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F or FA

Pikaholic
Posted 30/01/2012 - 22:00 Link
I'm seeking a Pentax 50mm 1.7 lens with a KAF mount. Can you explain the difference between a F and FA prefix. I have seen both listed in the ad's pages. Any advice will be appreciated.
Old hand, slow fingers.
Pentaxophile
Posted 30/01/2012 - 22:16 - Helpful Comment Link
To all intents they are the same lens, but the FA version is scarcer and cosmetically nicer, so commands a higher price.
[link=https://500px.com/will_brealey/[/link]
Mike-P
Posted 30/01/2012 - 22:19 - Helpful Comment Link
I have both the F and FA versions of the 50mm f1.7 and optically can't see any difference between the two. The F is a little heavier (and some say uglier) and that's about it.

I have a F version for sale on here but would happily keep it and sell the FA version instead. The only reason I kept the FA was because it matches my 28mm.
George Lazarette
Posted 30/01/2012 - 22:22 - Helpful Comment Link
FA lenses have the ability to transfer MTF data to the body, which enables the latter to select the best aperture (if you have told it to do that in the settings menu).

Most F and FA lenses are optically identical, though there might be minute differences in the lens coating. Certainly the 50mm 1:1.7 lenses are considered to be the same.

Given the choice, you might feel that it is worth paying more for an FA, on the basis that it will be a younger lens. Though how much younger will be impossible to know, unless the seller has the original purchase invoice.

Personally, I have the F version, and have never felt the need to replace it with an FA.

Good luck

G
Keywords: Charming, polite, and generally agreeable.
Pikaholic
Posted 31/01/2012 - 12:42 Link
Thank you all for your helpful comments. They all add to my limited education in these matters.

On sober reflection and checking the listed prices, I have decided that the cheaper 'A' lens will suit my limited requirements sufficiently. I will now watch the ad's again.

Kind regards

Bob
Old hand, slow fingers.
Edited by Pikaholic: 31/01/2012 - 12:58
JAK
Posted 31/01/2012 - 13:06 Link
I've got both versions of the 50mm f1.4 and can see little difference between them other than cosmetic changes. + There's nothing wrong with the A lens version if you are OK focussing it yourself!

John
John K
Edited by JAK: 31/01/2012 - 13:07
Pikaholic
Posted 31/01/2012 - 13:29 Link
Thanks John, I rely on the focus confirmation to help me.

I have been testing my 55mm f2 screw lens from original SP1000 and the results are very sharp but it's too much of a fiddle to mount.

I am guessing that a 1.4 would be much better for low light and bokeh but would it be as sharp as the 1.7 at f5.6 say?

Bob
Old hand, slow fingers.
johnriley
Posted 31/01/2012 - 13:43 - Helpful Comment Link
Quote:
am guessing that a 1.4 would be much better for low light and bokeh but would it be as sharp as the 1.7 at f5.6 say?


Yes, it would be as sharp at say f5.6, so would the f1.2 lens.

The differences between the 50/55mm lenses are subtle and more to do with other properties that sharpness. We expect all lenses to be sharp.

Older 50mm lenses may peak later, maybe at f11, but may have higher fine resolution. Newer lenses may peak at f5.6 and be more contrasty, at the expense of fine resolution. But it really is something that you get to know after a lens has been used for a while, it's not something that will be obvious immediately, especially in an image for Web.

The short answer is that all Pentax 50mm lenses are essentially excellent lenses. A perfectly assembled f2 will be just as good as the more expensive ones, but they were made in very high quantities so getting a well treated one may be more of a lottery.
Best regards, John
gartmore
Posted 31/01/2012 - 15:01 - Helpful Comment Link
I would never, ever part with my F 50mm f1.7. Its wonderful for portraits on a DSLR and almost unbelievably sharp especially around f8/f11.

I dont think they were sold as part of a kit, the F28-80 performed that role, I seem to remember it being quite expensive when I bought it around 1990.

here is one at f6.7

Comment Image
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -
Edited by gartmore: 31/01/2012 - 15:08
Pikaholic
Posted 31/01/2012 - 17:20 Link
Thank you gentlemen.

