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

[cxc]

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 movements, if the latter have enough range. In other words, the more expensive/arcane movements are, not to put too fine a point on it, nothing but a convenience. Am I right?

 

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Inching my way towards a purchase...

 

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TIA,

 

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CXC

[per_volquartz1]

In theory yes...

 

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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...

[cxc]

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_volquartz1]

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...

 

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Product - and architectural photograhy can benefit from having

micrometer swings and tilts. Landscape not really (most of the time)...

[ellis_vener_photography]

Actually you are wrong.<P>Swing and tilt front standard

movements only affect depth of field. <P>Swing and tilt on the

rear standard effect depth of field (focus distribution) <U>and

perspective rendition.</U> 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. <P>

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.<P> 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.

[jerry2]

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.

[cxc]

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.

 

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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.

 

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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.

 

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Just trying to understand as best I can,

Christopher

[ellis_vener_photography]

Christopher,<P> They are not the same.<P> 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.

[cxc]

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.

 

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I appreciate your help,

Christopher

[robert_lawrence]

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_patti1]

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

 

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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.

 

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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.

[kinesisphotogear]

This thread seems to talk mostly about yaw-free or not. I personally think the asymmetrical 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 feature 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.<br>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.<br>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_photography]

Pete, <P>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_photography]

Pete, <P>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.<br>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.<p>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.<br>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.<br>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.<p>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.<br>The question really is whether the extra convenience of

'yaw-free' is worth the higher price of the camera to you.