Scheimpflug and another question

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Bill Backhouse
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Re: Scheimpflug and another question

Post by Bill Backhouse » Tue Sep 13, 2011 11:24 pm Etc/GMT-1+01:00

timparkin wrote:
Can you explain what you mean by 'back/up' -- maybe in terms of which side of which standard comes towards or moves away from you. E.g. normal rear tilt for near far is rear tilt, top of rear standard moves towards you.
By tilt 'back/up' I mean from behind the camera looking towards my subject the tilt brings the top of the lens board towards me and the lower edge away from me towards the subject. I assumed to bring my plain of focus towards the ground i needed to point the lens towards my plain of focus eg top of lens board away from me and bottom toward me when I'm behind the camera, not the direction my speed graphic tilts. Have I got the wrong end of the stick here?

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Re: Scheimpflug and another question

Post by timparkin » Tue Sep 13, 2011 11:56 pm Etc/GMT-1+01:00

Bill Backhouse wrote:
timparkin wrote:
Can you explain what you mean by 'back/up' -- maybe in terms of which side of which standard comes towards or moves away from you. E.g. normal rear tilt for near far is rear tilt, top of rear standard moves towards you.
By tilt 'back/up' I mean from behind the camera looking towards my subject the tilt brings the top of the lens board towards me and the lower edge away from me towards the subject. I assumed to bring my plain of focus towards the ground i needed to point the lens towards my plain of focus eg top of lens board away from me and bottom toward me when I'm behind the camera, not the direction my speed graphic tilts. Have I got the wrong end of the stick here?
Yes it sounds like you might have. The best way to work this out is

1) Looking at the side of your camera, draw a line through the lens plane and extend it to meet a line going through your film plane.

2) With the rear tilt you describe (to of rear standard moving closer to you), these should meet at a point below the camera.

3) The plane of focus will always go through this point, tilting as you focus.

This rule works with swing too.

1) looking down at the top of your camera do the same


If you can get your head around the intersection of two planes, this is how it works with compound movements.

p.s. Your speed graphic should be set up for base tilt and is correct for the typical near/far composition.

nice diagram here (for front tilt but as tilts are relative between the front and rear planes this will be the same for rear tilt - approx)

http://www.trenholm.org/hmmerk/HMbook18.html



Tim
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Re: Scheimpflug and another question

Post by Joanna Carter » Wed Sep 14, 2011 9:57 am Etc/GMT-1+01:00

Bill Backhouse wrote:Have I got the wrong end of the stick here?
No, you haven't got the wrong end of the stick :D

Tim seems to be thinking only about tilting the rear standard, whereas you are talking about the front standard. If you don't have back tilt on the front standard, then you would need to tilt the rear standard forwards, but not forgetting to tilt the whole camera back the same amount if you are doing architectural shots :?
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Re: Scheimpflug and another question

Post by Nigels » Wed Sep 14, 2011 10:34 am Etc/GMT-1+01:00

Remember it like this;
Moving the lens further away from the film focusses on closer objects (obvious, I know). When you tilt or swing (either standard) you are moving the lens and film closer together on one side and further apart on the other.
With the inverted image that is why tilting the lens downward or the film upward both focus closer on the bottom of the image. The top of the standards are moved further away from each other.
The choice of which one to move is a whole other discussion!
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Bill Backhouse
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Re: Scheimpflug and another question

Post by Bill Backhouse » Wed Sep 14, 2011 10:47 am Etc/GMT-1+01:00

Ahh. think I get it, to simplify the graflex has no rear movements, just the front standard has about 20deg of tilt, the bed can be dropped 20deg down (but no use on wide lenses) then maybe an inch of rise and 1/2" shift either way.

I'm sure at some point the penny will drop with a resounding thud and I'll really get it, I think the issue is practice.

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Re: Scheimpflug and another question

Post by Thingy » Wed Sep 14, 2011 5:28 pm Etc/GMT-1+01:00

Of course you could always go for a camera with assymetric tilts to make life easier. :mrgreen:
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Re: Scheimpflug and another question

Post by Neil Barnes » Wed Sep 14, 2011 7:17 pm Etc/GMT-1+01:00

Thingy wrote:" easier "
:mrgreen:

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Re: Scheimpflug and another question

Post by Bill Backhouse » Thu Sep 15, 2011 9:45 am Etc/GMT-1+01:00

I have a cambo monorail (for sale ;) ) with lots of movements everywhere. my brain cannot that many ways to cock up a picture :) hence I bought a simple graflex (and its more easily portable).

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