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My new PK mount lens won't focus past 15 meters, help
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PostPosted: Fri Aug 12, 2022 4:32 pm    Post subject: My new PK mount lens won't focus past 15 meters, help Reply with quote
I recently bought a Miranda Auto MC 135mm f2.8 lens for Pentax K mount. I am using it on my Fuji XE2 camera with a no-name PK to FX adapter (not had any other issues with the adapter with various lenses).

The maximum focusing distance is 15 meters. Is the lens defective or is there perhaps something that can be done to fix the issue? Or maybe it is common? I tried using it with a 2x teleconverter which doubled the focus distance to 30 meters, but that isn't going to cut it for a lens I want to use for wildlife.

Please let me know if you have had, or heard of, similar experiences. I bought the lens off eBay the other day so I can return it if it is indeed defective.

It is a nice lens, I would buy it again if I could get one that really focuses to infinity. I just compared it with my Pentax-M 135mm f3.5 and it easily beat it for stuff within 15 meters.

Thanks


PostPosted: Fri Aug 12, 2022 5:06 pm    Post subject: Reply with quote
Probably a misalignment of the focussing helicoid.


PostPosted: Fri Aug 12, 2022 5:59 pm    Post subject: Reply with quote
D1N0 wrote:
Probably a misalignment of the focussing helicoid.

Thanks. Sounds like it warrants a return to the seller.


PostPosted: Fri Aug 12, 2022 6:21 pm    Post subject: Reply with quote
There are plenty of 135mm lenses to go around so no need to go to the trouble of repairing one.


PostPosted: Fri Aug 12, 2022 6:45 pm    Post subject: Reply with quote
Looking at your pics it may be that the helicoid can be separated by loosening some grub screws on the distance scale ring and sliding that off. Does it look like this has been done (would corroborate incorrect reassembly theory)? If this is the case, you could have a go at trying to reassemble but engaging the helicoid thread in a different position.
There's a lot of threads on 135mm lenses, you could go for eg a classic minolta or canon cfd given you are using mirrorless.


PostPosted: Fri Aug 12, 2022 8:40 pm    Post subject: Reply with quote
marcusBMG wrote:
Looking at your pics it may be that the helicoid can be separated by loosening some grub screws on the distance scale ring and sliding that off. Does it look like this has been done (would corroborate incorrect reassembly theory)? If this is the case, you could have a go at trying to reassemble but engaging the helicoid thread in a different position.
There's a lot of threads on 135mm lenses, you could go for eg a classic minolta or canon cfd given you are using mirrorless.


No. And I don't know anything about taking lenses apart. It's in good condition, no signs of repairs. But perhaps it is fairly unused because it is defective and perhaps that's why it was so cheap. I will just send it back.


Irrelevant ramblings: Even though it is plagued with aberrations, I like that my Pentax M 135mm has the right filter thread size (probably 49mm) for an Olympus teconverter on the end, so I can put one on both ends. It's a much lighter alternative to my Super Takumar f4 200mm with one teleconverter. Need to do a battle as the Pentax is likely to be far worse optically.

After getting 2 junk lenses in a few days that need to be sent back, I am thinking of sticking with Super Takumar lenses for now. Especially as a 55 1.8 just arrived and it is great on first impressions.


PostPosted: Fri Aug 12, 2022 9:01 pm    Post subject: Reply with quote
You might like Takumar or Tele-Takumar 1 : 5.6 / 200 (10-bladed iris versions, although 8-bladed versions have same optics)

https://takumarguide.weebly.com/1--56--200-347.html
https://takumarguide.weebly.com/1--56--200-351-43510.html
https://www.pentaxforums.com/lensreviews/Takumar-Tele-Takumar-200mm-F5.6.html


PostPosted: Fri Aug 12, 2022 10:33 pm    Post subject: Reply with quote
visualopsins wrote:
You might like Takumar or Tele-Takumar 1 : 5.6 / 200 (10-bladed iris versions, although 8-bladed versions have same optics)

https://takumarguide.weebly.com/1--56--200-347.html
https://takumarguide.weebly.com/1--56--200-351-43510.html
https://www.pentaxforums.com/lensreviews/Takumar-Tele-Takumar-200mm-F5.6.html


