Axis or base tilts ???

I've been reading about the different "types of tilts" available on field and view cameras but am still unclear as to what the differences are. One article on this site suggests that you may wish to adjust focus (one of the steps) by using the base or the axis tilt method. Is there a way to tell which tilt adjustment is which on a camera ? I presently have a Calumet C400 and also a Prinzdorff field camera which I am comparing to attempt to see if there is a difference. I also have read that cameras like the Ebony and Sinar have asymmetrical tilts and was wondering if anybody could offer a simple laymans explanation on what this does ? Thanks for any help that you may offer.

Grey Wolf: Your Calumet C400 has axis tilts. Can't remember what the

Prinzdorff has. Haven't seen one in years. The axis tilts are at the

center of the lens or back, base tilts are at the bottom. I prefer

axis tilts for the lens and base tilts for the back. With lens axis

tilts, less refocusing is needed when the lens is tilted. I prefer

base tilts for the back for the same reason. When the camera is

tilted down and focused into the scene, the back can be tilted to the

rear to straighten verticles and bring the foreground into focus a

little easier than having to move the whole standard. Either will

work, but that is my preference. The Sinar tilts around the base, but

it slides in the tilting mechanism to keep the lens and back in the

same place. It is kinda what you get used to, as both systems can be

set up quickly with practice.

 

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Regards,

Grey, the base tilts are usually designed to be yaw free...yaw only

comes into play when using front tilt and swing simultaneously. If

the pivot point of the tilt is below the swing point, then the camera

is yaw free, and has base tilt. The benefit of this is, you do not

have to continual adjust one of the two movements when changing the

other. If the tilt point is just slightly above swing point, then

the camera is not yaw free, but still has base tilt. In landscape

shooting, Yaw is a very rare occurence, and in my opinon the loss of

axis or assymtrical tilts is not worth the benefits of yaw free.

 

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Axis tilts are just that, they tilt on a given axis, some

cameras have fixed axis tilts which are usually at the center of the

lens, (hence the name lens axis tilt) which is ideal, while other

cameras such as Horseman L series has variable axis tilt, the user

slects at what axis the lens will be tilted from.

 

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Doug, I am confused about what you write. I do understand that

rear tilt will alter the perspective, however, wont it also throw the

film way out of the plane of sharp focus? If you pointed the camera

downwards and kept the standards paralell, you would have converging

verticals, but the plane of sharp focus will be exactly on the film

plane. Now if you use rear tilt to rid the converging verticals, the

plane of sharp focus still lies paralell to the front standard, but

yet the back is tilted moving the film way out of the plane of sharp

focus. At the very center of the film it should be fine, but at the

top and bottom it would far exceed the allowance that Depth of Focus

would permit, regardless of the f stop shot at? Can you, or anyone

else, explain how this works? I see this written in view camera

books, but it never addresses how this focus shortcoming is

overcome? thanks

Note to Bill: When setting up the shot with the camera pointed down

slightly and a lot of foreground included, you make the initial focus

point the more distant point, such as the horizon or distant

mountains, etc. When you tilt the back to get the foreground in

focus, you will find the back is just about verticle. If you have

verticles that are critical, you may need to touch up the fine focus

with front tilt, but most times not as stopping down takes care of

the tiny bit of refocus needed. Tilting the back means that the top

of the back is being moved away from the nearest object, in effect

giving more bellows extension as if you were focusing on a closer

object. In use, it is very quick to do and only needs minor refocus

after making the movement. It also makes the foreground objects

slightly larger, which I find desirable in most instances. If you

look at the camera from the side, you will that the back, lens and

plane of focus intersect as they should. Play with your camera a

little and you can see on the ground glass what is happening. The

same thing can be done with axis tilts on the back, but you have to

refocus a bit more. Hope this help,

 

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Regards,

The Sinar assymetrical tilts and swings (only on the P, P2, X, and

only on the rear standard of the C & C2 models) are a sort of

modified base tilt system that places the tilt axis into the picture

area, but well below the center line of the negative. Arca has an

optional similar system (Orbix) but only on the front (lens)

standard.

