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Pentax 645 120mm 4.0 A vs FA/AF

kasperbergholt
Posted 17/09/2023 - 15:47 Link
Clever people,


A while I back I got great feedback on macro lenses for a Pentax 645D.

At that time, the minium focus distance of the 120mm and 90mm lenses didn't work out.

Now I have some new projects where the minimum focusing distance won't be a problem.

The 90mm is above budget - but the 120mm 4.0 is not. There seems to be two different versions - some listed 'A' and some 'FA'. I assume the last is an auto-focus lens, whereas the first is not?

Are there other differences between them? E.g. coating or handling of interfacing shutter speed and aperture with the camera? I'd be using the lens with either 645D or 645Z.

Any other things to take into consideration?


Thanks in advance
-- Kasper Bergholt
Defragged
Posted 17/09/2023 - 18:48 Link
Kasper, have you had a look at the information found here?:- link

Hope you find the answers you are looking for.
C.O.L.B.A.S victim
(Compulsive Obsessive Lens Buying Addiction Syndrome)

What you need are lenses, more lenses, bigger lenses, better lenses, faster lenses, vintage lenses and when you have these, your pictures will be perfect!
kasperbergholt
Posted 17/09/2023 - 19:53 Link
Defragged wrote:
Kasper, have you had a look at the information found here?:- link
Hope you find the answers you are looking for.

Thank you for the link

I get the main difference between 'auto focus' and 'non autofocus', and 'DA' and 'DFA'. But I don't think the overview article has the answer to if both lens versions pass relevant parameters on aperture (what Nikon calls 'Aperture Indexing', I'm not sure about Pentax' term for the same) to the camera.

And there's not a comparison of (minor differences) in materials, coatings and mechanics of the focusing system.

Weights seem af bit different, but I guess that's due to the autofocus system (A version: 695.2g; AF version 735g.).
-- Kasper Bergholt
Edited by kasperbergholt: 17/09/2023 - 19:56
Jonathan-Mac
Posted 18/09/2023 - 06:40 - Helpful Comment Link
"A" series lenses are manual focus.

"FA" series lenses are autofocus.

Both can have the aperture controlled from the camera body and therefore allow Program and Av modes (with the lens set to the "A" position). The autofocus is the only functional difference though it's possible that some coating improvements were made between the two series (but I wouldn't expect a big difference there). This goes for lenses designed for 135 format as well as 645.

The "D" in "DFA" simply designates that the lens was designed for digital cameras rather than originally for film although I think that the 645 DFA lenses all have an internal focus motor rather than using screw-drive AF and they may not cover the full film 645 image circle.
Pentax hybrid user - Digital K3, film 645 and 35mm SLR and Pentax (&other) lenses adapted to Fuji X and Panasonic L digital
Fan of DA limited and old manual lenses
kasperbergholt
Posted 18/09/2023 - 08:32 Link
Jonathan-Mac wrote:
"A" series lenses are manual focus.

"FA" series lenses are autofocus.

Both can have the aperture controlled from the camera body and therefore allow Program and Av modes (with the lens set to the "A" position). The autofocus is the only functional difference though it's possible that some coating improvements were made between the two series (but I wouldn't expect a big difference there). This goes for lenses designed for 135 format as well as 645.

The "D" in "DFA" simply designates that the lens was designed for digital cameras rather than originally for film although I think that the 645 DFA lenses all have an internal focus motor rather than using screw-drive AF and they may not cover the full film 645 image circle.

Thank you, Jonathan-Mac - this was exaxctly the information I was looking for

Would you happen to have experience with either of the two?
-- Kasper Bergholt
Posted 18/09/2023 - 16:15 - Helpful Comment Link
Hi
I use the 120 FA on my 645N ii and z. I enjoy the results. I use Macro lens for portrait work along with macro. When using as a portrait lens I use a 1/4 black mist filter.
kasperbergholt
Posted 18/09/2023 - 17:37 Link
denverclassic wrote:
Hi
I use the 120 FA on my 645N ii and z. I enjoy the results. I use Macro lens for portrait work along with macro. When using as a portrait lens I use a 1/4 black mist filter.

Thank you for the feedback!
-- Kasper Bergholt

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