SMC Takumar 300mm F4 (screw mount)

Discussion in 'Pentax Lenses' started by VidThreeNorth, Mar 6, 2019.

  1. VidThreeNorth

    VidThreeNorth No longer a newbie, moving up!

    Joined:
    Oct 21, 2016
    Messages:
    440
    Likes Received:
    51
    Can others edit my Photos:
    Photos NOT OK to edit
    As best as I can remember, I bought a used 300mm F4.0 Super Multi-Coat Takumar lens at a Flea Market before 2015 when the only Digital Interchangeable Lens Camera body that I had was a Panasonic Lumix GF3. Some people would call that a silly purchase since the GF3 was not a very capable camera. In fact, I had a vague idea that I might use it for pictures of the Pan-Am Games in Toronto. But in 2015, I was mainly concerned with video, and I never got around to using that setup.

    These days, I mainly use my Sony a5000 E-Mount and three M4:3 bodies. But I have no current use for the 300mm lens. It has sat on the shelf for all these years. With my recent interest in the "Red Cat" 250mm F4.9 telescope, I thought I should finally take out the 300mm and give it a try. I am glad I did this because I learned a few things, mostly good, and, unfortunately, some bad.

    A Quick History of Pentax 300mm F4 Lenses:
    [Most Info From "Pentax Forums"]

    Takumar 300mm F4 (1st) 1958 - 1961
    - 3 elements in 3 groups
    Takumar 300mm F4 (2nd) 1962 - 1965
    - 4 elements in 4 groups
    Super Takumar 300mm F4 1965 - 1971
    - 5 elements in 5 groups
    Ultra=Achromatic Takumar 300mm F5.6 1968 - ?
    - 5 elements (some flourite) in 5 groups (corrected to infrared)
    SMC Takumar 300mm F4 1971 - ?
    - 5 elements in 5 groups, Open aperture metering
    SMC Pentax 300mm F4 1975 - 1981
    - 7 elements in 5 groups
    [There are more but I'm stopping here.]

    If you think about the availability of computers in the world, one wonders when computers started being used for designing lenses. It is surprising that Japan lagged behind other industrial countries in adopting computers. There was reliance on the abacus and the slide-ruler. But Asashi Pentax products were distributed in the US by Honeywell, which began a computer business around 1955. I do not know whether Asahi was influenced by Honeywell, so it would be interesting to find any historical notes of when Asahi Pentax started using computers in lens designs.

    Looking at the 1965 Super Takumar lenses, without using a computer, the 5 element design would have been very difficult, so it is not a surprise that the basic optical design does not change again till the 1975 K-mount "Pentax" version. The fact that the lens was probably looked on as competitive would also be a factor. I have no comparitive information, but I do recall the SMC Takumar lenses being generally competitive with Canon, Minolta and Nikon through the 70's.

    After the SMC Takumars, the SMC Pentax (K-mount) lenses, the 300mm F4's had substantial upgrades (there was a jump from the 5 elements in 5 group to 7 element). So as a general rule, if you find any of these on the used market, prefer to get the latest version you can, at least up to the first Auto-Focus versions. Unless you actually buy a Pentax camera body, there are no autofocus adaptors for other brands of cameras, so that technology is wasted. So why bother to pay for it?


    The Tests:

    First The Bad News:

    The setup I had would not have worked. I have been using a M4:3 to Pentax K mount adapter, and I had a Pentax K-mount to screw thread adapter to mount the 300mm. Using this setup on my Olympus OM-D EM10, I found I could not focus to infinity. The farthest I can focus is about 100M. That would have been useless for covering Sailing. I have re-tested my M4:3 to K-mount adapter using my 50mm F2.0 M series Pentax lens (K-mount) and there is nothing wrong with that adapter. The 50mm focuses out to Infinity with no problems. My screw mount adapter is Pentax's own, and it would not have any problems that would account for this either. It seems to be the effect of combining the adapters that is causing the problem. I think that the solution is simply to buy specific screw mount adapters directly for the M4:3 mount and/or also another for my E-Mount.

    This would have been inconvenient back then because I was busy, and is still "a problem" for me, but it is not impossible.

    My test procedure was supposed to be a simple "compose - focus - shoot" using only F4.0 and F8.0. I can usually tell which pictures are which by looking at the EXIF data. When I found I could not focus to infinity, I left the focus and looked for compositions that were at the right distance. It worked well enough, but later I realized that I could have just focussed on objects a bit closer, which could have provided more variety.

