Mamiya RB67 180mm Sekor C rear element?

fmajor · Feb 1, 2011

Hi Gang,

OK, this is about the most NEWB question ever posted here, but.....

Do RB67 180mm Sekor C lenses have rear elements?

I bought my 180mm Sekor C for my RB67 Pro-S some months ago, but haven't been able to do anything w/my RB Kit until recently (put new light seals in).

As i was looking things over, i noticed on my lens that there was no glass in the rear-element area - i could simply touch the apeture blades if i so desired. I'm sorta panicking....

Did i get ripped off?

Thanks

MattKing · Feb 1, 2011

If I read the lens diagram for that lens correctly, the aperture is behind the rear element.

So if I'm correct, your lens is too!

FWIW the blue dot 135mm lens I have for my Mamiya TLRs is the same way.

fmajor · Feb 1, 2011

Thanks MattKing - when you say "behind the rear element" from which direction do you mean? Sorry i'm not understanding you..

Ultimately, is it appropriate for my lens' aperture to exposed as it is - that i can touch it?

jpreston · Feb 2, 2011

My 180mm 4.5 C is just the same as yours, so I would say yes, you should be able to see the aperture blades in between the rear opening of the lens and the first element from the rear of the lens.

MattKing · Feb 2, 2011

fmajor said:
Thanks MattKing - when you say "behind the rear element" from which direction do you mean? Sorry i'm not understanding you..

Ultimately, is it appropriate for my lens' aperture to exposed as it is - that i can touch it?

The aperture is at the very rear of the lens - closest to the film.

All the lens elements are in front of it - farther from the film.

And yes, it is appropriate that the aperture is exposed - just be reasonably careful with it.

Jeff Kubach · Feb 2, 2011

It is a great lens, really like mine!

Jeff

fmajor · Feb 2, 2011

@MattKing/jpreston - thanks so much.

WOW! This is very peculiar to me for something so "delicate" to be so exposed. Just plain weird. Yea, i'll definitely not be handling it as loosely as i'm able with other lenses (more a concern about dust/dirt/etc than pushing my finger through...).

I'm excited to use the lens, but now all the more "concerned" with an even greater need to exercise care w/my gear. I'm usually *very* careful with my stuff, but a delicate, exposed assembly like an aperture takes things up another notch...

brucemuir · Feb 2, 2011

fmajor said:
WOW! This is very peculiar to me for something so "delicate" to be so exposed. Just plain weird. Yea, i'll definitely not be handling it as loosely as i'm able with other lenses (more a concern about dust/dirt/etc than pushing my finger through...).

These are my thoughts exactly.
I need to check my RZ version but if it were the same I think I would've noticed.

Steve Smith · Feb 2, 2011

I have owned a 180mm RB lens for a few years now and hadn't noticed that!

Steve.

fmajor · Feb 2, 2011

I can't imagine a design so delicate as that which is implemented in the 180mm Sekor C to persist into the production years of the RZ Series.

Maybe this particular focal-length lens was specifically intended for studio work/portraits only? That would seem luxuriously work-specific/limiting (from a use-perspective) in a lens model line-up which was not particularly rich with selections (compared to 35mm lens ranges).

I don't understand these things, but am thankful for the Members of this Community who do!!!

CGW · Feb 2, 2011

fmajor said:
@MattKing/jpreston - thanks so much.

WOW! This is very peculiar to me for something so "delicate" to be so exposed. Just plain weird. Yea, i'll definitely not be handling it as loosely as i'm able with other lenses (more a concern about dust/dirt/etc than pushing my finger through...).

I'm excited to use the lens, but now all the more "concerned" with an even greater need to exercise care w/my gear. I'm usually *very* careful with my stuff, but a delicate, exposed assembly like an aperture takes things up another notch...

And that's why God, in his infinite wisdom, created lens caps and saw that they were good--especially for the Mamiya 180...

fmajor · Feb 2, 2011

Steve, i hadn't noticed it either until i was looking to make sure the aperture was in it's "released" state to protect all those internal springs (and delay an inevitable trip to Ron Paul for a tune up!).

I don't mean to spread my OCD tendencies! I should be quarantined!!!

fmajor · Feb 2, 2011

I've got the caps.... it's just the in-between time from capped to mounted that makes it all the more interesting!!!

MattKing · Feb 2, 2011

As noted above, the 135mm lens for my Mamiya TLRs has a similar configuration. I've used mine for decades, including doing wedding work.

It isn't that fragile!

The focal plane shutters on most 35mm SLRs (and many medium format SLRs) are similarly exposed, and they seem to be able to handle the situation.

Mamiya RB67 180mm Sekor C rear element?

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