Forgot Password
Pentax Camera Forums Home

Pentax Lens Review Database » Film Era Pentax K-Mount Lenses » A Prime Lenses
SMC Pentax-A 100mm F2.8 Review RSS Feed

SMC Pentax-A 100mm F2.8

Reviews Views Date of last review
17 71,639 Sat April 29, 2017
Recommended By Average Price Average User Rating
100% of reviewers $216.67 9.41
SMC Pentax-A 100mm F2.8

This lens is optically similar to its M version.

SMC Pentax-A 100mm F2.8
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (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 °
Built-in, slide out
Hard case HA-98
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
63 x 56 mm
260 g
Production Years
1984 to 1989
Engraved Name
smc PENTAX-A 1:2.8 100mm
Product Code
User reviews
Manual FocusBuilt-in HoodAperture RingAutomatic ApertureFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax-A 100mm F2.8
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-15 of 17
Junior Member

Registered: January, 2013
Location: Texas
Posts: 32

2 users found this helpful
Lens Review Date: April 29, 2017 I can recommend this lens: Yes | Price: $270.00 | Rating: 10 

Pros: Light, telescopic hood, I.Q.
Cons: None
Sharpness: 9    Aberrations: 9    Bokeh: 9    Handling: 10    Value: 10    Camera Used: Pentax K30, K70   

A wonderful all-round lens, under the radar due to common focal length and aperture.
It is already very good at 2.8 from center to edge, and excellent everywhere at f/4.0 and above.
Very convenient also: light, telescopic hood.
Its only problem in my opinion is the 100/2.8 Macro D-FA-WR: a little bit larger and heavier, but not so much, and it has macro capability and autofocus.
New Member

Registered: May, 2014
Location: Paris
Posts: 9
Lens Review Date: September 28, 2015 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Sharpness: 9    Aberrations: 6    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Pentax K-3   

One of my best lenses, even though I'm also using DA* lenses (Studio (Products and Portraits) & Documentary Reports). Great feeling while focusing, sharp and precise, would highly recommend it!

here are some examples:

Inactive Account

Registered: October, 2014
Posts: 7
Lens Review Date: March 30, 2015 I can recommend this lens: Yes | Price: $200.00 | Rating: 10 

Pros: sharp ,nice bokeh
Cons: none
Sharpness: 9    Aberrations: 9    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K5II   

very happy to own this little jem. always used wide open.
Site Supporter

Registered: November, 2010
Location: California
Posts: 2,223

1 user found this helpful
Lens Review Date: January 2, 2015 I can recommend this lens: Yes | Price: N/A | Rating: 10 

Pros: small, A setting
Cons: not that sharp wide open, the S-Tak 105/2.8 is a much better lens and cheaper
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 10    Value: 10    Camera Used: K5 & K3   

I recommend it for those who want a portrait lens. It is not the Pentax DA 77mm f1.8, but it has soemthing that the 77 does not have in terms of character.
Loyal Site Supporter

Registered: April, 2013
Location: Northern Minnesota
Posts: 1,812
Lens Review Date: November 23, 2014 I can recommend this lens: Yes | Price: $190.00 | Rating: 9 

Pros: Easy to focus, sharp, great color and contrast, nicely built
Cons: Hood is too short so CA is a minor problem in high contrast

I got this cheap because the original owner had engraved his name and phone number on the barrel. Well, I won't be selling it, so the engraving is just an historical artifact. This manual focus lens picks up lock immediately and I DO NOT have to bracket focus as I do on my A135/2.8. Because of the quick focus, I think it is as fast on stationary subjects as any auto focus lens. The colors and contrast are special and the focal length is very useful for me. I love this lens.
Senior Member

Registered: April, 2012
Location: Seattle, WA
Posts: 128

2 users found this helpful
Lens Review Date: August 12, 2013 I can recommend this lens: Yes | Price: $180.00 | Rating: 9 

Pros: sharpness, relatively low cost, great color
Cons: stupid built-in lens hood, rare, bokeh
Sharpness: 10    Aberrations: 9    Bokeh: 8    Handling: 10    Value: 10    Camera Used: *ist D, MX   

I got this lens used for about $180USD from an Ebay seller… he apparently bought it, decided he didn't want it, and ended up selling it at a $50-100 loss. (Mostly because he didn't list it correctly.)

