Image circle of a Pentax 67 lens (105mm 2.4)?

[joshdaskew]

Hi, I realise that this is not a large format lens as such but I am planning on attaching it to a large format camera and using it with a roll film back for portraits. Am looking to try and find the data for the image circle of the Pentax 67 105mm 2.4 and see if it is possible to do small movements on the 5 x 4? Would mainly be small amounts of swing or tilt... Anyone have any ideas or thoughts on this? It would be greatly appreciated! Ok, thanks so much. Best Regards Josh

[ic-racer]

I suspect it would only be usable with small movements on 6x6cm format. In my experience, lenses like this are designed to limit the image circle to help minimize internal reflections in the camera etc and if I were to guess at the image circle I'd say 90mm.

In fact, my Horseman 105/4.5 SUPER 6x9cm view camera lens allows massive movements on 6x9cm format but still just clips the corners of 4x5in (IC=160mm) and does not allow any movement with 4x5.

105mm lenses that cover 4x5 are rare (why??). That is too bad because I love 210mm on 8x10 and there are many 210mm lenses for 8x10.

Also, a 105mm on 4x5 is going to be a quite wide lens for portraits, unless they are 'environmental portraits' or something.

[Brian Ellis]

Since the lens isn't designed to move when it's on the 6x7 camera for which it's designed, it's presumably just wide enough to cover the four corners of a 6x7 negative, plus maybe a little to spare. So if you measure the diagonal of a 6x7 negative (sorry but I'm too lazy to do it) I would think you'd pretty much have the useful image circle.

[joshdaskew]

Thanks so much, pretty much as I expected I guess. Maybe i am better off with a lens that is designed for the 6 x 9 format but is still relatively fast. I know that there is a Xenotar 100/105 2.8 that covers this format. Anyone have any other suggestions? Ok, thanks once again, much appreciated! Best Regards Josh

[Drew Wiley]

The person who would know is Francis Sakamoto. He's jerry-rigged Pentax 6X7 gear
more than anyone else I can think of, and probably still has a personal website. I think
he now uses a big Toyo 8x10 with a Nikon on the back for ultra-telephoto work. But
these medium format lenses are designed quite a bit different from view lenses, without
movements in mind. Otherwise, it is a very sharp fast lens.

[Drew Wiley]

The other thing which comes to mind, is that there probably isn't going to be room to fit a shutter behind this thing anyway. I believe the leaf-shutter version of the lens
was actually 90mm.

[joshdaskew]

Thanks so much once again for all the responses! It is very helpful! I will contact Francis and see if he can help. In terms of the shutter, I was planning to throw it into one of the new Shen Hao XPOs that are available to use with the Sinar Shutter.... I dont know so much about it but I dont see why it wouldnt work.. The only problem is getting sharpness with roll film at a wide open aperture. My tests so far have been less than impressive! Have been testing with a 150mm 2.8 Xenotar and have had some sharp images and some not. Actually, it has driven me a little crazy so I hate to think of it when I actually have people in the shot.. Thanks again..

[Paul Ewins]

I held the 105/2.4 in front of my Super Graphic and it looked like it was very close to covering. At portrait distances you might just get away with movements, particularly if you shot against a dark background. I tried the 90/2.8 and 150/2.8 and the edges of the image circle were a lot more obvious so I don't think they will work.

[joshdaskew]

Hi Paul, Thanks for the response.. When you say that the 105mm 2.4 was close to covering, what are you referring to? A full 5 x 4 frame? Or a much smaller format (like 3 and a quarter )? Thanks.

[erie patsellis]

You may want to look at RB lenses, fairly simple to adapt, inexpensive and fairly large image circles. The 90 illuminates 4x5 with room to spare.

[Mark Sawyer]

If you're using a roll film back, I'm guessing you're not shooting 4x5 format, just using a 4x5 with a smaller format. If it's 6x6 or 6x7, you're covered, 6x9 might be okay, especially at portrait distances.

The big issue might be getting a short enough bellows extension, especially if you're using movements. Some of those MF lenses are actually telephotos, (focusing at less than the indicated focal length). I'd check the back focus and see whether it's workable on your 4x5.

[erie patsellis]

The P67 flange to focal plane distance is 85.95mm, the RB is 112mm (from http://en.wikipedia.org/wiki/List_of_lens_mounts). Depending on your camera, regular non bag bellows likely is all you'll need.

For RB lenses, my standard bellows worked fine on my Toyo and work fine presently on the Sinar.

