distance scale on lenses

Chan Tran · Jul 22, 2016

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 · Jul 22, 2016

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

pbromaghin · Jul 22, 2016

Theo Sulphate said:
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 · Jul 22, 2016

Theo Sulphate said:
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 · Jul 22, 2016

pbromaghin said:
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 · Jul 22, 2016

Theo, thank you for that information.

RalphLambrecht · Jul 23, 2016

Chan Tran said:
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 · Jul 23, 2016

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 · Jul 23, 2016

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

Chan Tran · Jul 23, 2016

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

bdial · Jul 23, 2016

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 · Jul 23, 2016

bdial said:
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 · Jul 23, 2016

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

BrianShaw · Jul 23, 2016

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

Chan Tran · Jul 23, 2016

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.

distance scale on lenses

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