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03-14-2012, 07:56 AM   #1
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Pentax SMC FA 50 mm f/1.4 Standard Autofocus Lens

Hello friends,
I recently got the Pentax SMC FA 50 mm f/1.4 Standard Autofocus Lens, when I mounted it on Pentax K5 the F letter keeps on blinking on screen. So I took the lens off and put it back on and then it worked fine. Does anyone know why? Also exactly same thing happens when I try to rotate the aperture ring (even when I am in manual mode). Any suggestions?


03-14-2012, 07:59 AM   #2
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When you move the aperture ring from A, the lens goes into manual aperture mode. Under manual aperture mode, the lens does not communicate the aperture with the camera, hence the blinking F in the aperture settings. Set the aperture to A and the camera will control the aperture.

if the lens is set to A and the camera reads a blinking F in the aperture settings, there is something affecting the communications of the lens with the camera. Wipe the little circular metal contacts at the back of the lens and at the front of the camera to make sure dirt is not affecting the connection. You state that after taking the lens off and putting it back on, it solved the problem. That implies that either the dirt blocking the connection was removed, or the lens was not screwed on fully.
03-14-2012, 08:00 AM   #3
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You have to set the camera to "allow use of aperture ring in order to use the lens on any position other than "A". Of course, you can do anything you want while set on "A", so there isn't really a need to do it, but you would for a lens without the "A" setting.
03-14-2012, 08:34 AM   #4
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what both the other said is true, also remounting it may have put it back fully on the "A" setting.

To set your camera to allow manual Aperture setting you have to go into the menu and set it to allow the use of manual.

On the K-5 you press "Menu" and then under the "C" tab change the "Using Aperture Ring" (C,4,27) setting to "2" (Permitted).

03-14-2012, 03:19 PM   #5
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Thank you all guys, your quick reply is really appreciated

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