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Pentax Lens Review Database » Film Era Pentax K-Mount Lenses » M Zoom Lenses
SMC Pentax-AF 35-70mm F2.8 Review RSS Feed

SMC Pentax-AF 35-70mm F2.8

Reviews Views Date of last review
7 72,497 Fri December 20, 2019
Recommended By Average Price Average User Rating
100% of reviewers $113.17 8.57
SMC Pentax-AF 35-70mm F2.8

SMC Pentax-AF 35-70mm F2.8
SMC Pentax-AF 35-70mm F2.8

The SMC Pentax-AF 35-70mm was the first autofocus lens from Pentax. The autofocus motor is built into the lens which also has room for 4 AAA type batteries. This first generation autofocus technology only works with the PENTAX ME-F camera. On all other bodies, the lens functions like an M-series lens which is why we list it in this section for M-lenses. No other smc PENTAX-AF lens was ever made available.

SMC Pentax-AF 35-70mm F2.8
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Automatic, 8 blades
7 elements, 7 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
AF (in-lens motor)
AF only with ME F camera
Min. Focus
120 cm
Max. Magnification
Filter Size
58 mm
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 45-23 ° / 38-19 °
Full frame: 63-34 ° / 54-29 °
RH-60 slip-on
Dedicated hard case
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
73 x 77 mm (2.9 x 3 in.)
580 g (20.4 oz.)
Production Years
1981 to 1988
Engraved Name
smc PENTAX AF ZOOM 1:2.8 35-70mm
Product Code
User reviews
Autofocus only works with the Pentax ME F. On all other camera bodies this lens works like an M-series lens.
Aperture RingAutomatic ApertureFull-Frame SupportDiscontinued
Price History:

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Loyal Site Supporter

Registered: November, 2015
Posts: 3,691
Review Date: December 20, 2019 Recommended | Price: $100.00 | Rating: 7 

Pros: Optically very good
Cons: Mechanically and ergonomically a disaster
Sharpness: 8    Aberrations: 7    Bokeh: 8    Handling: 5    Value: 6    Camera Used: K1, ME-F   

There are really many ways to rate this lens, depending on what you plan on doing with it.

If you have a ME-F, you need it. It completes the kit and allows you to understand why Pentax did not decimate the camera market in the early 80s with this combo... wow. It's like piloting a steamship... "engine room, we need infinity focus..."

If you have any other camera, its rating will be driven by two factors and how you weight them: optics and ergonomics.
Optically, this thing is better than it has any right to be. Sharpness is surprisingly good from wide open.
Saying it is a stack of primes may be a bit of a stretch, but I wouldn't object to that designation.
When I looked at it against a bunch of more recent zooms (F35-70, two FA28-80s, FA28-105, and DFA28-105), the DFA was the only one with optics that could keep up (and even then at smaller apertures).
It does have some weird triangular flare in some conditions, but it's not troublesome.

But then there are the ergonomics. It's heavy, the zoom action is clunky, it's only 35-70, it doesn't do any automated aperture stuff, so you have to use the ring, and the focus control is thin and awkward. Basically, it does not want to be used the way you will want to use it. It wants to be back on a ME-F in 1982.

But if you can work with its ergonomic shortcomings and narrow zoom range by today's standards, it will give you some good photos for the effort.
Site Supporter

Registered: November, 2012
Location: North Wales
Posts: 2,781

1 user found this helpful
Review Date: May 9, 2017 Recommended | Price: $60.00 | Rating: 8 

Pros: Fast, constant f, good IQ
Cons: No close focus, heavy, clunky, designed for AF so MF isn't like using a classic lens.
Sharpness: 9    Aberrations: 9    Bokeh: 8    Handling: 7    Value: 8    Camera Used: K5, samsung NX20   

I noticed this lens on ebay and curiosity piqued, bid. I won at a pretty good price judging from those cited in the reviews.

The lens is in decent condition, good optically. I took it out for a spin on my K5, usual haunts - the castle etc.

On camera it fdoes feel a bit clunky, and the Af style manual focus doesn't offer the same sort of ergonomic feel that a classic MF lens does, however it works pretty well. But good IQ! I'm not sure if its definitely better than the tamron adaptall 17A 35-70mm (or its big brother the 01A), one point on which those adaptall lenses outgun this is close focus. But certainly my pics so far are a firm thumbs-up.

