cock and fire leaf shutter lens off camera?

[ghost1001]

Hi,

Can one cock and fire a medium format leaf shutter lens off-camera?

I would like to build a medium format camera and the lens would need to work this way.

If only some will please give me examples. I would be looking specifically at 6x7 lenses.

Thanks

 

[Steve Smith]

My Mamiya RB and Bronica ETRS lenses have pins in the back which have to be turned/pushed to cock and fire the shutters.

So yes, it can be done, but needs a bit of ingenuity to get it to work from the outside.

You could use a lens off of an old 6x9 format folding camera as these have the cocking levers and shutter release on the outside. As do the taking lenses of a Mamiya C series TLR. These are for 6x6 but would probably cover 6x7 o.k.


Steve.

 

[keithwms]

Erie Patsellis ripped the front of an old RB and sold it to me. Now I can mount, cock and fire RB lenses on anything.

Erie is a swell guy.

One day I will find that old lens that I owe him in return.

 

[panastasia]

What about view camera lenses? Some are designed specifically to cover MF film sizes.

Welcome to APUG!

Paul

 

[keithwms]

Paul, I don't mean to gush too effusively about the RB lenses, but... several are a good bit sharper than most affordable LF lenses and will also cover far beyond 6x7.

The flip side: they are very heavy, so one needs a serious rig to support them. I am using them only on metal-body view cameras like my cambo and my rittreck. They will crash a wooden field camera to bits!

 

[Steve Smith]

Erie Patsellis ripped the front of an old RB and sold it to me. Now I can mount, cock and fire RB lenses on anything.

That's an interesting idea. What is the coverage of these lenses?

I can see it being useful if you are exploiting extended coverage but there's not much point in pulling a medium format camera apart to make a medium format camera!

That reminds me of a story my father used to tell about someone who was marooned on a deserted island who found a wooden boat so he smashed it up to make a raft.


Steve.

 

[Nick Zentena]

You could always use a LF lens instead.

 

[ghost1001]

I thought of LF lens...but they are expensive (cost is the main factor for building).

The rb67 lenses are cheap used and the quality is what i am looking for.

I want to build a "compact" 6x9 camera and use the wide 67 lenses...judging form above it will work.

I can build it well, so it will handle the weight of the lens, I quess I need a front of an rb67 to start.

Thanks for all your help.

kevin

 

[keithwms]

Steve, the lens formulas are complicated so I can't think of an easy answer for how to estimate the coverage; I just go at it empirically, looking at ground glass.

Most RB lenses cover 8 or 9 cm at infinity for sure. On closer focus you can cover out to 4x5, no sweat.

Obviously there are some in the lineup that are not appropriate for this. But one nutty thing I have done is shoot full circles on 5x7 with the rb fisheye. No results I truly love yet, but when I get something nice I will post it. One of my recent shots in my apug gallery is on pola 665 with fisheye and you can sort of see the edge of the circle, almost. That was at close focus.

I honestly wouldn't be surprised if the rb 210 apo exceeds any LF 210s over ~8cm of circle.

Anyway Erie is the authority on this, I hope he will chime in.

 

[ghost1001]

Keith,

Just saw above....disregard below.

Do you know what RB67 lenses will work on 6x9...or you have a link or document with image circle sizes, I searched but could not find one?


Thanks

 

[keithwms]

Tell me what you have or want and I will compare with what I have and check on ground glass for you.

Slight correction/clarification of my previous post: I just had another look at that shot on 665 and in fact you cannot see the image circle:

(there was a url link here which no longer exists)

So I think even the wide-open fish covers 8x8 for sure; albeit, again, this shot was at close (~10 ft) focus.

 

[keithwms]

Oh I guess it might be best if I tell you what I have. Let's see, I have the 37 fish, the 65 (don't care for the 50), the 127 KL (love it), the 150 SF (love it), the 180 KL (love it), the 210 apo is out on loan, and the 360. I think that's it. It's possible that Erie's ripped-off mount will not accept the wider throat new KLs, I'll have to look.

N.b. that Chinese company shelro used to sell a nice mount for the rb lenses....

 

[Nick Zentena]

Mamiya used to publish coverage for it's lenses. It was so you could use them on the 6x8 back.

The sort of LF that only cover 6x9 aren't expensive. They'll also be much smaller then RB lenses.

 

[panastasia]

Paul, I don't mean to gush too effusively about the RB lenses, but... several are a good bit sharper than most affordable LF lenses and will also cover far beyond 6x7.

QUOTE]

Yes Keith,
The RB lenses are extremely sharp compared to my LF lenses, I'm quite aware of that - I own 7 of the SD/KL series and a couple of the C series. I was thinking about weight and simplicity. I'm not aware of their coverage beyond 6x7, though.

Paul

 

[ghost1001]

Hi Keith,

The 65 and the 127 would be the most likely ones. If you could check those it will be much appreciated.

Thanks

 

[epatsellis]

At infinity, the following lenses (from my experience) don't cover 4x5: 50, 65, 90 (sorta, but pretty mushy and slight vignetting) all the rest have monstrous circles, the 150 SF was one of my favorites of 4x5, and I'm building a Sinar version of the toyo lensboard I had.


erie

 

[panastasia]

At infinity, the following lenses (from my experience) don't cover 4x5: 50, 65, 90 (sorta, but pretty mushy and slight vignetting) all the rest have monstrous circles, the 150 SF was one of my favorites of 4x5, and I'm building a Sinar version of the toyo lensboard I had.


erie

erie,

I think it was you that showed a picture of one those interesting cameras you build on this forum. You told me it weighed about eight pounds - you obviously know what your doing. How about 5x7?

Paul

 

[epatsellis]

Paul,
Got you fooled too, huh???

5x7 is easily doable, might even have a set of bellows lying around that would work.


erie

 

[ghost1001]

Hi Erie,

How do you cock and fire these lenses when using them off the br67 body?

 

[ghost1001]

OH WAIT...I just found it on your site...great info, Thanks.

Kevin

 

[panastasia]

Paul,
Got you fooled too, huh???

5x7 is easily doable, might even have a set of bellows lying around that would work.


erie

I have a cousin who is the Director of Product Development in a small company that services the automotive industry. He has about 20 patents under his name. I was talking with him about designing a small view type camera a few months ago, but I became more interested in the 5x7 format.
I told him about your camera so he would be aware of what some other talented people were doing.

I'm also a mechanical designer.

Paul