Hello,
I'm designing a 3d-printed 4x5 camera based on a 90mm lens. I want to include movements in my design, but I don't really have a number for how many inches/mm if shift or degrees of tilt is useful. Are there any rules of thumb out there for how much tilt/shift is useful for a given focal length? I'd like to have a goal for how much shift or tilt I need for a field type 90mm 4x5 camera for architecture and landscape.
Thanks in advance for replies or research recommendations!
Why don’t you look at several popular cameras of the type you are making and see what they have for specs? They’re all published.
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-Chris
Architectural work is the most demanding, and some rise and swing can be useful as well. Once the mechanism for a movement is included in the design, it seems like a reasonable amount of adjustment would not be that hard to incorporate. I rarely if ever use the full range of a movement, and my camera is not exceptional (Meridian 45B). I think ease of use, stability, and precision are more important than very wide ranges of movements.Originally Posted by Andy_Arizona_01
Thanks for the replies! I'm trying to make a very compact camera that is pared down compared to most field cameras, so I really want to design in 'just enough' movements. I think I can calculate tilt with the Scheimpflug principle, but I haven't been able to find the math for shift effects yet.
For a 90mm Angulon, 90mm Super Angulon or any of the others in between? Big difference. The first doesn’t fully cover 45 and the others cover more then 57.
Over the years, I've accumulated lots of unrealized ideas about how to optimize movements on small, lightweight field cameras. Here are a few:
First, swings should be able to be designed so they are limited only by the bellows, or at least way more generous than needed. Tilts may be more limited, but should be simple to design very generously. Most important is to have enough back tilt and generous tilts on both standards in the forward direction (more later).
Having a lot of swing and tilt is essential if you want to limit rise/fall and shift and still want access to lots of movements because you can use the "point-and-tilt/swing" technique to get extra rise/fall and swing respectively. So, you can design the camera with fairly limited rise/fall and shift and still maintain maximum flexibility by intelligently designing the swings and tilts.
A bit of rise and a bit less fall on the front standard is needed to fine tune images. Shift is also indispensable in my view; I won't buy a camera without shift on one standard at least. There is also a design trick that could optimize both rise/fall and shift and allow you to design less into the actual camera. Design a square lensboard with a mounting hole positioned lower than center of the board, similar to the Technika-style boards, but with the ability to be mounted in any orientation. You could then get more effective rise by simply reversing the board. A bit of shift to either side could be accomplished the same way; by mounting the board at 90° to its usual position. I did this with some modified boards on my Woodman camera and really liked being able to get a lot of rise just by mounting the board upside-down. Of course, you'll have to have enough rise/fall built in to cover the intermediate distances, but that wouldn't be a great amount.
Really helpful would be a couple sets of detents or orienting marks for swings and tilts. One set to show when the standards were parallel with both standards tilted forward quite a bit for use with the "point-and-tilt" method of gaining extra rise. One would tilt both standards to the marks and then point the camera up until the standards were vertical (you are including a small level too, aren't you?), thereby easily gaining extra rise and ensuring that the standards were parallel without a lot of fiddling. A similar set of detents, but at not such an extreme angle would be great for back tilts for both standards in order to get the front of the camera bet out of the field of view when using wide lenses. This movement is almost always coupled with front rise, so maybe could be designed so that the upside-down mounting of the lensboard automatically positioned the lens at the optical center of the film when the back tilts were applied. Then it would be just tilt both standards back to the marks, switch the lens board around and point the camera. EZPZ bed drop.
Detents/orientation marks for "point-and-swing" to get more effective shift would be similar. Again the design should position both standards parallel but swung (right and left) with whatever shift movement you have designed in covering the intermediate distances.
A universal-style bellows that would accommodate lenses up to 240mm (or even 300mm) would be a great feature. Having a small bag-bellows section in the front allows generous and easy movements with short lenses. A longer pleated section would allow good compression and adequate focusing ability for longer lenses. Trying to use movements with short lenses with a pleated bellows is a royal PITA.
A recessed lensboard for shorter lenses would also be nice and not only help with movements, but also maybe allow the use of very short focal-length lenses.
Hope some of these ideas are helpful,
Doremus
Like Bob sez, and also note that you will have to choose your lens first, as some lenses fit inside the shutter, and some reach far back, and this difference can affect the tilt/swing angles...
Your best bet is to get an old cheap monorail 4X5 to use as an optical bench to take measurements on, and translate that to your design... Something with on-axis movements, but not a base tilt camera... You can then directly see how much movements apply to your design...
Good luck!!!
Steve K
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