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SMC Pentax 135mm F2.5

Reviews Views Date of last review
59 231,206 Fri January 26, 2018
Recommended By Average Price Average User Rating
100% of reviewers $182.46 9.31
SMC Pentax 135mm F2.5

SMC Pentax 135mm F2.5
SMC Pentax 135mm F2.5

The Pentax 135mm F2.5 is Pentax's second-fastest 135mm lens, weighing in at 500g. It's famed for its excellent image quality.

SMC Pentax 135mm F2.5
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Automatic, 8 blades
6 elements, 6 groups
Mount Variant
Max. Aperture
Min. Aperture
Min. Focus
150 cm
Max. Magnification
Filter Size
58 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 12 ° / 10 °
Full frame: 18 ° / 15 °
Dedicated hard case
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
68 x 86 mm
500 g
Production Years
1975 to 1985
Engraved Name
SMC PENTAX 1:2.5/135 (early version), smc PENTAX 1:2.5 135mm (later version)
Product Code
User reviews
Plastic clip-on hood, shared between 135/2.5, 200/4, 85-210/4.5.
Two variants were produced, only differing in the engraved name:
SMC PENTAX 1:2.5/135 (early version),
smc PENTAX 1:2.5 135mm (later version)
Manual FocusAperture RingFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax 135mm F2.5
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-15 of 59
New Member

Registered: January, 2018
Location: Paris
Posts: 8

2 users found this helpful
Lens Review Date: January 26, 2018 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: COLOR rendering and iQ, 3D pop at 2.5
Cons: Manual but easy with k1 and the smooth ring
Sharpness: 10    Aberrations: 7    Bokeh: 10    Handling: 9    Value: 10    Camera Used: K1 K5   

Why I bought this lens ?
First when I bought my k1, I found my FA77 short as I was used to shoot with my crop k5 sensor so quite a 115/120mm equiv range
Second I found ( in a poor town market laying on a table aside old kids toys and clothes!) a copy with no front cap, mud on the front element....but 40Ä!
After cleaning it was in fact in great shape

This old lady as such great optics (plus itís a pleasure to watch such a big front piece of glass and the build)

On my K1 I shoot only at 2,5 For subject isolation because of such a mix of great IQ/contrast/COLOR rendering which seems very close to my fa77 on k5.
Notice if you want to stp down With this =M mode +use of green button metering And you have to set -0,7 manual exposition correction (because over expo And contraste loss)

IAM not fond of the green button mesuring ... but when I need 3.5 or more I prefer the ease of use of an other old lense in m42 mount with A/M Switch also in 135mm (czj Sonnar, if you donít know what is clarity check this one, but slower than the K, they are complementary to my taste)

This K2.5 is a gem for the pic rendering with isolation . Itís a fame lens and it deserves it
Donít worry of the manual focusing even if you dislike, at the first pic at 2.5 you will have big smile.
Knowing this lens now I can tell you it worth easily a 150/200Ä bill average with no discussion and suit the k1 lovely

Be careful of the m135 3.5 you can find everywhere on eBay. I bought it 4 years ago for my k5 and resold it 1week after. Absolutely not not the same league.
Veteran Member

Registered: November, 2010
Location: London
Posts: 307
Lens Review Date: October 27, 2017 I can recommend this lens: Yes | Price: $100.00 | Rating: 10 

Pros: Sharpness, Colours
Cons: Fringing wide open in certain light

Really impressed with this lens though it has taken a while to get used to it as I rarely shoot over 55mm. Yes it is heavy-ish, but beautifully built and a joy to focus when you have an EVF. I love the colours I get out of this lens and actually being able to stand back a bit and compose due to the longer FL is an experience that is growing on me.
Lens is very good at F2.5 but really shines when stopped down to F8.
If you can find it for £100 or less, Id say go for it, as you won't regret it...
Forum Member

Registered: April, 2015
Location: Lower Saxony
Posts: 93

3 users found this helpful
Lens Review Date: July 24, 2017 I can recommend this lens: Yes | Price: $140.00 | Rating: 9 

Pros: Sharp and rich contrast wide open, mostly soft Bokeh, long focus screw, colors
Cons: OoF little cyan to magenta fringing wide open, sometimes rough Bokeh depending on background
Sharpness: 9    Aberrations: 8    Bokeh: 9    Handling: 9    Value: 9    Camera Used: K-30, K-5 IIs, K-1   

Owning it more than 2 years i rediscovered this lens the last 2 weeks.

