distance scale on lenses

[Chan Tran]

I wonder what the distance scale on the lens related to. The distance from the subject to entrance pupil or it's the distance from subject to film plane?

 

[Theo Sulphate]

Subject to film plane. There should be an engraved mark on the camera indicating the plane.

 

[pbromaghin]

Subject to film plane. There should be an engraved mark on the camera indicating the plane.

I thought it was to the center of the lens (the place where the image flips over).

 

[Chan Tran]

Subject to film plane. There should be an engraved mark on the camera indicating the plane.

I thought so too and I do know about the film plane marking but the trouble is most my lenses the scale do not agree with my measurement.

 

[Theo Sulphate]

I thought it was to the center of the lens (the place where the image flips over).

The reason the distance scale on the lens refers to the focal plane (where the film or sensor is) is so that the distance reading will be consistent among lenses.

http://www.photokonnexion.com/definition-focal-plane-mark/

"Various aspects of critical-focus work can be measured from the focal plane mark. It gives a consistent point for measurement. The focal plane remains in a fixed position regardless of which lens is in place. Thus, the focal plane mark acts as a fixed measurement point."

 

[pbromaghin]

Theo, thank you for that information.

 

[RalphLambrecht]

I wonder what the distance scale on the lens related to. The distance from the subject to entrance pupil or it's the distance from subject to film plane?

distance from nodal point to subject.

 

[Chan Tran]

If it is the nodal point then is it the front or the read nodal point? I guess the front would make more sense but of course there are lenses that the front nodal point is behind the read one.

 

[MontanaJay]

And now from our Department of Pointless Technology Department:
http://petapixel.com/2016/07/22/canon-lenses-may-soon-digital-display/

 

[Chan Tran]

It's not pointless I have been asking for such a feature for a long time. Provided of course it's accurate.

 

[bdial]

Just double-checked in a Hasselblad manual, and it states that the distance shown is measured from the film plane.
I am pretty sure this is true for Nikon as well, but I can't find any manuals that say it at the moment.

 

[Ricardo Miranda]

Just double-checked in a Hasselblad manual, and it states that the distance shown is measured from the film plane.
I am pretty sure this is true for Nikon as well, but I can't find any manuals that say it at the moment.

Page 44: http://www.cameramanuals.org/nikon_pdf/nikon_fg.pdf

 

[AgX]

If not explicitely stated otherwise, the distance scale on lenses is related to the film plane.

 

[BrianShaw]

If it were not from subject to film plane then infinity wouldn't focus correctly on the film, eh?

 

[Chan Tran]

I believed they meant to be from the film plane too. But if it is so then the scale on my Nikkors are wrong. The actual distance is somewhat more than what said on the scale.