Test composite - landscape at 35mm, samsung NX20 (20MPx, apsc). Click on the image to pull up the fullsized 4928x3398 2.5MB image. Image is already good in the centre at f2.8 but exhibits some softness, haloes/coma towards the edges. The edges, even on apsc, remain a bit softer at all f stops, but overall the iq is consistently pretty good.
New Member

Registered: February, 2013
Posts: 1

1 user found this helpful
Review Date: May 3, 2014 Recommended | Price: $50.00 | Rating: 10 

Pros: great color, low CA
Cons: manual focus
Sharpness: 9    Aberrations: 9    Bokeh: 8    Handling: 8    Value: 8    Camera Used: K01   

great sharpness&color, low CA,good lence!
Site Supporter

Registered: February, 2009
Location: Indianapolis
Posts: 522
Review Date: February 20, 2009 Recommended | Price: $200.00 | Rating: 7 

Pros: Fast zoom
Cons: Very Heavy, has to be the world's slowest Autofocus lens (on the ME-F)

The uniqueness and place in history of this lens maybe why you buy it. But it is VERY slow autofocusing on a ME-F, it searches and sounds pretty dreadful (at least the one I tested). Darn heavy too. I don't think I'd pick it up except for its place in history.
New Member

Registered: February, 2008
Location: Milano, Italy
Posts: 11
Review Date: January 13, 2009 Recommended | Price: $70.00 | Rating: 10 

Pros: Very precize, fast, comfortable and high quality images

I do have this lens!

First I have seen it in a workshop of my friend. He is still repairing film cameras, manual focus lenses and old cameras as well.. I have borrowed this lens from him just to try any mf vintage lenses since i knew it is possible to use them with dSLR.. and afterwards I didn't want to give it away anymore.. I just love it! But the price he wanted for the lens was quite high 150EUR. so I went to the e-bay and did a search.. I have found it and got it for 70$.. I am using it with my Pentax K10D..

Great lens for an excellent price!

Encl. Paired with K20D:

Paired with K10D

2 users found this helpful
Review Date: August 17, 2008 Recommended | Price: $199.00 | Rating: 10 

Pros: Fast
Cons: Weight

I owned this 35-70 2.8, along with an ME-F from 1985-1991. A very unique combination. I actually walked into a Ritz Camera store and saw this, brand-new for $199, including the lens and the 5fps motordrive! I was shocked! I immediately walked out to a pay phone (remember those?) to call another Pentax buddy. He told me to pick one up for him too.

I was shooting sports at the time and needed a fast zoom. I didn't care about the AF, which I hardly used. And yes, I totally agree about the tricky manual focus...but I did get used to it.

This is one beautiful piece of glass. Results at all focal ranges are sharp. I wish that I still had this lens. I did like the size. Very comfortable to hold onto.

I believe that this was part of the first auto-focus SLR. I always wondered where they all went. Never saw them again at any used camera store. That said, it took great images. Wish I had it for my K100d
Senior Member

Registered: August, 2007
Location: Los Angeles
Posts: 233

5 users found this helpful
Review Date: February 3, 2008 Recommended | Rating: 8 

Pros: Fast lens sharp from wide open.
Cons: Heavy, Manual Focus a bit more challenging.

This is a pretty unique lens. It is actually the fastest 35-70mm zoom Pentax every made. It has a unique red multicoating that I have not seen on any other Pentax lens. At a constant f2.8, it is faster than the Pentax M 35-70mm f2.8-3.5 which this lens derives from. The reason they needed a constant f2.8 (even though it increased the size and weight) was because the ME-F autofocus system. If you ever seen an ME-F you will noticed that the camera handles autofocus at f2.8 and f3.5 differently. There is actually a setting for lenses f2.8 and lower, and another for lenses f3.5 or higher.

The result was a rather large and heavy lens (58mm diameter). However performance wise, this lens is rather exceptional. The sharpness wide open is very good and it really only shapens up a bit more stopped down. On subjective tests, color, contrast and saturation are all very good. I honestly think they might have designated this lens a * lens if it wasn't such a prototype (and they were just starting that designation at the time).

It is a large lens. Others have complained it is very heavy (580g without batteries, which you don't need unless you have a ME-F), but I find the large battery case to provide a really nice grip. The current DA* lenses are actually heavier.

The only real complaint I have about this lens is the manual focusing. Since they wanted to work well with the autofocus, the whole focusing range is only a bit more than a quarter of a turn! As such, manual focusing can be a little bit difficult, but workable with practice. Of course, you do not get the well damped focusing feel of M lenses, rather you hear this "brrr" sound from turning the motor inside the lens.

I have a K10D and it is fun to use with that. I also have a fully operational ME-F, and it is really great to use with that. If you've even complained about autofocus times with a K10D you have no idea. On the ME-F, half the time it looses lock and the other half it takes about 15 seconds to focus. (It can only focus on really high contrast edges), but what to you expect? This was the debatably the first autofocus SLR.

I would not recommend this lens as a walk-around lens or an everyday use lens, but as an working historical piece (especially if you have a ME-F) and it is fun to just take it outside and play with it. It is a real conversational item. Where else but on a Pentax would you still be able to use such an unique lens on?
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