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SMC Pentax-M 40-80mm F2.8-4 Review RSS Feed

SMC Pentax-M 40-80mm F2.8-4

Reviews Views Date of last review
22 138,384 Sat June 10, 2023
Recommended By Average Price Average User Rating
82% of reviewers $43.88 7.36
SMC Pentax-M 40-80mm F2.8-4

SMC Pentax-M 40-80mm F2.8-4
SMC Pentax-M 40-80mm F2.8-4
SMC Pentax-M 40-80mm F2.8-4
SMC Pentax-M 40-80mm F2.8-4


The M-series 40-80mm has a unique focal length range among all Pentax zooms.  It offers a macro mode at 80mm.

User dkpentax has discovered that there are two variants of this lens. The older variant has felt liner at the rear, see the image above. Also, a dedicated metal lens hood was available.

SMC Pentax-M 40-80mm F2.8-4
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Automatic, 7 blades
7 elements, 7 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
120 cm
Max. Magnification
Filter Size
49 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 40-20 ° / 33-17 °
Full frame: 57-30 ° / 48-25 °
Dedicated metal hood or RH-R49
Dedicated hard case
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
66 x 76 mm
395 g
Production Years
1980 to 1984
Engraved Name
smc PENTAX-M ZOOM 1:2.8-4 40-80mm
Product Code
User reviews
Macro setting at the long end

Two variants. The older variant has felt lining at the lens mount

Manual FocusAperture RingFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax-M 40-80mm F2.8-4
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-15 of 22
Site Supporter

Registered: August, 2019
Posts: 6

1 user found this helpful
Review Date: June 10, 2023 Recommended | Price: $30.00 | Rating: 8 

Pros: Build quality, light weight, sharpness, small size
Cons: Macro really isn't -- well, OK, sort of -- but yes, it still works ...
Sharpness: 8    Aberrations: 9    Bokeh: 9    Handling: 7    Value: 9    Camera Used: K-3   

To add to the collection, arrived today from a very good used shop in Japan: a very nice example of ye olde SMC Pentax-M 40-80mm f2.8-4 in true pristine condition -- glass is excellent, overall super clean, with no signs of wear. I'd been curious about this lens and read the other reviews. Hmmm ... so I clicked it into place, set my K-3 on full auto, set the lens aperture to f8, and did a quick "test drive" walk-around after supper with cloudy, dimming light and a low, almost obscured Sun.

Did I waste a few bucks on a nothing burger? Nope. First blush: about 80 images (some intentionally challenging with shots direct into the Sun, maximum closeup with weird textures and sharp contrasts, etc. etc.).

My initial reaction? Nice and sharp. Great colour rendition -- the "classic" Pentax richness. The "thick" bokeh texturing was a very pleasant surprise -- I will look forward to planning ahead for good use of what the Bokeh offers with the next test run. The welcome compact design, heft and very good controls meant the lens was quite easy to use (and nothing was off-putting). It reminded me of going back in time to drive a nice car from the late 1980s with naturally-aspirated 4-banger and a four-speed manual transmission after now having lived happily (and brainlessly) for many years with a silent and powerful V8 and a butter-smooth 8-speed automatic.

The limited zoom range of this very solid all-metal lens is immediately obvious, but that's what this lens does and does very well. This is not a cutting-edge technical tour-de-force and will never be the love of my life, and quite honestly it fits into a strange "lens use" personal niche I didn't even know about -- but that's a very good thing.

Yes -- I like this lens. It's fun to "push the envelope" with old, limited, but very good quality technology like this. It works well and does its job exactly as designed. Why a positive view? Because taking it out into the field for "real use" immediately forces the "seeing eye" to see differently and the "compositional brain" to pause and look for new opportunities. With just one outing today, it felt very good to think about and test some "different" captures, and to anticipate and experiment with something new to the tool kit (and something old and very interesting, in this case).

Do I recommend this lens to everyone? No. But I do recommend it if you're a bit of an amateur connoisseur of older lens gear that works seamlessly and well when coupled to a recent camera like the K-3. I'll bet it will also be a pleasure to use with older film cameras, if that's your thing. And with the newest and the best DSLRs? I am not so lucky to own such things (yet) but I suspect a good copy of this lens will do its job there, too -- and be rewarding and fun in the process.

