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Pentax Lens Review Database » Film Era Pentax K-Mount Lenses » K Zoom Lenses
SMC Pentax 400-600mm Reflex Review RSS Feed

SMC Pentax 400-600mm Reflex

Reviews Views Date of last review
9 52,204 Sat February 19, 2022
Recommended By Average Price Average User Rating
100% of reviewers $353.33 8.33
SMC Pentax 400-600mm Reflex

This extreme-telephoto zoom is compact at the expense of speed.
The aperture cannot be adjusted but varies when zooming.
The front filter diameter is 67mm. A filter thread at the rear accepts 40.5mm filters.

SMC Pentax 400-600mm F8-12
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
12 elements, 7 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
300 cm
Max. Magnification
Filter Size
67 mm (Rear: 40.5 mm)
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 4.1-2.8 ° / 3.4-2.3 °
Full frame: 6.2-4.1 ° / 5.2-3.4 °
Dedicated hard case
Lens Cap
Plastic clip-on
Weather Sealing
Other Features
Diam x Length
82 x 108 mm
730 g
Production Years
1984 to 1999
Engraved Name
smc PENTAX REFLEX ZOOM 1:8~12 400~600 mm
Product Code
User reviews
Manual FocusFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax 400-600mm Reflex
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-9 of 9
New Member

Registered: May, 2020
Posts: 4

2 users found this helpful
Lens Review Date: February 19, 2022 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: Portable; can be handheld; compact
Cons: Focussing at 600mm can be a little challenging
Sharpness: 8    Aberrations: 5    Bokeh: 7    Handling: 9    Value: 8    Camera Used: Pentax K5   

Once you get the hang of nailing the focus it is great lens although it works best in bright conditions. Its a very handy lens to have in the kit if only for its reach. The results can be good although not everyone appreciates the doughnuts in the background, although these are not necessarily distracting. The fixed aperture can be a bit of a problem initially, but again with practice it does produce some excellent reults

Loyal Site Supporter

Registered: July, 2021
Location: Zuiderkempen - Grote Netewoud - Belgium
Posts: 328

3 users found this helpful
Lens Review Date: October 8, 2021 I can recommend this lens: Yes | Price: $400.00 | Rating: 9 

Pros: solid build lens - well performing mirror
Cons: aperture (low light)
Sharpness: 9    Aberrations: 8    Bokeh: 7    Handling: 10    Value: 9    Camera Used: K3II   

A bit pricy at 400$ (360€) but the lens is in excellent condition.
And I am a bit fascinated by tele's and mirrors, so i couldn't resist to a mirror zoom....

Mirrors have some reputation as difficult to shoot (low light, shallow DoF, grayish colors (low contrast)...) but this one performs actually quite well. So give it a 9 overall as it comes close to a classic (super)telelens .

Contrast is bit lower than a normal lens but fine for a mirror, also easy to correct in DCU5 or similar photo software. Sturdy feel and look, but still easy to use (when compared to a classic 400 or 600mm lens).

Manual focussing on a DSLR is a bit difficult on eye view/matte with F8-F12 but liveview and focuspeaking work well.

I am quite pleased with this mirror lens - I always say I buy mirrors only for fun but not for "daily" shooting but his one crosses that line ...

Handheld shot at 600mm from ~7 meters (with a K3II)

(exif will say 700 mm, but it is manual entry & and camera steps from 500 to 700)
New Member

Registered: March, 2013
Location: NE England
Posts: 13

1 user found this helpful
Lens Review Date: April 30, 2020 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: compact, build quality, sharpness, super-tele range.
Cons: heavy, rare, price, not the easiest lens to focus.....
Sharpness: 9    Aberrations: 9    Bokeh: 6    Handling: 8    Value: 7    Camera Used: KP, K-01   

Just recently tracked one of these down, unfortunately without the full rear filter kit but the price reflected that. What an amazing lens! I've used several mirror lenses in the past with the usual drawbacks of low contrast and soft focus, but this lens is another level entirely. The build quality is worth the price alone; yes its manual focus and fixed aperture but its all metal and precision optics. I've had outstanding results hand held on both my digitals, even with HDR mode on the KP. I've yet to try it on my MZ-s. It seems to be a rare beast at a good price but certainly worth searching for if this sort of focal length is something you would use.

Although very compact for its focal length, it is quite heavy compared to a modern lens. The grip on the KP certainly helps hand held situations, otherwise a tripod......

A superb piece of optics that shows how reflex should be done..............with a zoom function to boot!

Senior Member

Registered: February, 2014
Posts: 252

4 users found this helpful
Lens Review Date: January 8, 2020 I can recommend this lens: Yes | Price: $120.00 | Rating: 9 

Pros: sharp!
Cons: doughnut highlights
Sharpness: 9    Aberrations: 9    Bokeh: 6    Handling: 8    Value: 8    Camera Used: Pentax K-S1   

