Forgot Password
Pentax Camera Forums Home

Pentax Lens Review Database » Film Era Pentax K-Mount Lenses » K Prime Lenses
SMC Pentax 500mm F4.5 Review RSS Feed

SMC Pentax 500mm F4.5

Reviews Views Date of last review
12 84,690 Mon August 31, 2020
Recommended By Average Price Average User Rating
100% of reviewers $562.27 8.45
SMC Pentax 500mm F4.5

SMC Pentax 500mm F4.5
SMC Pentax 500mm F4.5

This focal length is unique to the K series. It is based on the screw mount Takumar 500mm F4.5 lens.

SMC Pentax 500mm F4.5
©, sharable with attribution
Image Format
Full-frame / 35mm film
Lens Mount
Pentax K
Aperture Ring
Yes (no A setting)
Manual, 10 blades
4 elements, 4 groups
Mount Variant
Check camera compatibility
Max. Aperture
Min. Aperture
Min. Focus
1000 cm
Max. Magnification
Filter Size
52 mm (Rear drop-in)
Internal Focus
Field of View (Diag. / Horiz.)

APS-C: 3.3 ° / 2.7 °
Full frame: 5.0 ° / 4.1 °
Built-in, slide out
Dedicated hard case
Lens Cap
Metal push-on
Weather Sealing
Other Features
Tripod Mount
Diam x Length
126 x 400 mm
3370 g
Production Years
1975 (start of production)
Engraved Name
SMC PENTAX 1:4.5/500 (early version), smc PENTAX 1:4.5 500mm (later version)
Product Code
User reviews
Compatible rear converters: A 1.4X-L, A 2X-L, A 2X-S, K T6-2X.
Filters are mounted at the rear.
Two variants were made, identical except for the engraved name:
SMC PENTAX 1:4.5/500 (early variant),
smc PENTAX 1:4.5 500mm (later variant)
Manual FocusBuilt-in HoodAperture RingFull-Frame SupportDiscontinued
Price History:

Add Review of SMC Pentax 500mm F4.5
Sort Reviews by: Date | Author | Rating | Recommendation | Likes (Descending) Showing Reviews 1-12 of 12
PEG Moderator

Registered: August, 2008
Location: Hielands o' Scootlund
Posts: 50,139

4 users found this helpful
Lens Review Date: January 16, 2018 I can recommend this lens: Yes | Price: $450.00 | Rating: 7 

Pros: Relatively cheap to buy
Cons: She's a big 'un
Sharpness: 8    Aberrations: 6    Bokeh: 6    Handling: 5    Value: 9    Camera Used: K1   

Forget hand holding, forget flimsy tripods, after that just enjoy this fine piece of older glass. It does take a bit of getting used to, but do persevere it's worth the effort.

Interestingly my engraved name is different it's SMC PENTAX 1:4.5 500mm, so don't know if mine is an early or late variant.

Senior Member

Registered: October, 2015
Location: Washington
Posts: 267

4 users found this helpful
Lens Review Date: March 15, 2016 I can recommend this lens: Yes | Price: $480.00 | Rating: 9 

Pros: Sharpness
Cons: none for the price
Sharpness: 9    Aberrations: 8    Bokeh: 10    Handling: 9    Value: 10    Camera Used: K-50   

Got it on E-Bay from Japan. Paid $480.00 including shipping. My lens came with carrying case.
This lens is beautifully built. Not super heavy considering it's size.
Very easy too use. Pure manual. Even at aperture set at f/8.0 it is very easy to focus, no need to open fully to f/4.5.
Bokeh is very nice. Some Chromatic Aberration at f-stop f/4.5 - 5.6. At f/8.0 and higher it gets really sharp and CA is almost gone.
Lens is worth every penny. There is no manual 500mm f/4.5 prime lens this quality on the market at this price period.

Here are some samples.