Like all "-A" lenses, the lens is well-built: all metal construction, fairly tight controls, and comfy rubber grip on the focus ring. This lens is so much smaller than I expected.

I've found this lens quite sharp, very contrasty, and plenty fast (for this focal length). I don't use it half as much as I ought to, even though I think it's my sharpest lens. The bokeh could be smoother—one forum poster once described it as "busy". It's not terrible, but it could be better.

Here are some samples!


Registered: August, 2008
Location: Worcestershire, UK
Posts: 415

2 users found this helpful
Lens Review Date: March 26, 2012 I can recommend this lens: Yes | Price: $285.00 | Rating: 10 

Pros: Compact, Smooth, Beautiful images
Cons: None for me
Sharpness: 9    Aberrations: 10    Bokeh: 8    Handling: 10    Value: 10    Camera Used: K5   

Probably the most under-rated lens in the Pentax A series line-up. I'm sure I'll be shot down in flames for saying this, but I believe its performance is almost worthy of a "Green Star" - indeed if they had given it a faster maximum aperture I'm sure it would have been.

The focus movement is beautifully smooth. It is superb quality right from f2.8, and It is light and compact (not as small as the DA ltd's). Sharpness and Background focus are not quite as good as the 85 1.4's, but are far better than most other lenses.

I bought a mint condition copy about 10 years ago for about $150, and sold it about 5 years ago making a little bit of profit. It was only when I was looking through some old photos a couple of years ago that I realised that a lot of the distinctive ones were taken with the 100mm A lens so I hunted down another copy and don't intend to let it go!

If you find one second hand don't hesitate to buy it
New Member

Registered: August, 2010
Posts: 9

1 user found this helpful
Lens Review Date: April 17, 2011 I can recommend this lens: Yes | Price: $260.00 | Rating: 10 

Pros: resolution, sharp, easy to focus
Cons: none

I love this lens! It produces astonishing pictures! Probably this is the best lens in my collection. I take it as a replacement of third party 135mm lens on my K10D. I'll never sell it!
Here is one example followed by a 100% crop from the same picture.

Veteran Member

Registered: June, 2010
Posts: 737
Lens Review Date: November 17, 2010 I can recommend this lens: Yes | Price: $330.00 | Rating: 8 

Pros: compactness, resolution, colour rendering, A setting
Cons: bit expensive, rare, bokeh
Sharpness: 9    Aberrations: 8    Bokeh: 7    Handling: 9    Value: 8   

This lens is lightweight, compact and discreet medium telephoto. 100mm lens effectively replaced my 135 and 85mm lens. Resolution wise i compared it to highly regarded SMC 135mm/2.5 and I cannot see any real difference. In my own opinion A 100mm produces better colours, maybe shifted a bit to warmer tones. It is easier to focus than 135/2.5 and but produces bokeh which is not that nice as K135/2.5 or K105/2.8. If i can I'll give it 8 for it is decent prefomer in compact body.
Veteran Member

Registered: April, 2008
Location: USA
Posts: 1,902
Lens Review Date: August 22, 2010 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: Sharp, very lightweight, Pentax build quality
Cons: short focus throw, lens flare

I was amazed at how light it was when I first received it. I was just expecting something heavier from an older lens. No complaints about sharpness and contrast. It does exibit a little flare though.
I will just let the image speak for the lens.

I would probably still have this lens but I noticed it had a bit of fungus so I returned it to K.E.H.
Forum Member

Registered: March, 2010
Location: Norfolk
Posts: 83
Lens Review Date: March 17, 2010 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: Compact with long reach on dSLR.
Cons: None

What a cracker this one is! It'll stay with me forever. So compact yet on the *istDS it provides a 150mm reach. With film it's the perfect portrait lens and good for selective landscape too. Great handling and no complaints about picture quality.

