>>3697463I have no experience with the other ones.
These will make your image softer so i think 1/2 would be pretty extreme and only usable for like 80'90's glamour shot things. Sometimes the light blooms are so strong with 1/4 that they can take over.
1/8 is probably nice but i think if you are going for an effect you would want it a bit more noticeable.
1/4 seems like a sweet spot