces very good images, absolutely comparable to some modern lenses.
Very sharp from f/2.2

I'm selling my modern Samyang 50mm f1.4 because it is much bigger and heavier and in most situations does not perform better.
New Member

Registered: August, 2018
Posts: 18
Lens Review Date: August 28, 2018 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: Cheap and realy good.
Cons: Manual focus. Boked, no made for.
Sharpness: 10    Aberrations: 9    Bokeh: 6    Handling: 8    Value: 9    Camera Used: K-x   

Very cheap, really good, but I prefer my FA50mm F/1.4
New Member

Registered: August, 2018
Posts: 2
Lens Review Date: August 27, 2018 I can recommend this lens: No | Price: $37.00 | Rating: 4 

Pros: Small, built like a tank
Cons: My copy had terribly low contrast/flare. Fog inside?
Sharpness: 6    Aberrations: 5    Bokeh: 5    Handling: 10    Value: 10    Camera Used: K3 and ME Super   

Maybe my lens had some internal issue. Terrible contrast and flare. Unusable.
Junior Member

Registered: June, 2018
Location: Lyon area
Posts: 33

1 user found this helpful
Lens Review Date: June 29, 2018 I can recommend this lens: Yes | Price: $40.00 | Rating: 9 

Pros: Very sharp around F4-5, viewfinder focus assist works, well built overall
Cons: Wide open is not super sharp
Sharpness: 9    Aberrations: 8    Bokeh: 7    Handling: 9    Value: 10    Camera Used: Pentax K-70   

Have it since a few days, it is the first time I shoot with a prime lens. This is also the first time I write review for any lens, so I like it but I'm not a pro or haven't tried dozen of lenses.

It has plastic rings (as opposed to SMC Pentax-M 50mm F1.7) but feels well build and sturdy, my copy is very clean except a little dent on the front side

First impression is wow, so much light coming in compared to my DA 18-135 zoom, need a time to adjust usual camera settings.

Wide open it can take shots in an almost dark room, this is inside my room without any lights on, and curtains almost closed. Useable at ƒ/1.7 with 1/50 exposure time ISO1000 is ok on the K-70 this helps. With a tripod you can certainly shoot with a longer exposure and get even less noise

In sunny situation, closing the aperture to F/5.0 rendered nice, this time at ISO100 it is real sharp you can count the pollens that have fallen on the petal beneath

The flare does not seems bad against the light

I should update this on I got it out for landscape or portrait pictures, but for the price paid I'm already happy I bought it.
New Member

Registered: April, 2017
Posts: 7
Lens Review Date: March 20, 2018 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: sharpness, colours, bokeh
Cons: a bit soft wide open
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 9    Value: 10    Camera Used: Pentax K-50, Fujifilm XT-20   

This 50mm/1.7 lens is a classic little jewel, like most legacy 50mm, indeed. On APS-C it is just a bit soft wide-open but improves almost immediately.
Manual focus with an APS-C camera is always an hazard, but with focus-peaking you can do good. The focus ring of my lens is a bit soft, yet precise. I must say the lens has definitely been used a lot.
In search for a portrait lens, I have pitted the Pentax-A 50mm versus the Nikkor 50/1.8 and the Nikon series E 50/1.8, and my overall preference went to the Pentax, here:
Veteran Member

Registered: July, 2007
Location: North West UK
Posts: 378

1 user found this helpful
Lens Review Date: October 9, 2017 I can recommend this lens: Yes | Price: $10.00 | Rating: 9 

Pros: Contrast, well controlled CA, "A" on the aperture ring. Nice sharpness
Cons: Not a tactile delight that the SMC-M version is.
Sharpness: 10    Aberrations: 9    Bokeh: 8    Handling: 8    Value: 10    Camera Used: K-3 K-1   

Lets get the one thing out of the way, the build. It is a bit plastic. There I have said it.
It does not have the tactile delight of the smooth metal build SMC-M version, even though it is identical optically. Yes it is just the same, don't let anyone tell you otherwise.

I got mine as part of a £30 bundle with the rather nice and underrated P30t I found in a local camera shop.

Why did I get it when I already have the SMC-M F1.7, the DA F1.8 and the FA F1.4? Well it has the A on the ring, and it was dead cheap. There are times you want to use TAv mode with the nice and contrasty F1.7, but you can't. You can with this.