Just acquired this lens for a song being full of fungus. However the fungus cleaned up nicely with little residual coating damage, apart from a slight deterioration to the balsam in the rear cemented pair of elements.
I have only tried some experimental shots so far, but I have found the lens probably the sharpest lens above 400mm I have ever used. It is also hand-holdable at as little as 1/60th, and my usual test image test of a glass solar lamp with filaments shows well-defined internal wiring. Focus is accurately confirmed in the v/f ( K-S1), and my adapted Canon plain matt focus screen makes sharp images very easy to achieve.
If you get a chance to try one, you will not be disappointed. I realise the mirror-related doughnuts of highlights are an acquired taste, but the photographs of wildlife I intend to take will probably avoid this issue.
Just an update. This lens IS sharp, but I have a Canon EF 300mm f2.8 lens which I rescued after the electronics failed. I removed the diaphragm, rigged up a manual focus system, and adapted it to PK mount. So it is a manual-focus f2.8( fixed) 300mm lens, and I tested it out with my K-S1. It is stunningly sharp, even at the fully-open f2.8. The first shot on my 'test bulb' is at 1/500 . I then tried it with my Teleplus MC7 at 1/200, and even given the slight deterioration common with teleconverters, this is STILL sharp. So I think the zoom 400-600 will probably go after all. Pity, but you cannot argue with the results.....I have uploaded a couple of test photos to the gallery.
New Member

Registered: February, 2016
Location: lake constance
Posts: 1

1 user found this helpful
Lens Review Date: February 17, 2019 I can recommend this lens: Yes | Price: $170.00 | Rating: 10 

Pros: unique, sharpness, quality
Cons: light equality
Sharpness: 10    Aberrations: 10    Bokeh: 10    Handling: 10    Value: 10    Camera Used: Sony A7   

This is a very special lens, as I know there doesnīt exist a comparable lens in the world. A reflex zoom lens of this compactness and comfort is unique. Because of my collector desease I bought it by a bargain for less money.

The reflex zoom is a sharp lens, in comaprison with the Nikkor reflex 500 8 of 1984. This lens didnīt convince me. So I sold it and bought the Pentax, wich is more versatile but it has a light bright circle in the images. You will remark it on monochrome pics only. Another weak point is to shoot against light - you will then see rainbow colours in your pic. But this are extreme situations. In the most cases you will be satisfied and the Bokeh is a dream, when you want to photograph birds or animals on water, because of the glittering background.

The photograph, wich I made in the early morning, is made free hand on 400mm.
I think it is a good example for using this lens digitally. In the analogue era, this image couldnīt have been made. So this lens doesnīt rest in the glass cabinet - it makes me happy in shooting with whenever I want to.

I am glad to have this light exotic lens in my Pentax collection.

Junior Member

Registered: June, 2012
Posts: 27

1 user found this helpful
Lens Review Date: June 4, 2012 I can recommend this lens: Yes | Price: $450.00 | Rating: 10 

Pros: Small, compact, can easily be hand held, Good color saturation and contrast
Cons: Poor bouquet
Sharpness: 10    Aberrations: 10    Bokeh: 4    Handling: 9    Value: 9   

I find this lens to be easily hand holdable. Getting a good exposure is a little tricky (with no F ring) but not too bad. This lens is best used
on a sunny day because it is a bit slow. The Bouquet can easily get out of hand and dominate the image if not used properly. That would be the only down side with this lens. I find that I use the 400mm end of the zoom the most so I cannot comment much on the 600mm end of it.

However, most of my photos have come out sharp with good contrast and color. Better then I would have expected from this lens.
Junior Member

Registered: June, 2010
Location: State College, PA
Posts: 44

1 user found this helpful
Lens Review Date: June 20, 2010 I can recommend this lens: Yes | Price: N/A | Rating: 9 

Pros: focal length, light
Cons: soft at 600mm

Before I began using the Pentax SMC reflex 1000mm, this lens was my lens of choice for birding photos. (I'm sorry that I don't remember the price, but I think I got it for about $200 on eBay.)

The bokeh can be unfortunate (if allowing the background to be x multiple of the foreground subject), but the 400mm is extremely convenient and can be remarkably sharp. (As a matter of fact, the one photograph I've sold to a magazine came from this lens at 400mm.)

On the plus side, the lens is quite light, and it is a joy at 400mm. At 600mm, one has to be spot on to have a good photo (and off by a hair, the subject is not at all sharp). In between, it a choice of dis and dat. When carrying and using a lens over several hours, one isn't going to be tired at the end of the day manually focusing, but the eyestrain at 600mm is a drag.
Site Supporter

Registered: November, 2008
Location: Tasmania, Australia
Posts: 7,681

3 users found this helpful
Lens Review Date: November 19, 2008 I can recommend this lens: Yes | Price: $500.00 | Rating: 5 

Pros: It's light, compact and amazes your friends.
Cons: It's damned hard to hold steady (tripod's a must) let alone focus.

I had been fascinated by the concept of a mirror zoom since I first heard about this lens, but was actually considering a Sigma 600 when a 400-600 came up on eBay, so of course I bought it, instead!

Frankly, the image quality isn't anything to brag about: the focus isn't particularly sharp, and the contrast is a bit flat. People seem to like the "bokeh", though.

I'm still waiting to find the perfect use for this lens, so I don't think I'll ever sell it - the fascination hasn't gone away, obviously.
Site Webmaster

Registered: September, 2006
Location: Arizona
Posts: 50,729
Lens Review Date: July 29, 2008 I can recommend this lens: Yes | Price: $480.00 | Rating: 5 

Pros: Compact long zoom, fun to use
Cons: Slow, hard to keep steady, no tripod mount, bokeh

About the only thing you can do with this lens is fool around; because of its slow speed (F8-F12), mirror consturction, and lack of tripod mount, its practical use is very limited. Its image quality isn't anything worth mentioning, and neither is its bokeh (obviously). I've used it for close-ups and landscape when on a tripod, though the setup was barely sturdy enough for the long shutter speeds the lens requires. I'd also say it's quite expensive and definitely does not pay off. It's a great collector's item, however!

If you're looking for a tele lens for birding or action shots, you'd be much better off with any 200 or 300mm along with a teleconverter.
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