Why did Pentax make using M42 leneses so awkward?

newarts · 07-18-2011, 02:55 PM

Originally posted by Laurentiu Cristofor

It may work for some lenses, but it won't work for others.

The notch solution requires a wide base - few of my M42 lenses have that.

In the end, these are hacks due to lack of a proper solution....

You are right of course these are hacks. In my experience Pentax m42's usually (and maybe always) have a wide enough base but many fine m42's do not. EDIT: RioRico checked a bunch of Pentax lenses and many have bases that are too small! https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/151857-why-did...ml#post1583835

I suppose a reasonable solution for the narrow based m42 might be to use a flanged type adapter and adjust the lens' infinity focus. Few of us are willing to try to adjust infinity focus on lenses however.

Bending adapter ears so they engage the mount securely helps a lot with loose lenses.

Last edited by newarts; 07-19-2011 at 06:40 AM.

RioRico · 07-18-2011, 07:32 PM - **1 Like**

Originally posted by newarts

In my experience Pentax m42's usually (and maybe always) have a wide enough base but many fine m42's do not.

I just tested my narrow-base Taks on my ZX-M --
SuperTak 50/1.4 -- MacroTak 50/4(1x): barely
SuperTak 35/3.5 -- SuperTak 55/1.8 and f/2 -- SuperTak 105/2.8 -- S-M-C Tak 135/3.5 -- TeleTak 200/5.6: no

The wider-base Taks are no problem --
S-M-C Tak 135/2.5 -- SuperTak 200/4: yes

But all the Meyers, Ennas, Jupiters: no

newarts · 07-19-2011, 05:53 AM

Originally posted by RioRico

I just tested my narrow-base Taks on my ZX-M --
SuperTak 50/1.4 -- MacroTak 50/4(1x): barely
SuperTak 35/3.5 -- SuperTak 55/1.8 and f/2 -- SuperTak 105/2.8 -- S-M-C Tak 135/3.5 -- TeleTak 200/5.6: no

The wider-base Taks are no problem --
S-M-C Tak 135/2.5 -- SuperTak 200/4: yes

But all the Meyers, Ennas, Jupiters: no

Good to know - thanks!

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07-18-2011, 02:55 PM	#76
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by Laurentiu Cristofor It may work for some lenses, but it won't work for others. The notch solution requires a wide base - few of my M42 lenses have that. In the end, these are hacks due to lack of a proper solution.... You are right of course these are hacks. In my experience Pentax m42's usually (and maybe always) have a wide enough base but many fine m42's do not. EDIT: RioRico checked a bunch of Pentax lenses and many have bases that are too small! https://www.pentaxforums.com/forums/pentax-slr-lens-discussion/151857-why-did...ml#post1583835 I suppose a reasonable solution for the narrow based m42 might be to use a flanged type adapter and adjust the lens' infinity focus. Few of us are willing to try to adjust infinity focus on lenses however. Bending adapter ears so they engage the mount securely helps a lot with loose lenses. Last edited by newarts; 07-19-2011 at 06:40 AM.

07-18-2011, 07:32 PM - 1 Like	#77
RioRico Veteran Member Join Date: Jun 2008 Location: Limbo, California Posts: 11,263	Originally posted by newarts In my experience Pentax m42's usually (and maybe always) have a wide enough base but many fine m42's do not. I just tested my narrow-base Taks on my ZX-M -- SuperTak 50/1.4 -- MacroTak 50/4(1x): barely SuperTak 35/3.5 -- SuperTak 55/1.8 and f/2 -- SuperTak 105/2.8 -- S-M-C Tak 135/3.5 -- TeleTak 200/5.6: no The wider-base Taks are no problem -- S-M-C Tak 135/2.5 -- SuperTak 200/4: yes But all the Meyers, Ennas, Jupiters: no

07-19-2011, 05:53 AM	#78
newarts Inactive Account Join Date: Dec 2008 Location: Ames, Iowa, USA Photos: Albums Posts: 2,965	Originally posted by RioRico I just tested my narrow-base Taks on my ZX-M -- SuperTak 50/1.4 -- MacroTak 50/4(1x): barely SuperTak 35/3.5 -- SuperTak 55/1.8 and f/2 -- SuperTak 105/2.8 -- S-M-C Tak 135/3.5 -- TeleTak 200/5.6: no The wider-base Taks are no problem -- S-M-C Tak 135/2.5 -- SuperTak 200/4: yes But all the Meyers, Ennas, Jupiters: no Good to know - thanks!