Let's start from the assumption that I purchased these filters and they were not sent to me to review them for free like other people, so I will give an unconditional and objective opinion.
Having said that, I chose not to return them and keep them with me because they are truly unbeatable in quality/price.
Specifically, I have absolutely not found any cons worthy of note but only pros, such as:
- Truly exceptional quality/price, with the cost of a black mist of any other brand you take home two with intensity 1/8 and 1/4 allowing you to modulate the effect based on different situations and conditions.
- Not excessive effect: for me it is absolutely a pro, because the effect that is given especially with the 1/8 is very limited but present, allowing you not to ""wash out"" the contrasts while always maintaining excellent blacks with a slightly more ""dreamy"" effect of the lights.
- threading on BOTH filters FORWARD and BEHIND! This is a fantastic thing because you can not only mount the 1/8 and 1/4 filters directly on top of each other to maximize the effect, but you can also mount an ND filter at the same time and this is the TOP.
I have attached 4 photos taken with Sony ZVE10, Sigma 16mm, F1.4, ISO125 in a completely dark room. The first photo is without filters, then 1/8, 1/4, 1/8+1/4.
I hope I was helpful.