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Forum: Welcomes and Introductions 6 Days Ago  
Chinon Auto 50mm f1.4
Posted By .a.t.
Replies: 7
Views: 327
Will do. Thanks for the reply.
Forum: Welcomes and Introductions 01-14-2022, 09:39 AM  
Chinon Auto 50mm f1.4
Posted By .a.t.
Replies: 7
Views: 327
@DocComPhoto,

If you have a chance, I'd enjoy hearing anything you know about the Sears and Tomioka relationship.
Forum: Welcomes and Introductions 01-06-2022, 10:30 PM  
Chinon Auto 50mm f1.4
Posted By .a.t.
Replies: 7
Views: 327
DocCom, that's really interesting to hear about Sears and Tomioka. Can you give me more details about that situation, please?
Forum: Welcomes and Introductions 01-06-2022, 12:48 PM  
Chinon Auto 50mm f1.4
Posted By .a.t.
Replies: 7
Views: 327
Welcome, Raymond!
Beautiful colors indeed! And I share your fascination with fast 50s.

That's an interesting discovery about the 6 vs 8 iris blades. My Auto Sears MC 50mm f/1.4 #C675617 is a rebadged Chinon with 8 blades. And I see in the lens review database, the pictured Chinon 50mm f/1.4 appears to have 6 blades.
Chinon 50mm f1.4 Lens Reviews - Miscellaneous Lenses - Pentax Lens Review Database

As mentioned, if you add your information there it would be appreciated.
Forum: General Talk 12-11-2021, 05:55 PM  
I am terminally ill...
Posted By .a.t.
Replies: 93
Views: 3,310
I forbid you to leave us, Steve!
We need you here.
Forum: Post Your Photos! 12-04-2021, 02:11 PM  
2021 Pentax Lens Tournament Takumar 58mm f/2.0
Posted By .a.t.
Replies: 4
Views: 122
Thank you, Michail. I appreciate hearing the opinions of others.
Forum: Post Your Photos! 12-04-2021, 02:02 PM  
2021 Pentax Lens Tournament Takumar 58mm f/2.0
Posted By .a.t.
Replies: 4
Views: 122
Thanks for the comment. I suspect most viewers would agree with you - about the distracting part, at least.

Yet this is the sort of abstract-ish photography I enjoy.
There's no accounting for taste, is there?
Forum: Pentax SLR Lens Discussion 12-03-2021, 12:36 AM  
Sears Mod. No. 202 Magic!
Posted By .a.t.
Replies: 17
Views: 11,790
Ah, okay. It sounds as though you may be having a mechanical issue. I'd suggest you start a new thread here:
Troubleshooting and Beginner Help - PentaxForums.com

If you list the camera and lens used and the circumstances of the problem, I'm confident someone will be able to help you.
Forum: Pentax SLR Lens Discussion 12-01-2021, 10:40 PM  
Sears Mod. No. 202 Magic!
Posted By .a.t.
Replies: 17
Views: 11,790
Yeah, my own Sears 60-300 is difficult to use at maximum magnification because that comes at 300mm focal length. I typically use a tripod in those situations.

If you want more magnification than your Sears can give, it's not necessary to buy a genuine macro lens. There are less expensive ways to get close. See this thread:
CHEAP MACRO -- Buying or exploiting a lens for ultraclose work - PentaxForums.com




Agreed. And if you haven't already, check out the Sears Lens Club thread:
Sears Lens Club - PentaxForums.com
Forum: Pentax SLR Lens Discussion 11-30-2021, 10:50 PM  
Sears Mod. No. 202 Magic!
Posted By .a.t.
Replies: 17
Views: 11,790
Those are magnification ratios.
https://photographylife.com/what-is-magnification

An excerpt from the linked website:

Magnification, also known as reproduction ratio, is a property of a camera lens which describes how closely you’ve focused. Specifically, magnification is the ratio between an object’s size when projected on a camera sensor versus its size in the real world. Magnification is usually written as a ratio, such as 1:2, which is said aloud as “one to two magnification.”
Forum: Pentax SLR Lens Discussion 11-15-2021, 11:33 PM  
Pentax-M 135mm f/3.5 Lens Dissasembly
Posted By .a.t.
Replies: 7
Views: 684
You're welcome. And I wish you success in expunging the fungi, Aoresteen! :D
Forum: Pentax SLR Lens Discussion 11-15-2021, 06:26 PM  
Pentax-M 135mm f/3.5 Lens Dissasembly
Posted By .a.t.
Replies: 7
Views: 684
This is a quick guide intended primarily for accessing the elements. I didn't do a total disassembly.

