645 Lens "A" vs "FA"

BBC5 · 11-01-2014, 09:41 PM

In the Pentax Lens Review Databaseit says that "A" lenses are manual focus (1980's) and "FA" lenses are autofocus (1990's)
Are there any difference between these 645 lens ("A" vs "FA") besides focus function?

Adam · 11-01-2014, 09:45 PM

The barrels are different, and many FA lenses have different optical formulas compared to the A versions. All that info should be in the lens database for each individual lens

BBC5 · 11-01-2014, 10:32 PM

Originally posted by Adam

The barrels are different, and many FA lenses have different optical formulas compared to the A versions. All that info should be in the lens database for each individual lens

How about image quality between the versions? Infinity focus the same between them?

Adam · 11-01-2014, 11:42 PM

Originally posted by BBC5

How about image quality between the versions? Infinity focus the same between them?

The best place to look is the user reviews. But yeah, they can all focus to infinity of course.

Adam
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**Ed Hurst** · 11-02-2014, 02:16 AM - **1 Like**

As Adam says, best to look at each one you're interested in. Some of them are different optically between FA and A, others seem to be much the same (though the coatings might be updated on the FA). There just isn't a single answer for all A-FA comparisons.

BBC5 · 11-02-2014, 10:09 AM

Originally posted by Adam

The best place to look is the user reviews. But yeah, they can all focus to infinity of course.

And if the lens doesn't focus to infinity, I must of got a bad copy of the lens...

mikeSF · 11-02-2014, 12:06 PM

IMO, some of the best lenses of the 645 mount are the A-series (35 & 120). There are some differences here and there and hard to say that across the board, FA are better/worse.
I have a few of each as well as some 67 mount lenses for my 645D and overall very pleased with my kit.

**Ed Hurst** · 11-02-2014, 05:56 PM

I also prefer the 35mm A to the 35mm FA. With the 120, I think they are optically identical (can't be sure coatings didn't change slightly, but can't see any difference whatever in performance); that it is to say both are world class!

**Ed Hurst** · 11-02-2014, 05:58 PM

One example where the lenses are quite different is the 150. The FA is not just faster but better all round IMO. So, in short, treat each case separately and do the homework ;-)

**yurihuta** · 11-02-2014, 05:58 PM

Some non-lens possibilities...

Could it be that the focusing screen is not seated properly and/or misaligned?

Another possibility is that the mirror is not stopping in the correct position.

Originally posted by BBC5

And if the lens doesn't focus to infinity, I must of got a bad copy of the lens...

BBC5 · 11-02-2014, 06:10 PM

Originally posted by yurihuta

Some non-lens possibilities...

Could it be that the focusing screen is not seated properly and/or misaligned?

Another possibility is that the mirror is not stopping in the correct position.

Thanks, but I'm using live view to focus...

mikeSF · 11-03-2014, 10:07 AM

Originally posted by Ed Hurst

One example where the lenses are quite different is the 150. The FA is not just faster but better all round IMO. So, in short, treat each case separately and do the homework ;-)

agree

Flyflickr · 11-05-2014, 04:10 PM

I noticed the FA 45-85 gets great marks but there is no reviews for the A version. Does anyone have a comparison of the two? Or has anyone here used the manual A 45-85?

BBC5 · 11-06-2014, 03:06 PM

Originally posted by Flyflickr

I noticed the FA 45-85 gets great marks but there is no reviews for the A version. Does anyone have a comparison of the two? Or has anyone here used the manual A 45-85?

this may help: https://www.pentaxforums.com/forums/48-pentax-medium-format/268494-45-85mm-fa-v.html

https://www.pentaxforums.com/forums/48-pentax-medium-format/189788-645-45-85-vs-fa-lens.html

Jonathan Mac · 11-06-2014, 03:16 PM

The FA 45mm gets far poorer reviews than the A version. I think they changed the optical formula, no idea why. 55mm is plenty wide enough for me on medium format.

11-01-2014, 09:41 PM	#1
BBC5 Junior Member Join Date: Aug 2014 Posts: 31	645 Lens "A" vs "FA" In the Pentax Lens Review Databaseit says that "A" lenses are manual focus (*1980's) and "FA" lenses are autofocus (1990's*) Are there any difference between these 645 lens ("A" vs "FA") besides focus function?