    Trying to find compositions at a set distance resulted in compositions where I do not recall exactly what was in focus. Also, thanks to the unusual lighting conditions (the snow) I am less positive about the aperture of some of the pictures. I also found that once, I checked the aperture and it was at 5.6 instead of 4.0, but at most there might have been one or two pictures that were not 4.0 or 8.0.


    The Good News:

    Aside from not being able to focus to infinity, I was able to test the lens, and it is very nice. I will look forward to the day when I can use it "completely".


    The Result Details:

    This version of the 300mm F4 had chromatic aberration from about 1/3rd out from center onward, occurring at F4. It reduces when stopped down and is almost gone below F8. It probably does not completely go away.

    The lens is a bit soft wide open but again, sharpens up at F8 and probably peaks by about F11. It is generally considered a very good lens, particularly for its age. Later versions are, as mentioned above, a bit better. Note that the company also produced a 300mm F5.6 "Ultra-Achromatic-Takumar" during this period which was a superior and quite expensive lens featuring two Flourite elements.


    "P3010003a-Crop01.jpg"
    - a full resolution detail crop F4.0


    "P3010012b-rsz1640-C1.jpg"
    - probably F8.0
    Date taken 2019-03-01 15:10:42
    Size: 7,686,900 Bytes
    Partial EXIF:
    Dimensions 4608 x 3456
    Bit depth 24
    Resolution unit 2
    Color representation sRGB
    F-stop ?
    Exposure time 1/2000 sec.
    ISO speed ISO-200
    Focal length 0
    Metering mode Center Weighted Average
    White balance Auto

    - this image has been adjusted for brightness and colours but no sharpening has been added -- not that it really matters considering the size reduction.


    "P3010012c-Crop01-C1.jpg"

    Here is a full resolution detail crop from the original camera JPEG. There are a few "sparkles" which are reflections of the sun which is behind me. This is a good example of the real sharpness. The fine edge of the sparkles are "hard" contrast from light cyan to very dark. They cyan is caused by chromatic aberration, but the high boundary contrast requires a very high quality lens.


    "P3010030a-rsz1640.jpg"
    - probably F8.0
    This picture is straight from the camera, but resized.
    Date taken 2019-03-01 15:18:36
    Size: 7,363,347 Bytes
    Partial EXIF:
    Dimensions 4608 x 3456
    Bit depth 24
    Resolution unit 2
    Color representation sRGB
    F-stop ?
    Exposure time 1/1600 sec.
    ISO speed ISO-200
    Focal length 0
    Metering mode Center Weighted Average
    White balance Auto


    "P3010030b-Crop01-C1.jpg"
    The full resolution detail crop shows excellent resolution but there is still magenta-cyan chromatic aberration.


     

    Attached Files:

  2. petrochemist

    petrochemist TPF junkie!

    Joined:
    Mar 9, 2014
    Messages:
    1,501
    Likes Received:
    439
    Location:
    North Essex UK
    Can others edit my Photos:
    Photos OK to edit
    I thought the problem with infinity focus was probably your PK-M42 adapter. (It should sit completely within the K mount, but many adapters have a extra ring so as to engage the lens locking pin.) but I see yours is the pentax version so it' does sit in the mount. That implies your lens is faulty. Long focal length lenses hide errors in adapters & if your adapters work at shorter FLs they must be reasonable.

    A photo of the rear of your lens might just give some clues. If your example shots are about the maximum focus distance it can achieve its a long way out!

    I regularly stack adapters with no issues, in fact it's my usual approach with MFT where I use EF adpters with added features followed by an EF-lens adapter. (Usually with a helicoid, but sometimes a focal reducer or tile adapter).

    Your best bet may be to use a helicoid type adapter there are short camera to M42 adapters made for these (both MFT & NEX) then a 17-31mm M42 helicoid would allow the lens to be closer to the body than a normal M42, and then extended to further than normal. This should restore infinity focus (if it's not way out, you might get away with working directly on the short M42 adapter if it really is way out) and also give you closer focusing ability. Cost from e-bay should be less than £30 for all three (helicoid & 2 short adapters)

    I have the second version from the 60's a nice lens but so heavy! I have used it on a Pentax DSLR but not since I got the F100-300 which is AF, lighter & nearly as fast...
     
    • Useful Useful x 1
  3. compur

    compur Been spending a lot of time on here!

    Joined:
    Mar 6, 2008
    Messages:
    3,462
    Likes Received:
    645
    Location:
    L.A.
    Some lenses focus beyond infinity. That could be the case with the 50mm lens you used to test the adapter. If so, that would mean your M4:3 -> K mount adapter may still be the culprit.
     
    • Useful Useful x 1
  4. VidThreeNorth

    VidThreeNorth No longer a newbie, moving up!

