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11-16-2011, 04:44 PM   #1
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Advice on Pentax FA* 300mm f4.5 - clutch broken


I am looking for some advice (and I thank you all in advance).

I have recently acquired a Pentax FA* 300 f4.5. I know the reputation this lens has, and have seen the prices on ebay and elsewhere.

The glass is very clean, although the body paint is definitely scuffed from use. But here’s the ‘but’ – it works great in autofocus mode, but when you switch to manual focus (by way of the ‘clutch’ the lens has) the ring just spins and doesn’t engage the focus.

Does anyone have experience with this? Is it fixable, or does the clutch require parts that are long gone? I am thinking of selling the lens, but of course am wondering if people will buy it if it only works in autofocus mode.

Thanks for your advice. Forgive me if I have posted this in the wrong place.

Last edited by skism; 11-24-2012 at 01:32 PM.
11-16-2011, 05:30 PM   #2
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I cannot comment on FA*300 in specific, but when I tried to have my FA*24 fixed (for a different problem though) I was told there are no avilable spare parts, not even on order from japan. Quite sad...
Is it still good optically?
11-16-2011, 05:30 PM   #3
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To use the FA*300mm f4.5 ( and I have one) in MF, you need a dual action:

(1) Switch the camera mode to MF, and

(2) Push the FA* focus ring to engage the MF. I mean push the ring away from the camer body. You will see a line 'Manual Focus' appearing above the line 'Auto focus' seen in your picture.

Then you can MF the lens.

The FA*300mm f4.5 is an awesome lens. The IQ is outstanding.

From my own experience, I prefer to use the lens in AF. The MF ring is not as precise as in true MF ring. (I have some VL and CZ lenes with very accurate focus rings.) When combined with the K-7, the camera in Hypermode (P) sometimes jump the ISO (too high). At dusk and dawn, I tend to set manually the ISO on the K-7. (The K-5 may not have this issue.)

Overall a great lens. I bought mine (over the DA*300mm f4) for the smaller size and the absence of SDM. I work often in the bush, backpacking and bushwalking. The weight of the lens together with the risk of SDM failure are both real issue, hence my selection of the FA*300 f4.5.

Hope that the comment will help.

Last edited by hcc; 11-16-2011 at 05:35 PM.
11-16-2011, 06:08 PM   #4
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QuoteOriginally posted by hcc Quote
(1) Switch the camera mode to MF, and
Really not necessary with FA*. Normally only switch on the lens is enough.

11-16-2011, 06:22 PM   #5
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QuoteOriginally posted by elho_cid Quote
Really not necessary with FA*. Normally only switch on the lens is enough.
As long as you want to only shoot when the AF is locked, then yup, you are right.

If you bought a faulty FA* I would return it and try to get a new one (or get a DA* 300mm), as chances are that it can't be fixed.

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11-16-2011, 06:26 PM   #6
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Have you checked that you pull the ring all the way back and not end up in some middle position where the ring doesn't engage?
11-16-2011, 07:00 PM   #7
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Original Poster
Thanks everyone for the advice. There is definitely something up with the manual focus - the ring won't push forward as suggested, and I don't want to force it any more than I have (that is, I can't see the Manual Focus words). All the way back (it won't go any further) the ring just spins, and when pushed forward so I can see Auto Focus it, as expected, works as auto focus. It seems like the clutch just isn't right.

On the very plus so, the autofocus works fine, and the optics are great. As people have said, this is a very sharp lens and I like the bokeh. That having been said, I'll probably sell it! (I have the small Pentax DA 55-300).

Thanks again

11-16-2011, 09:06 PM   #8
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You might want to give Eric a call or an e mail on an opinion and estimate. He does great things.


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