Mini CS mount telephoto lens - bad idea?

[Ags]

My ASI 178 MM has a little sensor and the below lens (75mm, F1.8) is WAY cheaper than a Canon 85mm f1.8 (less than 50 euros). It supports 8 megapixel resolution for a 15mm image circle, so it is best suited to sensors with 4.8 micrometer pixels (I don't know if that is the wide-open resolution). The ASI 178 pixels are half that size so it would require binning. It is easier to make a small lens than a big one, so is it possible this could work for AP? Also note it has M37 filter thread on the front.

https://www.aliexpress.com/item/32656983113.html?spm=a2g0o.productlist.0.0.45767326eAzVYZ&algo_pvid=7634b0a7-7f6c-4e05-acb5-aaf4b936a63a&algo_expid=7634b0a7-7f6c-4e05-acb5-aaf4b936a63a-19&btsid=0b0a182b15847098141292503efe8c&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

The lens body says F2.8 but the product description says F1.8... 😐

Edited March 23, 2020 by Ags

[Ags]

Hmm, if the front thread is M37, the lens can't be F1.8 as if it was the front lens would have to be over 40mm....

[Ags]

This one may or may not be F1.8:

https://www.aliexpress.com/item/32776332053.html?spm=a2g0z.12010612.8148356.28.732e47f4i0cO1Z