Finding optical center of a lens

[AgX]

What practical way apt for a home workshop is there to find the optical center of a given spectacle lens.

 

[AgX]

Of course I thought of the optician in town. But, as I am considering the use of cheap plastic lenses a DIY approach would be more appropriate.

 

[Dr Croubie]

Is this for lens-building (centre of element), or for panoramic-stitching (centre of lens)?

For Panos there's always the DIY way, which is just keep taking shots and rotating and making sure they line up with no parallax (possible on film, but a lot cheaper with more recently-invented technology).

For finding the centre of an element, maybe you could do the same thing? Depends if you need precision to within a few mm, or a few microns.

 

[AgX]

It is for lens building. More precise for diopter modification. Plastic spectacle lenses are not only cheap but also easy to cut.

I just remembered that spectacle frames often show the center distance. Thus the easiest way I guess would be just to take that figure, center it and cross it with half of the lens vertical diameter, to get somewhere near the center of the lenses...

 

[ath]

The Vertometer is called "Scheitelbrechwertmesser" in german and completed auctions on ebay Germany start at about 50€.
If I would start lens assembly I would buy one.

 

[johnielvis]

What practical way apt for a home workshop is there to find the optical center of a given spectacle lens.

You're usually such a know it all asshole, why don't you figure it out yourself?

 

[paul ron]

Curious... I took a closer look at my prescription glasses n found the centers of the lenses also seems to be the thinest part of the lens.... Of course assuming the center would cooincide with where my pupils seem to align as center to center.

 

[AgX]

Yes, I also thought of measuring the lens thickness. I am interested in positive menisci. Thus I would have to fix a tiny sphere to one of the ends of a micrometer caliper. Something well in the range of a DIY workplace.

 

[AgX]

Never ever seen such. (And I thought I would know a bit about tools...)