Why are these images different?

Thanks John,
I reset all the Custom functions to factory defaults this morning before I started. I've checked the Drive Mode and it is set to single frame shooting. I've pressed the +/- button and the EV compensation was set to 0.0. Does that cover all the auto-bracketing and EV options?
Fran

I think so Frankie, time to try it out....

The aperture is closing on my 35mm lens, and at both ends of two other zooms (50-200 & 55-300), is also closes at the 135mm end of my 18-135 lens but not at the 18mm end.

What does that mean?

Fran

That wouldn't account for the fact that the exif data of the two vastly different exposed photos shows the same exposure. Each exposure of a bracketed set shows the setting used.

I would still suspect the lens diaphragm playing up. Have you physically checked the lens stop down off the camera and on the camera in optical preview mode? That is make sure the aperture is 'nice and snappy' to quote an ebay phrase and hasn't got sluggish.

I agree that doing a full reset may well help to put the camera back to normal if it isn't that so it would be a good idea to do that.

John

It does sounds like a problem with the lens. Suggest you contact the supplier with a view of getting it changed or repaired under warranty (presume it still is?)

John

Thanks John,
Yes its still under warranty and thanks for helping me work it out. I'm really glad its not the camera or me.
Thank you everyone for all the help, I think you're all great

I must say I've never heard of a lens problem quite like that before. Hope you get it resolved ASAP.

John

I've phoned Devon Camera's in Exeter, whom I bought it from, and they said bring it back for repair under warranty. The problem was getting worse and worse the more I used the lens while my other lenses were showing no problems at all. I was also wondering if it could have been a software problem, I'm running version 1.12 so I suppose my next step would have been to upgrade to version 1.13. I'm not particularly mechanically minded so I don't understand why the problem should be more obvious at 18mm as opposed to 135mm but I might just search the net to see if I can find any reason for that.

If you haven't had the lens long I'd try and get it exchanged for a fresh one if possible. You could also be entitled to a refund - you can choose to 'reject' it, give it back and get your money back which would allow you to get another fresh one. If it was a bargain though getting it repaired might still be sensible.
I can't think why the wide angle end should be more affected than the telephoto end. That's strange. At least you still have other lenses to use in the meantime.
It is worth upgrading to v1.13 as it seems to give a slightly improved autofocus performance (Pentax haven't stated that though!)

John

I've just had a look at my receipt. It was bought as the kit lens with my K5 on 30/08/11. Would you believe it though - the receipt is for a "Nikon" K5. Anyway when I spoke to Devon Camera Centre they said a replacement for something a couple of weeks old was probable but not for something 6 months old. I should have spotted it sooner but I kept thinking that I must be doing something wrong.

If you have photos taken the with lens showing this problem going back to when you purchased the camera/lens you can possibly prove it was inherently faulty and did not conform to contract. (Ref Sale of Goods Act 1979.)
Ideally this should have been done in under six months after purchase when it would be for the retailer to prove the lens did conform to contract, whereas after six months and until the end of the six years it is for the consumer to prove the 'lack of conformity.' But you might well be able to do that.
If you are happy with a repair then no issue providing it is returned within a reasonable time. Did you speak to the shop manager or one of the sales assistants? The latter may be more inclined to try and fob you off!

John

I spoke to the Manager but I didn't push for a new lens. It has gone for repair. They were surprised by the fault but could see it, and think it could be the spring which pulls the blades closed has lost its springiness, so probably needs a new spring. They had no idea how long it would take to repair. I'll have to have a trawl through my photos to see if I've kept any that went inexplicably wrong. If I did it was probably because it was the only one I had of something which isn't going to prove much on its own.
Thanks again for your help John.

Pleased I could help. At least posting here gives the opportunity for quite a few heads to get together and hopefully help work it out. Hope it isn't away too long.

Regards

John