How thin would you surface 1.67 for a -12.00

[icare]

Just curious how thin most labs would surface 1.67 on a higher minus job. I'm looking at an Autograph PAL that came through at 1.8 ct. Would many labs go thinner? We simply specified "thin as possible." Curious if we could have gone much thinner. TIA

[rbaker]

Any thinner and neither you nor your customer would notice any difference. In this case, its not "thin" but "safe."

[Lab Insight]

Any thinner and neither you nor your customer would notice any difference. In this case, its not "thin" but "safe."

1.2mm ct is optimal. Anything less may result in poor distorted optics and oil canning in frame.

[lensmanmd]

Just curious how thin most labs would surface 1.67 on a higher minus job. I'm looking at an Autograph PAL that came through at 1.8 ct. Would many labs go thinner? We simply specified "thin as possible." Curious if we could have gone much thinner. TIA

Speaking with Zeiss and IOT, our 2 main freeform designs, both have stated that 1.8 is optimal for FF. We set ours @ 1.5 for traditional surfacing, primarily for the backside spin coating, and let the sdf dictate CT for FF desings. We have found that any thinner than 1.5, the center warps.

[Chris Ryser]

1.2mm ct is optimal. Anything less may result in poor distorted optics and oil canning in frame.

Perfect advice Lab Insight......................................

We all know why somebody would like to have the thinnest appearing -10.00 or higher lens. Better cosmetic appearance.

During the 1960's and 1970's my old lab days we developed the most perfectly appearing hida bevel for high minus lenses that nobody ever picked up ever since, even if we could charge an extra $ 20.00, doing it manually in those days.

Instead of having a small protruding V bevel on the standard flat one, we made two grooves side by side into the flat bevel to create an inverted V towards the center of the lens and to hold the lens in the frame. This eliminated just about all reflections and looked many times better, either polished or not, and that is for better cosmetic appearance.

Any high minus lens user would probably pay a lot more for such a lens job these days, as no automatic bevel edger can make a job like this today and they are stuck in 40 a years old grinding technology with no research done on it.

[Craig]

Perfect advice Lab Insight......................................

We all know why somebody would like to have the thinnest appearing -10.00 or higher lens. Better cosmetic appearance.

During the 1960's and 1970's my old lab days we developed the most perfectly appearing hida bevel for high minus lenses that nobody ever picked up ever since, even if we could charge an extra $ 20.00, doing it manually in those days.

Instead of having a small protruding V bevel on the standard flat one, we made two grooves side by side into the flat bevel to create an inverted V towards the center of the lens and to hold the lens in the frame. This eliminated just about all reflections and looked many times better, either polished or not, and that is for better cosmetic appearance.

Any high minus lens user would probably pay a lot more for such a lens job these days, as no automatic bevel edger can make a job like this today and they are stuck in 40 a years old grinding technology with no research done on it.

Can you show a picture?

[rbaker]

Also, back in the day (60's) there was a company called "Ancyclo, in Baltimore ? ? ?" that did an amazing surfacing and hid-a-bevel and edge coating to match the frame coloring. I have never seen anything to match the quality of their work. I do believe that they closed up shop with the advent of polymer lenses. They did amazing things with 1.8 index glass lenses.

[Sledzinator]

Speaking with Zeiss and IOT, our 2 main freeform designs, both have stated that 1.8 is optimal for FF. We set ours @ 1.5 for traditional surfacing, primarily for the backside spin coating, and let the sdf dictate CT for FF desings. We have found that any thinner than 1.5, the center warps.

With this being the case I wonder at what power range you switch from a 1.5 ct poly to a 1.8 ct high index.