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Deniskellyjr
1-Aug-2010, 07:11
Greetings Everyone,
Am I correct to believe that one may assume a tilt value will consistently yield the same rotation axis point? If so, then I can set up my camera to the same full tripod height position, level it, zero the movements, apply the 2 points of front tilt that layed the plane of focus along the ground previously, focus, and it should work again. Is that correct? I understand that if I want the PoF to be higher or lower than my tripod feet, I'd need a different degree of tilt.
Thanks for your help. Peace, Denis
P. S. I use a Sinar F1 4x5
Www.deniskelly.com

Joanna Carter
1-Aug-2010, 07:59
Am I correct to believe that one may assume a tilt value will consistently yield the same rotation axis point?
If you mean, will it yield the same hinge point, the answer is not necessarily. It also depends on the bellows draw length.

If so, then I can set up my camera to the same full tripod height position, level it, zero the movements, apply the 2 points of front tilt that layed the plane of focus along the ground previously, focus, and it should work again. Is that correct?
Only if you also have the same bellows draw.

I understand that if I want the PoF to be higher or lower than my tripod feet, I'd need a different degree of tilt.
No, you may also need to adjust the bellows draw length.

Don't forget that, if you set the plane of focus along the ground, then half of the available depth of field will below below ground level, thus "wasting" that half of the DOF.

Deniskellyjr
1-Aug-2010, 11:37
Greetings Joann,
Thank you for your response. I enjoyed looking at your site. I believe I understand your comment regarding bellows draw. I expect that bellows draw is functionally equivalent to focus. Isn't that correct? Therefore bellows draw will determine the angle of the plane of focus that will rotate around the "hinge point", aka "axis of rotation". If the ground is sloping up, I'll use a different bellows draw than if it is flat ground or downward sloping. I also get your point that I probably should not lay the PoF on the ground but rather a little above it so that Depth of field can be maximized.

I am trying to be clear about the concept and efficient in setting up compositions.

Thank you,
Denis
Www.deniskelly.com

Deniskellyjr
1-Aug-2010, 11:39
Pardon me Joanna, once my post went up, I realized I neglected the last "a" in your name. Thanks again. Denis

Joshua Dunn
1-Aug-2010, 15:24
What this Scheimpflug tutorial (http://www.youtube.com/watch?v=gR4m70xr9mE)on You Tube using a Sinar. It helped me.

-Joshua

Deniskellyjr
3-Aug-2010, 18:42
Greetings,
I tried several times to watch the video but I can not get it to work. I also tried searching for it on youtube but failed again. Thanks any way. Denis

sun of sand
4-Aug-2010, 00:12
im not understanding this but its sounding to me like youre asking if i take the same picture twice will the settings for the first work for the second
i would say yes
efficient in setting up compositions is throwing me

f64 would be the most efficient -if im understanding the desire corectly
then only a slight tweak of tilts would be needed to -grossly- compensate for varying terrain/compositions/perspectives

mortensen
4-Aug-2010, 01:32
Greetings Everyone,
Am I correct to believe that one may assume a tilt value will consistently yield the same rotation axis point? If so, then I can set up my camera to the same full tripod height position, level it, zero the movements, apply the 2 points of front tilt that layed the plane of focus along the ground previously, focus, and it should work again. Is that correct? I understand that if I want the PoF to be higher or lower than my tripod feet, I'd need a different degree of tilt.
Thanks for your help. Peace, Denis
P. S. I use a Sinar F1 4x5
Www.deniskelly.com

...interesting thought - just considered the same idea the other day.
As long as you make your observation on realtively strict criteria, it should work, shouldn't it? For instance: 90mm lens, tripod at full height, bottom of frame focused at 3-5m, middle of frame focused at infinity (final image, not gg)... a scenario like that would sort out quite a few situations for me and it would make a good, rough starting point for fine tuning focus. but you need a camera with fine scales for your axis tilt...