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View Full Version : Nikon D50 + Tokina 12-24mm + NN3mkII



amkrisis
05-09-2008, 12:05 PM
Hi

I just purchased a NN3MkII to use with my Nikon D50 and Tokina 12-24mm lens.
Does anyone know where the entrance pupil is on that lens?

I couldn't fine a setup guide on the website.

Is it always more or less the golden ring? If so, then my camera can't go back enough to reach it.

I also noticed that i can't rotate my camera all the way up so that it faces straight up.

Any help is appreciated!

amkrisis
05-09-2008, 12:15 PM
I just did a quick test, NN set to 99mm
Jpeg made with autopano: www.bennyvermeulen.com/panotest/pano1.jpg

If it's set up correctly i should get an image that is 100% straight at the top and bottom right?
So should i set it to a higher mm range or lower?

Or am i just talking rubbish :001_smile:

John Houghton
05-09-2008, 12:43 PM
If it's set up correctly i should get an image that is 100% straight at the top and bottom right?
Wrong. The curved tops to the images are quite normal and expected in the equirectangular projection. To check whether the camera is positioned at the correct point to avoid the effects of parallax, you need to do some tests specifically to reveal the presence of parallax. All this involves is taking two overlapping shots exactly as you would when taking a full panorama. Arrange for there to be an object very close to the camera in the overlap and seen against a distant view containing some detail so that you can judge whether the near object appears to change position with respect to the background in the two successive shots, i.e. whether there is any parallax shift. Check the images in Photoshop. Adjust the rail position until this test reveals no parallax shift. It's quite straightforward. I use a short length of tape stuck to the inside of a window looking out onto a distant view. Alternatively, you could use a pole or stick. Make sure the tripod is on a firm footing, though.

John

amkrisis
05-09-2008, 01:04 PM
Wrong. The curved tops to the images are quite normal and expected in the equirectangular projection. To check whether the camera is positioned at the correct point to avoid the effects of parallax, you need to do some tests specifically to reveal the presence of parallax. All this involves is taking two overlapping shots exactly as you would when taking a full panorama. Arrange for there to be an object very close to the camera in the overlap and seen against a distant view containing some detail so that you can judge whether the near object appears to change position with respect to the background in the two successive shots, i.e. whether there is any parallax shift. Check the images in Photoshop. Adjust the rail position until this test reveals no parallax shift. It's quite straightforward. I use a short length of tape stuck to the inside of a window looking out onto a distant view. Alternatively, you could use a pole or stick. Make sure the tripod is on a firm footing, though.

John


Like this?

www.bennyvermeulen.com/panotest/panophotoscreenshot.jpg
www.bennyvermeulen.com/panotest/nodaltest.jpg

Not the most clear shots i must admit, but it's getting dark over here.

John Houghton
05-09-2008, 02:51 PM
Yes, that's looking good, with very little parallax shift. There is some, as can be seen in this animation:

http://www.johnhpanos.com/nodaltest.gif

For that, I did a rough stitch of the images in PTGui and generated a layered PSD file, from which I generated the animated gif. If you think very carefully, you can decide from the direction of movement whether the entrance pupil is located in front of or behind the axis of rotation. (Just hold up a finger and move your eye from side to side and you will get the idea). If it's behind, then you can try moving the camera forwards a mm or two. If in front, then move the camera back. It's up to you how precise you want to make it.

John

amkrisis
05-25-2008, 12:43 PM
Another thing though:

I can't rotate my camera all the way up.
The body just hits the bottom of the NN3!

This is probably because the Tokina is to big?
Has anyone successfully used the Tokina 12-24 with a D50 (or similar with the same body size?) I guess detaching it and reattaching it might work?

nick fan
05-25-2008, 11:20 PM
a zenith shot is not always necessary. The angle of view of your lens is big enough to close the zenith. You can take a hand held zenith shot for ceiling with lots of features such as church.


Nick