So, build is not as good as the earlier one, but does it perform? Well yes! Even now, the F1.7 is one of the better nifties out there for Pentax wide open. It is small, bags of contrast, a lot more than the F1.4, reasonably good CA control (and better than - ahem - the 43mm F1.9 wide open).

Stopped down, the CA does get better, but the FA F1.4 overtakes it when it comes to sharpness and rendition. Not that this is a bad thing, it is just that the FA is stunning, and one of the best fifties from F2.8 through to F8.

If you want a great, and I mean great, 50mm wide open, with some decent control, and you don't mind the less than perfect build quality, then for bang for the buck, get this. It is FAR less than the "perfect" F1.7 - the SMC-F F1.7, which are as rare as hens teeth.

Registered: April, 2009
Location: Madrid, Spain
Posts: 5,363

1 user found this helpful
Lens Review Date: June 24, 2017 I can recommend this lens: Yes | Price: $75.00 | Rating: 7 

Pros: Small, light, good optics, "A" setting
Cons: Poor build quality
Sharpness: 9    Aberrations: 9    Bokeh: 8    Handling: 7    Value: 7    Camera Used: K200D, K3   

The A series 50mm f/1.7 is optically identical to it's predecessor in the M series, except perhaps the SMC coating, and performs very similarly. It produces images which may have a touch more contrast, giving them a more modern look. The Pentax f/1.7 and f/1.8 standard primes are superb optically and this one is no exception, producing images which may be use-able wide open (depending on circumstances) and are very sharp indeed by f/2.8.

The problem with the A series is the very poor build quality. The plastic build of the barrel is not a problem per se, but the plastic build of the internals, especially the aperture ring, is a big problem. My copy had an aperture ring which was gritty and difficult to move and another copy I tried, while externally fine, had an aperture ring that simply wouldn't go below f/8. This is because the aperture ring is plastic inside and just gets worn out very easily.

While images from this lens were very good, I sold it because I don't get any pleasure from using it. I stick to my other 50mm lenses which are K, M, Taks or third-party offerings with similar high quality build.

It's worth noting that the f/1.4 version has similarly poor construction while others in the series, like the 28/2.8 or 50/2.8 macro, are considerably better and have properly constructed aperture rings.

I would recommend the K or M series fast fifties over this one, especially the M, which is the same size, almost as light, just as sharp, and much more pleasurable to use due to the superior build quality. It's also less than half the price. If you get one which works and plan to always use it in the A setting then you won't experience the aperture ring problems.

Sample photo (taken wide open in low light):

by Jonathan MacDonald, on Flickr

At f/2.0

by Jonathan MacDonald, on Flickr

Wide open:

IMGP2763a A50_1.7
by Jonathan MacDonald, on Flickr

100% crop of above:

IMGP2763a A50_1.7 100pc
by Jonathan MacDonald, on Flickr
Loyal Site Supporter

Registered: May, 2015
Location: Hampshire
Posts: 800

1 user found this helpful
Lens Review Date: June 23, 2017 I can recommend this lens: Yes | Price: $15.00 | Rating: 9 

Pros: A setting on Aperture ring, easily obtainable.
Cons: Nice....but great?
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 9    Value: 10    Camera Used: K-5   

I picked up another copy of the -A 50mm F1.7 today. That makes 4 that I have along with 3 -M 50mm F1.7 and one each -A and -M F2 lenses. Plus Chinon and Ricoh 50s.
The woman in the charity shop found it downstairs, yet to be priced. While I was browsing for books, she asked me if I was looking for anything specially. I described the books I was looking for and mentioned that I did not see many cameras or lenses in charity shops anymore. She then mentioned that the shop had a lens downstairs and came up with a clean apparently functioning lens. I asked how much and she looked up Ebay listings on her phone and said "they are selling for between £40 and £50 but you can have it for £25. I shook my head and she reduced the price to where I could not be expected not to put my hand in my pocket. What a bargain!
Getting the lens home and putting it on the camera briefly gave me a worry as the aperture was not showing on the lcd, checked the camera with another -A lens, wiped the "clean" lens mount on the lens and fitted it again to find it now showed the aperture. A few images show that it works as well as the other 3 -As and the Ms.

