Not focusing to infinity

I've just bought a used Pentax FA 28mm F2.8 lens.

Judging by my split-image screen when attempting to focus manually on far-off subject, this lens can't focus to infinity. I don't mean it goes beyond infinity, I mean it doesn't even go as far as infinity: actually not far enough to focus on something less than 100 yards away, perhaps less than 50 yards.

None of my other lenses are like this, so I reckon the camera (K10D) and focusing screen are fine.

Is this a problem you have heard of or experienced before with this type of lens? What could be the cause? Damage from dropping? The filter ring has got a ding in it.

This ring damage was mentioned in the ad, but I'm inclined to demand a refund for the focusing problem.

Pete,

When you shake the lens - do you hear anything abnormal?

I had a similar problem with a K mount A version a while back - and this lens had no visible signs of a problem. There was a clunky rattle - something moving around freely.

My feeble attempts to diagnose and repair failed miserably and the lens was used for closer work only - a silly application for a wide angle.

Finally it failed to focus at all and was consigned to the bin.

I hope your story has a happier ending!

I also hope someone has a solution.

But, I'd go for a refund while the purchase is still recent.

Good luck!

It depends how far out it is as to whether it's a problem or not. There is more DOF at further distances, so you might find that results are actually fine.

A few shots should establish whether or not there is a problem and if there is then you could indeed try to get a refund.

As a general rule I don't buy lenses with any impact damage, but to be fair even without visible damage we never know if a lens has been dropped or mistreated, especially with older lenses that have been around for maybe decades.

Sometimes I find problems with older cameras, folders for example, because people who don't understand them try to operate them and foul up the works. Statements like "I've thoroughly cleaned it" fill me with a sense of foreboding.

There is a low-piched rattle as if the front element is loose. It is reduced when I hold the focusing ring, but my FA 50mm doesn't have the same rattle even when not touching the ring.

I've taken a few shots and I'm not happy with the results. I will ask for a refund.

Cheers.

Pete,

That sounds ominously like my lens.

I managed to tighten the front element (which I suspect had been removed in an attempt to repair the larger problem).

There was still internal movement when I shook the lens, and the infinity focus was still erratic.

I think you're correct to demand a refund.

Many folks sell lenses that have "clear glass, no dust, no oil on the blades, etc.", but don't have a body to mount it on and check focus and function. Often the lens is then sold "As is".

This is where I now start asking a lot of questions.

I've learned the hard way to stick with sellers like Batty, SRS and K Mount Treasures.

Best of luck.

I've returned the lens and got a full refund - including my return shipping.

It's not put me off buying lenses via Fleabay, but I will be more careful about any that have any kind of damage mentioned!

Glad it worked out well in the end.