IMGP5318 by Mako_Elite, on Flickr

IMGP4790 by Mako_Elite, on Flickr

IMGP7893 by Mako_Elite, on Flickr

IMGP9453 by Ludovit Tatos, on Flickr

IMGP9405 by Ludovit Tatos, on Flickr

IMGP3811 by Mako_Elite, on Flickr
Site Supporter

Registered: October, 2008
Location: Vancouver, Canada
Posts: 6,908

2 users found this helpful
Lens Review Date: December 19, 2009 I can recommend this lens: Yes | Price: $520.00 | Rating: 9 

Pros: Fast, reasonably sharp and well built. Cost.
Cons: Heavy, manual diaphragm/stop-down metering.
Camera Used: K Series film bodies (K1000, KM, KX, K2, K2DMD)   

The K500/4.5 is now my second longest focal length lens. The K500/4.5 was in production from 1975-1998. There was no M or A version of this lens.


- sights for focusing
- camera positioning lock to move between vertical and horizontal shooting
- removable filter/camera mount that accepts filters with a 52mm thread
- built-in lens hood
- tripod seat
- manual diaphragm/stop-down metering
- no front filter thread
- padded hard leather case with shoulder strap
- mental front lens cap


This is a heavy lens and there is no chance of hand holding it. (3.37kgs or 7.4lbs)
You will need a tripod and head that supports at least 4kg, as you have to include the camera weight. I initially used this lens with a ball head and found it very hard to move the lens, as the head has only one lock leaver. I switched to a 3-way pan & tilt head and I find this a lot better for moving targets. Other forum members find the gimbal heads good for these large lenses.


The K500/4.5 is very fast for a lens of this focal length and also quite sharp. I was able to capture the heat shimmering/mirage created by a helicopter landing. As a film user I have found no CA or PF issues with this lens. Stopping-down the lens & manual focusing, does make it hard to capture fast moving targets. I find the K500/4.5 better suited for taking pictures of ships in the harbor or resting wildlife. Focusing a lens with this long focal length does take a bit of getting used to, especially when your subject is far in the distance. You just have to make sure you have the DOF you want. The minimum focusing distance is 10 meters, so you are a bit limited on close subjects.


Overall I would recommend the K500/4.5 over the K400/5.6. Even though the K500 is over 2.5 times the weight, the extra 100mm FL & 2/3 of a stop makes it a better value. (Both lenses sell for around the same price.) Compared to what an A*, F* & FA* super telephoto lens sells for, the K500/4.5 is an outright bargain.

Sample shots taken with the K500/4.5. Photos are medium resolution scans from original slides.

Camera: K2 Film: Fuji Provia 400 ISO: 400

Camera: KX Film: Fuji Velvia 100 ISO: 100

Veteran Member

Registered: October, 2008
Location: Albuquerque NM
Posts: 9,829

1 user found this helpful
Lens Review Date: April 20, 2015 I can recommend this lens: Yes | Price: $500.00 | Rating: 7 

Pros: Great quality and nice speed for price. Works well with 1.4x AL
Cons: Huge. Manual everything. Funky mount. No close focus.
Sharpness: 8    Aberrations: 7    Bokeh: 8    Handling: 6    Value: 10    Camera Used: K3, K01, Sony A6000, A7R   

I have gotten into birding and with a blind and a tripod, and I thought this a very nice companion to my FA*300. I have now used this combo for a few months, and am somewhat less enthused.

First impression is that this is a honking big lens. It is all metal and glass (even the lens cap), and weighs in at 7.5 lbs. It is a 500mm lens that is 440mm long--more of a long lens than a telephoto. Images are reasonably sharp and with nice contrast. The F/4.5 is great for a snappy focus, and the lens stops all the way down to f/45 for some depth of field. So far, I have not used it smaller than F/16, but F11 seems to be a sweet spot for getting enough of the subject in focus to do well.