 

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I prefer a yaw free design, which by necessity of design

eliminates axis tilts (unless as Bob Salomon of Linhof's USA

distributor, you tilt your camera on it's side.) eliminates axis tilt

designs. A yaw free design requires the tilt mechanism

(regardless of where the axis is) to be located below the swing

mechanism. Not all base tilt designs are yaw free.

Actually Ellis the first yaw free camera ever produced was the

original Linhof Kardan which had a unique knuckel type joint that did

both the tilts and the swings from the same point.

 

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That joint was called a kardiac (sp) joint in German and was the

derivation of the Kardan model name that Linhof uses today.

 

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Currently Linhof makes 3 different yaw free cameras and one that can

be nodified to be yaw free.

 

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Both the GT and GTL models have 2 tilt points. One on each camera

below the swing point. On the GTL there is also an in the film plane

tilt point and on the Gt a center tilt.

 

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The E can be modified to become a GT.

 

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In 69 the M679 has 2 tilt points as well, one below the swing and one

above the swing point.

Bob's history is correct. But more to the point, why should you

want a yaw free camera?

 

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If you ever make photos with the base of the camera inclined and

both front and rear standards tilted back or forwards and then

swing used, being able to keep the two standards vertically

parallel to each other makes your life much simpler. This

situation occurs often when photographing products in the

studio and in some architectural situations.

 

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If you are making landscape photos which make fewer

geometrical demands on the camera, this situation is less likely

to occur so you may not need a camera that is yaw free if that is

your primary goal. Still my feeling is it is better to have than not.

If you have a center axis camera the image shifts are minimal or (with

optical axis cameras) virtually non-existant.

 

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If you have a base tilt camera the image and focus shifts can be

severe and with those types of cameras a yaw free design may be

preferable. Especially as with a base tilt camera when doing a tilt

and a swing it is possible to create enough yaw that the subject may

not be able to reposition as the shooter wishes.

 

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Although Linhof rather quickly discontinued the original yaw free

Kardan and went instead to designs with a large degree of direct

shifts and canter tilts Sinar did not. The original metal Sinar was a

base tilt design and for that design a yaw free movement became

important. especially as it was a camera commonly used for 3 point

perspective.

 

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So do you need yaw free? Probably not. The vast majority of all large

format images ever made for all fields have been with yaw prone cameras.

But, especially with base tilt designs, yaw free can be worth the

additional weight.

How many of us would use a view camera if its only advantage was the

larger size of the negative (or positive)? With the problems of film

flatness, the shrinking availability of film types, the extra weight

of the equipment etc. combined with the excellence of medium format

cameras and films, why bother?

 

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Of course the answer, at least for me, is the amazing control of the

image that camera movements can provide.

 

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I enjoy the intellectual exercise of looking at a scene and trying to

visualise how the application of various movements will affect the

focus, position, and shape of the image on the ground glass (and then

seeing if I'm right). To do this successfully requires an

understanding of what each movement or combination of movements does

to the image. Whether your camera has axis or base or asymmetrical

tilts doesn't really matter as long as you appreciate that the effect

of tilting the lens does vary between the various types.

 

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I prefer axis tilts because of the relatively minor effects they have

on focusing. Base tilts not only alter the distance between the

centre of the lens and the film plane (requiring a greater degree of

refocusing), they also inevitably produce a slight fall in the

position of the centre of the lens - so using base tilts can make it

more difficult to accurately predict what effect the sum of all

planned movements will produce.

 

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As to yaw, I agree with Bill and Ellis that it is of little or no

relevance to most landscape photographers and all else being equal, I

would personally go for a camera with axis tilts rather than one with

a yaw-free design.

The real answer is that no method is without its advantages and

disadvantages. The advantage of on-axis swing or tilt is that the

focus isn't disturbed too much (although this depends on the lens

design, and whether a sunken lensboard is used). The disadvantage

is that the optical axis of the lens no longer intersects the

centre of the film plane, and so some shift must also be applied if

the lens is to give optimum image quality.<br>The disadvantage of base

tilt is that the focus is invariably shifted, but the advantage is

that some compensation for optical axis shift is automatically applied

when the lens is tilted forward.<p>Whatever system your camera has,

you quickly get used to it. Like the gear change on a car, no two are

the same, and none are perfect, but few people actually let their

lives revolve around it.