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SMC Pentax-M 100mm F2.8

Reviews Views Date of last review
49 212,749 Thu October 3, 2019
Recommended By Average Price Average User Rating
100% of reviewers $105.40 9.27
SMC Pentax-M 100mm F2.8

SMC Pentax-M 100mm F2.8
SMC Pentax-M 100mm F2.8

This is a compact non-macro 100mm telephoto lens.

SMC Pentax-M 100mm F2.8
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Automatic, 6 blades
5 elements, 5 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
100 cm
Max. Magnification
Filter Size
49 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 16 ° / 14 °
Full frame: 24 ° / 20 °
Clip-on hood for 85mm/100mm lenses
Dedicated hard case
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
62.5 x 55.7 mm
225 g
Production Years
1977 to 1984
Engraved Name
smc PENTAX-M 1:2.8 100mm
Product Code
User reviews
Manual FocusAperture RingFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax-M 100mm F2.8
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Site Supporter

Registered: June, 2013
Location: Utrecht
Posts: 29

1 user found this helpful
Lens Review Date: September 9, 2019 I can recommend this lens: Yes | Price: $80.00 | Rating: 10 

Pros: Light, compact, sharp and contrasty, super sharp stopped down
Cons: Some purple fringing, easy removable
Sharpness: 9    Aberrations: 8    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K1ii, K-01 and film   

I bought this long time ago for fl 100,- ( no euro's that time) and it was my most used short tele / portrait on film. This lens also shines on digital. Always use a hood to avoid flaire. This lens is well build, light weight, decent sharp already wide open (though little contrast), has superb color reproduction and at from F4 - F8 nice contrast. I compared this with the DFA 100 macro 2.8, you can find it here:

The DFA is sharper wide open, frings less and produces more contrast. But the difference is minor.

If you can grab it for little, you won't be disappointed. It's not a macro b.t.w.. If you own it for portraits, you can save the money buying a DFA for that purpose.

Digital on K-01:

Scanned older color negative:

Veteran Member

Registered: March, 2013
Location: Montreal
Posts: 495

3 users found this helpful
Lens Review Date: October 23, 2018 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: IQ in general, Sharpness, colors, small and light
Cons: Can cause LBA?
Sharpness: 10    Aberrations: 8    Bokeh: 8    Handling: 9    Value: 10    Camera Used: MX, K10D, K20D, K-5II, K-1   

Ok, so this lens kind of changed everything for me. Found at a garage sale, and not putting in my price here because it was unrealistically low. I knew nothing about this lens, but for less than the price of a pint, hard to resist.

I have used this lens mainly with digital, though excellent with film too. On digital it seemed a world above my M50/1.7 and M28/2.8. Not sure what the magic of this lens might be - great combo of sharpness and color? Compact easy handling? Someone had mentioned using all auto-focus lenses other than this - because somehow this particular lens seems to focus automatically anyway?!? Ok, not quite, but....

Ok, who knows what it is, but if I'm unhappy with photos I'm taking, I put on the M100/2.8 and my day gets better. Not sure why.

Yes there's some PF, and sometimes colors seem too bright and too strong? But...

And then I think this caused a bit of LBA... Could other lenses change my day the way this one can?

Yikes, hadn't meant to write a new-agey review! Will add more sometime...
New Member

Registered: September, 2016
Posts: 3

2 users found this helpful
Lens Review Date: October 30, 2016 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: Quality through and through
Cons: Can't think of any
Sharpness: 10    Aberrations: 9    Bokeh: 8    Handling: 10    Value: 10    Camera Used: K-30   

Metering and auto white balance is spot on with my K-30, which isn't to take for granted with legacy lenses. No need to dial in any + or - EV.

So much fun to shoot with this lens, so small for this focal length, yet so well constructed. Focuses like a dream and focus throw is not too long which makes for fast shooting even though it is a manual lens. Focuses close enough that it's even usable indoors in spite of the long focal length.

Still sharp enough wide open but with some very slight PF in harshly lit areas. Immaculate image quality stopped down from F4 onwards. Great contrast and rendering. Very nice out of focus areas. Faultless prime. Price I paid for an excellent copy is laughable. Some lenses you know you will never get rid of, and this is one of those for sure.

