Well, most probably it is memory and such. JC Penney lenses are really not good usually, most of them are super cheap.

Testing the Venus Optics LAOWA STF 105 mm f/2 (T3.2) was a real pleasure for me. Not only it is able to generate exceptionally sharp images but also it provides an additional function, allowing you to play with out-of-focus blur in a creative way. What’s more, the lens is very well-done, engaging pleasantly your sense of sight and sense of touch.

http://www.lenstip.com/index.php?test=obiektywu&test_ob=480

This all-metal mechanical lens reminds me of 1970s Japanese third-party lenses: it's all anodized aluminum with engraved markings. It's a solid all-metal lens; there is no plastic. It's tough and simple.

It's super-sharp. Even wide-open in the corners of my 50 megapixel Canon 5DSR it's still super sharp. There is the tiniest bit of red-blue lateral color at the sides at 50 MP, but it's too minor to notice in actual photos and Nikon cameras correct this automatically. There are no dedicated profiles for Canon cameras.

http://www.kenrockwell.com/tech/laowa/105mm.htm

Field test

http://www.imaging-resource.com/lenses/laowa/105mm-f2-stf/review/#fieldtest

Review

https://matthewdurrphotography.com/2017/06/14/venus-optics-laowa-105mm-f2-stf-review/

Samples

http://www.photographyblog.com/previews/laowa_105mm_f2_stf_photos

Review

https://sonyalpha.blog/2018/01/21/laowa-105mm-f2-t3-2-stf-smooth-trans-focus/