Everything is manual from the focus to the aperture. Meter and focus is stop down. The K-mount seems to be an afterthought, with a funky mount required to attach the bayonet to the lens. The screw on connection to the mount can get a little loose sometimes and has to be re-tightened, but it is not a big deal.

No hand holding possible. The front of this baby is bigger than your average saucer.

This is not a lens for close work, and it barely works for shots in the back yard. Nearest focus is 10 meters. The shots below are at about as close as this lens gets. The more I use this lens, the more the lack of close focus gets in the way. I'm tempted to find an extension tube, because it is very hard to get small birds to fill the frame without a rear converter.

This lens needs to be on a sturdy tripod with a gimbal head. Figure the gimbal into the cost of the lens. The best use of this lens is to focus on a nest, feeder, bath or other spot where birds or wildlife frequent, and turn on the Flu card control. Use another body on a monopod to move around. Even better, put the lightest body possible on this lens, More and more, I'm using a mirrorless Sony E mount, because a heavy body will cause the focusing to bind, and with a manual lens, you lose nothing with an adapter. Also, to keep the tripod stable, it is better to keep the lens lower, and a body with an articulated screen is very helpful.

Below are some images from my early outings. These are all crops, because they are small birds, but the crop of the finch on the bird bath is 100%, and the sharpness is only limited by his movement and the shutter speed of 1/125. Not bad for a 1975 design, but my current thinking is that this 500mm alone, does not offer enough advantage over the DA*300 +1.4x HD converter to be worth the loss of AF, auto aperture and portability. After the initial testing and shots, my use of this lens is now limited to using it with the A 1.4x L converter (with the snout) from the '80s to get 700mm. Partly, this is because the more I have used the DA*300 + 1.4x, the more amazed I am at the performance of the DA* combo and the less use I see in a manual lens that offers only an additional 80mm of reach.

The manual focus and aperture as well as the sheer size of this two foot lens make hitting the right focus difficult. The F/4.5 sounds great, but hitting the point of focus you want is tough on anything that moves. Keeping the lens pointed where you want on a tripod is very difficult without a gimbal head and an ARCA-type mount that allows the balance of the lens to be adjusted.

A bright spot is that the performance of this lens on APS-C does not change that much with the 1.4x AL converter. If you have a distant subject, and you need 700mm, and the lighting will support it, this combo is useful enough to schlep this beast and its required Gimbal head tripod. It also works nicely on the tripod and 1.4x L with 36mp full frame.

Inactive Account

Registered: January, 2013
Posts: 1

1 user found this helpful
Lens Review Date: March 26, 2014 I can recommend this lens: Yes | Price: $900.00 | Rating: 10 

Pros: Filter easy , sharpness
Cons: No AF
Sharpness: 10    Aberrations: 9    Bokeh: 10    Handling: 8    Value: 10    Camera Used: K3   

It is a simple and effective goal. For use with APS-C I put a rectangle to cover the front lens, which improves contrast and reduces flare. The best hours are 8 - 9.5 - 11 to 16 which is great for photos of the sun (with a 1000 ND filter). Filters do not cost much and you can use several diameter 52 or 55 or 49 with an adapter ring.
The sharpness is better than the 400mm 5.6 Tokina / Hoya / Mitsuki and with a higher magnification.
Operation is simple, there is a viewfinder above. The picture is clear in the viewfinder even 8-11. (Or LiveView). Then pressing the green button on the camera.
Use a tripode but I like the idea of ​​bean bag
Site Webmaster

Registered: September, 2006
Location: Arizona
Posts: 49,707

1 user found this helpful
Lens Review Date: January 14, 2009 I can recommend this lens: Yes | Price: $499.00 | Rating: 8 

Pros: Sharp, fast, inexpensive
Cons: Heavy, prone to CA/fringing

This telephoto lens is a solid performer, considering its reach and low cost. Optically, it is the same as its screwmount Takumar counterpart. It works very well with the 1.4x-L converter, and is quite sharp. The only downside is that CA is quite severe and can rarely be avoided, especially at wide aperture settings.