Downscaled original sample + 100% crop, shot at F5.6 if I remember correctly. Impressed with the sharpness which can be seen in the rendering of the window frame, where the finely corrugated stone border is resolved without any issues.

New Member

Registered: June, 2013
Posts: 18

2 users found this helpful
Lens Review Date: October 6, 2016 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: Great image quality in small package
Cons: I wish it has more aperture blades.
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Sony a7   

This is my main portrait lens on my a7. My copy is in great condition, like new, the glass was incredibly clean and cosmetically in perfect condition. The focus grease was a bit dry, so I relubed it and now it really is a joy to use. The lens is very small, with is a big plus.

I was astonished when I saw the first portraits. I didn't expect such a great image quality. At f2.8 is very sharp, but not excessively sharp, and contrast was a bit flat. But microcontrast is at a very good level at this point. It vignettes a bit. Very good for portraits. At f2.8 it has a bit of purple fringing, but not so much! When stopped down it becomes great. At f5.6 sharpness in incredibly high, and focusing at infinity gives excellent sharpness across the frame on a FF camera. Very impressive. Bokeh is very beautiful and smooth at all apertures and seems to resist flare very well.

The six aperture blades make a smi-circular shape until f5.6, but I really wish it had more of them. 8 blades would be perfect.

I recommend this lens!
Veteran Member

Registered: July, 2014
Location: Nagoya
Posts: 577

2 users found this helpful
Lens Review Date: July 31, 2016 I can recommend this lens: Yes | Price: $180.00 | Rating: 10 

Pros: Sharpness/clarity, size, build, handling
Cons: None worth mentioning

Sharp and contrasty pictures from f2.8, compact, classic M series quality, ideal for portraits, flowers and longer street shooting (I use it for street with black and white film a lot, and it really shines).
Even for Ł100 in Exc+ condition I think it's a bargain. Definitely recommended. Get a cheap 49mm tele hood for best results.

K1000, Fomapan 100, f4:

New Member

Registered: June, 2015
Posts: 1

1 user found this helpful
Lens Review Date: July 5, 2015 I can recommend this lens: Yes | Price: $80.00 | Rating: 10 

Pros: Value, Sharpness, IQ
Cons: Contrast
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 8    Value: 10    Camera Used: NEX-5R   

Outstanding lens for the value. If you can snag this for under $100, you'd be hard pressed to find a better option at a similar price (but that's true for most of the M-series'). Around $175-ish the max for what I would pay for this lens.

Build quality is excellent, as is form factor.

Bokeh is quite good, and the 100mm is not too large on a APS-C that still makes for a very affordable portrait lens. Sharpness can actually be a bit too much for a portrait lens stopped down, but is wonderful wide open.

The only down side is I almost always have to PP the color and contrast (but that's true for most legacy lenses).

Bottom line is this is one of the best values out there.
New Member

Registered: November, 2014
Posts: 13

1 user found this helpful
Lens Review Date: November 24, 2014 I can recommend this lens: Yes | Price: $100.00 | Rating: 10 

Pros: sharp, fast, beautiful image color
Cons: nothing I can think of
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K2000   

I bought this lens used with my K2000 back in 2009 and it's been my favorite since then. I've used it on many occasions, but mainly for portraits. The color and sharpness I manage to get out of it nearly every time I use it blow me away. Without a doubt it produces the finest images I've made with my limited experience. I just barely upgraded to the K3 and can't wait to try it out on that.

Here's a portrait I took last December. f2.8. That bokeh!

Senior Member

Registered: March, 2010
Location: Texas
Posts: 195

1 user found this helpful
Lens Review Date: September 19, 2014 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: sharpness every aperture, bokeh, size, color and contrast
Cons: nothing of note

I didn't go looking for this lens. I just came across one somewhere years ago at a very minimal price and in mint condition. I took a few sample shots and thought they looked very good but didn't understand just how fine the lens was. Now, I often find myself thinking this is my best lens. It covers for an 85 and 135. It's easily in league with the best of those focal lengths. Superbly sharp at 2.8 and already producing perfect color and nice bokeh. Takinami is right-@ f16, this lenses sharpness is in the top tier of the best of the best. What a combination. It's a great portrait lens and a great landscape lens in a small package. I don't mind that it's only 2.8 because of the total dependability at all apertures. It's just about a perfect lens for what it is. How many lenses are this good?

