saw your question on panoguide yesterday and did some research on DP-Review. Seams to be that 550D and 500D use the same body. If that is true, you cam use the data of 500D. I am a Nikonian, so I will try to help you around. I only own a M1-L.
For LRS = lower rail setting you have to use H1 from Wiki database. Now measure the distance from center of the plate mounted to the top of the lower rail to the top of the camera plate mounted on upper rail. You can move it down to the lower rail to measure the offset more quickly. Add this distance to H1 and you should have the LRS.
Easier: mount the camera without lens to M1-S, move the camera sideways till the lens release "Knob" on the lens flange is on top of the center of rotation of the Rotator. You can use a ruler or a laser to check. Or to try to place it through the viewfinder.
URS + upper rail setting is L1+L2 plus "basic rail set of NN rail".
I do not own a M1-S. That's why I had to review my answer to you. The center of QRS 40A on M1-L shows a rail setting of 20mm on M1-L upper rails MFR170/210. So you would have to add 20mm to Wiki's L1+L2.
Have a look to the upper rail center of your M1-S QR Clamp: Add this setting, may be 20 or 15 mm to L1+L2 from Wiki database. And test it with you own equipment.
Thanks for the detailed posting - but looks quite over-complex................
I would have thought setting up the M1-S would be the same as with my NN5 & NN3 in the past. I always use Smooth's thread over on the Easypano site: for aligning and has always worked fine. I'm setting up gear for a friend who's going to help me out with the photography side of my business, and thought someone might just have the settings availale straight off.
I only have a M1-L System, which is different from M1-S.
Because of a complete different design of M1-Line from NN5, NN4, NN3, you have to understand these differences in the beginning. In this case the camera is fixed via QRS-Clamp to the upper rail. This rail, and not the camera fixed to the old upper rails of NN3/4/5, slides into Rotation Center of the Upper Rotator. Plus we use a lot of QRS Clamps.
Just ruined my longer answer by doing spelling check, so I answer in a short way. Use Smooth method to fine tune LRS. Place the camera into the upper rail clamp, move forward till the golden ring meets the rotation center of rotator.The Sigma NPP is always around it.
During my setting tests for the new M1-L Line, have a look to my posts if you like, I found out that specially Sigma 8mm/f3.5 and Samyang 8mm/f3.5 show the upper rail in the pic. Thanks our friend DennisS who asked this, I tested if this shows in the stitched pano as well, in most cases the rail does not show. It does with Nikon D3100 and D5100 with all popular fisheye lenses 10.5, 16, Sigma/Samyang 8mm.
Anyway, I do not like something wrong in my pic. So I will use the New QRS 40B in combination with QRS 40A which comes with the panohead. Nick has designed it to be able to avoid the rail in the picture. You can move the upper rail backwards in the rotator clamp till it does not show beyond the Rotator QRS. Then, with this combination QRS 40A/QRS 40B, you can slide the camera forward on the rail - old system, camera moves - till the golden ring hits the rotation center of the upper rotator.
But test yourself, though the Sigma showed rail in most cases, it did not show in the stitched pano besides D3100 and D5100. I am Nikonian, so you have to test the combination yourself. Just take 4 or 6 around, stitch, and you know all about it.
That's why the answer was a bit longer, a new System, and all of us had to learn how to use it properly. But once you have understood the principals and to reed the rail marks, you will be happy with it.
Success for you, feel free to ask,
Last edited by hindenhaag; 09-08-2011 at 06:03 AM.