Summary: I have pictures and such in my blog article on this lens: http://photographybanzai.com/2010/11/24/lens-review-pentax-da-300mm-f4-sdm/
Pros: What I like about the lens:, - While I have not scientifically tested the lens, I feel that it is sharp enough from it’s widest aperture and have never found an image that was was not good enough due to optical quality., - It follows the tradition of Pentax rendering with vivid contrast. This len...
Cons: What I’m not too fond of:, - Maximum aperture of f4 is challenging at times with my K-7 because I like to keep the ISO low, but I’m not sure how much having f2.8 would really help…, - The lens isn’t cheap hovering around $1100, but good lenses hold value well., - Pentax SDM hasn’t had the best tr...
Pentax 300mm f/4 ED IF SDM SMC DA* review by sjwaldron
24 November 2010
Summary: What I like about the lens: - While I have not scientifically tested the lens, I feel that it is sharp enough from itâ€™s widest aperture and have never found an image that was was not good enough due to optical quality. - It follows the tradition of Pentax rendering with vivid contrast.
Pros: Sharp low chromatic aberration lens with quality build and WR.
Summary: Seems to be extremely sharp at all apertures except wide open (f/4). This is a big improvement over the non-ED(IF) lens. Blistering sharpness all the way down to minimum aperture. Integral tripod mounting collar on barrel balances a 67II body at precisely the right "sweet spot".
Pros: Extremely sharp optics, Tripod mounting collar built-in, Polarizer operating window in hood, excellent balance due to IF, can be hand held with fast film and high shutter speeds
Cons: Heavy...not for the faint of heart, Expensive (but worth it)