[Scythels]

I highly doubt there is any acryl plastics instead of glass in that lens.

Why is that?  There's nothing wrong with acrylic - the second best corrected category of lenses (phone lenses) are largely acrylic.  Acrylic has a refractive index similar to K10 or NFK15.  It has stronger dispersion but it becomes gelatinous (Tg = temperature of 'gelatination') at a low temperature and is the material of choice for most "hybrid" and "molded" aspheric lenses.  There are few low Tg glasses available and they are expensive (80-100x the price of BK7).

 

Here's Ohara's current calendar - notice that there are over 100 normal glasses and 16 low Tg glasses.  This is after Ohara has discontinued 40% of its normal glass catalog to meet environmental regulations in the last 5 years.  I can give you Schott's catalog as well but low Tg glasses are not nicely separated in theirs - there are about 17 covering a similar range as Ohara's.  PK52A is an extremely nice glass that has low Tg and very minimal dispersion and only 13x BK7 cost, but it has poor stain and poor abrasion meaning you can mold it easily but the mold must be extremely precise as it is very difficult to change the surface through grinding or traditional polishing methods.

 

The common myths of "glass lenses are superior" - especially ones with 'nice, german glass' (i.e schott) are old photographers' myths.  Certainly any lens made mostly of acrylic would be extremely difficult to correct for polychromatic aberrations but it is a fairly nice material to work with and is in no way inferior.  There are many glasses which are much worse than Acrylic.  People may also be surprised if they learned that lots of the national associations for glasses are 'invalid'... both Schott (DE) and Ohara (JP) produce extremely large volumes of optical glass in the US.

 

There could be acrylic in a phone lens, or a photographic lens, or a $10M one of one large optic, or a $50k cinema lens, or any other application - it's not bad.  The f/0.48 lens we have in the lab I work in contains an acrylic element and it is a far more impressive specimen than most any photographic lens.