D90 + 10.5mm Fisheye rail settings?

[amt2002]

Sorry to post a question but I'm having a horrible time trying to find the rail settings manually (I have followed John's guide but am still struggling to get it nailed - unlike with my D70 set up that was good to go within a half hour of fine tuning!)

I'm using a Nikon D90 with Nikkor 10.5mm Fisheye lens using the NN3 (II) (with NCP camera mounting plate - which adds 10mm to the lower rail if anyone is wondering)

If anyone is using this combo (surely it's quite a popular one) then please could you post your settings?

Many thanks,
Alex.

[DorsetJohn]

Hi Alex
Yes, I've just invested in a D90 and a Nikon 10.5, with an NN3 Mk 2 - so far I've found bottom rail stop set at 78 and the top rail at 95 - but I'm still adjusting a mm at a time - initially I had the extreme bottom corner of the splay on the upright in the bottom corner of the frame - that's now gone, but I don't yet know whether I've over-compensated and could reduce it slightly!! That's the next trial - just a matter of finding the time to experiment. What settings are you working on and what is your subject matter, interiors?
Regards
John

[hindenhaag]

Hi guys,

all nikon F-mount cameras have a distance lens flange to sensor of 46.5 mm. We only find differences in the tripod mount position of the cameras.

When looking for a lens try to find it in the data base. D200 with 10.5 has an upper rail setting of 86. Distance for D200 lens flange tripod mount is 40mm. Now rail setting of 86 minus 4 = 82.

Now we are at the "neutral position lens flange" , now add your LF TM distance, and you should be with the right upper rail position.

Cause i try to set up a new database, please tell me the distance for the D90. FF = Lensflange, TM = Tripod Mount. Everybody who reads this, please tell us the distance for your nikon model. Thanks in advance.

By the way, all Canon EOS models have a distance of 44.0 mm LF to Sensor, Sony Alphas a distance of 44.6.

Does it work for you?

Heinz

[DorsetJohn]

Thanks Hindehaag, the NN database is very good but there were no dims for a D90 on it when I started to set up my rig - I started from the D80 data with a 10.5 and worked from there....I have noted another small wrinkle (I haven't had my NN3 very long, so this comment may be obvious to more seasoned users) that can make quite a difference to the settings and that is the orientation of the base plate. I was setting up for a session recently and rather casually unfastened it from the top rail, screwed the mounting plate into the camera tripod fixing, squared it up and fixed it back into the top rail - the lens was positioned way too far forward - I realised that there was something like a 20mm error arising from the base plate being mounted back to front, due to the offset of the two mounting screws - I won't do that again! This 'Gotcha' is not mentioned in the set-up and it's just the sort of inadvertent error that recent converts can easily make and then could have an up-hill struggle trying to make their set-up match the dims stated in the database / on the forum.

I'm also still slightly puzzled about the vernier style scales along the sides of the camera base plate - especially as there are no accurate reference points on the side of the top rail, only a single line on the back that aligns with the top rail scale.... so are the 'saw tooth' side scales functional or just fancy?? If functional, what are they for and how are they referenced to the top rail??

[DorsetJohn]

Hi again Hindenhaag - Sorry to be pedantic, but I have just re-read you post and I'm afraid I don't understand the maths - LF to Sensor 46.5mm - Yes - got that. It's the D200 example that I am having a problem with - upper rail setting 86 - OK, I understand that - Distance for LF to tripod mount 40mm - OK - But why is the rail setting of 86 then reduced by 4mm - where does the 4mm come from? I'm new to this so it may be something that I should know - I must apologise in advance for my ignorance!!!
Regards
John

[John Houghton]

Distance for LF to tripod mount 40mm - OK - But why is the rail setting of 86 then reduced by 4mm - where does the 4mm come from?

Obviously you need to subtract 40 from 86 to get the position of the lens flange on the upper rail scale. Then add the tripod mount to lens flange distance of a different camera (having the same sensor to lens flange distance) to get the correct upper rail setting for that camera.

John

[hindenhaag]

Hi John,

Sorry for my mistake, it has to be 40mm instead of 4. So John H. is right, it is 86mm upper rail setting from D200 minus 40mm distance lens flange/tripod mount D200, plus distance LF/TM of the D90, which is 40mm as well: upper rail setting is 86mm.

Cause the distance LF/TM are the same for the D200 and the D90 = 40mm, you just can transfer the data for lenses and upper rail settings from the D200 to the D90.

I borrowed a D90 for the weekend to check some data. The lower rail setting i found for the D90 checked with a levelled laser is 53mm.

Now some hints on how to use the base plate: look to it from the bottom side and you see a single strip on top and below the yellow screw: only these lines are used for the rail settings. the other lines on the side of the plate are ment to be used to set the plate in 90 degree to the body of the camera, by comparing these lines to lines on the bottom of the camera.

Now take the plate, watch the two lines and turn the plate 180 degrees around the screw, doesn't' matter the long side to the right or the short side. The reference point will always be the same.

I am short in time today so i will send pictures about this to you the next days.

Heinz

[DorsetJohn]

Hi Heinz (and John H)
Thanks for clearing up the 4mm question - a typo!! The 40mm makes complete sense!!

I have tried the base plate rotation 'test' on my NN3 and the top rail setting changes from 82mm to 92mm depending on the orientation of the plate (with the stop retained in its usual position). The offset between the brass camera body fixing and the tread for the top rail mounting screw is the clue to the offset. It was the ease with which this could be misaligned that caused me to ask - it could be too easy to set it up wrongly in haste and not realise until too late when you get back to the computer only to find that the alignments for stitching are simply not there!!

Regards

John