Hello Stefan,
I think I may be able to help clarify what exactly you’re planning to offer, but I still have some questions about it. Perhaps a list of statements and questions will help. You can let us know which are correct and which are incorrect.
1) You are offering to perform a modification to people’s 14-24 lenses, where you remove the petal hood part and replace it with a hoodless cylindrical part custom made by Nikon (identical paint, for example), in order to accommodate shifting without vignetting. (as shown in your pictures) But you mention both service and modification. Service?
2) As flare situations might be aggravated (evidently this is an issue with the 17 TS-E, not sure how much or in what ways exactly), it would be good to have some basic advice on this issue and how it works, because new flare for non-shift usage or future repurposing may cause a lens owner to want to go back to having the hood. I assume that the front element needs to be removed to replace the outer portion of the lens barrel. I see from the picture that the retaining ring for the front element is screwed into the outer body/ring of the lens barrel so that must be the issue. Partial disassembly. The rear surface of the front element of this lens, the one with the most radical curvature, required the nano-crystal coating, a fantastically effective but also fantastically fragile surface, so that surface would be exposed during the modification. (As an aside, this coating, which can and is only used on a few critical air-glass surfaces such as this one, where light entering the element at an extremely high angle of incidence must be able to get through, is fantastically effective, essentially resulting in flat pieces of glass being invisible. The coating is anything but smooth on a microscopic scale.) The front element might then also require a critical optical re-centering.
3) It sounds as though you are designing a special version of Markus’ EOS to NEX/FE T/S adapter which uses interchangeable camera mounts made by Novoflex, so that the entire setup can be used with an a7R or other A7 family/FE mount camera, or any of the other smaller formats you mentioned (taking into consideration the improvements in sensor performance which are tending to make smaller sensors viable for fine work).
4) You have the Novoflex Nikkor G to EOS 2.5 mm thick adapter between the Nikkor G lens (14-24 in this example) and the Mirex EOS to NEX/FE (etc.) adapter, which includes the movable lever to set the aperture. This lever moves a total of only about 7 mm but nevertheless allows good control over aperture, even in a fairly quantitative way, if you count f/stops using the camera’s light meter readouts. The lever impinges on a movable piece on the back of the lens. It’s fortunate that the Nikkor G lenses are unlike the EOS lenses in this respect, the EOS being all-electronic.
5) Your special version of the new Mirex (original version only started shipping a few months ago, and which like a number of the Mirex adapters is not shown on their site) would also be intended for use with a new collar-type mounting foot of your design, much sturdier than the Novoflex ASTAT collared foot, which isn’t very sturdy, indeed, as reported by others and as I can tell by looking at pictures of it. And that would mean that the outer frame, the front piece of the Mirex would loose it’s foot-mounting feature (protrusion) and become entirely cylindrical, to accommodate your rotatable collar. There could also be a modification to keep the collar aligned well the Mirex, such as a groove or a ridge.
6) This collar would rotate freely so as to allow the Mirex shift movements (which move up to 15 mm from the axis in one line only (left and right or up and down, etc.) in 1 mm steps, not restricted to one direction from the axis, like the Schneider T/S lenses for example)
7) One hopes the collar would help to achieve precisely zero and 90 degree positions so as to have the sensor be straight relative to the top of the tripod head. You could use engraved and painted alignment marks or a more positive (detent) approach.
8) The point of the rotatable collar is to avoid the need to use an L-plate with the Mirex foot, to switch to Rise/Fall from Shift/Shift. Currently one can use the Acratech Universal L-plate or one of the Hejnar universal plates (made from your choice of lengths of each side of the L), or even the Arca-Swiss universal-style adjustable L-bracket. But having a good rotating collar is most convenient and stiff. And then there’s the worst way, just turning the tripod head 90 degrees.
9) Have you found any other lenses by Nikon or another vendor (the Nikkor T/S lenses can’t work, and as you explained, the Canon TS-E’s can only work wide open or if stopped down using a Canon body) which have usable image circles large enough to do shifting on the Mirex EOS to NEX/FE T/S adapter? Any shifting at all with good quality to the corners? For some things, e.g. a vertical sensor with tilt, a shift of just 2 or 3 mm each way, left and right, would give you 28 x 36 or a bit wider, instead of 24 x 36 capture (from two frames), which makes a much nicer vertical 4 x 5 equivalent than a cropped 24 x 36, with about 42 MP instead of 30.