I have had my Pentax DSLR for four years but it was not until a joined PU that I started to use it more seriously. Until then I found my Panasonic FZ30 bridge camera more convenient to use. I have found the comments on my gallery postings very encouraging and I feel drawn to do better. I think a 50mm lens will enable me to try areas so far unexplored. I now have to decide how much I'm prepared to spend to get there.

I only mention all this as a testimony to the benefits of being a PU member.

Kind regards

Bob
Old hand, slow fingers.
johnriley
Posted 31/01/2012 - 17:41 Link
Very glad to hear that Bob. I think given time the Pentax will prove much easier to use well than any bridge camera or compact is.

You don't have to spend a fortune, as always it's worth remembering that it's the photographer that makes the image. The camera is only the tool that takes it.
Best regards, John
Algernon
Posted 31/01/2012 - 17:41 Link
According to the Fishwicks 1990-91 Catalogue

The F50 f1/7 was sold as part of the SFXn and SF7 Kits, that's why
there are so many kicking about. Cost SFXn and F50 f1/7 £349.95

The camera could also be bought with the 28/80mm £399.95 or the
35-70mm £429.95

I actually bought the SFXn body only £289.00 plus the
24-50mm zoom £255.00 = £544..... Ouch!!

The 50mm lenses alone were: f/1.4 = £100 f/1.7 = £60

I already had F50 f1/7 and later bought the FA50 f/1.4
I used to find the f/1.4 sharper on film, but on the K20D
the f/1.7 was sharper at every aperture up to f/8

The 'A' 50mm f/1.7 was just slightly better than the F 1.7
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
George Lazarette
Posted 31/01/2012 - 21:50 Link
Just one word of warning.

The A 50mm 1:1.7 is an excellent lens - I have owned three - but they do have a weakness. The ball bearing in the aperture ring is prone to come adrift. They were one of the very first "A" lenses, so this may be why.

If you do buy one, my suggestion would be to keep it permanently on the "A" setting - which is what you probably would do anyway unless you acquired a taste for film and decided to buy an MX or ME Super.

G
Keywords: Charming, polite, and generally agreeable.
gartmore
Posted 31/01/2012 - 22:43 Link
Algernon wrote:
According to the Fishwicks 1990-91 Catalogue

The F50 f1/7 was sold as part of the SFXn and SF7 Kits, that's why
there are so many kicking about. Cost SFXn and F50 f1/7 £349.95

The camera could also be bought with the 28/80mm £399.95 or the
35-70mm £429.95

I actually bought the SFXn body only £289.00 plus the
24-50mm zoom £255.00 = £544..... Ouch!!

The 50mm lenses alone were: f/1.4 = £100 f/1.7 = £60

I already had F50 f1/7 and later bought the FA50 f/1.4
I used to find the f/1.4 sharper on film, but on the K20D
the f/1.7 was sharper at every aperture up to f/8

The 'A' 50mm f/1.7 was just slightly better than the F 1.7

Thats interesting, I wonder what those prices equate to now.
Ken
“We must avoid however, snapping away, shooting quickly and without thought, overloading ourselves with unnecessary images that clutter our memory and diminish the clarity of the whole.” - Henri Cartier-Bresson -
Algernon
Posted 01/02/2012 - 09:24 Link
gartmore wrote:
Thats interesting, I wonder what those prices equate to now.

It's not often that a price comparison works out so simple

The RPI for Jan 1990 was 119.5
The RPI for Dec 2011 was 239.4

So that's an increase 0f 2.003x..... near as dammit 2x

So the 50mm f/1.7 would be £120 and
the 50mm f/1.4 £200

The cheapest SFXn + 50mm f/1.7 kit would be £700

Looking at other lenses the prices today look very much
on the high side apart from Macro lenses which are
cheaper.
Half Man... Half Pentax ... Half Cucumber

Pentax K-1 + K-5 and some other stuff

Algi
Edited by Algernon: 01/02/2012 - 09:25

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