Sinar Tilt Calculator Help

I'm using a Sinar F2 for landscapes and would like to know if there are any

Sinar users who could answer my question relating to the Tilt calculator on the

camera. I understand that to determine the tilt angle I need to first focus on

the bottom dotted line on the groundglass. My problem is that it seems like

rarely the subject is on that dotted line. Does anyone know of method in which I

can still use the calculator even when the subject doesn't lay on the dotted

lines? thanks

 

Nick

Measure the distance on the ground glass between your near point and far point, and adjust accordingly. The distance between the dotted lines is 7cm, but e.g. if on the ground glass your near point and far point are 5cm apart, you'll need to modify the angle indicated by the calculator by 1.4 (7/5).

I think the Sinar tilt calculator must use the method described by Bob Wheeler for calculating tilt angle. I wonder if you could verify this for me by telling us precisely what the instructions say. I tried a google search without too much success.

 

Wheeler's method involves taking the distance between the near and far points on the rail and dividing it by the distance between those points on the gg. You then multiply this by the distance of the top of the front standard to the tilt axis, and that tells you how far forward you have to move the top of the standard. Alternately, this can be expressed as a tilt angle. It appears from what you say that that you are supposed to fix the near and far points by referring to fixed lines on the gg. The f-numbers on the focusing knob are proportional to distance moved on the rail from a reference position. So it appears that all the necessary information is there, but it would be nice to know just what the instructions tell you to do with it.

Here are the instructions I have from Sinar.

 

1. Focus on the bottom horizontal dotted line on the groundglass.

 

2. Zero the angle calculator on the left side of the rear standard by turning it until the 0 lines up with the white mark.

 

3. Focus on the top horizontal dotted line on the gg, using the fine focus on the rear standard. The angle calculator will automatically indicate the required degree of tilt.

 

4. Set the front standard tilt to the angle indicated on the dial.

 

5. Adjust focus if needed.

Thanks Nick. That confirms my conjecture about how they do it.

 

Let me add that while Jean-Baptiste's suggestion will work well enough in most practical situations, it is only an approximation and it could fail in certain circumstances. You want to be sure the angle the tilt calculator suggests is not very small or very large, and that the multiplier (1.4 in the example) is not too large. Of course, in any event, any such method should only be taken to provide a first approximation to the tilt, and it should be refined by iteration.