Pentax SMCP-M* 67 400mm f/4 ED(IF)

I found this lens by reading luminouslandscape web site. There is an extensive review on this lens. I brought it three years ago, but used it only a few times so far. However, pictures from this lens if very sharp! Few people can outdo luminouslandscape's review, but here I found how sharp this lens is using my D2x. Yes, I used the Nikon D2X, a home machined adaptor, and measured the lens! The D2X has the higest density of pixels on the market with 181 pixels per mm. It most likely would out perform any color film by a wide margin. I found that this lens is as sharp as the 200mm VR lens at f4! I shot 200mm lens at half the distance of the Pentax 400mm. The Pentax lens is sharper than 200mm VR+1.4 converter, and clearly sharper than that with a 2x converter. I also tested this lens against the Pentax 645 300mm ED lens: it beats the latter handsomely interms of resolution and contrast. This lens is super sharp at F4, 5.6, 8 (it seems that one might get a bit more info from this lens if the D2X chip has more pixels). Excellent at 11 and 16, fair at 22, poor at f32 and 45. F5.6 may be A BIT SHARPER BUT VERY HARD TO TELL. Now with converter. With 1.4x converter, this lens is as sharp as the prime lens at f5.6, 8, still excellent at 11, good at 16 and poor at 22. You would think that adding converter reduce the quality of the image, not with this lens. My nikon lenses do get worse with 1.4x. With 2x, slight loss of contrast but very sharp at f8, excellent at 11, good at 16 and poor at 22. I am thoroughtly impressed by this lens. I just brought a 600mm f5.6 ED lens for the Pentax 645 and waiting for shipping, thinking that I am going to sell the 400mm lens. But now, no way. I am keeping this gem until something can beat it. I am excited that I can use this lens with my Nikon D2x, my pentax645, Pentax 67. It would be nice though if I can compare this lens with the famous NIkon 500mm F4 EDIF P lens. My bet, it is going to be close.

Sharpness, even with 1.4x (the gray one) and 2x (gray colored) converters. Solid built. This lens made me more serious with telephoto photography.

heavy.

Most lenses for pentax67 under 400mm. 300mm ED f4 Pentax 645n Nikon 70-200 VR, 17-55mm. Nikon 300mm EDIF AFS f4 Large format.

none needed

If you need a long lens for the 67, and cost is secondary, this is it. I expect that the 1.4TC would have no effect on image quality. Hope to try it eventually. However, lens is big and heavy. I like it.

Vry sharp even wide open; as good as it gets; very well made. Rear filters do not affect image quality.

Front heavy; must be used on tripod; slow shutter speeds induce blur from shutter, even with mirror locked. Working on this.

None in MF; 300 F4 Nikon; 500 F8 Nikon.

None.