SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (2025)

Pentax Lens Review Database » Film Era Pentax K-Mount Lenses » M Prime Lenses


Sharpness

9.3

Aberrations

8.5

Bokeh

8.9

Handling

9.3

Value

9.5

Reviews Views Date of last review
58 282,583 Thu August 31, 2023
SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (2)
Recommended By Average Price Average User Rating
100% of reviewers $103.83 9.23
SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (3)


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supersize

Description:

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

SMC Pentax-M 100mm F2.8
© www.pentaxforums.com, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Diaphragm
Automatic, 6 blades
Optics
5 elements, 5 groups
Mount Variant
K
Check camera compatibility
Max. Aperture
F2.8
Min. Aperture
F22
Focusing
Manual
Min. Focus
100 cm
Max. Magnification
0.13x
Filter Size
49 mm
Internal Focus
No
Field of View (Diag. / Horiz.)

APS-C: 16 ° / 14 °
Full frame: 24 ° / 20 °

Hood
Clip-on hood for 85mm/100mm lenses
Case
Dedicated hard case
Lens Cap
Plastic clip-on
Coating
SMC
Weather Sealing
No
Other Features
Diam x Length
62.5 x 55.7 mm
Weight
225 g
Production Years
1977 to 1984
Engraved Name
smc PENTAX-M 1:2.8 100mm
Product Code
23660
Reviews
User reviews
Features:
SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (4)SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (5)SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (6)SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (7)
Price History:

Author:

Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 46-58 of 58

kp0c

Veteran Member


Registered:January,2010

Location:Montreal

Posts:761

Review Date: March 28, 2010 Recommended |Price:$160.00 |Rating:9

Pros: Fast, extremely sharp, size (so small)
Cons: nothing major

I got this lens about a month ago and I love it more and more each time I use it. I bought it mostly for indoor photography, concerts and stuff. Famous Marc Sab. was recommending it.

I mostly use this lens wide open and I find the lens very sharp. It's the sharpest wide open lens I have tried so far.
The lens is very small and well built. Focus is smooth and after some practice, it's very easy, and quick, to focus with.

I strongly recommend this lens, if you can get it at a good price. I could have waited a little bit longer and thus find a better deal but I really wanted to try it out. Now, I don't see myself selling it, until I get my hand on a A version... of course.

Just my two cents

Unregistered


1 user found this helpful

Review Date: March 19, 2010 Recommended |Price:$120.00 |Rating:10

Pros: Size, weight, image quality
Cons: None really

As various versions of the Pentax 85mm lenses are demanding absurd prices in the second hand market, this 100mm is an excellent alternative.

Light but strongly bulit as all M lenses. Not much differernce in the focal length comparing with 85mm, and with the much sought after milky bokeh.

It handles nicely, with excellent sharpness and image quality, although with the APS-C crop factor it is a 150mm equivalent, and is no longer a traditional "portrait lens"

ajuett

Inactive Account


Registered:July,2008

Location:Vancouver, Canada

Posts:1,100

1 user found this helpful

Review Date: March 18, 2010 Recommended |Price:$100.00 |Rating:9

Pros: Sharp, Bokeh, Contrast, Weight
Cons: nothing really

This is one of the sharpest lenses I have owned. f/2.8 is fast enough for me at this length. The bokeh is fantastic, very smooth and the contrast is excellent as well.

Set your aperture on the lens, focus, meter with Green button and fire, very easy.

kidcadaver

Junior Member


Registered:February,2009

Posts:43

1 user found this helpful

Review Date: April 28, 2009 Recommended |Price:$76.00 |Rating:8

Pros: Sharp, Relatively Inexpensive for a fast 100mm F2.8, Good Build Quality
Cons: Purple Fringing in harsh light.

Got this used at KEH (BRG condition) still very excellent quality overall.

Good colors & contrast. Slightly soft wide open at F2.8, but when stopped down to F4 the images become very sharp. Purple Fringing was evident when in harsh lighting conditions (e.g. direct sunlight).

Sample Photos:

http://www.flickr.com/photos/jwfchu/3480553381/
http://www.flickr.com/photos/jwfchu/5644331043/
http://www.flickr.com/photos/jwfchu/5644892786/

winglik

Senior Member


Registered:October,2008

Location:NYC

Posts:258

Review Date: April 18, 2009 Recommended |Price:$80.00 |Rating:9

Pros: Sharp, compact
Cons: Wish aperature can be wider

Very good portrait lens, very sharp image even at f2.8, small and compact for a 100mm lens, f2.8 wide open might is kind of slow for low light, but over all it's a great fast prime lens

