What's the difference between F and FA series 50mm f1.7?

dgaies · 06-30-2010, 10:47 AM

Originally posted by Eruditass

I don't think they're talking about the lens correction, but MTF information (for K20D and K-7's MTF program line)

Correct, from what I've read there is more information contained in the FA version in terms of MTF information.

Neither the F nor FA 50/1.7 can take advantage of the in-body lens correction. That only works with DA lens (and FA limiteds via firmware update).

Indecent Exposure · 06-30-2010, 09:04 PM

Originally posted by dgaies

Correct, from what I've read there is more information contained in the FA version in terms of MTF information.

Neither the F nor FA 50/1.7 can take advantage of the in-body lens correction. That only works with DA lens (and FA limiteds via firmware update).

This is absolutely correct information.

My findings from use, are the F is easier to manual focus if one is doing so. Like an earlier poster said the F and FA are "spot on focus" when in AF mode.

One issue I have had with the FA was when I was pointing the lens downward to photograph a butterfly on the ground. The front element shifted and rendered the lens useless. It had to be sent back to Pentax for repair. Pentax replaced the lens with a brand new one.

It was rather disturbing to have a lens nearly fall apart when it was rather new out of the box. Has anyone else experienced anything like this? I am literally afraid to point this lens downward.

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06-30-2010, 10:47 AM	#16
dgaies Veteran Member Join Date: Oct 2009 Location: Maryland / Washington DC Posts: 3,917	Originally posted by Eruditass I don't think they're talking about the lens correction, but MTF information (for K20D and K-7's MTF program line) Correct, from what I've read there is more information contained in the FA version in terms of MTF information. Neither the F nor FA 50/1.7 can take advantage of the in-body lens correction. That only works with DA lens (and FA limiteds via firmware update).

06-30-2010, 09:04 PM	#17
Indecent Exposure Inactive Account Join Date: Sep 2008 Location: Michigan Photos: Albums Posts: 78	Originally posted by dgaies Correct, from what I've read there is more information contained in the FA version in terms of MTF information. Neither the F nor FA 50/1.7 can take advantage of the in-body lens correction. That only works with DA lens (and FA limiteds via firmware update). This is absolutely correct information. My findings from use, are the F is easier to manual focus if one is doing so. Like an earlier poster said the F and FA are "spot on focus" when in AF mode. One issue I have had with the FA was when I was pointing the lens downward to photograph a butterfly on the ground. The front element shifted and rendered the lens useless. It had to be sent back to Pentax for repair. Pentax replaced the lens with a brand new one. It was rather disturbing to have a lens nearly fall apart when it was rather new out of the box. Has anyone else experienced anything like this? I am literally afraid to point this lens downward.