I have had my non-beta Lensbaby for 11 days now. So here is what I've learned about this bendy lens in regards to apertures (beta versions had fixed f5.6 to f8 aperture so I have known for awhile what the darker apertures do).
F2.8 is very diffused giving a soft focus look in the sweet spot in addition to the very soft edges. A sharp image can be distinguished from the diffused areas if you have attained proper focus. It can be hard to focus at f2.8 as the diffusion is a bit confusing on the eyes.
I'm finding that f4 is a good balance for general subject matter. Sharpness is mixed with a little diffusion at f4 even in the sweet spot and focus falls off fast.
At f5.6 the diffusion is minimized but focus falls off fairly fast even still.
F8 is about as sharp in the center as my 50mm f1.4 Nikkor is in its center when shot wide open. F8 gives a subtle blurring around the edges that is nice for scenes where too much blur will detract from the subject matter instead of compliment it.
The plane of focus is curved so if you are looking through a window frame at a distant image the window frame will have more sharpness than you might expect when the sweet spot is focused on the distant object. The "sharp" window frame will still have some color issues because these lenses focus all three colors together only in the central sweet spot.
The below images were shot at f4.
Have a super day.
-Craig
You could not step twice into the same rivers; for other waters are ever flowing on to you.
Heraclitus of Ephesus
