[TwoUptons]

I have a couple of large format lenses that I use with 4x5 inch film, but I’d like to use them on my digital bodies.

I’d like to adapt them to K-mount and mount them using either my bellows or helicoid extension tube (depending on focal length).

Does anyone know of some kind of adapter from a Copal shutter to K-mount? I think most of my lenses are Copal 0 or Copal 1…

I have a 3D printer heading my way now, so I can print one (if it’s not too big), or if there is one available for sale, that’s an option, too.

I’m not terribly excited about mounting the digital camera to the back of the film camera, though, as I don’t think my Graflexes can bring the lens board back far enough if I’m using a Pentax SLR on the back (I’m not trying super long lenses)

-Eric

[stevebrot]

I have a couple of large format lenses that I use with 4x5 inch film, but I’d like to use them on my digital bodies.

If focal length is greater than 45.6mm + adapter minimum depth, it should be no problem. If it were me, I would adapt to the lens board you usually use and use some sort of slider for focus, perhaps by adapting directly to a K-mount bellows.


Steve

[bobbotron]

You could get one of these, use the movements of a large format body!

Pentax K Mount (PK) D/SLR SLR Lens to Large Format 4x5 View Cameras ? Fotodiox, Inc. USA

[Bob 256]

You're going to need some means to focus the lens since that's not built-in as it is with K-mount lenses. Using a large format lens directly on a digital body wouldn't allow for focusing other than one fixed focus unless a means to focus is included in the adapter and because of the longer back focus of a large format lens, the lens would need to be further from the camera than a normal K-mount lens, so the above recommendations are best.

3D printed adapters leave something to be desired in terms of strength and long-term wear. Also, they can shed small particles which you don't want in your digital camera sensor box.

[TwoUptons]

You could get one of these, use the movements of a large format body!

Pentax K Mount (PK) D/SLR SLR Lens to Large Format 4x5 View Cameras ? Fotodiox, Inc. USA

I’ve thought of that, but between the Pentax registration distance and the thickness of the cameras, I don’t have lenses long enough…
I’m looking to fit a 90mm, 105mm, and a 147mm, which are all pretty short lenses, which would make that hard to work, but they’re also pretty small…

I think the Graflex lens boards are a bit under 4 inches, and that’s pretty large to taper down to 45-ish mm without losing a lot of space
I could almost mount them in a K body cap, which would go right on the front of the bellows, but all of mine are thick plastic and uneven… or the thin ones that clip over the mount instead of in it.

-Eric

[Wheatfield]

I’ve thought of that, but between the Pentax registration distance and the thickness of the cameras, I don’t have lenses long enough…
I’m looking to fit a 90mm, 105mm, and a 147mm, which are all pretty short lenses, which would make that hard to work, but they’re also pretty small…

I think the Graflex lens boards are a bit under 4 inches, and that’s pretty large to taper down to 45-ish mm without losing a lot of space
I could almost mount them in a K body cap, which would go right on the front of the bellows, but all of mine are thick plastic and uneven… or the thin ones that clip over the mount instead of in it.

-Eric

I took a thin piece of plywood and a mount off the back of a lens and made a camera mount for my view camera.

My field camera is too small for recessed lens boards, but a few years back I was given a monorail camera, I forget the brand. I think it would get short enough for my 150.
Losing 45mm of bellows draw to the DSLR is a pain, but it's unavoidable.

[Digitalis]

If focal length is greater than 45.6mm

Considering that 65mm on a 4X5 is roughly the Fov equivalent of a 21mm lens on FF It is safe to say that most 4X5 lenses can be used on a DSLR. Though obtaining infinity focus might be difficult.

[bobbotron]

I haven't done this, so perhaps I'm not thinking of it correctly, but I think with a 90mm or 120mm lens you should have lots of room to focus on a view camera. Hrm!

[stevebrot]

Considering that 65mm on a 4X5 is roughly the Fov equivalent of a 21mm lens on FF It is safe to say that most 4X5 lenses can be used on a DSLR. Though obtaining infinity focus might be difficult.