Starting at the rear, the rear elements group can be removed with a spanner without removing the mount. But I went a little further just to see how the lens is built.

If you want to go deeper, first remove five screws from the mount. The mount and aperture ring will come off.
Be aware of the aperture ring click stop ball bearing. It's located in an opening in the barrel aligned with the red diamond infinity mark. My bearing didn't have a spring underneath, so it stayed put when I took the aperture ring off. But I took it out for safe keeping.

Attachment 555635




Next, remove three screws from the sub mount / depth of field scale piece (green circle in the first photo).
The sub mount can come off. The inner, plastic, iris stop down ring might also lift off with the sub mount. My stop down ring stayed put and I wiggled the sub mount off over the stop down ring. Either way - the stop down ring is easy to remove and replace.
And that's as far as I went at the rear.

To access the front elements, apply gentle heat to the rubber focus grip - with a hair dryer, for example. Lift off the grip with a pry tool of some sort. I used a small, flat blade screwdriver.
With the rubber grip off, turn the focus ring to infinity and extend the lens hood forward. Now, through holes in the focus barrel, you'll have access to three screws securing the lens hood and beauty ring.

Attachment 555631




With the lens hood and beauty ring removed, using a rubber glove for grip, the front element groups unscrewed. I also removed the rear elements group and it's on the right in the photo.
Regarding the iris, I ignored it, so I can't give any steps for removing it.

Attachment 555632




I didn't need to access the focus helicoids, but if you want to, it appears that the small, focus stopper screw will need to come out. Then the focus ring should turn until the helicoids separate.

Attachment 555634
Forum: Troubleshooting and Beginner Help 11-14-2021, 09:09 PM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
Thanks, Robot. That sounds like a clever method. If I had a proper brass piece to spare, I'd give it a try.
Forum: Troubleshooting and Beginner Help 11-14-2021, 09:49 AM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
More knowledge! Thank you, Don.
Forum: Troubleshooting and Beginner Help 11-13-2021, 06:46 PM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
Yes, I've been looking at those thread files again and I'm having trouble visualizing how they'd work on internal threads.
I might just go ahead and try the tool I linked to in my previous post instead.




Thanks for the tip. I've used Birchwood Casey Aluminum Black for touch ups and it works, too:
Aluminum?Black Metal Finish, 3 fl. oz. Bottle - Birchwood Casey
Forum: Troubleshooting and Beginner Help 11-13-2021, 05:45 PM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
Thanks to all for your replies and suggestions. I think you've helped point me in the right direction.


Yes, the damage is limited to what's in the photo. And for that basket case lens, I'd be willing to try your suggestion as an experiment. But I have another lens with the same problem with which I'd like to be more gentle.


If I had a pair, I'd give it a try. But I think a dedicated tool would probably be more effective.


@crazy4oldcars & @MikeMcE : I'm going to buy a file as you suggested.


Also, this tool looks to be a possibility:
McMaster-Carr
It appears they don't have a metric .75 pitch die, but I believe the 24 TPI die would be equivalent.
Forum: Troubleshooting and Beginner Help 11-13-2021, 12:12 PM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
Thanks for the quick reply, marcus!

Yes, I tried a small screwdriver blade before I took the above photo. So I may have already improved the threads a bit. As they are now, I can force a lens hood on, but it's not easy.
I was hoping to clean them up as well as make them functional again.

If no one knows of a simple tool - say costing no more than $50 - I'll try the screwdriver blade again.
One problem with that method is I don't have a good enough magnifying tool to really see what I'm doing.
Someday I'll probably start a thread about that topic, too...
Forum: Troubleshooting and Beginner Help 11-13-2021, 11:55 AM  
Restoring lens accessory threads?
Posted By .a.t.
Replies: 17
Views: 753
Is there a tool to repair mangled lens accessory threads? I'm not asking about dent repairs. I know there are vises and DIY methods for fixing dents.

Rather, I'm wondering about threads such as these:

Attachment 555392


I've been searching for thread "repair" and "restore" tools, but there are many varieties and I'm just not sure what I'm actually looking for.

Any guidance?
Forum: Troubleshooting and Beginner Help 11-11-2021, 12:12 PM  
Counting element reflections?
Posted By .a.t.
Replies: 5
Views: 497
Thanks for the tip, CarbonR.
Forum: Troubleshooting and Beginner Help 11-04-2021, 07:07 PM  
Counting element reflections?
Posted By .a.t.
Replies: 5
Views: 497
Aha! Thank you for the answer and explanation, photoptimist. One of life's small mysteries has been solved. :)

Now I better get busy on the remaining 999,999.
Forum: Troubleshooting and Beginner Help 11-04-2021, 04:04 PM  
Counting element reflections?
Posted By .a.t.
Replies: 5
Views: 497
This week I've been disassembling and cleaning a Ricoh Auto Rikenon 55mm f/1.4 lens which has a modified Nikon F mount. One source I've seen claims this lens has eight elements, while other sources say it has six.

