Originally posted by Miserere Kelly,
I don't have any suggestions for spherically-aberrating lenses, but I can suggest a good therapist that could help you with your...issues. PM me for more info.
Noo! I want to continue to believe that life is better through spherically aberrated, rose-colored glasses!
Originally posted by troyz Agreed! Two references for optics/physics nerds:
This one focuses (actually, defocuses
) on test charts:
Bokeh
This one discusses the Nikon DC lens (where you get to dial in the spherical abberation correction you want
)
Nikon | Imaging Products | NIKKOR - The Thousand and One Nights, Tale 32 : Ai AF DC Nikkor 135 mm f/2S
So I wonder:
-- Could one make a reliable, easy standardized test for foreground and background blur disk shape (like the grid-of-white-dots in the first reference)?
-- Could one predict real-world bokeh performance from the test results?
Great links Troyz. Admittedly, I'd be quite curious to experiment with those Nikon lenses. That said, I was also quite surprised to learn how dramatically AF performance holds sway over the optical formulation of a lens. I'm left to wonder in how many cases the need for ever faster AF has influenced optical design to the deteriment of other considerations, such as 'pleasant' OOF rendering?
I suspect the market plays to each demand in such that one can find both extremes - quick focusing kit lens types and manual bokeh monsters like the Nokton. I'd also suspect that science minimizes the impact of these trade-offs - but the fact there are trade-offs was eye-opening, for me. I wonder if there is any correllation between that and the fact I'm left with only 1 AF lens at all (the FA31), which I barely use? huh... food for thought.
With regards to your suggestion of standardized tests for oof rendering - I think as long as the scope remained catagorically objective, it would be helpful. Then if you knew you liked several spherical aberrators for example, you could isolate your search to others of the ilk. Strictly adhering to scientifically minded observations could be helpful in this way, though even if a conclusive list of oof characteristics was able to define all lenses, it still wouldn't get us any closer to knowing which were more pleasing - we could never quantize beauty.
I sort of wonder why this hasn't been attempted already for informational purposes... maybe now is the time?
Originally posted by k100d as per my rangefinder craving, been reading into different lenses and it seems the sonnar designs have a tonne of Spherical abberation for some very interesting bokeh. however, it seems that one of the side effects is focus shift. for rangefinders this is killer because you don't know for sure where the true focus point is.
some samples
Flickr: Search
and here is what zeiss had to say about their 50mm Sonnar lens
source:
Zeiss M-Mount Lenses ... the review is critical of the lens but at the time it was written, zeiss had not made this statement explicitly clear
More cool linkage. I wonder how an email to Zeiss about the possibility of producing a sample of the Sonnar in K would be received? I suppose it may not even be possible, but can it hurt to ask?
Meantime, I'm off to research M42 Sonnars, lol.
EDIT - The Sonnar 50/1.5 doesn't exist for M42... one less thing to covet.