"nodal"ing about at DVinfo.net

Tito Haggardt · December 23rd, 2008, 03:18 PM

aloha

I am wondering if the nodal point on my EX-1 changes with the position of the zoom lens or is it measured from the sensor, which i assumed stayed stationary. i could have misread something yesterday which has lead to my confusion. i thought that the nodal point for the lens at its widest point would be in one discernable place and the nodal point would change to another discernable point when fully zoomed in. any other lens position would be between those two points. yesterday i read the nodal point in digital photograph was the point where the image struck the sensor.

i am hoping someone can comment and also let me know about where the nodal point is on the EX1.

happy holidays
tito

Giroud Francois · December 23rd, 2008, 04:12 PM

i am not sur that so important since it is probably not noticeable.
but logic would be that nodal point is moving inside the zoom lens.
you can do a simple test by aligning two objects (one far, one close) and rotating the cam.
the objects should stay aligned , whatever they are in the field of view (center or border).
repeat with different zoom.

Tito Haggardt · December 23rd, 2008, 07:34 PM

Thank you
so is the sensor in the zoom lens?
or does the position of the sensor have no effect on the nodal point in a digital camera?
tito

Brooks Graham · December 23rd, 2008, 08:04 PM

Quote:

Originally Posted by Tito Haggardt

Thank you
so is the sensor in the zoom lens?
or does the position of the sensor have no effect on the nodal point in a digital camera?
tito

The sensors are in the camera body proper. Are you interested in the nodal point for VR/panoramic photography? If so, then what you should be looking for is known as the "entrance pupil". There are a couple of terse articles on the subject on Wikipedia:

http://en.wikipedia.org/wiki/Cardinal_point_(optics)
Entrance pupil - Wikipedia, the free encyclopedia

HTH

Tito Haggardt · December 23rd, 2008, 11:18 PM

thank you Brooks
i started looking at nodal points for CG effects using models and real objects.
all this is of interest.
tito

December 23rd, 2008, 03:18 PM	#1
Tito Haggardt Regular Crew Join Date: Dec 2007 Location: Ocean View Hawaii Posts: 88	"nodal"ing about aloha I am wondering if the nodal point on my EX-1 changes with the position of the zoom lens or is it measured from the sensor, which i assumed stayed stationary. i could have misread something yesterday which has lead to my confusion. i thought that the nodal point for the lens at its widest point would be in one discernable place and the nodal point would change to another discernable point when fully zoomed in. any other lens position would be between those two points. yesterday i read the nodal point in digital photograph was the point where the image struck the sensor. i am hoping someone can comment and also let me know about where the nodal point is on the EX1. happy holidays tito

December 23rd, 2008, 04:12 PM	#2
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	i am not sur that so important since it is probably not noticeable. but logic would be that nodal point is moving inside the zoom lens. you can do a simple test by aligning two objects (one far, one close) and rotating the cam. the objects should stay aligned , whatever they are in the field of view (center or border). repeat with different zoom.

December 23rd, 2008, 07:34 PM	#3
Tito Haggardt Regular Crew Join Date: Dec 2007 Location: Ocean View Hawaii Posts: 88	Thank you so is the sensor in the zoom lens? or does the position of the sensor have no effect on the nodal point in a digital camera? tito

December 23rd, 2008, 11:18 PM	#5
Tito Haggardt Regular Crew Join Date: Dec 2007 Location: Ocean View Hawaii Posts: 88	thank you Brooks i started looking at nodal points for CG effects using models and real objects. all this is of interest. tito