So far I've counted five elements: three in front of the iris, and two behind it. But I'm unsure about this housing which sits directly behind the iris. I haven't been able to get it apart, but it's wide enough to hold two elements.
Are these the reflections you'd expect to see from two elements? (Lit by a single bulb lamp.)


Attachment 554558

Attachment 554557
Forum: Troubleshooting and Beginner Help 10-30-2021, 03:53 PM  
Canon fit for Takamar lens
Posted By .a.t.
Replies: 15
Views: 718
Sorry to hear that, but not surprising, I suppose.

Regarding better quality adapters, I've used only cheap ones found on ebay. I've heard Novoflex mentioned many times, but I've never used their products. I've read they're known to have high quality and higher prices!

In fact, just looking now I found this:
Adapter combination Pentax 67-lenses to Canon EOS cameras

Nearly €300 ! :eek:
Unless you really love your Takumar, you might want to search for a native Canon or more easily adapted lens.
Forum: Troubleshooting and Beginner Help 10-29-2021, 09:39 AM  
Canon fit for Takamar lens
Posted By .a.t.
Replies: 15
Views: 718
That's the smaller, round piece on the bottom of the adpater which will attach to the tripod head. This way the weight of the lens will be borne by the adapter and tripod instead of the camera mount. So the larger the foot, the more stable your setup will be. Unfortunately, the adapter in the ebay link appears to have a small foot.

... Oh, I think I worry too much! ;) Even if it isn't perfect, the adapter should work and allow you to use your Takumar on your Canon.

This is a picture of my Pentax 6x7 to Pentax K adapter. The larger hole in the foot is for the tripod screw and the two smaller holes hold the two attachment screws I mentioned earlier.



Attachment 553718
Forum: Troubleshooting and Beginner Help 10-29-2021, 01:35 AM  
Canon fit for Takamar lens
Posted By .a.t.
Replies: 15
Views: 718
If it works as advertised, yes, it should do the job.

Just remember that such adapters are made to a price and won't be rock solid in use with a large lens. The tripod foot is probably - I'm just speculating - held in place by a couple small screws.

... Actually, I just went and fetched my own third party Pentax 6x7 to Pentax K adapter. My adapter looks similar to the Canon adapter in the ebay link. And the tripod foot is indeed secured by two small screws - which were loose. It took just a moment to tighten them though.
In fact, I recall now that I had to file off some metal from the bayonet of my 6x7 adapter before it would fit onto my camera...

I'm not trying to discourage you, woldsweather, but I just want you to know these "cheap" adapters typically don't have the highest levels of build quality and precision machining. That said, my 6x7 - and other cheap adapters I own - do work as intended and I'm happy they're available at an affordable price.
Forum: Troubleshooting and Beginner Help 10-29-2021, 12:24 AM  
Canon fit for Takamar lens
Posted By .a.t.
Replies: 15
Views: 718
Ah, you have a 6x7 medium format Takumar? Is this your lens? :
SMC Pentax 67 / S-M-C Takumar / Super Takumar 6x7 300mm F4 Reviews - 67 Telephoto Primes - Pentax Lens Reviews & Lens Database

6x7 (or "67") medium format film Takumars have a bayonet mount entirely different from the M42 screw mount of Takumar lenses made for 135 format film.

I don't know much about 6x7 lenses, but for your 6D Mk2 you wouldn't need that Sony adapter which is included in your Amazon link. For about the same price, here's an adapter specifically for Canon which includes a focus confirmation chip:
amazon.com : Fotodiox Pro Lens Mount Adapter Compatible with Pentax 6x7 (P67, PK67) Mount SLR Lens to Canon EOS (EF, EF-S) Mount D/SLR Camera Body - with Gen10 Focus Confirmation Chip : Electronics?tag=pentaxforums-20&

I've never used a Canon adapter with a focus confirmation chip, so I don't know if it's worth paying extra for it.

---------- Post added 10-29-21 at 12:36 AM ----------

Edit:
Unless you shoot exclusively hand held, woldsweather, I'd look for an adapter which includes a tripod mount. A 6x7 300mm is too long and heavy to hang from your Canon's mount without some support.
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