11-01-2014, 09:45 PM	#2
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	The barrels are different, and many FA lenses have different optical formulas compared to the A versions. All that info should be in the lens database for each individual lens Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

11-06-2014, 03:06 PM	#14
BBC5 Junior Member Join Date: Aug 2014 Posts: 31 Original Poster	Originally posted by Flyflickr I noticed the FA 45-85 gets great marks but there is no reviews for the A version. Does anyone have a comparison of the two? Or has anyone here used the manual A 45-85? this may help: https://www.pentaxforums.com/forums/48-pentax-medium-format/268494-45-85mm-fa-v.html https://www.pentaxforums.com/forums/48-pentax-medium-format/189788-645-45-85-vs-fa-lens.html Last edited by BBC5; 11-06-2014 at 03:53 PM. Reason: more info

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11-01-2014, 10:32 PM	#3
BBC5 Junior Member Join Date: Aug 2014 Posts: 31 Original Poster	Originally posted by Adam The barrels are different, and many FA lenses have different optical formulas compared to the A versions. All that info should be in the lens database for each individual lens How about image quality between the versions? Infinity focus the same between them?

11-01-2014, 11:42 PM	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by BBC5 How about image quality between the versions? Infinity focus the same between them? The best place to look is the user reviews. But yeah, they can all focus to infinity of course. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

11-02-2014, 02:16 AM - 1 Like	#5
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	As Adam says, best to look at each one you're interested in. Some of them are different optically between FA and A, others seem to be much the same (though the coatings might be updated on the FA). There just isn't a single answer for all A-FA comparisons.

11-02-2014, 10:09 AM	#6
BBC5 Junior Member Join Date: Aug 2014 Posts: 31 Original Poster	Originally posted by Adam The best place to look is the user reviews. But yeah, they can all focus to infinity of course. And if the lens doesn't focus to infinity, I must of got a bad copy of the lens...

11-02-2014, 12:06 PM	#7
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	IMO, some of the best lenses of the 645 mount are the A-series (35 & 120). There are some differences here and there and hard to say that across the board, FA are better/worse. I have a few of each as well as some 67 mount lenses for my 645D and overall very pleased with my kit.

11-02-2014, 05:56 PM	#8
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	I also prefer the 35mm A to the 35mm FA. With the 120, I think they are optically identical (can't be sure coatings didn't change slightly, but can't see any difference whatever in performance); that it is to say both are world class!

11-02-2014, 05:58 PM	#9
Ed Hurst Site Supporter Join Date: May 2010 Location: Sydney Posts: 1,657	One example where the lenses are quite different is the 150. The FA is not just faster but better all round IMO. So, in short, treat each case separately and do the homework ;-)

11-02-2014, 05:58 PM	#10
yurihuta Site Supporter Join Date: Nov 2008 Location: Washington DC, USA Photos: Albums Posts: 632	Some non-lens possibilities... Could it be that the focusing screen is not seated properly and/or misaligned? Another possibility is that the mirror is not stopping in the correct position. Originally posted by BBC5 And if the lens doesn't focus to infinity, I must of got a bad copy of the lens...

11-02-2014, 06:10 PM	#11
BBC5 Junior Member Join Date: Aug 2014 Posts: 31 Original Poster	Originally posted by yurihuta Some non-lens possibilities... Could it be that the focusing screen is not seated properly and/or misaligned? Another possibility is that the mirror is not stopping in the correct position. Thanks, but I'm using live view to focus...

11-03-2014, 10:07 AM	#12
mikeSF Pentaxian Join Date: Jan 2009 Location: East Bay Area, CA Photos: Gallery Posts: 6,620	Originally posted by Ed Hurst One example where the lenses are quite different is the 150. The FA is not just faster but better all round IMO. So, in short, treat each case separately and do the homework ;-) agree

11-05-2014, 04:10 PM	#13
Flyflickr Junior Member Join Date: Sep 2014 Posts: 26	I noticed the FA 45-85 gets great marks but there is no reviews for the A version. Does anyone have a comparison of the two? Or has anyone here used the manual A 45-85?

11-06-2014, 03:16 PM	#15
Jonathan Mac Pentaxian Join Date: Apr 2009 Location: Madrid, Spain Posts: 10,897	The FA 45mm gets far poorer reviews than the A version. I think they changed the optical formula, no idea why. 55mm is plenty wide enough for me on medium format.