So little is known about usable image circles of 35mm format lenses, other than the T/S lenses, because no one has had the means to examine them until you built your Hartblei Cam and until Markus built the new Mirex adapters to go from EOS (as the universal donor of lens mounts) to the new Sony full-frame format. So this will be an interesting area of discovery, and indeed, the MTF data for the 14-24 from Nikon, wide open are very encouraging at the wide end and the long end both, so we hope that the outer region of the lens at the various focal lengths holds up well enough to be satisfactory too, at least at the smaller apertures when shifted as far as you are saying. More comments on this critical issue (acknowledging lens to lens variation as a likely significant issue) would be welcome, of course, along with corner image samples. I know it’s a lot of work to try to explain that in a clear way, but the entire premise depends on that performance being acceptable (whatever that may be for a given photographer and a given picture).
10) I am quite baffled by the 1.4X tele-extender. You’ve got an older, manual aperture Mamiya 35mm, is it? on a Mamiya 645 to EOS T/S Mirex (no foot is possible on this adapter, insufficient space), itself attached to a “1.4x EX” extender, presumably a Mamiya tele-extender?, itself connected to the EOS to NEX Mirex T/S adapter. This strikes me as a combination very likely to have any of many issues, from this particular lens not being great (I’m not sure — my Mamiya 35 AF is quite good but the older 45 Man. Focus Mamiya lenses were not usable though the newer 45 AF lenses are), to the extender not being great even if it were connected normally to the back of the lens (I don’t imagine a Mamiya 1.4X would have been intended for that lens in any case), etc. Perhaps small apertures and close-in work would look fine though, flare issues possibly excepted.
By the way, there are a couple of surfaces on the inside of my Mirex P645 to EOS T/S adapter which I believe are the sources of potential significant flare. Not the obvious ones which face the lens when a shift is applied, rather surfaces which are oriented as a throat would be, like the walls of a square tube. Surfaces which are of inconsistent width, but only about ¼” wide at the widest. I am considering adding ProtoStar black furry flocking material to them in a very delicate operation. Many subjects work fine for a vertical sensor triple-shift capture with my Mirex as it is now, but some might encounter this flare and have un-retouchable (un-repairable) results owing to subject matter and nearby light sources.
So then, despite the positioning of the tele-extender roughly 20mm behind the rear of the Mamiya lens instead of right against it, you can still focus at infinity with this double-Mirex setup? And is the extender the only way to make a double Mirex setup work fairly well, what with light path vignetting issues and flare issues? This is surely one of those things that simply must be tried to find out how it works. Too complicated to predict!
11) You mentioned a large area net capture, all from shift stitching, done with the 14-24: “Even shifted and stitched at 14mm you will get about 34x46mm”. Did you mean 34 x 36mm? 34 x 46 is impossible with an all-shifting approach. Besides, it wouldn’t cover if it were (if the limit is 5 mm in any given direction). The Mirex cannot position the center of the sensor both up and to the left, or up and to the right of the optical axis (nor down and left or down and right). It can only go to the left or right, or rotated, it can go up or down, but never both at the same time, unless you were using two Mirex’s stacked atop one other, and were using then a medium-format lens, not a Nikkor or other 35mm format lens. So I can picture a cross-shaped stitched image, where shifts were done left-right, then the setup rotated and rise/fall captures also done, but not a rectangular stitched image resulting from shifting movements in two axes at once.
So, if I understand you correctly, what you are offering is an improved Mirex solution (switchable camera-side adapters and a sturdy, rotatable collar for mounting to the tripod without parallax and the ease-of-use benefits of foot mounting (tilt does not shift the composition much at all, weight balance is improved) with rotatable Mirex with the ability to more easily switch from shift/shift plus tilt, to rise/fall plus swing, easier than with an L-plate and stiffer too. Plus the Nikkor modification which enables a very flexible, good way to get superwide results with those movements, given the happy accident of big coverage.
Right?
12) Oh! One more thing: You mentioned a change to the way the Mirex locks. I must presume you were referring to the tilt, because the shift already locks at 1 mm increments (sawtooth mechanism). I didn’t mention the other great benefit of using a tripod foot with the Mirex, which is that it removes nearly all force from the weight of the lens or camera on the tilt locking mechanism, thus making medium to large lenses usable on a Mirex. This is because the axis of rotation of the Mirex tilt runs right through the middle of the camera, very close to the sensor, and thus also close to the center of gravity of the camera. Still, moving the camera left and right for a shift stitch requires that one lock the tilt, lest one’s hands disturb the tilt angle. A more positive tilt lock would be an improvement, but the increments of tilt must remain extremely fine. I can manage about a quarter degree of tilt increment, if that, I forget, but the infinitely adjustable feature of the tilt would need either a gear drive (probably impossible to squeeze in) or tilt angle steps which would need to be so fine if they were some kind of detent as to be impossible, I would have thought.
Thanks very much Stefan. I look forward to seeing what you and Markus come up with for the new collared foot. This does all sound like a promising combination, given the changes I <think> I understand you to be working on.
Best,
Joseph Holmes