Apart from that, this sample shot says it all:

Pentax K10D | SMC K 500mm F4.5 | Pentax A 1.4x-L Teleconverter (100% crop)

Site Supporter

Registered: February, 2008
Location: MT
Posts: 1,286

1 user found this helpful
Lens Review Date: March 17, 2008 I can recommend this lens: Yes | Price: $900.00 | Rating: 7 

Pros: inexpensive, sharp, light weight for this class
Cons: color issues, not ED glass

Sharpness is pretty decent, but the color rendition is washed out. Several years ago, tested it side by side with an FA*300/4.5. In drab light shooting an osprey on the nest, the color difference was VERY noticeable and severe. Probably best for black and white work where sharpness will be pronounced, color issues less noticeable. I'm presuming the difference results from ED glass in the FA* lenses.
Perhaps the color issues can be resolved digitally? If so, this lens would be a great bargain!
Site Webmaster

Registered: September, 2006
Location: Arizona
Posts: 49,707

1 user found this helpful
Lens Review Date: February 10, 2007 I can recommend this lens: Yes | Price: $500.00 | Rating: 9 

Pros: Fast, sharp, well-built
Cons: Heavy, prone to CA

This 500mm was never produced in a future series by Pentax, but it's a great telephoto nevertheless. It performs very well wide-open, and it's ideal for moon shots. The manual diaphragm also makes metering a bit easier on DSLRs, and the photos it produces are tack-sharp overall

Its low price and relatively fast aperture make it one of the best manaul extreme-telephoto lenses out there; it features a very sturdy and elegant build.

Now, for the negatives:

I won't complain about its size (44cm long) and weight (3.4kg), but this makes it rather hard to transport and use in the field (you'll always need a tripod). It's also prone to CA, and finally, although it has a want-to-be front filter thread, it only accepts 49mm filters in the back.

Registered: January, 2007
Location: Warsaw
Posts: 338

1 user found this helpful
Lens Review Date: February 1, 2007 I can recommend this lens: Yes | Price: $700.00 | Rating: 9 

Pros: cheap, good contrast and quite sharp
Cons: BIG, HEAVY, thin DOF

It costs just tens of % of other 500/4.5. It works with Sigma TC1.4 and even TC2.0.

It is manual focus in pure mode. First you need to focus wide open then you go from 4.5 (here DOF is thin like sheet of paper) to 8 or 11 and take shot. Not easy but works even with 1/100 sec with my DS (no any SR). Of course you need to have very stable setup - I use bean bag. I always use it from my car - too heavy to carry and use tripod. There are some CA at borders from time to time. But it is not big problem as I always crop my pictures with birds.
Some examples can be found here

Hood is very deep and works perfect.
Forum Member

Registered: July, 2020
Posts: 60
Lens Review Date: August 31, 2020 I can recommend this lens: Yes | Price: $356.00 | Rating: 9 

Pros: excellent optics; tripod collar; extendable hood; solid aperture and focusing rings
Cons: takes a lot of patience to use; lens cap; chromatic aberration
Sharpness: 10    Aberrations: 5    Handling: 9    Value: 9    Camera Used: K10D, K-3 II   

I got a superb copy off Ebay from Japan (my favorite place to buy used lenses because the Japanese seem to be so trustworthy in their descriptions, supplying many photos from different angles for the lenses that they sell). As always in my reviews, my price paid includes shipping (and tax if any). This is a big, heavy lens that requires a tripod, and it requires patience to use. But very sharp photos come from patient use of this lens. I can say pretty much the same things about this lens as I did in my review of the Pentax-A 400-mm f/5.6 lens, regarding the optics (sharp images, in this case especially by f/8) and the chromatic aberration. And like the 400-mm lens, it's relatively light for the aperture (mine has a 110-mm-diameter front lens), lighter and smaller than you'd get for an f/2.8 or f/4 lens at 500mm.

