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07-23-2011, 04:45 PM   #1
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Need help with FA 50mm F2.8 macro with my k-x

I got this lens from keh.com and almost 2 weeks. When I had my first test with k-x today, I found out it only can focus the object between 20 feet and me. All the objects I made focus under 20 feet, i can hear the "bit" focus sound to confirm.

But..... all the objects out of 20 feet or infinity, i have never heard the "bit" sound for focus confirmation and it is out-focus when i hit half shutter. I can still take the pic without "bit" sound from this lens, but it is totally out-focus.

Not sure anyone have experience/suggestions on this issue?
Thank You.

07-23-2011, 04:53 PM   #2
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Can you focus on infinity using manual focus?
07-23-2011, 05:41 PM   #3
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Does it have a focus range limiter switch or clamp engaged?
07-23-2011, 05:54 PM   #4
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when i turn my focus to Infinity in MF, it still can not make thing in focus out of 20 feet.

07-23-2011, 08:20 PM   #5
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it has a clamp on/off switch, but it is for the traction of MF?
07-23-2011, 08:30 PM   #6
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QuoteOriginally posted by Kenneth3aracing Quote
it has a clamp on/off switch, but it is for the traction of MF?
Yes, it adds resistance when you're using MF. It should be turned off when using AF.

But if you can't manually focus to infinity, it sounds like there is very likely an issue with the lens itself.
07-23-2011, 08:52 PM   #7
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try cleaning the contacts first, then try focusing again. if it still doesn't focus, try adjusting the AF on the menu. then set the necessary tolerance value. you got to play with every value til you hit the one with the sharpest image. if it still doesn't work, it could be a misalignment and you need to return it and get a working copy.
07-24-2011, 12:02 AM   #8
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+1 with Pentaxor,
If this is not something that you can fix very simply, contact the seller (keh) and return the lens.

Generally keh.com has a very solid reputation and they are known to assess conservatively their items. They have a good return policy and you should use it.

Sorry to hear your trouble. I tried a FA50mm f1.8 macro recently and I love the lens.

07-24-2011, 09:43 AM   #9
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In k-x, can i set the lens adjustment? I saw there is a lens correction/input focal length, but it is disable when I put the FA 50mm macro on.
Whatever i can set the lens adjustment, it means the lens which I purchased has problem, it is better to ask them return / repair.
07-24-2011, 09:58 AM   #10
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QuoteOriginally posted by Kenneth3aracing Quote
In k-x, can i set the lens adjustment? I saw there is a lens correction/input focal length, but it is disable when I put the FA 50mm macro on.
Whatever i can set the lens adjustment, it means the lens which I purchased has problem, it is better to ask them return / repair.
The K-x does not have a focus correction in the menu. The "input focal length" entry is for entering the focal length of a manual lens where the camera cannot automatically read it (for use with the SR system). In the case of the FA50 macro, the K-x knows it's a 50mm lens so the option to enter it manually is disabled. Lens correction is also something different. That is used to correct distortion and CA and is not an option with the FA50/2.8 macro because that feature only works with DA lenses (and on some bodies the FA limited lenses).

The only way to adjust the AF on a K-x body is through the debug menu, and that alters how the body behaves with all lenses, not just the FA50/2.8. In this case, it sounds like an issue with this particular lens. As others have suggested, my advice is to return the lens if it's not working properly. KEH is very good about returns and it should have no problems dealing with them.
07-24-2011, 04:17 PM   #11
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QuoteOriginally posted by dgaies Quote
Yes, it adds resistance when you're using MF. It should be turned off when using AF.

But if you can't manually focus to infinity, it sounds like there is very likely an issue with the lens itself.
The clamp on the FA macros are different than on the DFA macros. The later just give resistance, the older ones actually limit the focus range to close focus only. So the switch could be the cause of this. But if you turn it off and you still cannot focus on infinity, I'd say the lens is broken. Either you have a serious mess with the lens elements, or the focus limiter mechanism is broken so that it is always on.
07-24-2011, 05:57 PM   #12
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QuoteOriginally posted by Douglas_of_Sweden Quote
The clamp on the FA macros are different than on the DFA macros. The later just give resistance, the older ones actually limit the focus range to close focus only. So the switch could be the cause of this. But if you turn it off and you still cannot focus on infinity, I'd say the lens is broken. Either you have a serious mess with the lens elements, or the focus limiter mechanism is broken so that it is always on.
I'm not sure that's true, at least on the FA50/2.8 macro. I just pulled it off the shelf and mounted it to my camera and regardless of whether the clamp is on or off, you can still focus through the entire range. I know the FA100/2.8 macro has a focus limiter, but as far as I can tell, the FA50/2.8 macro has just a clamp that has no effect on limiting the focus range.
07-24-2011, 07:32 PM   #13
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I tested it tonight again..........same issue. Some focuses needed several times to confirm. Also, the focus speed within 20 feet is slower than my F 50mm F1.7. Is it a slow focus lens?
I just contacted the customer service. Thinking about just let them repair/totally return...
07-24-2011, 07:34 PM   #14
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QuoteOriginally posted by Kenneth3aracing Quote
I tested it tonight again..........same issue. Also, the focus speed within 20 feet is slower than my F 50mm F1.7. Is it a slow focus lens?
I just contacted the customer service.
Yes, the FA50/2.8 should be slower in AF than the F50/1.7.
07-25-2011, 05:31 AM   #15
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QuoteOriginally posted by Douglas_of_Sweden Quote
the older ones actually limit the focus range to close focus only
The clamp on the FA50 is ONLY to add resistance for MF, it does nothing else.

QuoteOriginally posted by dgaies Quote
Also, the focus speed within 20 feet is slower than my F 50mm F1.7. Is it a slow focus lens?
The F50 f1,7 is one of the fastest focusing lens out there. The FA50 macro is not Just turn the focus ring manually and you'll see why : the throw is about 3-4 times as long on the macro. AND the f1,7 lets more light in, helping the AF system.
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