An overlong intro to the review but here goes;
Very good lens with the A setting so exposure is a given on digital, no manual stopping down as on the M lenses.
Smooth focussing, 49mm filter thread, easy to focus, good IQ, light enough and plenty out there so bargain prices possible.
Almost every Pentax owner probably has one and if not then they are probably missing out. Even the most fervent AF lens user could use this manually.
However it does need to be stopped down a bit for images that are not soft.

I have rated this lens as a 9 is probably better than a 9, however there may be there is a better 50mm lens that is sharper wide open (maybe the F1.4 lenses, I shall keep looking for one) or maybe with "pixie dust".
Very good...but not brilliant. Value for money though...absolutely a 10!
New Member

Registered: November, 2013
Posts: 5

1 user found this helpful
Lens Review Date: March 19, 2017 I can recommend this lens: Yes | Price: $65.00 | Rating: 9 

Pros: very sharp lens
Cons: few CA's wide open
Sharpness: 9    Aberrations: 8    Bokeh: 10    Handling: 9    Value: 9   

what a nice lens!!!

stopped down to f 2.8 to use for astro shootings

stopped down to f 4-5.6 for single portraits (face)

stopped down to f 8-11 for flowers and butterflies

this lens is a good performer for high quaöity 2x-tele-converters with 7/5 or 6/4- elements, not for 4/4 type!!!
Senior Member

Registered: December, 2015
Location: Brisbane, Australia
Posts: 134

2 users found this helpful
Lens Review Date: January 22, 2017 I can recommend this lens: Yes | Price: $40.00 | Rating: 8 

Pros: Good image quality, nice bokeh, very good handling
Cons: Typically overpriced compared to M and K versions, doesn't have the rendering of the 'radioactive' Takumars
Sharpness: 8    Aberrations: 6    Bokeh: 8    Handling: 8    Value: 6    Camera Used: K3-II   

You would have a hard time telling the different K-mount 50mm f1.7 lenses apart, but this is the most 'capable' of the lot, all because the A-series contacts means that it meters properly on DSLRs. Being able to shoot in any mode is nice!

Sharpness is quite usable wide open, and improves very rapidly. For portraits and more artistic shots you are unlikely to care about any loss in sharpness at f1.7. If you need sharpness above all else, stop down to f4 or beyond. Between the two you can balance bokeh with how bleedingly sharp you want the photo to be.

Aberrations are as you should expect for a 50mm lens. A bit of fringing wide open, easily dealt with in post. Gone when you step down. Not something to worry about! Lens flare can happen, getting a hood is recommended, luckily there are plenty of cheap options available (check ebay).

Bokeh is lovely, decently smooth and you can play a little with the aperture before it starts loosing its charm. You won't do any better for the price.

Handling is what you expect from a manual lens. Focus is nicely dampened, the aperture ring, being plastic, isn't a smooth as you find on those with metal rings, but as it is an A-series lens you will likely leave it on A when ever you have it attached to a DSLR anyway. The A mounts are just the icing on the cake - lets you concentrate on composition and focus.

Value is good, given what you get, but compared to the K and M versions, those A contacts make this lens come with a premium. If you find a well priced sample, grab it!
Veteran Member

Registered: July, 2014
Location: Nagoya
Posts: 577

2 users found this helpful
Lens Review Date: October 11, 2016 I can recommend this lens: Yes | Price: $40.00 | Rating: 10 

Pros: Image quality, value, build quality
Cons: None

There isn't much left to say about this lens, apart from to reiterate how brilliant it is and what great value it represents. Performs wonderfully with every film and sensor, smooth handling, nice bokeh, A setting for easy DSLR use, and ever so cheap. In many ways, the perfect fast 50.
Senior Member

Registered: November, 2015
Posts: 120

2 users found this helpful
Lens Review Date: July 26, 2016 I can recommend this lens: Yes | Price: $60.00 | Rating: 9 

Pros: Cheap and very very good!
Sharpness: 10    Aberrations: 8    Bokeh: 9    Handling: 9    Value: 10    Camera Used: K-1   

When I purchased my K-1 I felt I had to invest in some good glass, so I naturally went out and purchased the much praised FA43 Limited. To cut a long story short I'm seriously considering selling the FA43 as this lens is as good as and exceeds the FA43 in many ways imo. As I shoot still subjects and people manual focus adds to the experience as far as I'M concerned. A very impressive and versatile lens highly recommended.
New Member