This 500-mm lens is more unwieldy to use, by far, than the lighter 400-mm lens, and much more thought has to be given to taking it out (vs. taking out the 400-mm lens) for photography. But for the price I paid ($356 USD incl. shipping), I think it's a great value in an optically sharp 500-mm lens. You do need a sturdy tripod and lots of patience. The tripod collar is convenient and works well; it can be rotated. And there's a crude metal sight with a "V" cut in it, like on the end of an old rifle. There's a convenient screw near the end of the lens (where the K-mount plate is for your camera) that allows you to pivot the camera around -- nifty idea. The aperture ring is big and wide, very easy to use in the dark, and has a nice solid feel to it. The rubber focusing ring is big, wide, and also has a solid feel, and has a long rotation, for really fine focus at long distances. The hood extends nicely (build-in hood extension) -- nice design, which is common on many of the older Pentax lenses of 120-mm and longer focal lengths (I have 120-, 135-, 200-, 400-, and 500-mm Pentax lenses all having these extendable lens hoods built in).

Mine came with the dedicated case; the case strap is sturdy and much needed, because the lens in case is quite hefty. The large metal lens cap doesn't fit snugly and is always falling off when I don't want it to; I may try to put some felt along the edges to help make a more snug fit. [Edit: one reader of this review noted that he used a thin strip of electrician tape on the inside part of the lens, and that it works well.]

But this is a handsome lens to behold, and built like a tank, and designed for good use by careful manual-focusing photographers. My handling grade above started out as an "8" or even less because it takes a lot of work to use and it's big and heavy, but people buying this lens will understand that in advance, so I upgraded it to a "9" -- considering the features that make this a great photographic tool (see my second paragraph above). My testing for sharpness is based mostly on my lunar photography so far, but I've also photographed Saturn and Jupiter (as with my 400-mm lens, as discussed in that review) and I feel that I'm more limited in resolution by my K10D sensor than by the lens' optics, so am eager to try this lens out on my new K-1 MkII in a few weeks. My overall rating could be an "8" because of the chromatic aberration, but to me the CA isn't a huge deal, so I gave it a "9"; sharpness and functionality (aperture/focus controls) are my biggest concerns, and it wins honors in those categories. I intend for this lens to be in my arsenal of big lenses for eclipse photography, due to its sharpness and relative ease of use (and ease to focus).

I found a useful manual for this lens online: ... I learned a couple of things from the manual, such as that there are two sights, to line up with each other. ... I hadn't noticed that before. I don't plan on inserting any filters, and the instructions suggest that it's a pain to remove a large section of the rear of the lens to insert the 52-mm filter. Nothing in the manual (or in the Pentax Forums introduction to this lens above) indicates the objective lens' filter size, but it does appear that there are threads and it appears that the filter size would be close to 110mm. I very much want an objective-lens filter to protect the outside lens from possible damage, so will be looking into that.

photos showing the 500-mm f/4.5 lens on my camera (one on tripod, the other lined up next to my Sigma 70-210mm f/2.8 lens and my Pentax DA 12-24mm lens on adjacent cameras, for size comparison):

New Member

Registered: October, 2019
Posts: 4
Lens Review Date: October 29, 2019 I can recommend this lens: Yes | Price: $380.00 | Rating: N/A 


I just bought a 500mm f4.5 Takumar. However, the lens doesn't join up properly in the middle. i know this lens breaks up in two but it just seems unduly loose and i can't find a way to screw it tight together, nor can I find a manual online to see how it's done, how it separates.

Can anyone help, please?
Inactive Account

Registered: September, 2006
Location: D/FW area, Tx.
Posts: 1,712
Lens Review Date: January 8, 2007 I can recommend this lens: Yes | Price: N/A | Rating: 9 


see my review under takumar lenses. pretty sure they are the same.
Add Review of SMC Pentax 500mm F4.5

All times are GMT -7. The time now is 05:16 AM. | 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]