Best wishes to all / cheers / BlueLeezard
New Member

Registered: February, 2019
Posts: 15
Review Date: January 18, 2023 Not Recommended | Rating: 7 

Pros: Small and compact
Cons: Blurry Macro and weak 40mm
Sharpness: 8    Aberrations: 6    Bokeh: 7    Handling: 8    Value: 6    Camera Used: K2 ME Super Sony Alpha   

Good for film users, but pointless for digital users as you can use a finer quality prime 50mm or prime 35mm and simply crop in software.

Mechanically, this feels superb in the hands. It's so good to use until you switch to "macro" and you are trying to compose a picture at the same time. It's slightly heavy, but that makes it perfectly balanced on a light camera for stable shooting. A perfect lens for urban walkabout if you want to stay minimalist, and it's also superb for any kind of photography for people who don't want to carry around half a camera-shop of gear; fumbling from one lens to another.

It could be sharper across the f-stop range. Best sharpness at f8 and f5.6 as with most zooms, and not too bad at f11, but that's not a problem as I seem to take most photos in that kind of range. At those ranges sharpness is good in the centre and only slightly less sharp at the edges. 40mm is weak and seems soft at every focal length when focusing on infinity. 80mm is not strong at infinity, either. So if you knock off the extremes and use it as a 50-70mm then it's not bad at all. But that's a rather slim and pointless range these days.

But it's a nice little piece of kit that has no more major problems except:

1. Rather too much flare and aberration fringing in brightly lit/shadow contrast situations.

2. Things seem slightly over-exposed at times and a lens hood does not help much.

3. The "macro" function is not easy to use and it always seems blurry. It leaves me underwhelmed. But I don't use that much.

Get a good one reasonably priced at about $45 and it's a great everyday lens, but go over that and you may as well save a bit more and spend your cash on two primes to cover most of the focal range of this zoom.

Read more at:
New Member

Registered: November, 2018
Posts: 2
Review Date: May 6, 2019 Recommended | Price: $39.00 | Rating: 10 

Pros: Cheap n' sharp
Cons: Long minimum focusing distance
Sharpness: 9    Aberrations: 8    Bokeh: 8    Handling: 10    Value: 10    Camera Used: Pentax K-1   

Cheap, sharp lens.

Usually I use this lens for filming. I think it's great for this. The zoom and focus rings are very convenient to use. Especially this second feature is helpful during filming.

Unfortunately, the distance of the minimum sharpening is quite large.

But the quality in relation to the price is great.

I recommend and regards,

New Member

Registered: March, 2013
Location: NE England
Posts: 13
Review Date: September 30, 2018 Recommended | Price: $20.00 | Rating: 9 

Pros: Quirky focal length, cheap, Pentax.
Cons: Very ugly compared to most M series lenses! Lacks built in hood.
Sharpness: 8    Aberrations: 8    Bokeh: 8    Handling: 8    Value: 10    Camera Used: KP   

An interesting but very ugly lens! Probably doesn't get the praise it deserves. Well made, but can be prone to the zoom ring becoming sloppy. I have found colour and sharpness up there with many of its fellow M series lenses. Worth having if you find a good example, if only because of the odd zoom range (I think that's the collector in me!). Pity it doesn't have the built in hood of other M zooms/teles.
Forum Member

Registered: July, 2014
Location: SF BAY AREA
Posts: 63
Review Date: March 21, 2016 Recommended | Price: $30.00 | Rating: 8 

Pros: solid, IQ, portrait, product photography, f2.8
Sharpness: 8    Aberrations: 8    Bokeh: 7    Handling: 9    Value: 10    Camera Used: K-50   

40mm to 80mm - pretty good range on a DSLR for head/body shots or small/medium product photography. You can be as close as 16-18 inches by my estimation and have the optical physics benefits of a long lens. Plus you have the flexibility of a ZOOM when the model moves around or the items change size when doing a set of products in a shoot.