Unregistered


1 user found this helpful

Review Date: January 22, 2009 Recommended |Price:$150.00 |Rating:10

Pros: very sharp
Cons: manual

Very great and sharp lens.
SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (8)
SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (9)

Marc Sabatella

Veteran Member


Registered:September,2006

Location:Denver, CO

Posts:10,685

3 users found this helpful

Review Date: December 15, 2008 Recommended |Price:$118.00 |Rating:9

Pros: great combo of focal length, speed, IQ, size, build quality, and cost
Cons: much more purple fringing in very high contrast situations than other lenses

As I said in my summary above, this lens provides a fantastic value proposition - a really useful focal length (both on 35mm and APS-C, if for different reasons), decent speed, fine IQ, incredibly compact, solid build. And it's a bargain - I paid a little over $100 for mine, but also I bought one for my wife for a little *under* $100.

One of the things I do most is concert photography - digital - and I've decided this lens is as close to perfect a single prime lens as I could hope for. Wide open, I'm pretty sure it is outresolving what my (K200D) sensor can muster at the high ISO levels typical of concert photography. The focal length is pretty much ideal for isolating performers from a vantage point near to the front as you'd likely be if you're at least somewhat serious about it. It could work as a portrait lens outdoors or for really tight head shots, and it's just long enough on digital to feel like a "real" telephoto lens in other situations as well (if, obviously, not a wildlife lens). On 35mm, it would make a great portrait lens or for certain types of street candids, and would also work for concert photography if you like a little space around your subject or intend to shoot from right on stage.

So for me, it's pretty tough to beat on paper just based on specs, assuming it takes a picture at all. But I suppose most people will concentrate more on IQ :-).

Below, I'll link to a comparison against a couple of other M series telephoto lenses. But for now, I'll summarize that by saying it's the sharpest of the bunch at f/2.8. At high ISO, it's probably more resolution than my camera can use, and at lower ISO levels, I can clearly see my reflection in the eye of a portrait of my cat.

Stopped down, it's clearly at least as good as a consumer zoom like the 50-200 or Tamron 70-300. And comparisons posted by "Douglas of Sweden" on the SLR Lens forum show the optically-identical "A" version to hold up quite well against the extraordinarily well-regarded DA* 50-135 wide open. But I do suspect the 50-135 would win more clearly at f/5.6 or f/8, as the M100/2.8 doesn't actually perform dramatically better at these apertures compared to f/2.8. The resolution tests published by Yoshihiko Takinami show it not reaching maximum resolution until f/16, and while I haven't done any formal testing, this does seem consistent with what I've noticed.

Because I use the lens primarily for low light concert photography, I did notice the Achilles heel of this lens for quite some time. But shooting high contrast subjects wide open in bright sun, it has more purple fringing than any other lens I have used. Not that shooting high contrast subjects wide open in bright sun is a particular common thing to be doing. That fact that the lens lacks the built-in hood of the M120/2.8 and M135/3.5 is a disadvantage, too.

The bottom line for me regarding IQ is that at f/2.8, it's competitive with just about anything else, it seems, which is saying a lot considering the price and the size. At f/8, it's competitive (at least) with a consumer zoom, if perhaps not with a DA* or a macro. And at f/16, it's probably competitive again with any high end lens that started to become diffraction-limited at f/8 or f/11.

Here is my comparison against the M120/2.8 and M135/3.5:

https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/137220-shootou...5-3-5-a-2.html

My conclusion from a few posts later in the thread:

SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (10)Quote:

The 100 is the sharpest when comparing images at constant magnification (by a small margin over the 120 and a larger margin over the 135). And not that the others are particularly large or heavy (they aren't!), but the 100 is *noticeably* smaller and lighter. However, it has the most purple fringing by far, it lacks a built in the hood, and it can't blur a background to the same extent as the other two. It is the most generally useful portrait focal length of the three, but it has the least "reach". It is not too hard to find with a little patience, and it usually goes for $100-$150.

Again, given what you're getting for the money, it's a really great package!

Sample concert shot at f/2.8:

SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (11)

jensm

Senior Member


Registered:December,2007

Location:Denmark

Posts:146

1 user found this helpful

Review Date: August 7, 2008 Recommended |Price:$20.00 |Rating:8

Pros: Sharp, bright, small, light, nice build quality
Cons: Some pf wide open, bokeh sometimes slightly "busy"

Got this lens as part of an M lens bundle for next to nothing. It's great if just a little long for portraits, and surprisingly sharp wide open. The sharpness is what drives my rating.

It does, however, show some pf/ca (don't know which is which) when wide open with very contrasty shots.

