Tilted Super Tak 50mm F1.4 lens on DSLR?

stevebrot · 05-27-2014, 09:35 AM

Originally posted by tim60

I could not believe how they could make thread align so well over such a huge amount of production.

Those have been my thoughts as well.

Steve

**c.a.m** · 05-27-2014, 10:05 AM

Originally posted by tim60

I could not believe how they could make thread align so well over such a huge amount of production.

My understanding is that the design of threads on components is guided by mathematically-based principles, well-established equations, and standards, which have existed for a long time. The other major elements in the manufacture of precise threaded components is the production tooling itself, and the quality-control processes.

Takumar lenses, for example, are well known for their mechanical precision, and the OEM Pentax K adapter is also well made. I'm not surprised they mate exceptionally well and consistently. They're 'Pentax' after all!

- Craig

tim60 · 05-27-2014, 01:24 PM

I just did some mental arithmetic. The accuracy of positioning of my worst takumar on my OEM adapter suggest an axial positioning error in the thread start of about 25-30 microns. Worst deviates by about 30*. The metal working machinery must have been pristinely clean to enable tool positioning of that accuracy over so much production. And this is on a dimension that does not affect performance, only aesthetic experience of the user.

vonBaloney · 05-27-2014, 02:19 PM

Originally posted by tim60

I just did some mental arithmetic. The accuracy of positioning of my worst takumar on my OEM adapter suggest an axial positioning error in the thread start of about 25-30 microns. Worst deviates by about 30*. The metal working machinery must have been pristinely clean to enable tool positioning of that accuracy over so much production. And this is on a dimension that does not affect performance, only aesthetic experience of the user.

The old auto aperture pins had to line up with the lever on the body...

stevebrot · 05-27-2014, 06:16 PM

Originally posted by vonBaloney

The old auto aperture pins had to line up with the lever on the body...

The actuator in the body* is a flip-up plate describing about 60 degrees of arc.

Steve

* At least the M42 bodies on my shelf...

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
White Dot on 50mm f1.4 Super-Tak	roboticspro	Troubleshooting and Beginner Help	7	07-20-2018 01:47 PM
white balance on Tak 50mm f1.4	Wired	Pentax SLR Lens Discussion	14	12-12-2013 11:21 AM
Found a Pentax mistake in Super Tak 50mm f1.4	cheekygeek	Pentax SLR Lens Discussion	8	08-14-2013 05:20 AM
For Sale - Sold: Pentax DA 12-24mm f/4, 50mm M f1.4, Tak. 135mm f2.5, Tak. M42 55mm f1.8 (US)	DenverDutchman	Sold Items	2	11-25-2010 10:06 AM

05-27-2014, 09:35 AM	#16
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by tim60 I could not believe how they could make thread align so well over such a huge amount of production. Those have been my thoughts as well. Steve

05-27-2014, 10:05 AM	#17
c.a.m Site Supporter Join Date: Jan 2013 Location: Ottawa, Canada Photos: Gallery \| Albums Posts: 4,189	Originally posted by tim60 I could not believe how they could make thread align so well over such a huge amount of production. My understanding is that the design of threads on components is guided by mathematically-based principles, well-established equations, and standards, which have existed for a long time. The other major elements in the manufacture of precise threaded components is the production tooling itself, and the quality-control processes. Takumar lenses, for example, are well known for their mechanical precision, and the OEM Pentax K adapter is also well made. I'm not surprised they mate exceptionally well and consistently. They're 'Pentax' after all! - Craig

05-27-2014, 01:24 PM	#18
tim60 Pentaxian Join Date: Apr 2011 Photos: Albums Posts: 8,748	I just did some mental arithmetic. The accuracy of positioning of my worst takumar on my OEM adapter suggest an axial positioning error in the thread start of about 25-30 microns. Worst deviates by about 30*. The metal working machinery must have been pristinely clean to enable tool positioning of that accuracy over so much production. And this is on a dimension that does not affect performance, only aesthetic experience of the user.

05-27-2014, 02:19 PM	#19
vonBaloney Pentaxian Join Date: Oct 2011 Location: Albuquerque, NM Posts: 6,029	Originally posted by tim60 I just did some mental arithmetic. The accuracy of positioning of my worst takumar on my OEM adapter suggest an axial positioning error in the thread start of about 25-30 microns. Worst deviates by about 30*. The metal working machinery must have been pristinely clean to enable tool positioning of that accuracy over so much production. And this is on a dimension that does not affect performance, only aesthetic experience of the user. The old auto aperture pins had to line up with the lever on the body...

05-27-2014, 06:16 PM	#20
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007	Originally posted by vonBaloney The old auto aperture pins had to line up with the lever on the body... The actuator in the body* is a flip-up plate describing about 60 degrees of arc. Steve * At least the M42 bodies on my shelf...