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SMC Pentax-A 50mm F1.7

Reviews Views Date of last review
125 406,088 Mon October 9, 2017
Recommended By Average Price Average User Rating
99% of reviewers $61.55 8.99
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
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (A setting)
Automatic, 6 blades
6 elements, 5 groups
Mount Variant
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
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
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Veteran Member

Registered: July, 2007
Location: North West UK
Posts: 377

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: 4,613
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
Loyal Site Supporter

Registered: May, 2015
Location: Hampshire
Posts: 527

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!!!
Site Supporter

Registered: December, 2015
Location: Brisbane, Australia
Posts: 119

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!

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.

Senior Member

Registered: June, 2015
Location: Melbourne, Australia
Posts: 242

3 users found this helpful
Lens Review Date: March 2, 2016 I can recommend this lens: Yes | Price: $30.00 | Rating: 9 

Pros: Sharp, wide
Sharpness: 10    Aberrations: 6    Bokeh: 7    Handling: 10    Value: 10    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. Even wide open at f/1.7, it is possible to get a razor sharp portrait (at the actual focus plane) 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 razor 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. Under certain circumstances there is a fair amount of flair so a lens hood or using your hand is recommended.

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.

Excellent value.
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 :-)
Site Supporter

Registered: December, 2015
Location: Blue Mountains, NSW, Australia
Posts: 1,134

2 users found this helpful
Lens Review Date: January 31, 2016 I can recommend this lens: Yes | Price: N/A | Rating: 7 

Pros: Price! (it was free lol, passed down by my father)
Cons: No AF
Sharpness: 7    Aberrations: 6    Bokeh: 9    Handling: 2    Value: 8    Camera Used: Pentax K-50   

I got this lens from my dad during a recent trip to Scotland (where he is based, I now live in Australia). Of all the lens he passed onto me this was my fav.

I am still learning a lot with this lens, too many of my pics were taken at 1.7 whereas the sweeter spots are 2-2.8, but still it was fun to see that incredible bokeh come alive.

I have compiled a nice handy little flickr album that contains only pics taken with this lens and my K-50. Feel free to have a look, I am particularly happy with the black and white portrait photos of my father, father-in-law and grandpa.


Junior Member

Registered: December, 2015
Posts: 48

1 user found this helpful
Lens Review Date: January 6, 2016 I can recommend this lens: Yes | Price: $40.00 | Rating: 9 

Pros: The colors, bokeh at F1.7, long focus ring
Cons: Not very sharp at F1.7
Sharpness: 8    Aberrations: 7    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Pentax K-50   

An amazing lens for the price. Coming from a DA 18-135mm F3.5/5.6, the change is absolutely worth every penny for portraits and low-light pictures.

Video filming in low-light with F1.7 has become a real pleasure, with extraordinary bokeh and color rendering.

Not very sharp at F1.7, count F4 if you like good sharpness. But this lens make it up to you at F1.7 by giving you a depth-of-field so amazing you will fall in love with it.

I recommend to test it before you buy, see if it fits your needs. Mine (low light in interiors, video) are, and I'm really happy with it.

Note that this is a A lens, so don't expect autofocus. You'll also need to change the aperture option (by default, you will not be able to shoot with this lens and a recent Pentax DSLR. Thankfully, it's only 1 option to change in the submenus of the configuration panel.) to "allow non-A", and then you'll be able to manually play with the aperture ring.

The feel of this lens, in the hand, is good. It is light, small, and yet feels solid. It looks old and doesn't really "fit" visually with my black Pentax K50, but who cares, right?

all @1.7

(1/40, ISO 125)

(1/400 - ISO 100)

(1/4000 - iso 100)
New Member

Registered: January, 2012
Location: Budapest
Posts: 13

1 user found this helpful
Lens Review Date: December 20, 2015 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: Sharp at wide open; excellent build quality
Cons: some purple fringing
Sharpness: 10    Aberrations: 9    Bokeh: 9    Handling: 10    Value: 10    Camera Used: K-5   

Lovely lens. The purple fringing can be removed in LR easily. The six blade not my favourite for bokeh but it is suggested to use that lens wide open most of the time (circular bokeh). If I do not need fast aperture I prefer to use my zooms with AF. This lens is mainly for use of F1.7
New Member