8540tomg

Veteran Member


Registered:February,2008

Location:Waterloo, Ontario

Posts:4,461

1 user found this helpful

Review Date: February 24, 2008 Recommended |Price:$150.00 |Rating:9

Pros: Sharp, contrasty, good portrait lens, light
Cons: Fully manual
Sharpness: 10 Aberrations: 10 Bokeh: 9 Handling: 10 Value: 10

I had this lens for a number of years prior to purchasing the A-series 100 f 2.8 macro. I sold it with some regrets as I just couldn’t justify having two 100mm lenses. It may have been a mistake. Prior to the arrival of the macro the M 100 f 2.8 was one of my favourite pieces of glass. It was light, sharp, reasonably fast and balanced well on my MX. It was the first lens I reached for when taking people pictures. It wasn’t large enough that it scared people and it had just enough length to put the subject at ease. Many of my best portraits were a product of this lens. I actually kind of miss this aspect of the M 100mm f 2.8 as I look at its larger, heavier and much more expensive replacement. This lens did not have a flare problem but I bought the Pentax lens hood for the 100 just as I do for all my other optics. I believe lens hoods protect the front element and serve a useful purpose in keeping out stray light. In addition they look pretty cool. Boz Dimitrov provides techincal details:

(Non working link removed)

The Pentax M 100 f 2.8 would be an ideal fit mated to an LX or any of the K or M series cameras. For film I would highly recommend this lens to one and all. On digital I can only speculate but based on personal experience with several other M-series lenses I suspect it would still deliver the goods. There would be, however, all the limits to be expected when using a fully manual lens in this format. Metering will be stop down, no AF and no f stop information in the viwfinder.

kjelle

New Member


Registered:January,2008

Location:South of Sweden

Posts:10

Review Date: January 8, 2008 Recommended |Rating:9

Pros: Sharp, very solid metal built, small for a f2,8
Cons: autofocus!
Sharpness: 9 Aberrations: 8 Bokeh: 8 Handling: 10 Value: 9

I bougt this lens for my ME Super for about 20 year's ago, i'm now using it on my K10D very often and even att 100% pixel peeping i find this lens very sharp and with good contrast. It's also very good in low light situations wide open i think.SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (12)
Kjell

MysteryOnion

Giveaway winner!


Registered:December,2007

Location:beantown

Posts:944

1 user found this helpful

Review Date: December 14, 2007 Recommended |Price:$145.00 |Rating:9

Pros: Sharp and solid built
Cons: feels too light
Sharpness: 9 Aberrations: 9 Bokeh: 10 Handling: 10 Value: 10

Its a good lens and the weight is comfortable as M series tend to be light, but feels well built.
A little test I ran back in 2002ish, but my choice of film made things less than clear so with a grain...
My little test rated the lens at about 74lpmm average @f4 and 81lpmm @f5.6 and 84lpmm @f8, is that good? My test is less than scientific lab perfect and the test lighting was not great, but the lens to my eyes is superb. Had the lens since 1999 with matching hood and case. Not found my test results for wide open, but regular use shots seem very good.

Also worth noting... GET A HOOD FOR YOUR LENS! I found a 8 to 14 lpmm jump in some tests due to glare being controlled. SMC is great, but not absolutely perfect.

Syb

Veteran Member


Registered:August,2007

Location:Near Utrecht, Netherlands

Posts:1,221

1 user found this helpful

Review Date: September 22, 2007 Recommended |Price:$125.00 |Rating:9

Pros: Small, nice handling
Cons: none, really
Sharpness: 9 Aberrations: 8 Bokeh: 10 Handling: 7 Value: 8

I bought this lens in 2002, I think, to go with my MZ-5N, for indoor portraiture. It met all my expectations from day 1 one. I like the feel of the lens; and I found that 100mm is a great focus distance for portraiture. I even got so used to it, that I think the 135mm is too close.

That's immediately why I do not use it very often, anymore. Since I have a DSLR, the crop factor turns this in a "feels-like-150mm-lens" and that is too close.

In my experience the lens makes very sharp images, even under pretty hard circumstances. A big pro is that it is so small.

Falcons

Inactive Account


Registered:September,2006

Location:Perth

Posts:669

1 user found this helpful

Review Date: September 15, 2007 Recommended |Price:$120.00 |Rating:9

Pros: Solid Build, relatively sharp wide open
Cons:

I bought this lens for when my two hobbies come together (martial arts & photography) as I needed something relatively fast to take indoor shots and freeze the action. Not having the funds for one of the new DA* zooms (or even one of the F or FA variants) I decided to try an m series prime.

This lens performs its duties admirably pictures are sharp even at f2.8 I am very happy with this solid little lens. I do find I need to tweak the contrast up a little with this lens compared to my DA 16-45 - but that may just be a matter of my taste.

SMC Pentax-M 100mm F2.8 Reviews - M Prime Lenses (2025)
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