Pentax FA 50mm f1.4 and F 50mm f1.4- difference?

dinneenp · 02-10-2011, 06:28 AM

Hi,
What is the difference between these two lenses?
FA is more common but which is better & why? which one should I buy or are the differences so small it doesn't matter.
I read both in the lens review section and these bits from people comments in the review section-
F build quality a little less than FA-sibling

F Build quality-wise it looks and feels a bit cheaper than the newer FA 50mm, but since they're optically identical, i could not care less

I was able to tell a difference between the FA and the F versions although the optics are supposed to be the same, perhaps a QC issue with the FA's (not that they are not very good lenses). The F's were just sharper.

Thanks,
Pa

dgaies · 02-10-2011, 06:48 AM

Optically they are the same. I'm sure there are copies of the F50/1.4 that are sharper than a given FA50/1.4 just as the reverse is true as well. Build quality is similar, I would say there might be a slight edge to the FA series, but not by a substantial amount IMO. The F50/1.4 is much more rare than the FA50/1.4, which is probably the primary reason that used F50/1.4 lenses sometime exceed the price of newer FA50/1.4 lenses. I believe the FA series lenses have more info on their chip in terms of MTF info, but I don't think that matters unless you're using "P" mode, and even then I don't know how much of a difference it would make.

wlachan · 02-10-2011, 07:43 AM

The F is believed to receive tighter QC, and the old photodo results suggest the same. As a Pentax users for 2 decades, I feel QC has slipped since the FA series, and worst now.

jjdgti · 02-10-2011, 10:33 AM

In my opinion. Difference between F50 1.4 and FA 50mm 1.4 is about $100 more for the F50 because it is more difficult to find one. I do not like much the F look on the lenses. I like the FA look more. It will be matter of preference. If you are looking for a lens that holds its value more pick the F50. Otherwise you can't go wrong with the FA (look for the ones made in Japan).

selar · 02-10-2011, 03:39 PM

Originally posted by dgaies

I believe the FA series lenses have more info on their chip in terms of MTF info, but I don't think that matters unless you're using "P" mode, and even then I don't know how much of a difference it would make.

IMHO, MTF info in the chip makes a big difference. When you set P mode to MTF, the camera auto selects the best aperture of the lens given the shooting conditions. Sort of like an aperture priority mode without having to shoot in Av mode, if all you are controlling Av manually is for getting the best resolution out of the lens.

dgaies · 02-11-2011, 12:42 PM

Originally posted by selar

IMHO, MTF info in the chip makes a big difference. When you set P mode to MTF, the camera auto selects the best aperture of the lens given the shooting conditions. Sort of like an aperture priority mode without having to shoot in Av mode, if all you are controlling Av manually is for getting the best resolution out of the lens.

Well, even without the MTF info, I was under the impression camera has default values it uses that I imagine are pretty close, even if they're not perfect. I've never really shot in "P" mode so I can't say I haven't given it a lot of thought. Put it this way, having the extra info there certainly can't hurt and all things equal I'd rather have it than not have it.

02-10-2011, 06:28 AM	#1
dinneenp Senior Member Join Date: Mar 2010 Location: ireland Photos: Gallery \| Albums Posts: 166	Pentax FA 50mm f1.4 and F 50mm f1.4- difference? Hi, What is the difference between these two lenses? FA is more common but which is better & why? which one should I buy or are the differences so small it doesn't matter. I read both in the lens review section and these bits from people comments in the review section- F build quality a little less than FA-sibling F Build quality-wise it looks and feels a bit cheaper than the newer FA 50mm, but since they're optically identical, i could not care less I was able to tell a difference between the FA and the F versions although the optics are supposed to be the same, perhaps a QC issue with the FA's (not that they are not very good lenses). The F's were just sharper. Thanks, Pa

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02-10-2011, 06:48 AM	#2
dgaies Veteran Member Join Date: Oct 2009 Location: Maryland / Washington DC Posts: 3,917	Optically they are the same. I'm sure there are copies of the F50/1.4 that are sharper than a given FA50/1.4 just as the reverse is true as well. Build quality is similar, I would say there might be a slight edge to the FA series, but not by a substantial amount IMO. The F50/1.4 is much more rare than the FA50/1.4, which is probably the primary reason that used F50/1.4 lenses sometime exceed the price of newer FA50/1.4 lenses. I believe the FA series lenses have more info on their chip in terms of MTF info, but I don't think that matters unless you're using "P" mode, and even then I don't know how much of a difference it would make.

02-10-2011, 07:43 AM	#3
wlachan Veteran Member Join Date: Sep 2006 Location: Canada Photos: Albums Posts: 2,625	The F is believed to receive tighter QC, and the old photodo results suggest the same. As a Pentax users for 2 decades, I feel QC has slipped since the FA series, and worst now.

02-10-2011, 10:33 AM	#4
jjdgti Veteran Member Join Date: Jun 2008 Location: NJ Posts: 1,824	In my opinion. Difference between F50 1.4 and FA 50mm 1.4 is about $100 more for the F50 because it is more difficult to find one. I do not like much the F look on the lenses. I like the FA look more. It will be matter of preference. If you are looking for a lens that holds its value more pick the F50. Otherwise you can't go wrong with the FA (look for the ones made in Japan).

02-10-2011, 03:39 PM	#5
selar Veteran Member Join Date: Jul 2007 Location: Sydney, Australia Photos: Gallery \| Albums Posts: 2,042	Originally posted by dgaies I believe the FA series lenses have more info on their chip in terms of MTF info, but I don't think that matters unless you're using "P" mode, and even then I don't know how much of a difference it would make. IMHO, MTF info in the chip makes a big difference. When you set P mode to MTF, the camera auto selects the best aperture of the lens given the shooting conditions. Sort of like an aperture priority mode without having to shoot in Av mode, if all you are controlling Av manually is for getting the best resolution out of the lens.

02-11-2011, 12:42 PM	#6
dgaies Veteran Member Join Date: Oct 2009 Location: Maryland / Washington DC Posts: 3,917	Originally posted by selar IMHO, MTF info in the chip makes a big difference. When you set P mode to MTF, the camera auto selects the best aperture of the lens given the shooting conditions. Sort of like an aperture priority mode without having to shoot in Av mode, if all you are controlling Av manually is for getting the best resolution out of the lens. Well, even without the MTF info, I was under the impression camera has default values it uses that I imagine are pretty close, even if they're not perfect. I've never really shot in "P" mode so I can't say I haven't given it a lot of thought. Put it this way, having the extra info there certainly can't hurt and all things equal I'd rather have it than not have it.