Thanks for the recommendations and that website looks ideal for me. Just earlier today I was thinking I want to know more about Super Takumar in general, like what the name meant to Pentax. Like 1 small

The 200mm f5.6 doesn't seem appealing at first but the weight changes everything with the 200mm f4 being 190g more. Plus the 5.6 gets high praise. But the big thing is that it also has the 49mm filter ring, which would be great for daytime wildlife with a normal 2x teleconverter and the Oly 1.5x teleconverter on the front. F11 or so will be pretty restrictive, maybe it will be f16 with 2 teleconverters. Alas, it's too rare at the moment but will keep an eye out.

Actually, the Pentax Super Multi Coated Takumar 135mm f3.5 has 49mm filter size, so just grabbed that. The 200 f5.6 is a similar size but I think the shorter lens may be better with more light. 135mm is an OK focal length on APSC, whereas 200mm is a bit long, so that would be a very specific one: only wildlife and only in good light. I used a 110mm f3.5 (55mm f1.8 with teleconverter) last night on a semi wildlife walk and it was good in golden hour. The 200mm f5.6 would've been too dark. But will keep an eye out for a cheaper one.


PostPosted: Mon Aug 15, 2022 12:48 am    Post subject: Reply with quote
Takumar was the name given by Asahi Optical (Pentax) to their line of lenses.
It was used in honor of the brother of the founder (Takuma Kajiwara).


PostPosted: Mon Aug 15, 2022 10:09 am    Post subject: Reply with quote
There is:
Takumar: First series m42 lenses for slr , they got their name from the earlier m37 lenses which got their name from Asahi optical founder's brother. These lenses have preset aperture and most a 46mm filter thread instead of 49mm.
Auto-Takumar: Typically they have a semi-automatic aperture. Meaning you have to cock it first and then it will automatically close down when doing the shot (and will stay closed until you cock it again). Most still with 46mm filter threads.
Super-Takumar: feature a fully automatic aperture that will close down automatically to the set value and open up again.
Super-Multi-Coated Takumar: Adds multi-coating and light meter coupling telling the camera which aperture is set.
SMC Takumar: The same as the previous version but with rubberized focus ring.

Some features of later generations already appear in earlier ones. There are auto-takumars that are actually super-takumars (no cocking lever but a/m switch). Super-Takumars with multi-coating. (You can only tell by a green/blue coating layer that is visible). There are also some super-Takumars with light meter coupling. But those are exceptions to the general rule above.


PostPosted: Mon Aug 15, 2022 6:03 pm    Post subject: Reply with quote
D1N0 wrote:
There is:
Takumar: First series m42 lenses for slr , they got their name from the earlier m37 lenses which got their name from Asahi optical founder's brother. These lenses have preset aperture and most a 46mm filter thread instead of 49mm.
Auto-Takumar: Typically they have a semi-automatic aperture. Meaning you have to cock it first and then it will automatically close down when doing the shot (and will stay closed until you cock it again). Most still with 46mm filter threads.
Super-Takumar: feature a fully automatic aperture that will close down automatically to the set value and open up again.
Super-Multi-Coated Takumar: Adds multi-coating and light meter coupling telling the camera which aperture is set.
SMC Takumar: The same as the previous version but with rubberized focus ring.

Some features of later generations already appear in earlier ones. There are auto-takumars that are actually super-takumars (no cocking lever but a/m switch). Super-Takumars with multi-coating. (You can only tell by a green/blue coating layer that is visible). There are also some super-Takumars with light meter coupling. But those are exceptions to the general rule above.