Yes, infinity focus would be very difficult given the 45.6mm minimum for the mirror box and 44mm throat diameter.

45.6mm (flange distance) + 65mm focal length for infinity focus will only work if rear extension of the lens is less than ~19mm.


Steve

[stevebrot]

I haven't done this, so perhaps I'm not thinking of it correctly, but I think with a 90mm or 120mm lens you should have lots of room to focus on a view camera. Hrm!

They do, if the sensor is at the nominal film plane rather than 45.6mm further away. Add that extra extension with a 90mm and we are in 1:2 near macro territory. Move the dSLR 45.6mm deeper into the view camera body and even the rear of a 90mm gets pretty close the adapter opening.

The Fotodiox solution is not a bad one, they just don't explain that you need other than a wideish lens. Using the demonstration video on the linked page as a guide, notice the view camera bellows extension (31s mark) before they refocus with the adapter in place. That is the focal length of the lens being used. I estimate about 150mm.


Steve

[Digitalis]

That is the focal length of the lens being used. I estimate about 150mm.

150mm lenses are common in the 4X5 world, I'd like to seem them try it with something more exotic like the 65mm Goerz hypergon...

---------- Post added 2021-08-11 at 04:15 PM ----------

45.6mm (flange distance) + 65mm focal length for infinity focus will only work if rear extension of the lens is less than ~19mm.

The widest 4X5 lens have on hand is the Rodenstock 55mm APO-Grandagon-N which gives me only 7.5mm of wiggle room for movements in any direction, oh and I have to use a special recessed wide angle module on my cameras with that lens. What would be really fun is try to get one of the Nikkor convertible 600/800/1200mm teles and use it for wildlife, though with about 400mm of bellows draw the Nikkor 600mm f/9 would look rather bizarre on a DSLR.

[TwoUptons]

Both my 4x5 cameras are made by Graflex, and both of them include focal plane shutters, which take up space, making the Fotodiox solution harder.
That's why I want to try it without the camera body, using either my Bellows K or the off-brand focusing extension tube I have in drawer somewhere - either should allow infinity focus if I get the length right.

I wish I had a wider lens for the 4x5. I still may pick up a 75mm at some point (the 75mm Kodak enlarging lens I have is, frankly, not very good, nor does it fully cover 4x5).
I think that's the shortest I can easily use to infinity on the Speed Graphic...
But for now, the 90mm will have to do (originally intended for a Wanderlust)

-Eric

[One3rdEV]

What about the resolving capability of the large format lenses?

For many many years I have had an uninformed impression that large format (e.g. 4x5") lenses don't perform well on imaging medium smaller than about 6x9 cm. Although this was an impression originating back in the film days. For example; I have an old Sinar brochure 'Info 32' from 1988 that shows for a multicoated Sinaron S 210mm lens an MTF graph measured between 80-88% (f11-32) in the angle of field area of 54 degrees at 5 line pairs per millimeter.

[bobbotron]

What about the resolving capability of the large format lenses?

For many many years I have had an uninformed impression that large format (e.g. 4x5") lenses don't perform well on imaging medium smaller than about 6x9 cm. Although this was an impression originating back in the film days. For example; I have an old Sinar brochure 'Info 32' from 1988 that shows for a multicoated Sinaron S 210mm lens an MTF graph measured between 80-88% (f11-32) in the angle of field area of 54 degrees at 5 line pairs per millimeter.

Only one way to find out. I bet they'd to fine unless you're getting fussy about it.

[stevebrot]

For many many years I have had an uninformed impression that large format (e.g. 4x5") lenses don't perform well on imaging medium smaller than about 6x9 cm.

Similar observations might be made for native 645 or 6x7 lenses.

Several contributors to this thread shoot both 4x5 and 120 film (some of whom with the same camera), yet none has made cautions regarding potential poor quality at the center 22mm of the image circle. It is probably enough to say that if adapting 645 or 6x7 lenses to Pentax K makes sense, so might doing so with large format glass.


Steve