One tiny criticism: the slide-out hood is not deep enough. I usually screw in a better one.
Forum Member

Registered: April, 2009
Location: Sterling, VA
Posts: 70
Lens Review Date: December 10, 2009 I can recommend this lens: Yes | Price: $25.00 | Rating: 8 

Pros: Small, great optics

What a great lens. I use it for portraits and it performs fantastic. The build quality is what one would expect and the sharpeness of the pics are first rate. Picked this in a pawn shop. Definitely won't sell it.

Registered: September, 2009
Location: Southern California
Posts: 3,229

1 user found this helpful
Lens Review Date: December 9, 2009 I can recommend this lens: Yes | Price: $200.00 | Rating: 10 

Pros: Top quality wide open; nice A-series color; small and light
Cons: none

This lens really is a 10. I almost hate to say this, because it may become more expensive if I ever have to replace it , but it really deserves it.

At first I was skeptical of the high ratings because I hadn't seen many extraordinary sample photos (it's hard to find many examples), but when I found one for sale I decided to give it a try. This is a lens I can simply count on to give me a high percentage of "keepers," so besides its genuine nice qualities, I guess that's the secret to this lens.

I suppose the only drawback is it doesn't have macro, but most great "close up" shots, such as typical flower shots, don't require a macro anyway, and this lens really delivers. And, since it isn't a macro, it's surprisingly light and compact. If I want a lens that I know will pick up the beautiful colors or lighting in a scene, I choose this one or my A24/2.8.

Along with the A24/2.8 and A50/1.7 I have a nice A series collection. The rest of my lenses are FA (with a couple of DAs and an F) and I like them all, but none of them quite give me the feeling I have something "special" like these three A series lenses do (although a few come close - specifically, my FA20-35/4, F50/1.4, and FA28-105/3.2-4.5 (for its unique color)).

The sharpness is good on this lens too - better than my A24/2.8, and as good or better than my new (old stock) FA135/2.8 or my previous A135/2.8. It gives excellent results at f/3.2. When I first got it (about 4 months ago) I took a couple dozen sharp test shots on my K100D Super before realizing I'd left the camera at f/2.8 the whole time - something I would have noticed from reviewing the pictures on most lenses. It also does well with the K200D and K-x I now have, as well as on film.

The 10 rating is not intended to suggest it's equal to a * or Limited lens, but I doubt many photographers would be ashamed to have it in their kit. I don't have any of those pricier lenses to compare it to, but amongst its peers, it's at the top of its class!
Veteran Member

Registered: September, 2007
Location: La Crescenta, CA
Posts: 7,454

1 user found this helpful
Lens Review Date: October 30, 2009 I can recommend this lens: Yes | Price: $50.00 | Rating: 10 

Pros: Great build quality, sharp from wide open, lightweight and small, smoooooooth bokeh
Cons: Rare, generally pricy (I got lucky)

Found this in mint condition (basically never used) on my local Craigslist. What a find! Very sharp from f/2.8 and razor sharp stopped down. Great colors, contrast, and very creamy bokeh. Manual focusing is buttery smooth, and the A-contacts are a great plus. I don't think I'll ever sell it.
Veteran Member

Registered: January, 2009
Location: N Carolina, USA
Posts: 475

1 user found this helpful
Lens Review Date: August 2, 2009 I can recommend this lens: Yes | Price: $250.00 | Rating: 9 

Pros: Great build quality, IQ, size, bokeh
Cons: Rare

I just want to 2nd the previous comments. Generally, this is a great little lens.
Sharpness, color and contrast are excellent. And like the others have said, the bokeh at large apertures is fantastic.
Also, for me the fit, feel and balance is near perfect on the K200D. The combo fits easily onto the palm of my (sz x-Lg) hand and my fingers fall naturally on the focus ring. It just feels good and is easy and quick to use.

I also highly recommend this lens, if you can find one.
Add Review of SMC Pentax-A 100mm F2.8

All times are GMT -7. The time now is 09:07 PM. | See also:, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]