Thank you for the excellent breakdown. I have also learned they briefly brought back the Takumar name for some budget PK mount lenses known as "Takumar (Bayonet)" as one lens similar to the above I lost a bid on was one, a 135mm f2.5, but it sounds like I was lucky not to get it. I have also started reading a helpful Wiki about Takumar lenses (I only got to the first paragraph so far which covers the name, thanks titrisol70 for the above re: name) http://camera-wiki.org/wiki/Takumar and I may order the book which is sold through a member on here. I also saw the long list of 55mm variations and am tempted to buy a few more. Feel like I am joining the Takumar cult. Wink


PostPosted: Mon Aug 15, 2022 6:48 pm    Post subject: Reply with quote
The K-mount "SMC Pentax" Takumars often have the same optics as M42-mount versions and often sell for less, but they lack the all-metal and finely machined look of M42s. https://www.pentaxuser.com/forum/topic/smc-takumar---k-1227

More reading on the finer points of Takumar collecting: https://takumarguide.weebly.com/takumarology.html


PostPosted: Mon Aug 15, 2022 6:51 pm    Post subject: Reply with quote
https://www.amazon.com/dp/B00U4JXQ1C


PostPosted: Mon Aug 15, 2022 11:12 pm    Post subject: Reply with quote
BnG_Murphy wrote:
D1N0 wrote:
There is:
Takumar: First series m42 lenses for slr , they got their name from the earlier m37 lenses which got their name from Asahi optical founder's brother. These lenses have preset aperture and most a 46mm filter thread instead of 49mm.
Auto-Takumar: Typically they have a semi-automatic aperture. Meaning you have to cock it first and then it will automatically close down when doing the shot (and will stay closed until you cock it again). Most still with 46mm filter threads.
Super-Takumar: feature a fully automatic aperture that will close down automatically to the set value and open up again.
Super-Multi-Coated Takumar: Adds multi-coating and light meter coupling telling the camera which aperture is set.
SMC Takumar: The same as the previous version but with rubberized focus ring.

Some features of later generations already appear in earlier ones. There are auto-takumars that are actually super-takumars (no cocking lever but a/m switch). Super-Takumars with multi-coating. (You can only tell by a green/blue coating layer that is visible). There are also some super-Takumars with light meter coupling. But those are exceptions to the general rule above.


Thank you for the excellent breakdown. I have also learned they briefly brought back the Takumar name for some budget PK mount lenses known as "Takumar (Bayonet)" as one lens similar to the above I lost a bid on was one, a 135mm f2.5, but it sounds like I was lucky not to get it. I have also started reading a helpful Wiki about Takumar lenses (I only got to the first paragraph so far which covers the name, thanks titrisol70 for the above re: name) http://camera-wiki.org/wiki/Takumar and I may order the book which is sold through a member on here. I also saw the long list of 55mm variations and am tempted to buy a few more. Feel like I am joining the Takumar cult. Wink


Yeah Pentax brought the name back in the eighties for cheaper alternatives to their own lenses. No SMC coating. Some of those had the same optics as their smc brothers, others didn't. The Takumar Bayonet is in no way as good as The S-M-C Takumar 135/2.5. It is a lens with good looking specs but 2.5 is just stretching it too far for the optics. Too much spherical aberration. I think if it were 2.8 and had SMC it would be a good enough lens. It still haven't found a SMC Pentax-A 135mm/2.8 at a good price, so I can't compare.


PostPosted: Tue Aug 16, 2022 12:08 pm    Post subject: Reply with quote
I had one of those bayonet takumar and it just didnt feel right
Pictures had a "meh" quality, construction felt mediocre and I gave it away


Takumar Bayonet 135mm f/2.5
by titrisol, on Flickr

D1N0 wrote:


Yeah Pentax brought the name back in the eighties for cheaper alternatives to their own lenses. No SMC coating. Some of those had the same optics as their smc brothers, others didn't. The Takumar Bayonet is in no way as good as The S-M-C Takumar 135/2.5. It is a lens with good looking specs but 2.5 is just stretching it too far for the optics. Too much spherical aberration. I think if it were 2.8 and had SMC it would be a good enough lens. It still haven't found a SMC Pentax-A 135mm/2.8 at a good price, so I can't compare.
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