Basically by trial and error. Here's the process I used as recommended to me by Rob:
I hung a plumb bob from a light fixture (actually a piece of string with a QR plate tied to the end), Set up tripod about 1-2m back from the string, correctly leveled, so that when the camera is mounted the string is in line with a door frame behind it. The slide positioned at my best guess of the nodal point. Lens focused at infinity, aperture at f11 or there abouts Rotate the camera so the string is just at the left edge of the frame, and take a shot, Rotate the camera so the string is at the right edge of the frame, and take another shot, Note the slide measurement & frame numbers. Repeat at different slide positions until parallax error becomes obvious in the VF. If it's a zoom lens, repeat at each of the marked focal lengths. The reason for taking the shots & not just doing it by eye is you can't guarantee that your eye is always square and giving you false results Open the files in PS and overlay the the 2 frames and observe to difference. The final lens FL & slide offsets are made up into a table and kept in my camera bag. It's a boring process, but it saves a lot of computer time when it comes to stitching the shots later on. Cheers, Dave On 1/2/07, J. C. O'Connell <[EMAIL PROTECTED]> wrote: > Curious, How do you accurately determine the nodal point on > the lens, especially the zooms, in order to > position the camera correctly on the head? > jco > > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of > David Savage > Sent: Monday, January 01, 2007 9:23 PM > To: Pentax-Discuss Mail List > Subject: Re: Do it yourself pano head > > > It sure ain't pretty (the vertical arm that is). Made from scrap in > about half an hour. > > The 'L' bracket has since been black anodised and works great with the > horizontal pano head. > > Cheers, > > Dave > > BTW, If anyone is interested in an 'L' bracket for their K10D let me > know. > > On 1/2/07, Paul Stenquist <[EMAIL PROTECTED]> wrote: > > Nice. Not pretty, but nice. I may copy your design. > > Paul > > On Jan 1, 2007, at 8:44 PM, David Savage wrote: > > > > > Here's a prototype I made based on my horizontal pano head: > > > > > > <http://www.arach.net.au/~savage/Misc/Images/IMGP4647.jpg> > > > > > > And here's some info about the pano head & "L" bracket I made: > > > > > > <http://www.arach.net.au/~savage/Misc/LBracket/Misc_009_1.htm> > > > > > > Today or tomorrow I'm going to gather the materials to make a new > > > "L" bracket for the K10D. > > > > > > Cheers, > > > > > > Dave > > > > > > On 1/2/07, George Sinos <[EMAIL PROTECTED]> wrote: > > >> Here's an interesting article on building your own pano head. Seem > > > >> like a reasonable thing to do if you're just experimenting. > > >> > > >> <http://www.wikihow.com/Build-a-Panoramic-Tripod-Head> > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