[Paul Ewins]

Hi Paul, Thanks for the response.. When you say that the 105mm 2.4 was close to covering, what are you referring to? A full 5 x 4 frame? Or a much smaller format (like 3 and a quarter )? Thanks.

It was close to covering 4x5 although the cut off is abrupt. I'm not sure how wild you want to go with your movements but if you are only shooting 6x7 or 6x9 then you should have plenty of room to move.

[joshdaskew]

Cool, thanks so much! Movements wouldnt be too extreme, maybe just enough to get someones eyes sharp on a close up portrait, when shooting them at an angle. Something like that anyway. Is it going to be a big issue to mount a lens like this on a Sinar style board? Is it something I can do myself or would I need to send it to a Machinist like S.K Grimes? Ok, thanks so much again! Best Regards Josh

[Paul Ewins]

If you don't mind a permanent solution then you could unscrew the mount from the rear of the lens and use that as a template to locate screw holes in the sinar board and to work out how large a hole to cut in the board. You would probably need to buy longer screws to replace the mount screws and need to be fairly precise drilling the new holes but that would be the simplest/cheapest path.

Next best would be to buy a short extension tube and follow the same procedure to mount it to the board, allowing you to try any P67 lens you want without damage. If you could get a donor 6x7 body then you could use the lens mount from that which would be easier to attach but would require more stuffing around to get the dismount button to work.

I might just try this myself sometime (but not soon) as I am interested to know what the 35 fisheye would look like on 4x5.

[Mark Sawyer]

Personally, I'd butcher a rear lens cap and epoxy that to a lens board.

[rdenney]

Personally, I'd butcher a rear lens cap and epoxy that to a lens board.

Yup. Epoxy it to the board, then drill the hole. That's a good enough approach for experimentation.

Rick "who has routinely mounted barrel lenses in a body cap and then attached that to the bellows of a Pentacon Six" Denney

[Paul Ewins]

OK, I admit it, I'm prone to over-engineering things. :-)

[engl]

You may want to look at RB lenses, fairly simple to adapt, inexpensive and fairly large image circles. The 90 illuminates 4x5 with room to spare.

Could you elaborate on this? Does it cover the full 4x5 even at infinity? And any approximations (such as rise/fall in landscape orientation at infinity) of how much room there is to spare?

These are occasionally selling for ~50$ which would make them very cheap wide angle lenses. Im thinking they could be put in a press camera and focused using the helicoid.

[Math]

Could you elaborate on this? Does it cover the full 4x5 even at infinity? And any approximations (such as rise/fall in landscape orientation at infinity) of how much room there is to spare?

These are occasionally selling for ~50$ which would make them very cheap wide angle lenses. Im thinking they could be put in a press camera and focused using the helicoid.

Though I've personally never checked when it comes to image circle, I can however inform you that RB67 lenses have no helicoid, and are focussed by the bellows inside the camera.

[engl]

Though I've personally never checked when it comes to image circle, I can however inform you that RB67 lenses have no helicoid, and are focussed by the bellows inside the camera.

Ah I see, thanks. As you might have noticed Im not very familiar with pro MF gear :)

Actually, a nearby store had a RB67 Mamiya 90/3.8 for about 30$, with some scratches (at least that is what the label said, I was not able to find them visually...). I looked at the image circle by looking at the projection of the store lights on the table, it did not look to me like it would cover 4x5, but obviously my test was far from scientific.

I dont know how many Mamiya 90mm lenses there are, but if they are all supposed to be optically identical, I might pick up it and try it out on my Crown.

[erie patsellis]

I stand corrected, and apologize for misleading you. I just checked mine on the Sinar, at infinity the 90 just misses the corners, and the 127 illuminates fully (not necessarily sharply, I haven't used it at infinity). At tabletop type distances, where I've been using the 90 and 127, it works fine (and even more so with the scan back @ 7x10 image area). I've been spending far too much time with this Dicomed scanback, it's getting to the point of getting used to that 7x10 capture area and forgeting that it's far from 4x5.

I originally built this to be able to use the RB stuff for architectural work, and it's use just gravitated to 4x5 over time:
http://i144.photobucket.com/albums/r181/epatsellis/DSCF7015.jpg

I've been spending a great deal of time with still lifes and the 150, if you don't have a Imagon and desire that nice soft look, that my work for you as well and likely a lot less expensive too.