I give a 10 in review to lenses that are most nearly the best so that they won't become underrated in comparison to other lenses, even very good ones. So, this one has to receive a 10. I only review lenses I've used extensively and that stick out from the rest of the pack.
New Member

Registered: December, 2012
Posts: 7

4 users found this helpful
Lens Review Date: January 10, 2013 I can recommend this lens: Yes | Price: $120.00 | Rating: 10 

Pros: Sharp, Light, Easy to Handle, Wonderful colors
Cons: none
Sharpness: 10    Aberrations: 9    Bokeh: 9    Handling: 10    Value: 10    Camera Used: Olympus OM-D E-M5   

I just picked up a mint copy of this lens on fleabay and it is a marvel. So light and and so sharp at all apertures. I have the Pentax-M 100mm f4 Macro and two copies of the Pentax-A 50mm f1.7 and can offer some comparative analysis. All three are very sharp, light, and easy to use manual lenses on the Olympus OM-D E-M5. The camera does not have peak focusing in the version 1.5 firmware but it is still very easy to get accurate focus on that camera with any of these lenses. In terms of sharpness I would rank them this way:

1. 50mm f1.7
2. 100mm f.28
3. 100mm f4

I use the 50mm with extension tubes and it is sharper at 1:2 than the 100mm f4. Its not as convenient to use and the focus distance is fine for flowers and other things that don't move, but the detail and contrast (with a hood) are better. For portraits all three are extremely sharp. Photograph someone over the age of 50 and they will not be pleased with the level of detail. But beyond portraits and street photography, at longer distances, the differences in the lenses become clear. The f1.7 and the f2.8 can do both short range and long distance. I find the f4 macro not well suited for landscapes on my camera. Near or at infinity and the photos show low resolution in trees and distant objects. The 100 f2.8 does not share this limitation. It is an all around useful lens.

When I travel, I will take the 100mm f2.8 in my bag. It is so short and light it will be perfect for candid street portraits as subjects will never suspect they are being photographed with such a diminutive lens on a little camera far across the street. It will get use indoors at concerts and events. And I will use it for focused landscapes. It is a wonderful little lens that continues my love affair with legacy Pentax glass.
Veteran Member

Registered: May, 2009
Location: North Carolina
Posts: 638

1 user found this helpful
Lens Review Date: July 1, 2012 I can recommend this lens: Yes | Price: $120.00 | Rating: 10 

Pros: Inexpensive, Lightweight, Sharp, Smooth focus ring
Cons: Long MFD
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 10    Value: 10    Camera Used: LX   

I love this lens! When I switched to an LX over the K-5, I needed a long lens for portraits. On the K-5 I had the 100mm WR Macro, but it doesn't have an aperture ring (and it was a bit long on APS-C anyway). I got this lens instead, since I wanted something a little shorter for full-frame. I also looked at the 135, but I felt since 150 (effective) on APS-C was a little long, maybe 135 on full-frame would be too. I am so happy I decided to get this lens. Not only is it cheaper than a comparable 135mm, it's just as sharp as the 100 Macro.

The focus and aperture rings are smooth, very easy to operate, and the lens is also very lightweight. Without having scales, I'd say it weighs about as much as the SMC-M 50mm f/1.7. This lens is sharper than the 50mm, and makes a fantastic portrait lens.

I use this lens with my LX and Portra 160 for studio and scenery portraits, it works beautifully. The only gripe I have with it is a long Minimum Focus distance of about 3.3 feet. This lens won't replace the 100mm WR Macro for close-ups, but I may end up getting some extension tubes instead of buying a dedicated Macro. I need a good portrait lens much more frequently than I need a good macro lens.

In short, this lens is all I hoped it would be. Sharp, light, fast, and a luxury to use on the LX. I highly recommend it!
Senior Member

Registered: April, 2011
Location: LODINGEN, Northern Norway
Posts: 275
Lens Review Date: June 20, 2012 I can recommend this lens: Yes | Price: $42.00 | Rating: 10 

Pros: Shrap, nice bokéh, cheap
Cons: None
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 9    Value: 10    Camera Used: K-5 and K20D   

This is my only 100mm. It has served me well for many years. I just love the chrisp and sharp pictures it deliveres.

