Are back, base, and yaw-free movements more than a convenience?

[Christopher Condit]

My understanding is that any shot possible with yaw-free, front and back, base/ center/asymmetrical movements, can also be taken with simply front/yawed/axis mo vements, if the latter have enough range. In other words, the more expensive/ar cane movements are, not to put too fine a point on it, nothing but a convenience . Am I right?

Inching my way towards a purchase...

TIA,

CXC

[Per Volquartz]

In theory yes...

However, yaw-free movements (like on a Sinar P) lets you work direct and fast...I cannot count the number of images I have taken through the years - which would have been a nightmare to shoot with "standard" movements...

[Christopher Condit]

Per, what sort of shot benefits most from yaw-free? Is it strictly table-top still lifes, or is it also useful outside in the real world sometimes?

[Per Volquartz]

I used to do a lot of photography of supersonic aircrafts; and always found myself up against the wall; never enough space. To be in control of the image "design" I relied heavily on the ability to dial the swings and tilts with micrometer precision in order to get exactly the composition I sought...

Product - and architectural photograhy can benefit from having micrometer swings and tilts. Landscape not really (most of the time)...

[Ellis Vener]

Actually you are wrong.

Swing and tilt front standard movements only affect depth of field.

Swing and tilt on the rear standard effect depth of field (focus distribution) and perspective rendition. So the answer is no: front movements alone do not do as much as rear movements alone and neither front or rear only movement designs have near the real world problem solving abilitiy of a camera with full movements ((rise or rise/fall, shift, tilt, swing and focus) on the front and rear standards.

I have used many cameras: Sinar (F, P & C models) , Horseman, Toyo, a Linhof or two, a Canham DLC and an Arca-Swiss F-line. I have used these cameras for architectural work, landscape, portraits and still life. Both in and out of the studio enviroment. There is no doubt in my mind that a yaw free camera is quicker to set up and easier to use than a axis tilt design. yaw free designs really come into their own anytime you have to tilt the base or monorail. using axis tilt designs i found myself having to make corrections to correct for problems previous corrections induced and I think it is a bad idea to get into a cycle of "correcting the corrections." My idea of how it should work is that you start by pointing the camera directly at the object or subject correcting the standards back to verticals to the degree you deem they need correcting , shifting and or using rise fall (front or rear0 to frame the image you desire and then using either tilt or w=swing or both to get the image on the ground glass to appear as close to the final image as possible 9and stopping down for the wanted depth of field. I don't like fiddling with equipment unnecessarily.

The camera I have settled on is the Arca-Swiss F-line but the Sinar C is in the dsame class if you don't want the full weight of the Sinar P or P2. I dislike the Sinar F series but many people like them and they do a good job.

[bglick]

Chris, I am sure you know this, but Yaw free only comes into play when you use tilt and swing simultaneously. Try to analyze just how often you think you will need to use these simultaneous movements. Than you can determine how important this feature is. I went with a Yaw free design and regret it. I would have much preferred lens axis tilt and forego the yaw free aspect, for landscape work.

[Christopher Condit]

Ellis, I understand that rear movements are better for perspective rendition, but isn't it possible to reposition the entire camera and get the same results with only front movements? The geometer in me says that movements in either the front or back accomplish the same thing, changing the angle and position of the lens with respect to the film. I see no reason why all possible relationships couldn't be accomplished with only front movements, along with repositioning the entire camera by tripod movements. Again assuming sufficient range of front movements.

I can imagine that complex movements could be difficult and extremely tedious to make with front-only, but not that they would be impossible. Perhaps they would even be so exasperating that one wouldn't bother, or the light would change in the meantime.

Wait, there is one clear-cut difference, which is evident when the bellows position is added to the equation. I can picture instances when the severity of movements required because front-only could introduce vignetting due to extreme bellows displacement. But this problem theoretically could be alleviated by using a camera with a large lensboard, or by using a bag bellows.

Just trying to understand as best I can, Christopher

[Ellis Vener]

Christopher,

They are not the same.

I pondered this quandry for a long time too. The best answer I came up is that when you move the lens you are moving the lens relative to the subject and to the film plane and not just the film plane. when you leave the lens in the same relationship to the subject but move the back you are moving only the film relative to the lens. I realize the change of the lens position or alignment to the subject might be minor but through the wonder of optics it ends up being quite significant relative to the final image. Many very respected architectural photoraphers try to only use rear movements and resort to front movements of the lens only as a necessity. i won't be so audacious as to suggest that I even think that I am in their league but it is the approach I try to follow as well.

[Christopher Condit]

Thanks, Ellis, I finally understand. I hadn't thought of the necessary change in relationship between the lens and the subject, and if I had, I never would have guessed that it makes a difference.