My Dobi Koma
K-1 + K 1:2.5/135; @f/2.5; linked to original out of camera jpg

Ms 3586
K-1 + K 1:2.5/135; @f/2.5;linked to original ooc jpg

Lord of the Flies
K-1 + K 1:2.5/135; @f/2.5; linked to original ooc jpg.

K-1 + K 1:2.5/135; @f/2.5; linked to originl ooc jpg.

...and 254 more ooc shots with this lens @f/5.6...a german doberman show 2017.08.06; a flickr album...
Senior Member

Registered: October, 2011
Location: British Columbia
Posts: 170

1 user found this helpful
Lens Review Date: July 17, 2017 I can recommend this lens: Yes | Price: $180.00 | Rating: 9 

Pros: Sharp wide open, pleasant soft bokeh
Cons: Size, flare resistance, bokeh past f/5.6 gets geometric
Sharpness: 9    Aberrations: 8    Bokeh: 10    Handling: 7    Value: 10    Camera Used: K-1 (digital), K-2 (film)   

Superb lens. I'm quite fond of the colours that this lens produces and the bokeh it creates both in the foreground and background are some of the best I've seen from a 135mm lens. It's worth noting, however, that the specular highlights can become rather geometric (octagonal) when stopped down past f/5.6. This lens is not the lightest of the pack when it comes to Pentax 135mm primes, but is hardly a burden to carry. I reach for this lens when I want more compression in the frame than the FA 77mm can grab.

Having owned the M-135mm f/3.5, this K-135mm f/2.5 is quite an upgrade in terms of sharpness, bokeh, and contrast.

Although focusing can be challenging, the lens itself is very sharp wide open. See unsharpened photos below @ f/2.5 with 1:1 crop.

New Member

Registered: July, 2017
Posts: 1
Lens Review Date: July 5, 2017 I can recommend this lens: Yes | Price: $40.00 | Rating: 8 

Pros: built like a tank, compact, sharp wide open
Cons: purple color fringing
Sharpness: 9    Aberrations: 8    Bokeh: 10    Handling: 10    Value: 10    Camera Used: canon 5dc   

Beautiful lens, buttery long focus throw, solid metal and glass and the best bokeh of all my pentax lenses (I have 6)

I was very surprised how sharp it was at f2.5 but when I stopped it down to f5.6.... BOOOM! it seemed to turbocharge my Canon 5dc

Purple fringing is a problem, best to stay away from contrasty shots but many programs can deal with 90% of it

I paid just $40 US so I'm an extremely chuffed ole fellow!
Site Supporter

Registered: December, 2014
Location: Colorado
Posts: 351
Lens Review Date: April 29, 2017 I can recommend this lens: Yes | Price: $160.00 | Rating: 9 

Pros: Sharpness, build, bright aperture,
Cons: Difficult to nail focus
Sharpness: 10    Aberrations: 8    Bokeh: 10    Handling: 9    Value: 10    Camera Used: K1   

I used this lens for some time on K-1. Very nice build. As to sharpness I give it 9.5 which is rounded to 10. The only complaint that I have is the razor-thin depth of field, making it difficult to focus. With some patience, however, you will get amazing photos.
New Member

Registered: July, 2016
Posts: 4

2 users found this helpful
Lens Review Date: December 28, 2016 I can recommend this lens: Yes | Price: $180.00 | Rating: 9 

Pros: Build quality, bokeh, flare resistance, sharpness
Cons: CA, long minimum focus distance
Sharpness: 8    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 9    Camera Used: Sony A7s, Sony a6000   

Good lens with excellent build quality and handling. Sharp enough wide open with beautiful bokeh and good contrast and colours. Some CA wide open, and could focus closer than 1.5m, but otherwise excellent.

