Help with Ebony asymmetric mov.

[galupi20]

This is a post from Carl Mathisen ( 1 Aug 2005 ) without an answer. I Have the same doubt. Can anybody help us ?

Carl Mathisen

Join Date: Jan 2005
Posts: 1

how to use asymmetric movements
This all makes sense to me except for one thing. The horizontal asymetric tilt axis is located near the bottom of the ground glass. When shooting landscapes, this axis more often than not coincides with the portion of the image containing sky, since the image is upside down. Generally (again, for landscape photography) the desired horizontal plane of focus passes through foreground and background elements below the horizon. On the upside down image , both of these elements appear above the horizontal asymetric tilt axis on the ground glass. In this case, can the horizontal asymetric tilt be used to implement a non-iterative focus solution? I supose you could tilt the entire cameara towards the ground to foucs, and then recompose. How do the acutal users of cameras with this feature manage in this situation? Sorry if I've missed the obvious; large format is relatively new to me. Cheers!

Thanks a lot

Luis

[timparkin]

Hi Carl,

The first step becomes simple when you realise that when your standards are parallel, any point will do to focus on. For the 'sky' case, focus your camera at infinity.. Now you have the 'variable' where it will do most good, near the foreground..

But really there won't be a single ideal position and I think the design is more to do with allowing maximum rear tilt down and keeping the fixed point as close to structural rigidity as possible.

I might be self justifying the answer as I've never thought what it would be like if it was at the top.. Lets think it through... I could easily get my first point because it's the foreground.. However now I have to tilt down to find my second point in the sky?

Both ways have their problems by the looks of it... The main goal of the assymetric movements is to make the axis on a visible, and likely useful, part of the ground glass..

Does that make sense?

Tim

[Steve Hamley]

Generally (again, for landscape photography) the desired horizontal plane of focus passes through foreground and background elements below the horizon.

That's only true if the sky has no detail that you want rendered, such as clouds, especially at sunset, sunrise and the background elements mentioned above are close in comparison to infinity focus. If the sky has clouds or compositional elements then the position above begs the question of why the sky is in the composition to begin with.

All movement points are a compromise and none is perfect for every composition. Asymmetric movements generally make for faster composition, although there are exceptions. It's important to understand that the angle of the back can be positioned the same regardless of whether the swing/tilt point is symmetric or asymmetric.

Perhaps the best advice is to worry less about where the pivot point is and more about the image sharpness on the ground glass.

Cheers,

Steve

[David A. Goldfarb]

I'm not sure if this works on an Ebony, but on a Sinar P/P2 the technique when the tilt or swing axis doesn't fall in a useful place is to use rise/fall and shift to move the axis, find the tilt angle, and then you recompose using rise/fall or shift and adjust focus. On the Linhof Master GTL, I think you can just move the tilt and shift axes independently of the rise/fall and shift.

[galupi20]

Found this answer from Baxter Bradford.

" The Dotted lines on the GG are fixed. Of course you can use the tilt with rise/fall and it is very straightforward.However, the dotted lines do not always line up with your intended composition, but there are work arounds. I tend to use a tempoary rise/fall to get key elements on the axes, focus on distant (bottom) dotted line, apply tilt so that it comes into focus on the near (top) dotted line, lock off the tilt knobs, then recompose by adjusting the rise/fall properly. A small focus correction then brings it all back in again. This is since the position of the rise/fall effectively alters the lens pane to film plane distance. Thus I fully expect that swing can be used with shift in a similar manner. "

Answer given via email from Ian Wilson ( Ebony )

"As for Baxter Bradford's response to your question about elements that appear above the tilts axis line, he's absolutely right!"

Period

Luis