Other than that, the open aperature, solid M-quality build, and Pentax IQ are always a plus. recommended.

at 60mm

at 80mm

New Member

Registered: March, 2015
Location: Oklahoma
Posts: 16
Review Date: August 3, 2015 Recommended | Price: $60.00 | Rating: 8 

Pros: Image quality, contrast, sharpness, solid build
Cons: distortion and CA change with focal lenth and aperture
Sharpness: 9    Aberrations: 7    Bokeh: 7    Handling: 7    Value: 8   

I have used this lens since 1985, primarily with Kodachrome 64 and ME Super. It works well with my K-500 digital.

Hand held, 80mm, f5.6, 1/25 sec, ISO 500, late afternoon shade, back-lit by open blue sky.

Route 66, Round Barn - a Mother Road icon
Veteran Member

Registered: November, 2013
Posts: 1,740

1 user found this helpful
Review Date: April 16, 2015 Recommended | Rating: 7 

Pros: cheap, light
Cons: not sharp
Sharpness: 6    Aberrations: 7    Bokeh: 7    Handling: 9    Value: 9    Camera Used: MX   

The Pentax M40-80 f2.8-4 is one of the many so called "standard zooms" that were sold in the 80s as replacement for prime 50-55 mm lenses and sold as kits for amateurs. This one came with a beaten MX and is beaten up accordingly,

As all the other siblings it was supposed to do too many things (50 mm replacement, wide angle, short tele, macro) and to be as cheap as possible, so in reality it doesn't do anything quite right, but like many M lenses is very small (unlike other standard zooms of the era) and light, so it can be see limited use for street photography.


Registered: April, 2011
Location: Lost in translation ...
Posts: 18,075
Review Date: October 2, 2014 Recommended | Rating: 7 

Pros: Good IQ & color possible, range, solid build for my copy ...
Cons: Not a "macro" @ 1:4, MFD, needs stopping down ...
Sharpness: 8    Aberrations: 7    Bokeh: 7    Handling: 8    Value: 7    Camera Used: K-5, K-r   


This is a lens that may deserve more credit than it gets. Just look at the images by unartist; not bad at alI.

I gave an "7" overall rating which is may be unkind, but it's not an"8" ... wish that there were half points possible.

For a lower tier zoom (IMHO), this M lens does quite well. It can produce nice images stopped down. I am a bit irked that this lens would labeled as a "macro" with only a "1:4" ratio ... come on, get real Pentax.

My copy is solid and well built, but I find it odd that there are two different ring grip patterns used ... small rectangles for the focus ring and long linear line for the zoom ring ... how odd and never noticed this upon another Pentax lens; maybe it's just me.

Some sample images maybe later on ... Salut, J
New Member

Registered: May, 2013
Location: Jakarta
Posts: 2
Review Date: May 2, 2014 Recommended | Price: $80.00 | Rating: 8 

Pros: color contrast, IQ, built quality
Cons: push pull zoom, heavy, relatively rare
Sharpness: 8    Aberrations: 9    Bokeh: 8    Handling: 7    Value: 7    Camera Used: K5   

I had this lens twice, i'm not sure for the first lens, it's sold
latest i have the second one, it is surely I have the good copy, with perfect coating, how lucky I am!
really like this lens, although a little awkward when shooting macro, here are the sample shot in wide open (F2.8), ISO100, no post processing, RAW to JPEG convert:
Senior Member

Registered: January, 2013
Location: San Luis Obispo
Posts: 146
Review Date: March 21, 2013 Recommended | Price: $60.00 | Rating: 8 

Pros: Sharp, Cheap, Good Color
Cons: Heavy.
Sharpness: 8    Aberrations: 8    Bokeh: 7    Handling: 6    Value: 9    Camera Used: K-5, K10D   

Nice lens for Macro job and Portrait. Doesn't seem to be possible to put on other uses.
Good sharpness and color.
New Member

Registered: September, 2008
Location: Australia
Posts: 13

1 user found this helpful
Review Date: September 8, 2012 Recommended | Price: $60.00 | Rating: 9 

