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Tuesday, May 07, 2013

I've Cropped My Pentax 645 Lenses Myself, in 1.6X! :-o

Since an original 645 lens when put onto an 135 FF body is cropped only 1.6X, I have decided to do this! :-o :-)

I suppose the degrade in IQ (in particular, the resolving power of the 645 lenses) would not be too much as this is exactly what Pentax has been doing/forcing us to do exactly the same thing with more or less the same crop ratio for all those K-mount film lenses of us when they are put onto *any* Pentax K-mount DSLR that was ever produced up till now! >:-[

Btw, the 645D is cropped in 1.3X on the original 120 FF format. So, this 0.3X difference could actually cost a lot, which I am not going to pay for that difference for that much anyway!

Consider also that the pixel pitch sizes of my 5D3 and the 645D are close enough, I suppose my FA645 lenses should be good enough to out-resolve the sensor at pixel level. :-)

Of course, for the overall resolution of the whole picture frame, the 645D still wins, i.e., 40MP over 22/24MP of the current 135 FF digital bodies which have the similar pixel sizes. Actually, this is what the line pairs per picture height or width (LP/PH or LP/PW) figure is going to tell.

Sample photos would follow.. The IQ of those old FA645 lenses on 5D3 is really impressive!


What is/are the Meaning(s) of a Cropped Digital System Now?

Comparison of Sensor Specs - 645D Against Others

This is What the Limited Lenses Should be Put Onto!

DIY: Adapting the Pentax FA*85/1.4 onto the Cantax K-5D Mark III