K20D Help

I've just about got my K20D set up to my likeing but i've a couple of questions.
When pixel mapping is activated is it on permanently.
what is catch in focus.

Thanks

When pixel mapping the camera identifies and compensates for faulty pixels, so once you've mapped I presume the camera knows from then onwards not to see those pixels but to fill in the blanks by some form of sampling from neighbouring ones.

Catch in focus works when a manual focus lens is on the body and the body is set to AF. The shutter will only release when the camera finds it's in focus and the green hexagon lights up. So if you prefocus on a spot and something is moving towards that spot, when it arrives at the point of focus the shutter will release. I haven't actually used this feature but I can see situations where I might find it useful.

I tried catch in focus at Goodwood. I was standing at a corner of the track and focused at a point on the corner then waited for the cars to come. Results not great. Possibly better with slower subjects.

Can pixel mapping be reversed once it's been activated.

An interesting question Richard, perhaps it could in the engineering menus, but why would we want to reveal faulty pixels? I know it's not quite the same but it would be a bit like having a faulty shutter repaired and then asking if the fault could be put back.

Are you concerned that by pixel mapping something is being lost? Maybe a faulty pixel could be OK again after a rest, or something like that?

I wonder if we pixel map again the camera looks at every pixel, or just the ones not previously removed.

I would of thought that in the set-up section the reset function should clear it. But how would anyone know ?.

The only way I can think is to view an image with a faulty pixel at 1600% in Photoshop and manually map its location.

Then pixel map and check it out. Then reset and check it again.

Alternatively, contact Pentax and see if they know. It might have to be the engineers in Japan that you have to ask.

Hmmmm tricky one.

I have just spoken to someone at Pentax Technical Support and he has reasured me that the reset fuction will deactivate Pixel Mapping. He agrees with you John that the only way to check it out is in PP. Also it's not a function that will always be needed. So i will be resetting.

It took over 4 months and over 2500 shots before I spotted a dead pixel on my K20D and I then went back and checked the first shots taken with the camera and found it there too. Once I had seen the dead pixel it got really annoying. I could see it on most of my shots. However pixel mapping sorted it out fine.

I suspect that it is being spread to ajacent pixels by the jpeg compression but once found a dead pixel is easy to spot at 100%. Here is a 100% crop of the dead pixel, albeit in a dark part of a photo:

[IMG]http://i172.photobucket.com/albums/w20/GlynM/Misc/IMGP2574-dead-pixel-100_crop.jpg[/IMG]

Certainly in a jpeg a dead pixel has a characteristic shape of a cross. I found another on my K-7 which looked the same.

Glyn

When you say over 4 months would it of still been within the warranty period.

Not confirmed by me but I would think that a single dead pixel on a k20D is not a warranty issue. With things like display monitors and TVs there is usually a minimum number of dead pixels that have to be exceeded before a warranty claim is accepted.

In the case of the K20D the pixel mapping function is provided to correct this fault and once applied it appears to be impossible to detect. With earlier Pentax DSLRs I believe that that warranty returns with dead pixels were addressed with pixel mapping at a service level.

Glyn

Have to strongly disagree there. A dead pixel is a manufacturing defect pure and simple. The Sale of Goods act 1974 covers this. Just because a certain amount of dead pixels are deemed OK by a manufacturer does not mean they should be accepted by you.

Had a a PSP with a dead pixel and was given the line that Sony accepts upto 5 before they will exchange, I just told them straight that it's a defect and I don't accept it, replace it or refund it. They argued the case for ages, til I said 'which part of the word 'dead' do you deem acceptable?' I'm aware it happens, I'm aware that you will be fobbed off, but I will always demand a product free from manufacturing defects as is my right under consumer law.

Sorry about the rant, but these kind of lamentable excuses just **** me off!

I can see that working with a display but with a DSLR how are you going to know if they replaced the sensor or just applied pixel mapping?

Glyn

Depends when you notice the fault I suppose. If the fault was there from point of purchase, I would demand an exchange. If they don't want to do that, or try to fob you off then just get a refund and go elsewhere with better customer service.

If it is noticed at a later date and then becomes a warranty issue, the honest answer is, you're not going to know. If the issue was fixed and unnoticeable I would probably be OK with it.