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Same Focal Length / NOT same angle of view ?? Panasonic 14mm, Olympus 12-40

Started Jul 5, 2015 | Questions thread
Guy Parsons
Guy Parsons Forum Pro • Posts: 40,000
Further

kdouglas7 wrote:

thanks Guy!

I'm chocking it up to the effect of the 'nodal point' , as you mentioned.

After some more tests, I realized that by moving the camera (w/zoom lens attached) back by a few increments I was able to achieve the same FOV as the 14mm prime lens.

'nodal point' ... good to know!

I may have been giving misleading info after doing a bit more reading.

Maybe the nodal point is not the answer but the front entrance pupil. Anyway, whatever it is called I find it when needed (for panoramas) by rotating the camera on a tripod head and observing the background in relation to a vertical stick or string held close to the lens.

Shift the camera back and forwards in respect to the point of rotation until the stick/string always obscures exactly the same part of the background. It may change position with zooming and focusing the lens.

I always called that the nodal point but now I think my terminology is wrong.

Have a read of this page http://www.johnhpanos.com/epcalib.htm to see my confusion and maybe get the right names.

Regards...... Guy

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