Registered: October, 2015
Posts: 8

1 user found this helpful
Lens Review Date: December 12, 2015 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: Very sharp, Smooth bokeh, Nice 1.7 maximum aperture, Smooth focus ring
Cons: None!
Sharpness: 9    Aberrations: 10    Bokeh: 10    Handling: 9    Value: 10    Camera Used: Nikon D5000 with Pentax PK mount to Nikon F adapter   

I love this lens, it's great for almost everything! I like how the focus ring is nice and smooth since I love doing macro video work. I use this lens with a Pentax PK mount to Nikon F on a Nikon D5000, and it works great! It is full manual on the D5000, unless your doing video in Live View. In my opinion, this lens is the best 50mm f/1.7 lens for video.
Site Supporter

Registered: October, 2008
Location: Vancouver, Canada
Posts: 5,470

3 users found this helpful
Lens Review Date: August 12, 2015 I can recommend this lens: No | Price: N/A | Rating: 6 

Pros: Excellent optics, “A’ setting.
Cons: Terrible plastic build and a bit too compact for my taste.
Camera Used: Pentax film bodies (K1000, KM, KX, K2, K2DMD, MX, LX, Super A, P50)   

The A50/1.7 was released in 1984 and was a direct replacement for the M50/1.7. The A50/1.7 was in production until 1989. The similar Auto focus F50/1.7 was available along side the A50/1.7 from 1987 onwards.

Excellent optics and the A50/1.7 is sharpest at f/8 & f/11.

Focal Length:
On film this is a normal/standard lens and your go to prime focal length. On APS-C you get the FOV of a short telephoto, interesting but less useful.

Unfortunately when Pentax introduced the A Series lenses in 1984 they also started using plastic on some of the “budget” lenses. The A50/1.7 has the same design/optics as the M50/1.7, but is 20 grams lighter, so the difference is the plastic used in the construction of the A50/1.7. The Achilles heal of the A50/1.7 is the plastic aperture ring/assembly, which is extremely prone to breaking and limiting the movement of the aperture ring.

This was a terrible design by Pentax and the A50/1.7 has the roughest moving aperture ring of any of my 70+ Pentax lenses and that’s after I spent $20.00 on a CLA. Yes you can leave the aperture ring in the “A” setting (if you can get it there) and use it happily on a DSLR or “A” Series & newer film camera, but that’s just not acceptable in my books. Would you want a lens that could only focus to infinity, as it was stuck there?

The A50/1.7, like the M50/1.7 is a bit small for my taste and doesn’t handle as well compared to the bigger K Series normal/standard prime lenses. As I only use this lens on film cameras, this FL is the one you interact with the most and handling is a big part of the usage of any manual focusing normal/standard prime lens. I tend to use hyperfocal focusing & aperture priority a lot with the A50/1.7 to compensate for the lenses size and flaky aperture ring.

There were four lens hoods that were available for the A50/1.7, 49mm square plastic, round plastic, round metal and round rubber. These hoods will also work on the other M, A, F & FA normal/standard 49mm filter thread primes. .

Normally f/1.7 would be considered a fast maximum aperture, but as this is the third slowest normal/standard prime at the time of the A Series release, f1.7 is just adequate. However the faster A50/1.2 & A50/1.4 were higher priced, so more people ended up with the A50/1.7 as their go to prime than the other two. There was also an even slower A50/2 in the A Series line-up, but it was only available as a kit lens for the K1000 camera.

The A50/1.7 vs my other similar FL normal/standard primes:
I also own the M50/1.7 and both lenses are basically identical except for the construction and the “A” setting on the A50/1.7. I like the optics a bit better on the A50/1.7, but would still choose the M50/1.7 over it, due to its metal construction.

If the A50/1.7 was built like the “M” Series version then I would have given it a 9. However its excellent optics are wasted on a plastic lens with a design flaw, so I can’t recommend the A50/1.7. There are many other manual focus Pentax 50mm-55mm primes that are better built with similar optics, so I would pick one of those instead. (Also avoid the A50/2 as it’s also a plastic build.) Having a broken lens, or one that breaks down when you are on holidays is just not worth the hassle.

I bought a Pentax Super A and the A50/1.7 came with the camera, so I don’t have a price for just the lens.

Sample shots taken with the A50/1.7. Photos are medium resolution scans from original negatives or slides. Shot one was taken in Vancouver, Canada and the second shot in Maupiti, French Polynesia.

Camera: Super A Film: CineStill 50 ISO: 50

Camera: LX Film: Fuji Provia 100F ISO: 100

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