Check out my detailed review of this lens with lots of image samples at
Senior Member

Registered: November, 2016
Posts: 168
Lens Review Date: November 25, 2016 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: Classic Pentax IQ, handling, build
Cons: Heavy
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Pentax Kx   

I bought this lens for only 50$ in perfect condition, and although I don't like heavy and long lens overall, I like it very much. Great image quality with a classic color rendering and 3D look, the things I always love from Pentax's ancient lens. Its build is superb and focusing ring, aperture ring are easy to use. It is a pleasure handling this lens every-time I put it on my camera. It is perfect for portraits and long snapshot. I even use it to take some landscape photo, although the long focal limit it a lot. If I have a full frame camera I think I will use this lens most of the time.

The only cons I can think of is maybe its weight and size. I'm a lazy person and I don't want to carry many things when going outside, plus this lens put on my Kx camera looks kind of a weird combination. If you don't mind some weight or if you have a bigger camera this is no problem.

With the price I paid it is an absolute bargain.

Junior Member

Registered: December, 2015
Posts: 48
Lens Review Date: August 30, 2016 I can recommend this lens: Yes | Price: $100.00 | Rating: 9 

Pros: Solid build, long focus ring, fast, sharp
Cons: color fringing
Sharpness: 10    Aberrations: 7    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Pentax K-50   

I own the early version (engraved 1:2.5/135). It's a super lens, both at use and for the eye.
The focus is smooth and comfortable, but hard to get @2.5. It does render wonderful colors and excellent contrast, but it also produces a lot of color fringing (purple and green).
The focus at infinity seems a little off, as said on another review, and the closest point of focus is somewhat far, I would say 1,8 meter.

But it is sharp, even on the corners @2.5. It sticks with the sharpness through the ring (2.5 to 32), the sharpest being, as far as I can tell, at 5.6 and 8, but it's almost not noticable.

Fantastic build, metal and rubber, I recommend it strongly.

@ F/2.5
New Member

Registered: March, 2016
Posts: 1
Lens Review Date: July 6, 2016 I can recommend this lens: Yes | Price: $230.00 | Rating: 10 

Pros: Sharp, Contrast, Amazing Colour and bokeh, Handling
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 10    Value: 10    Camera Used: NEX-7   

If you find this lens up to 150$, buy it ! True gem inside lens world.
Junior Member

Registered: December, 2012
Location: Cirebon
Posts: 29
Lens Review Date: February 21, 2016 I can recommend this lens: Yes | Price: $180.00 | Rating: 9 

Pros: 3D, Natural Color, Build, Clarity, Sharpness
Cons: Resolution at infinity

- Feels like FA/DA Limited image quality
- Superb for portrait
- 3D

- Don't use this lens at infinity.
Site Supporter

Registered: November, 2013
Location: Queensland, Australia
Posts: 73
Lens Review Date: November 12, 2015 I can recommend this lens: Yes | Price: $150.00 | Rating: 9 

Pros: Image and build quality are superb
Cons: Fringing wide open
Sharpness: 9    Aberrations: 8    Bokeh: 9    Handling: 9    Value: 8    Camera Used: K50 KS1   

I bought this from eBay a few weeks ago and it arrived in extraordinary condition. It appeared brand new, so I'm assuming it has been either refurbished or I am lucky enough to have a mint condition lens from 40 years ago. Either way, the lens is a testament to quality construction.

I use it primarily on the K50 as it meters well and balances better than on the KS1. I can't add any more than previous reviewers on the optical qualities of this lens. It's a beautiful piece of engineering that will produce stunning images.

A couple of images with minimal post processing. These are not wide open and stopped down to f4 if I recall
Site Supporter

Registered: August, 2015
Location: Stockholm
Posts: 15
Lens Review Date: November 10, 2015 I can recommend this lens: Yes | Price: $220.00 | Rating: 10 

Pros: Sharp, fast, IQ, 3D, build, size etc..
Cons: None
Sharpness: 10    Aberrations: 8    Bokeh: 10    Handling: 9    Value: 10    Camera Used: Pentax K5 IIs   

This is currently my favorite lens. It behaves a lot like a fast 50mm but with extra reach. It does require a lot of patience and focusing is critical to get good result but once you've figured it out, it is a rewarding lens. Using manual mode and 'green button' works great but using it in Av my K5 tends to overexpose more.

It is quite prone to CA, especially at 2.5, so don't even try using it without a hood. I have the original plastic hood that works for most use but I guess a deeper hood would be better. The CA however has never been a big problem for me and most of the times it can be cleared up easily in PP.

