Whats wrong with this lens?

Those wall photos look roughly on par to the distortions portrayed in the photozone review:

http://www.photozone.de/pentax/405-pentax_1650_28?start=1

So nothing obviously wrong with it. Might be worth checking the autofocus alignment in case you can make it even better with a slight tweak, but nothing to suggest it needs it.

John K

Thanks for the input guys. As I mentioned, I'm going to continue to use it and see if anything crops up, but as it is at the moment , I reckon I got a bargain there.

Just a thought. If the previous owner was using it on an early pre SDM Pentax it could appear faulty to them?

I haven't got one so not sure if it is screw drive compatible but I've presumed it isn't.

John K

On the brick wall shots I have to say that the whole wall on all of them is out of focus so it's almost impossible to say whether one part is worse than another. A DA*16-50 should produce sharper images than those of the brick wall - if these were shot with my DA 17-70 they would be a lot sharper. There's also a fair amount of distortion, which is to be expected.

I think you should do some tests of text shot both straight on and at an angle, e.g. a cereal box or similar. Compare these with another lens you know to be sharp and you'll see if there's an issue. Judging by the brick wall, if these are representative I would be a little worried.

BTW, have you calibrated the lens to your camera?

Regards
David

It does have screw drive compatibility unlike the DA 17-70 which is SDM only.

John

Thanks John.
David's suggestions above are excellent. I too wondered if the wall shots could be a bit sharper, so worth checking that.

John K

Thanks for taking the time to try and work this out for me everyone. I'm rushing around like a headless chicken at the moment trying to sort stuff for the big move. I'll try and get some better shots over the next few days and look into calibrating the lens to the camera. I did adjust the af to ensure that the lens was in the same position when focused as when in live view. But not sure if that's good enough?

Thanks again, It's very much appreciated! ( there needs to be a thumbs up smilie).

well , Ive finally got round to having a play with the lens and attempting to calibrate it.
The shot below is hand held at f2.8




100% crop, i focused on the eye.



It seems sharp enough doesnt it?

Who can say. You hand held the camera, so both the camera and the subject will be moving to some degree. Judging the point of focus under such conditions isn't very precise.

I wouldn't call it super-sharp but that will also depend on how the image for the web has been prepared. Too many variables....

I would disagree to some extent with John. The shot is pretty sharp - there looks to be nothing fundamentally wrong with the lens to me if it is capable of shots like this, although it is shot from a short distance, so it should be very detailed.

The 50-135 is a legendary lens - great for weddings and portraits.

Regards
David

As you say john. " hand held, possibly moving subject" surely if the detail is as good as it is in the crop from what we can view on the above post, then mounting to a tripod and shooting a static object , it can only get better can't. It?
Maybe If I get time, I'll try to set up the perfect scenario and test again.
Would a service centre be able / willing to run tests to establish if the lens can be improved? It might be easier. If they do, then it will definitely be more conclusive.

Thanks again guys.

I've had lenses in the distant past that I've felt vaguely unhappy with but it's been as much to do with other factors. Lenses don't always have the design parameters that suit a style. For example, the 120mm lenses I've never liked.

Can it only get better for your lens. Maybe, maybe not because we dooN't know whether or not you've already taken the best possible shot.

Why not do some tripod mounted images using this lens and another that is known to be good. A newspaper pinned to a wall will be a good target, but should be carefully aligned.