Norwegian Crow, no cropping

Green Finch
Inactive Account

Registered: April, 2012
Posts: 1
Lens Review Date: June 10, 2012 I can recommend this lens: Yes | Price: $85.00 | Rating: 10 

Pros: Sharpness, contrast, focus accuracy, ruggedness and compactness
Cons: Nothing to report
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Pentax K20D   

Purchased with its original hood in a package with other Pentax lenses, mounted on my K20D has shown a very strong purpose and opposed, not wide open, but still very evident. For the best sleep (5.6 or 8.0) is clearer than his brother M 100 f4.0 and the image it produces is also suitable for cropping.
Veteran Member

Registered: November, 2009
Location: Strand
Posts: 1,366
Lens Review Date: May 24, 2012 I can recommend this lens: Yes | Price: $210.00 | Rating: 10 

Pros: Small, light weight, sharp
Cons: no build in hood
Sharpness: 10    Aberrations: 10    Bokeh: 9    Handling: 10    Value: 10    Camera Used: k5, k20, nex   

A perfect lens for concert. Small, light, sharp wide open, far sharper than tokina, soligor.
Very good for manual focus.

I have used this lens in many events. Delivers superb results, both daylight, indoor, and concert in relatively lowlight.
I also have several 90mm, 100mm and 105mm, both AF and MF, but this lens is just perfect. MF when AF is giving up, small and light for walking tour. Currently the sharpest 100mm at f2.8

Highly recommend.

Veteran Member

Registered: January, 2011
Location: Minahasa, North Celebes (Sulawesi)
Posts: 585

1 user found this helpful
Lens Review Date: April 7, 2012 I can recommend this lens: Yes | Price: $150.00 | Rating: 10 

Pros: Sharp, very sharp. Compact, almost like a 50mm. Color/Contrast is very good.
Cons: Hood is badly needed.
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K20D, Super Program, KX   

The best lens I ever purchase so far -price & IQ wise. Sold several of my off-brands 135s to get shorter portrait lens. I was thinking of getting a 85mm at first, any brand is fine, since none from the Pentax house I can afford. I was also eyeing Adaptall 90/2.5 since I thought it could do portrait and macro altogether, yet again I must swallow hard looking at the skyrocketed price. A friend of mine was trying to sell this lens from December, but probably people are a lot more interested in 135s and 85s, so this lens was still on the shelf when I saw and grab it fast about two weeks ago. This lens has never been out of my camera bag ever since it arrived a week ago. For macro work, I couples it with a convenient screw-in Vivitar Macro Adapter. I don't think that Adaptall 90/2.5 can beat this now.

I'm willing to bet that this lens @f2.8 is just about as sharp as the M 50/1.7 @f1.7 and almost as compact in size. Images are very good, I was even startled at the first shot. What it needs is a hood, a fairly long one, then it really sings.


Registered: November, 2011
Posts: 4,046

2 users found this helpful
Lens Review Date: December 19, 2011 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: Compact, light, sharp, well-made
Cons: Manual focus
Sharpness: 10    Aberrations: 8    Bokeh: 8    Handling: 8   

This was a favorite lens for years on film with the LX, and now sees occasional use in digital on my K-x. There, I use stop-down metering with the green button, in M mode. For good meter readings on landscape, I've found a 50% sky/50% land mix to give the best results under most conditions (where the M50/1.4 works better with a 33% sky/67% land mix).

The lens has all the usual M-series characteristics: compact, light, sharp, solidly made. It is not as directly contrasty as many Pentax lenses, but the contrast is easily boosted in PP.

Here is a pair of MTF charts, at f/2.8 and f/5.6. I usually shoot this lens at f/5.6, where both the 40 lp/mm curves stay above the 50% level right out to the edge of the APS-C frame just shy of the 15mm radius.

A sample from the street:

Center crop:

Edge crop:

Add Review of SMC Pentax-M 100mm F2.8

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