    Joined:
    Oct 21, 2016
    Messages:
    440
    Likes Received:
    51
    Can others edit my Photos:
    Photos NOT OK to edit
    Thanks for the thoughts! My first thought was that it was the "adapter stack", but as "petrochemist" noted it could be the lens. I looked at the lens more closely and there are light tool-marks on the focus ring at the locking screws. I would guess that a previous owner found the focus ring got loose and tightened the screws, but did not realize that "infinity had slipped". I should have the right screw driver in a box somewhere here, so I should be able to fix it eventually. I do not know when I will get around to doing this. As usual, I'm a bit busy lately.

    Also, I forgot to mention that I ran the test using the camera on a monopod and with IBIS active. The effective field of view when used on the EM10 (Micro 4:3) was that of a 600mm lens on a 35mm camera. Normally I would have used this on a full tripod. Despite my general lack of steadiness, I could see that it was steady in the view screen. That's why I bought the EM10 in the first place. Of course all the real Pentax bodies have IBIS too.
     
    Last edited: Mar 8, 2019
  5. petrochemist

    petrochemist TPF junkie!

    Joined:
    Mar 9, 2014
    Messages:
    1,501
    Likes Received:
    439
    Location:
    North Essex UK
    Can others edit my Photos:
    Photos OK to edit
    It's far more common for longer focal length lenses to focus beyond infinity. They are more susceptible to changes with temperature so can need the extra movement.
     
    • Agree Agree x 1
  6. petrochemist

    petrochemist TPF junkie!

    Joined:
    Mar 9, 2014
    Messages:
    1,501
    Likes Received:
    439
    Location:
    North Essex UK
    Can others edit my Photos:
    Photos OK to edit
    The tool marks could mean a previous owner 'serviced' the lens - perhaps took it apart to clean - in such cases sometimes elements are put back the wrong way round, helicoids replaced on the wrong threads or worse.

    I wouldn't expect 300mm on MFT to be to much of a struggle, as long as the lights reasonable. I needed a monopod and a well braced position with my 600mm f/8 (1200mm equivalent), but with a focal reducer it's often hand holdable.

    Not all Pentax bodies have IBIS, none of my Pentax film bodies have it, but yes pretty much all their DSLRs have had it, right back to the K100d.
     
    Last edited: Mar 9, 2019
    • Informative Informative x 1
  7. compur

    compur Been spending a lot of time on here!

    Joined:
    Mar 6, 2008
    Messages:
    3,462
    Likes Received:
    645
    Location:
    L.A.
    It is still possible for a normal lens to focus beyond infinity. I have had some that did. It's also a possibly simple solution to the OP's issue and I would appreciate it if you would keep your dismissive know-it-all pronouncements downwind of me. Thanks. :)
     
    • Informative Informative x 1
  8. VidThreeNorth

    VidThreeNorth No longer a newbie, moving up!

    Joined:
    Oct 21, 2016
    Messages:
    440
    Likes Received:
    51
    Can others edit my Photos:
    Photos NOT OK to edit
    I've had a busy day, as usual, but I have news:

    I waited until I got new adapters by Vello. I bought one each for M43 and Sony E-mount each directly to 42mm screw mount (Pentax thread). Both have a "lip" to hold in the aperture pin (which I do not need for this particular lens), and both are zinc. A digression about zinc: Zinc is a hard metal, which is stable for size and shape, which is good, but somewhat "reactive" with other metals, such as aluminum, which is bad. Aluminum is often used in the camera industry. The mount on my YiM1 is Aluminum. The thread of the 300mm lens is aluminum (the paint is worn off and I can see it easily). My other thread mount lenses probably also have aluminum mounts. I'm not sure about the Sony E-mount. On the better bodies it is probably aluminum as well. On my a5000 it might be metal coated plastic. If it is metal coated plastic, then the metal is probably aluminum.

    So, knowing this, I would not want to leave the adapters attached to anything longer than necessary. That means being vigilant to disassemble the mount from the camera and lens when I am done. I don't like that. It was silly. I would have bought a cheaper Fotodiox aluminum type but I did not like the look of the thread machining. The thread depth was too short. It looked like about 3 turns deep. Another bad idea. Using the weakest metal available and then overstressing it and causing unnecessary wear by using a short thread depth? What's with these guys?