[joshdaskew]

Hi, Sorry it has been a while since I have logged in here and forgot I had posted this.. Thanks to everyone who replied to this thread, it has been very informative...

Erie, thanks for the information on the RB lenses, greatly appreciated! Was hopefully looking for something a little faster but if this is not possible then will investigate those further... Would both of those cover the 6 x 12 format on a roll film back? Also, is the Mamiya RB able to work because it has the shutter in it lens? Any problems with this? I think I asked about using a 110mm 2.8 on the Mamiya RZ but someone told me I couldn't because it had an electronic connection that connected it to the camera (or something like that).

Is there some way (as previously mentioned by Paul Ewins) that I could mount a short RB extension tube to a lensboard, that way enabling a whole bunch of lenses?

And last question, if i was to look at mounting a Pentax 67 lens (that doesn't have a shutter) does anyone have any experience of putting a Packard shutter or something like that in a field camera? Or maybe the Sinar one that I mentioned before in a non - Sinar camera?

ok, thanks so much again.. Much appreciated!!

[Policar]

I have a 110mm f2.8 mamiya and would be very interested to learn if it covers 4x5, even if not at infinity. It's not a fantastically sharp lens in general (although it's not bad, either) but it's very very impressive wide open relative to how bad it should be--so it would be a lot of fun to have such extreme shallow focus. Of course I assume coverage would be worst at f2.8, though.

It might be possible to do time exposures and/or 1/400th of a second mechanically, if I remember correctly. The camera has a special mode for when the battery runs out. It does have an electronic shutter, though, and aperture speeds controlled through the camera. It's also a very small lens by 6x7 standards, which means it's only kind of huge.

[GPS]

I have a 110mm f2.8 mamiya and would be very interested to learn if it covers 4x5, even if not at infinity.

...

Every MF lens can cover a 4x5 format when not used at infinity. The question is only at what magnifying ratio it does. Not difficult to see with a piece of white paper and the lens used for projecting an image (a light bulb etc.) at a "macro" distance.

[Policar]

I knew that...gah. Still so new to this.

Anyhow, it looks like the distance is either further than my bellows extends or at least so far toward macro that I couldn't shoot anything meaningful with it. Oh well.

[joshdaskew]

Hi, Thanks again for the responses! I have recently been able to borrow a friends 90mm RB lens and been able to hold it in front of my Chamonix and as previously noted, just misses out on covering 5 x 4. Am I able to trip the shutter on this lens with it being mounted on another camera? Do I need a special cable release?

To erie patsellis, how did you mount the lens to a board? Is that an extension tube in the picture, or is it the front of the RB that hyou have attached to the Sinar?

Ok, thanks so much for you help once again. Cheers Josh

[venchka]

The 105mm Tominon lens in a Copal shutter from a Polaroid copy camera covers 4x5 on my Speed Graphic.

[erie patsellis]

It is the front of an RB, with a handle attached to the cocking lever to enable shutter cocking and pre releast (to allow the use of the Mirror Up release on the lens)

[Paul Ewins]

I finally got round to building an adapter (6x7->Speed Graphic) and did a quick run through of the 6x7 lenses. Most had an IC of around 5". The 105/2.4, 75/2.8 and 120/3.5 were closer to 5.5" (i.e. just clipping the corners) while unsurprisingly the 75/4.5 Shift gave full coverage. More surprisingly the 55-100 zoom covered at 75mm but not at the extremes of the range. The 35 fish-eye gave a circular image of around 3.5".

Note when I say covers I really mean illuminates, since I haven't actually shot any film and have no idea how to calculate resolution. It looks like the 35 would be another candidate for an LF circular fish-eye solution should you need such a thing. If you wanted to shoot 6x9 and already had a SG or Sinar shutter and a P67 system, then maybe they could be useful but not much else springs to mind. On the other hand a set of adapters and a monorail would be a lot cheaper than buying the P67 macro bellows.

[Panopticus]

There is an RB-Graflex-adapter with release mechanisme. i think it had been shown here. and somebody certainly know for which cam.
since triggered manually and not by cable its prone to camerashake collegue told. but he didnt use. i have it but not the right cam.

[Tin Can]

RB to Sinar

https://live.staticflickr.com/65535/50656885356_5e520fc936_c.jpg (https://flic.kr/p/2kbnMa7)IMG_0062 (https://flic.kr/p/2kbnMa7) by TIN CAN COLLEGE (https://www.flickr.com/photos/tincancollege/), on Flickr