I also have the DA40 green ring lens. It is the most colorful lens among the Pentax DA lenses (I don’t think there is one), the bokeh is also good, and the workmanship is superb
In fact, the green lens is There is no big difference between the circle and the red circle in terms of imaging. I personally feel that the DA40 with the green circle looks better and is more low-key. The red circle is not Pentax’s traditional style.
In fact, the green circle and the red circle are the largest. The difference is the coating, one is SMC and the other is HD. At present, the HD coating will not bring a quality improvement to the lens, but only improves the anti-glare aspect, but the SMC coating itself is very powerful in anti-glare.
Therefore, Ricoh's replacement of HD coating is more due to business and packaging needs, because the SMC coating patent is still in the hands of HOYA. In order to avoid the patent, lower-cost HD coating is used.
My personal feeling is that between the green circle and the red circle, whichever is cheaper will be chosen