It is very sharp wide open and after f4 it is super sharp. It's quite heavy but that is not a problem for me. Walking around the city, even a really grey day this lens is very rewarding. It is a really good lens for B/W shooting, wich I do a lot. I guess that's a good way to circumvent the CA

A few wide open shots:
Site Supporter

Registered: July, 2012
Posts: 865

10 users found this helpful
Lens Review Date: April 6, 2015 I can recommend this lens: Yes | Price: $150.00 | Rating: 10 

Pros: Sharp, fast, excellent 3-D and bokeh rendering
Cons: Fringes, reasonably heavy, needs patience
Sharpness: 10    Aberrations: 7    Bokeh: 10    Handling: 8    Value: 10    Camera Used: K-3   

This lens can produce amazing images wide-open and is very sharp closed down. It is capable of that sought-after 3-D rendering quality. It's good for street scenes, landscapes (some users speak very highly of it as a landscape lens), flowers, and especially for portraits. On FF it should be a fantastic portrait lens. The bokeh wide-open can be smooth and buttery like a fast fifty. I often prefer using the lens to my K85/1.8; it seems to open up more opportunities.

The lens is quite heavy, not prohibitively so, for walking around, but it means one has to have a steady hand to avoid blur. It needs a deep hood, and it exhibits narrow colour fringing when wider-open, occasionally in two different colours, along the same lines, in the same area of an image. You just have be aware of fringing conditions. It's sharp at 2.5, but the dof is so narrow, focusing correctly is critical. Fortunately, the glass is large and bright. It can be a frustrating lens; the on-board metering is not always spot-on (a common issue with K series lenses), and generally, the lens needs/rewards patience.

Before the K135/2.5, I owned the K135/3.5, and that is a good lens, especially stopped down. However, the K135/2.5 is very special. Believe the hype!!

Here is my Flickr album with more photos:

And this one, stopped down to attract starbursts!

New Member

Registered: October, 2014
Posts: 4
Lens Review Date: January 14, 2015 I can recommend this lens: Yes | Price: $180.00 | Rating: 9 

Pros: sharp and happy
Cons: ca as usual for older lens
Sharpness: 9    Aberrations: 7    Bokeh: 8    Handling: 9    Value: 10    Camera Used: Pentax K-x   

I picked this lens mostly when I want to use a 135mm. When reviewers says this lens gives the 'pop' or 3D effect, what reference and comparison are they referring to? To a crazy prized zeiss or a 3rd party lens? I don't print my photos(99% usuall), my dslr is a humble k-x, my best critic is my wife who seriously cannot read without glasses.

We all know that manual focusing on original or unchanged viewfinder(screen) can be a real pain when it comes with low light and in those difficult moments: we have no control of the environment and moments happen to us at no choice. For a not so pro photographer and camera, this lens became a real star and rescuer.

I own a RMC Tokina 135mm f2.8 k mount, it produces pretty good and sharp pics. EBC Fujinon T 135mm f2.5 m42 is another stunner, sharp sharp sharp and beautiful color rendition and absolute treasure. But with the age of photoshop, what cannot be done? I know almost but not all ;-).

I don't like to buy too many m42 to pk adapters and I do have quite a fair amount of m42 lenses and i belong to the not-so-rich class. I favor the convenience of just 'fit, twist, fix'. I picked this Pentax lens mostly - You might encounter situations when you have 2 m42s with only 1 adapter and 1 pk lens out in the field, because you love primes and you want to switch lenses when situation demands that. I wondered sometimes 'what the *f-stop* am i doing?' And 'will i become a pro just because of these great primes?' :-D

It has a bigger range of f-stops(32-2.5), it gives me more room to play with ND filters where else the Fujinon gives me only f22-2.5. Well you may say why do you need such a big range of f-stops? We all know that not every f-stop is desirable.

I call this a happy lens coz when I see the resulting pictures on my comp, it just gives you the smiles and when I look back at the lens, it seems to look back smiling.

Using CIF with original k mount is straight forward, no need preparation compared to m42(sanding off the lens back to silver if you know what i meant or using metallic sticker or aluminium foil). More smiles generated.

I have pictures taken with cheapo lenses that landed smiles on me and my wife. we are easily satisfied folks. I have my LBA cured and PPA(pixel peeping addiction) cured unless I need to sweep off CA.
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