Help need with FA*300 focus issues

Started Apr 5, 2014 | Discussions thread
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gsrokmix Regular Member • Posts: 161
Help need with FA*300 focus issues


I recently bought an FA*300 to use for birding & general wildlife shots. I was going to use it with my 1.7x AFA. I took some test shots with this combo of some backyard birds, and none of the shots I got were in focus. I was locked down on a tripod using a Winberley Sidekick, and a cable release. I tried with both the SR on & off with similar results. I then started thinking that maybe my shutter speeds were just too slow. I remember reading here on the forum that a couple of guys were shooting handheld with this exact combo getting perfectly acceptable shots. My next thought was that it was the AFA causing the focus issues. I set up a test inside today using a focus chart at a 45 degree angle to the lens. I started with the AFA attached, and was still getting unusable shots at even f11 (corrected). I took off the AFA expecting to get completely different results, but to my surprise, the lens by itself didn't seem to perform any better. I was shooting about 20 feet away to make sure I was well past the MFD of the lens (which I understand is around 6.5 feet). I also tried coming closer to fill the frame with the test chart a little more. After all of my testing today I am at a loss & feel like this lens should be a lot sharper (even at f4.5) than it is.

I uploaded the shots I took here:

The shots are crops of the test chart about 9 feet away from the lens. I was shooting with a K-5ii on a tripod using a cable release & MUP, f4.5, ISO 1600, 1/640 sec, with no SR. The shots were: manual focus, AF w/ no adjustment, -10, -5, 0, +5, +10.

I really can't see a big difference here. Am I doing something completely wrong, or have forgotten something, or might there be a problem with the lens.

I appreciate any help and / or advice. Unfortunately I can't return the lens if in fact there is an issue with it. I've never had any issues with the AFA on any other lenses, and this is my first nice long lens, so I'm hoping it's my inexperience here and not a problem with the lens.



 gsrokmix's gear list:gsrokmix's gear list
Pentax K-x Pentax K-5 II Pentax smc DA 55-300mm F4.0-5.8 ED Pentax smc DA 40mm F2.8 Limited Tamron SP AF 17-50mm F/2.8 XR Di II LD Aspherical (IF) +13 more
Pentax K-5
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