I appreciate your help, Christopher

[Robert Lawrence - Fivebyfour Commercial Photography, UK]

Not true, for a sound technical reason. If your camera yaws then in a camera inclined situation with rear tilt and front tilt + swing you will not be able to achieve the Scheimpflug principle which require plane of sharpness, film plane and lens board to intersect in a common line, the emphasis being on line. On a yawing camera these planes intersect in a point, therefore the plane and extent of sharpness will differ to those on a yaw free camera. I am aware that Harold Merklinger does state that any complex combination of movements can be duplicated by a simple swing/tilt given a suitable camera vantage point, but I believe that the hinge rule is a necessary condition for this to work and in this particular combination of movements on a yawing camera the hinge rule planes also meet in a point (and hence the 'rule' does not apply). However, if the hinge rule is satisfied then the Scheimpflug principle automatically applies. A good case for a yaw free camera requiring this combination of movements (which occur very often, in my experience, in the studio still life/product scenario).

[Chris Partti]

I think that the original questions mixes up two different issues.

First, is the issue of what minimum combination of movements is necessary. It's worth knowing that if a camera has the correct minimum combination of movements, it can duplicate, by "indirect" movements, all the movements on a more full-featured camera. Examples of combinations that allow full "indirect" movements are (1) front and rear tilts and swings (2) rear tilt and swing and front rise, fall and shift (like the Eastman Commercial 8x10) (3) rear tilt and swing and front rise, fall, tilt and swing (like the Deardorff). Modern field cameras that allow every possible movement on both standards are a convenience but not a necessity. You do need some movements on both the rear and the front to accomplish this, however.

The presence or absence of yaw is a different issue which has to do with whether movements can be made independently or whether making them in combination affects one another. It is mostly important in work that requires a high degree of precision, such as table top photography. Landscape photographers generally don't worry about it, and all traditional field cameras have yaw.

[Richard Stum / Kinesis]

This thread seems to talk mostly about yaw-free or not. I personally think the a symmetrical movements vs. symmetrical movements as a more important feature. I was almost ready to buy a Horsemen when I finally did a side-by-side trial shot with a Horsemen (center tilt) and a Sinar p (off center or asymmetrical). The 2- point focus system in use on all Sinar cameras is the quickest time saver featur e and overwheliming reason I bought this brand. Yaw free was merely a added bonus.

[Pete Andrews]

Yaw-free is only truly yaw-free if the centre of tilt and/or swing coincides with the rear nodal point of the lens. Most so-called yaw-free designs assume that the optical centre of the lens lies in the same plane as the lens board, and this isn't always, or even commonly the case.I have a 210 mm Sironar that has its optical centre well behind the lensboard, as are the optical centres of nearly all WA designs like the Super Angulons and Grandagons. OTOH, telephoto lenses will all have their optical centres well in front of the lens.What this means in practise is that no yaw-free design works properly with most real lenses. They will all require some refocusing and re-centring after a swing or tilt is applied. And if you're going to have to readjust by even a millimetre, then the 'yaw-free' tag becomes an empty promise.

[Ellis Vener]

Pete,

True enough, but at least with the Sinar andnow Arca-Cameras I have worked with regularly it is close enough to not matter greatly. My understanding is that for the reasons you cite , ArcaCame out with the optional Orbix mechanism for the lens standard.

[Ellis Vener]

Pete,

True enough, but at least with the Sinar p and C and now Arca-Swiss cameras I have worked with regularly, it is close enough to not matter greatly. My understanding is that for the reasons you cite , Arca-Swiss addresses this issue with the optional Orbix mechanism for the lens standard.

[Pete Andrews]

Thanks Ellis.Yes. I see that some cameras allow a 'nodal slide' type adjustment above the goniometer table, but these must be carefully set up for each lens to make the best use of them.

What I'm getting at, in an attempt to give Christopher a better comparative overview, is that cameras with fancy goniometer adjustments really only offer extra convenience and ease-of-use, not greater functionality.In fact, a camera with a conventional 'U' shaped standard, that has both centre tilt and base tilt, can emulate any goniometer movement exactly; even being able to centre the node of the lens on the axis of swing.For example: Tilting the standard forward brings the axis of swing to the rear of the lens, where the optical node is more likely to be, and then that tilt can be augmented or reduced by using the centre tilt mechanism. Now the front standard can be swung, and the image will stay still on the ground glass.

All the same relative positioning of lens and film plane as the yaw-free design is possible, it just takes a bit more thought and fiddling to set up.The question really is whether the extra convenience of 'yaw-free' is worth the higher price of the camera to you.