D810 + 24-70mm f/2.8G No Paralax Points (Entrance Pupil)?

[dwswager]

I'm getting ready to find the No Paralax points for the 24-70mm lens on the D810.  Shooting with the D7100, I would normall use the 16-35mm f/4 VR.  I find it helpful to have a guide to get me in the ballpark for testing.  When I looked at Really Right Stuff's website I found the data below.  I find this data totally inconsistent.  A small difference in the mounts between the D700 and D3s can't possibly lead to the huge differences in data for the same lens.

In testing previous zooms I own, I have found the No Parallax Points tend to be a linear function of the focal length.  The 24-70mm is an odd lens as it is fully extended at 24mm.  Retracts as you move to 50mm and then begins to extend again out to 70mm.  Hence, reconfiguration of the lens elements might introduce an inflection point. 

If you are willing to share your 24-70mm f/2.8G no paralax points and the camera it was tested with, I thank You!

[AreBee]

dwswager,

If you are willing to share your 24-70mm f/2.8G no paralax points and the camera it was tested with, I thank You!

The following are the settings for a D300 and 24-70mm combination, based on the use of a 360Precision panoramic head:

@24mm: 156mm
@28mm: 148mm
@35mm: 136mm
@50mm: 132mm
@70mm: 124mm

Presumably it is the difference in the above values that will be of use to you, rather than the values in absolute terms.

Hope this helps,

Rob

[dwswager]

dwswager,

The following are the settings for a D300 and 24-70mm combination, based on the use of a 360Precision panoramic head:

@24mm: 156mm
@28mm: 148mm
@35mm: 136mm
@50mm: 132mm
@70mm: 124mm

Presumably it is the difference in the above values that will be of use to you, rather than the values in absolute terms.

Hope this helps,

Rob

Your results are within the margin of error you might expect with those reported for the D3s in my original post.  The values for the D700 reported on the RRS website are not cosistent with either the D3s values nor do they make any sense all on their own.

What I wanted is a starting point.  And if I get something similar to your results and the D3s results, it gives more confidence in my own results.

Attached is a graph of your results, and within the precision of the methodology in which we identify the no parallax point, it is linear with respect to focal length.  That is also consistent with all my other zoom lenses.

[dwswager]

I tested the AF-S Nikkor 24-70mm f/2.8G last night on the D810 body.

@24mm = 152mm
@28mm = 146mm
@35mm = 137mm
@50mm = 132mm
@70mm = 125mm

Linear Trend Line:  No Parallax Distance from sensor plane (mm) = -6.8*(focal length)  + 158.8, R² = 0.994  [positive numbers in front of sensor plane, negative numbers behind.  This trend line only good for the specific lens and focal lengths from 24mm to 70mm.]

I plotted the RRS data from the D3s and the Data provided by AreBee for the D300 as well as my own and the trend line for my data.  

CONCLUSIONS:  

1. Given the precision of the testing methodology and error in test setup, the No Parallax Points for the 24-70mm is probably linear with respect to focal length.  

2. The trend line can be used with the focal length reported by the camera for any intermediate focal length not tested.

3. It appears that (as one would expect) that the Nikon lens mount on all cameras are the same distance from the film plane or within the margin of error of the testing procedure and therefore camera body should not matter.  (I would love to know the variation, if any, in Nikon lens mounts distance from sensor plane for Nikon DSLRs.)

[NancyP]

If F mount lenses are to be fully interchangeable among all F mount cameras, the flange-to-film or flange-to-sensor distance must be held constant, in this case, at 46.50 mm.  Otherwise, you would not get infinity focus. That's also why Canon bodies (flange to sensor distance 44.0 mm) can be adapted to use Nikon lenses. http://en.wikipedia.org/wiki/Flange_focal_distance

[dwswager]

If F mount lenses are to be fully interchangeable among all F mount cameras, the flange-to-film or flange-to-sensor distance must be held constant, in this case, at 46.50 mm.  Otherwise, you would not get infinity focus. That's also why Canon bodies (flange to sensor distance 44.0 mm) can be adapted to use Nikon lenses. http://en.wikipedia.org/wiki/Flange_focal_distance

Yeah, that is what I figured.  It only makes sense.  But since it is also why every pano discussion talks about measuring the NPP for every Camera/Lens combination.  I guess that suggests that their mounting for each camera differs.  I know RRS has the identical distances, unless they had to offset the plate to be able to allow access to camera ports.

Which would allow a real definitive database of NPP values for each lens that is then adjusted based on the camera mounting.