    Anyway, I used the YiM1 as a test body for the adjustment. At first I thought it didn't look so bad, so I made small adjustments. Each time, I tested it and found I had not adjusted enough. In the end, I found that it needed more than my original estimate (remember I wrote that it looked like infinity was at about 100M?). After 4 tried, the set screw heads were starting to look a bit worn, so I decided to stop. I'm not sure yet if I got infinity to infinity or not. I think it is still a bit short, but not so far off that I care that much. I know that at around F8 it definitely looks good, so it is either it is within hyper focus, or the softness of the lens is cleaned up and it is actually is at infinity. I would have preferred to have infinity set to a bit past infinity to give me a bit of leeway, but I'm satisfied. I won't really need true infinity focus for anything I will do. At most I might try to record some sail boat races.

    My testing got out to around 5 Km and beyond. I will try again with one of my other bodies. I should mention that I was around the area where I made the previous test pictures. I estimated about 100M before? Well, that day was cold and windy, and I was walking. On a cold and windy day, distances can seem longer. I think the original focus and my pictures were more like around 50M range. So I had to do even more adjusting that I expected.
     
    • Informative Informative x 1
  9. VidThreeNorth

    VidThreeNorth No longer a newbie, moving up!

    Joined:
    Oct 21, 2016
    Messages:
    440
    Likes Received:
    51
    Can others edit my Photos:
    Photos NOT OK to edit
    These are test pictures after the focus adjustment. As I wrote above, I do not think I got "Infinity" quite right, but I stopped re-adjusting it because the set screw heads were starting to get too worn. If I can buy a new set of set-screws from Pentax, then I might finish the job. But as you will see from the pictures, it is close enough to real "infinity" that I am not really concerned about it.

    The pictures are standard JPEGs, not adjusted beyond what the camera did. The uploads are either resized versions of the whole image or 1:1 crops.

    Camera: Sony a5000
    Lens: Asahi SMC Takumar 300mm F4.0 (screw mount) lens
    Vello adapter
    - on tripod

    - All 300mm pictures taken at F5.6

    "A01-DSC01103.JPG"
    size 9,961,472 bytes

    Focussed on the far traffic signal (Yellow light on)
    [2019-0404 15:33]
    I checked the distance to the traffic lights and the far lights, that I focussed on are about 400m (about 0.24 miles).


    Partial EXIF [from JPEG Corel PaintShop Pro 2018]
    Software ILCE_5000 v1.10
    Date and time March 31, 2019, 17:57:02
    Pixel height 3632
    Pixel width 5456
    Component configuration YCbCr
    Compressed bits per 4.0
    Color space sRGB
    Exposure mode Auto bracket
    Exposure bias -0.70 ev
    Brightness 3.87
    Exposure time 1/1250 sec.
    F number f/0.0 [f/5.6 manual]
    Max aperture f/1.0 [f/4.0]
    Focal length 0.0 mm [300mm]
    Focal length in 35mm Unknown [450mm]
    ISO speed 200
    Metering mode Center weighted average
    White balance Auto

    Crop from 1570 x 1150


    "B01-DSC01112.JPG"
    size 5,519,136 bytes

    Focussed at Infinity mark (as far as possible)

    Partial EXIF [from JPEG Corel PaintShop Pro 2018]
    Software ILCE_5000 v1.10
    Date and time March 31, 2019, 17:58:30
    Pixel height 3632
    Pixel width 5456
    Component configuration YCbCr
    Compressed bits per 2.0
    Color space sRGB
    Exposure mode Auto bracket
    Exposure bias -0.30 ev
    Brightness 4.56
    Exposure time 1/1600 sec.
    F number f/0.0 [f/5.6 manual]
    Max aperture f/1.0 [f/4.0]
    Focal length 0.0 mm [300mm]
    Focal length in 35mm Unknown [450mm]
    ISO speed 200
    Metering mode Center weighted average
    White balance Auto

    Crop From
    5455, 1199
     

    Attached Files:

    Last edited: Apr 4, 2019
  10. Solarflare

    Solarflare No longer a newbie, moving up!

    Joined:
    May 24, 2012
    Messages:
    2,849
    Likes Received:
    382
    The Takumar 50mm f1.4 was famously better than anything Zeiss had to offer at the same time and was so expensive to make they sold it at a loss.

    One reason I fancy to get a mirrorless system, like Fujifilm GFX, is so I can adapt lenses like that. :)
     
  11. compur

    compur Been spending a lot of time on here!

    Joined:
    Mar 6, 2008
    Messages:
    3,462
    Likes Received:
    645
    Location:
    L.A.


    It was the 8-element version of the 50/1.4 that has this reputation. Most of the 50/1.4s were 7-element.

    1 : 1.4 / 50 358 (8 element)
     

Share This Page

Search tags for this page

foro pentax asahi smc

,

super takumar 300mm f4

,

takumar 300 mm f 4 review

,

takumar 300mm f4