Pros: Cheap
Cons: Heavy
Sharpness: 9    Aberrations: 9    Bokeh: 10    Handling: 8    Value: 10    Camera Used: K200D, ME Super   

Nice walk around lens on a film camera. Great portrait lens on a digital. Seems to take great pictures for me.
Inactive Account

Registered: October, 2010
Location: Baltimore
Posts: 2,542

4 users found this helpful
Review Date: April 19, 2012 Recommended | Price: $50.00 | Rating: 8 

Pros: Compact Focal Range
Cons: Soft at the Wide End, Minimum Focus Distance
Sharpness: 8    Aberrations: 9    Bokeh: 8    Handling: 7    Value: 8   

I find the Zoom Range of this little lens quite attractive but it's physical build, though typical M construction, is a bit ugly. With that said, I would probably never give up or sell this lens.

I have found the strength of this lens is from @ 50mm - 80mm one stop down. Macro is a bonus surprise, better than OK if you treat it like a macro, i.e. use a tripod. Wide open on the 40mm end, is soft, kind of like a soft focus portrait lens, one needs to stop down at least 2 stops before images become workably sharp. But wide open, on the 60-80mm or Macro end it's quite usable and simply stopped down one or two stops and accurately focused, this lens will deliver. My biggest problem is minimum focusing distance is 4 feet, which takes away a lot of photo options but the macro mode almost makes up for it...

If you know how to work and enjoy an M lens, you might like this lens, but be warned, it's not for the faint at heart

I think it's a 71/2 lens, I'll give it an 8 to bring it up a little...

Macro Mode 1 Stop Down Hand Held

Macro Mode by theunartist, on Flickr

@ 50mm 2 Stops Down

Contemplating 'Dog Days' by theunartist, on Flickr
Forum Member

Registered: March, 2010
Location: Norfolk
Posts: 85

1 user found this helpful
Review Date: December 7, 2011 Recommended | Rating: 8 

Pros: Useful 60~120 zoom range on digital; effective 'macro'; decent build quality
Cons: Fairly heavy

I have few complaints about this lens, which I bought new 25 years ago. It is no more difficult to handle than any other two-touch zoom and the push-pull macro function is a doddle. Surprisingly, under the skin it's optically similar to the one-touch 35~70/f2.8-3.5, both are 7/7 construction. The rugged build is reassuring and it still looks and feels good after service on an MX and ME-F, and occasionally on digital.

I don't shoot wide open on principle so softness and CA are rarely a worry. For digital this 40~80 is a useful walkabout lens with a 120mm reach. As with all M-series I find it works best on my old *istDS where the 'green'/AE-L button is perfectly placed under the right thumb for rapid metering when aperture values change while zooming. It's not so quick on the K-r and K-7 because the 'green' button is awkwardly positioned and not so user-friendly.

No IQ issues when stopped down a tad. There are certain subjects for which a 60~120 lens is ideal, so I wouldn't part with mine.
Senior Member

Registered: December, 2006
Location: Lincoln, UK
Posts: 229
Review Date: June 5, 2011 Not Recommended | Price: $75.00 | Rating: 5 

Pros: Cheap
Cons: IQ, size, handling

I believe this was a "cheap" alternative to the 35-70M and it behaves like it!

IQ wide open is poor and it takes a while before it inproves. It is bulky for it's range and the 2 ring operation makes it slow to use. This is doubl so unless you are using an auto mode because it loses nearly a whole stop from one end to the other.

It does have a macro facility but with the IQ, it's not something I would use. I bought mine new in a clearance sale 25 years ago and it still looks new because it never gets used. the 35-70M on the other hand looks well worn

Inactive Account

Registered: August, 2010
Location: Canada
Posts: 161

2 users found this helpful
Review Date: May 24, 2011 Recommended | Price: $40.00 | Rating: 8 

Pros: old smc pentax colors
Cons: bokeh, minimum focus

Maybe I got very lucky with my copy, but I'm totally dumbfounded by the ability of this lens. For general street photography, this lens can deliver, and deliver big.

The only real minus with this lens is that under certain conditions the bokeh can be somewhat harsh.
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