Home
SearchSearch MemberlistMemberlist RegisterRegister ProfileProfile Log in to check your private messagesLog in to check your private messages Log inLog in

Yashinon 5cm f2 and Pentax crop DSLR mirror hit?
View previous topic :: View next topic  


PostPosted: Sun Apr 14, 2019 1:45 pm    Post subject: Yashinon 5cm f2 and Pentax crop DSLR mirror hit? Reply with quote

Hello,

What do you think, would a Yashinon 5cm f2 (Tomioka) lens be safe to use with a Pentax crop sensor DSLR? I'm wondering if the mirror will hit the rear element or something sticking out. My M42-to-K adapter will allow focusing to infinity.

Photos of the lens in question:
Photo 1
Photo 2


Last edited by meian on Tue Apr 16, 2019 7:38 pm; edited 1 time in total


PostPosted: Sun Apr 14, 2019 2:16 pm    Post subject: Re: Yashinon 5cm f2 and Pentax DSLR mirror hit? Reply with quote

meian wrote:
Hello,

What do you think, would a Yashinon 5cm f2 (Tomioka) lens be safe to use with a Pentax crop sensor DSLR? I'm wondering if the mirror will hit the rear element or something sticking out. My M42-to-K adapter will allow focusing to infinity.


I use Pentax DSLR's, including one body with an Asahi PK-M42 adaptor permanently fitted, and would have no reservation about fitting this lens to my camera. The M42 "standard" was widely adopted in it's day and the Pentax DSLR's retain the same flange-to-sensor distance as the earlier film cameras. Problems may arise with some other manufacturers' cameras that were never designed to be backward compatible to M42, but this is not the case with Pentax.

Enjoy Smile


PostPosted: Sun Apr 14, 2019 2:52 pm    Post subject: Re: Yashinon 5cm f2 and Pentax DSLR mirror hit? Reply with quote

kypfer wrote:
meian wrote:
Hello,
What do you think, would a Yashinon 5cm f2 (Tomioka) lens be safe to use with a Pentax crop sensor DSLR? I'm wondering if the mirror will hit the rear element or something sticking out. My M42-to-K adapter will allow focusing to infinity.


I use Pentax DSLR's, including one body with an Asahi PK-M42 adaptor permanently fitted, and would have no reservation about fitting this lens to my camera. The M42 "standard" was widely adopted in it's day and the Pentax DSLR's retain the same flange-to-sensor distance as the earlier film cameras. Problems may arise with some other manufacturers' cameras that were never designed to be backward compatible to M42, but this is not the case with Pentax.
Enjoy Smile


Hi,

and thank you for your reply!

Yes, Asahi Pentax really did a marvelous thing there and I wouldn't have any doubt when adapting Takumar M42 lenses to K-mount Pentax cameras. But I'm not sure about other manufacturers' lenses.


PostPosted: Sun Apr 14, 2019 2:56 pm    Post subject: Re: Yashinon 5cm f2 and Pentax DSLR mirror hit? Reply with quote

meian wrote:
Hello,

What do you think, would a Yashinon 5cm f2 (Tomioka) lens be safe to use with a Pentax crop sensor DSLR? I'm wondering if the mirror will hit the rear element or something sticking out. My M42-to-K adapter will allow focusing to infinity.


It protrudes back quite a bit, eyeballing it I'd say by more than 1mm compared to Tak 50/1.4. It could be close. But you'll have to try it yourself - the rear element is protected anyway.


PostPosted: Sun Apr 14, 2019 9:06 pm    Post subject: Re: Yashinon 5cm f2 and Pentax DSLR mirror hit? Reply with quote

meian wrote:
Hi,
and thank you for your reply!

Yes, Asahi Pentax really did a marvelous thing there and I wouldn't have any doubt when adapting Takumar M42 lenses to K-mount Pentax cameras. But I'm not sure about other manufacturers' lenses.


The mirror in an APS-C Pentax DSLR is somewhat smaller than that in a Pentax film SLR, it can't possibly interfere. The only current Pentax camera I would have any reservations about would be a full-frame model, even then I'd be very surprised if there were any issues with an M42 lens originally designed for a film camera, the mechanical specifications simply don't allow there to be a problem!


PostPosted: Sun Apr 14, 2019 10:38 pm    Post subject: Re: Yashinon 5cm f2 and Pentax DSLR mirror hit? Reply with quote

meian wrote:
Hello,

What do you think, would a Yashinon 5cm f2 (Tomioka) lens be safe to use with a Pentax crop sensor DSLR? I'm wondering if the mirror will hit the rear element or something sticking out. My M42-to-K adapter will allow focusing to infinity.

Photos of the lens in question:
Photo 1
Photo 2

Unless the lens sticks out significantly toward the film plane from the mount, I wouldn't worry about it. Wide angle lenses are usually the ones to worry about.
From your posted pic, I wouldn't hesitate to mount it.


PostPosted: Wed May 15, 2019 8:48 pm    Post subject: Reply with quote

Confirmed: absolutely no issues with a crop Pentax DSLR. But I have some flange problems with Canon 5D (no surprise there) and even with a focal reducer adapter for my µ4/3 system - that I didn't expect. Will get back to this lens in another thread soon.