Pentax 645 FA lenses

itshimitis · 12-13-2014, 09:03 PM

Originally posted by Vaards

Rest in peace, Henri!
You used lenses on those days what we can`t beat even today!

Or our dear friend and pixel peeper Ansel - he carried his 8x10 camera everywhere. Imagine those unmached megapixels...

really soon it might be important - to enjoy crisp and clear image: Why Megapixels and Pixel Peeping may soon be important ? Thomas Fitzgerald Photography Blog

Solution? Print more rather than keeping your nose on a screen. I don't have an issue with resolution as only one of my cameras is below 36mp. But anyone that sees sharpness as being more important than the feel of a photograph is misguided.

rick_reddy · 12-14-2014, 12:55 AM

I appreciate your thoughts. Thanks for taking a moment to respond.

Kolor-Pikker · 12-14-2014, 02:41 AM

Ok, so I redid the test and I guess something WAS wrong when I tested the 120mm... because as it well should be, it's sharper than the 150 at every step of the way until f/8, at which point they look about the same.
However, the macro still has more CA, particularly in the corners, and while it's appreciably sharper in the center and corners than the 150mm until f/5.6, the 150 overtakes the macro in corner quality at f/8.

Even looking at photos of 3D objects, these lenses still only seem to become critically sharp at f/8, where stuff like the fibers on cardboard and dust pops into view, but is almost invisible at f/4 or wider. Regardless of the "sharpness doesn't make art" aspect of all of this, the original question of this thread was "Do the FA lenses resolve the 40MP sensor?", and in that sense, yes, they do, but only starting from f/5.6 I reckon. In practical terms, none of this is what I believe you would really see until you print 30x40" or bigger.

rick_reddy · 12-15-2014, 11:40 AM

Originally posted by Jonathan Mac

The digital 645s are both compatible with older A and FA series lenses in exactly the same way as A and FA K-mount lenses are compatible with DSLRs. They use screw-drive rather than the newer in-lens motors and they were designed and tested for use on film in an age where characteristics other than just sharpness were more highly valued. In short, they will work perfectly, but they may not produce the image quality of lenses designed for use on the digital bodies.

My three A series 645 lenses are fabulous, at least on my original 645 from the eighties

Jonathan Mac has a good point. It's silly of me to ask what kind of image quality results with a digital rig, when I know my 645n delivers stellar photographs!

In the old days, I remember photographers were snooty about 645 format, and they'd say it's really not medium format, and has all the disadvantages without the benefits. How uncharitable! My Pentax 645n is a great outdoor camera, and the image quality is superb.

For digital I ordered-up a humble Sony 7II, and will continue to use my 645n body and film. I would wager few people can tell the difference between 24 and 50 MP and for large prints I would probably grab a film camera anyway.

12-14-2014, 12:55 AM	#17
rick_reddy New Member Join Date: Mar 2010 Posts: 20 Original Poster	Thanks! I appreciate your thoughts. Thanks for taking a moment to respond.

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12-13-2014, 09:03 PM	#16
itshimitis Pentaxian Join Date: May 2011 Location: All over the place Posts: 3,535	Originally posted by Vaards Rest in peace, Henri! You used lenses on those days what we can`t beat even today! Or our dear friend and pixel peeper Ansel - he carried his 8x10 camera everywhere. Imagine those unmached megapixels... really soon it might be important - to enjoy crisp and clear image: Why Megapixels and Pixel Peeping may soon be important ? Thomas Fitzgerald Photography Blog Solution? Print more rather than keeping your nose on a screen. I don't have an issue with resolution as only one of my cameras is below 36mp. But anyone that sees sharpness as being more important than the feel of a photograph is misguided.

12-14-2014, 02:41 AM	#18
Kolor-Pikker Veteran Member Join Date: Dec 2014 Posts: 344	Ok, so I redid the test and I guess something WAS wrong when I tested the 120mm... because as it well should be, it's sharper than the 150 at every step of the way until f/8, at which point they look about the same. However, the macro still has more CA, particularly in the corners, and while it's appreciably sharper in the center and corners than the 150mm until f/5.6, the 150 overtakes the macro in corner quality at f/8. Even looking at photos of 3D objects, these lenses still only seem to become critically sharp at f/8, where stuff like the fibers on cardboard and dust pops into view, but is almost invisible at f/4 or wider. Regardless of the "sharpness doesn't make art" aspect of all of this, the original question of this thread was "Do the FA lenses resolve the 40MP sensor?", and in that sense, yes, they do, but only starting from f/5.6 I reckon. In practical terms, none of this is what I believe you would really see until you print 30x40" or bigger.

12-15-2014, 11:40 AM	#19
rick_reddy New Member Join Date: Mar 2010 Posts: 20 Original Poster	Originally posted by Jonathan Mac The digital 645s are both compatible with older A and FA series lenses in exactly the same way as A and FA K-mount lenses are compatible with DSLRs. They use screw-drive rather than the newer in-lens motors and they were designed and tested for use on film in an age where characteristics other than just sharpness were more highly valued. In short, they will work perfectly, but they may not produce the image quality of lenses designed for use on the digital bodies. My three A series 645 lenses are fabulous, at least on my original 645 from the eighties Jonathan Mac has a good point. It's silly of me to ask what kind of image quality results with a digital rig, when I know my 645n delivers stellar photographs! In the old days, I remember photographers were snooty about 645 format, and they'd say it's really not medium format, and has all the disadvantages without the benefits. How uncharitable! My Pentax 645n is a great outdoor camera, and the image quality is superb. For digital I ordered-up a humble Sony 7II, and will continue to use my 645n body and film. I would wager few people can tell the difference between 24 and 50 MP and for large prints I would probably grab a film camera anyway.