Registered: March, 2016
Posts: 11

1 user found this helpful
Lens Review Date: April 5, 2016 I can recommend this lens: Yes | Price: $68.00 | Rating: 8 

Pros: Sharp, reasonably priced, "A" setting
Cons: Hard to get correct focus on default focusing screens, weak aperture ring
Sharpness: 10    Aberrations: 9    Bokeh: 8    Handling: 8    Value: 9   

It is a good lens, pretty sharp in my opinion - provided one can get the focus right. Most of the time on Pentax K-x the little green hexagon and beeping are correct when indicating focus, however, sometimes they miss the focus ruining the shot. Getting aftermarket focusing screen with split prism seems to be pretty much prerequisite for making use of that lens well on DSLR. The lens is usable without third aftermarket focusing screen as well ofc (the test shots in the present review are done with the default focusing screen in K-x).

It is much better image quality than the 18-55mm kit lens.

For approx 65$ which seems to be the average price currently this is very good lens. My only and main serious complaint about this lens is particularly flimsy feeling aperture ring. It feels more like afterthought on that lens than something that is intended to be actually used. It sort of feels like Pentax decided to go without that ring at all during the initial design and then just somehow jury rigged the aperture ring into their design at last minute. It's even worse than on some of the Pentax cheapest zooms like the SMC 28-90mm which is almost fully plastic very cheap feeling lens. Ofcourse on Pentax body one should be able to get away by just setting it to "A" and leaving it there. In my case, however, the intention was to use the same lens also on Sony a5000 in addition to Pentax K-x and while I really like this lens I probably end up getting the Pentax-M version of this lens for the Sony a5000 as I'm afraid that if I would make consistent use of the plastic ring on Pentax-A version it would break pretty soon.

Some test shots as well - straight out of the camera jpg's shot in the "green mode" so the used apertures and ISO are present in the image metadata.


Registered: June, 2015
Location: Melbourne, Australia
Posts: 334

3 users found this helpful
Lens Review Date: March 2, 2016 I can recommend this lens: Yes | Price: $30.00 | Rating: 8 

Pros: Sharp
Cons: poor flare handling
Sharpness: 10    Aberrations: 6    Bokeh: 5    Handling: 10    Value: 9    Camera Used: Pentax K-50   

This is the second lens I bought after the kit lens, and I got it for amazingly cheap on Ebay.

It's super sharp when stopped down to f/2.8. Even wide open at f/1.7, it is possible to get a decently sharp portrait at the minimum focusing distance. Of course, at f/1.7 it's also a little difficult to focus. My advice is not to rely on the red square too much. Just get a feel for how much you need to turn the smooth focusing ring before it's precise. After a little practice it's not too difficult to get sharp focus wide open. Stopped down to f/2.8 it's an effortless portrait lens. Example at f/2.8:

The focus ring itself is solid, turns smoothly, and is much better than the kit lens for that.

This lens has a bit of fringing and chromatic aberration but it's easily correctable and not that noticeable anyway. Stopping down helps.

The only thing that might be distracting is it has ugly bokeh between f/2.0-2.5, where the bokeh shapes look like shurikens. But in the situations where the bokeh lights will appear, just shoot wide open or f/2.8.

Update: After using this lens for many years I still love it. It's a great portrait lens and perfect for studio and indoor work. I would add that in certain strong lights, the flaring really is quite bad and the contrast lost in these situations is only partly correctable.

Update 2: I lowered the rating of this lens a little bit due to even more experience with it. I still think it's a great buy, but beware that it is frustrating to use in harsher, outdoor light because it does not handle flaring very well.
New Member

Registered: February, 2016
Location: Montreal
Posts: 4

2 users found this helpful
Lens Review Date: February 22, 2016 I can recommend this lens: Yes | Price: $60.00 | Rating: 10 

Pros: Not expansive, good quality
Sharpness: 9    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K100D Super, K-7   

Excellent lens that you can find under 70$ (approx. 50-80$ for the A version). It was my first lens that I bought after the 18-5 and the sharpness and the bokeh are excellent.

It's an old lens without autofocus (you need to go to the FA or DA if you want it) but I really recommend this lens. Perfect to learn and progress :-)
Add Review of SMC Pentax-A 50mm F1.7

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