K3 resolution

Nothing I am saying is anything to do with the photography artistically or the photographers ability here. I would be very pleased to have taken them as well I believe he has posted them as very early examples from the new K3, with a view to some examination of them.

My interest here is not to be critical - not of the camera or photographer - the moire would be there the same for anyone pressing the shutter with the camera settings as they were. I'm interested in raising discussion about the new considerations we have now about moire risk, and the controls available to manage it.

I think the colour artefacts on the penguins head are noise, in LR5 I had the colour noise setting at the default 25, if I bump it up to 50 the colour artefacts dissappear, so probably noise not moire

I would tend to agree with this, but it's very difficult for us to tell at forum image sizes. I still think the 'moire' issue is vastly over-hyped and is not really a problem in day to day photography. Yes, it can occur, but I've seen it more on my K-01 than I have on my K-5iis!!

Regards
David

As I mentioned earlier, the reason I regard it as moire is because of the way the colours come and go as the textures change - noise would remain consistent across areas of the same colour tone. The jury's out though! Its interesting that the noise reduction had effect - I imagine it can deal with moire to an extent, in that it is a blurring function?

I do think its good to explore and become aware of potential subjects to be wary of - I think its much more than just the old 'knitting catalogue' joke! It will not worry anyone until they find patches of it ruining bits of their images, in areas they could never have noticed on the camera LCD.

Maybe there should be in a firmware update for an 'aa filter simulator bracketing' setting ! Now that would keep me awake at night !

If you needed a negative compensation it was front focussing.

It is very unlikely that colour effect on the birds is anything to do with moire but their natural iridescence. The colours in the feathers of a bird are formed in two different ways, from either pigments or from light refraction caused by the structure of the feather or sometimes a combination of both. Iridescent colouration is commonly caused by a prismatic feather structure that scatters and refracts light to give the feathers their changing colours (same effect as a rainbow.) Odd that people are keen to blame something that occurs naturally in nature on the lack of a camera AA filter.

John K

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Pretty much what I think, regarding the feathers .

I'm sure this is right in many cases of bird feathers, but I can't believe that is the explanation for this particular case - this penguin is black, and there's nothing on its head that would produce any 'iridescence'.

I'm not trying to overplay any moire here - no doubt it could be reduced in processing (as the OP said), and at average viewing sizes may not be noticed. I'm trying to highlight and help identify where the risk exists so that there can be some method to ensuring that the aa filter simulator is activated when needed - its too late once you're checking the image on a computer screen.

It is almost impossible to induce moire effects with the K-3. I know because I was trying to for a long time last night, without much success. I was pleased to read on the AP forum that Richard Sibley had been having the same problem.

The penguin head doesn't even come close to a problem image in this respect.

The PentaxForums guys didn't seem to have much trouble.

It may be true that in normal use, we'd be unlikely to encounter it, but to say that it's almost impossible to induce it seems a bit strong.

However, I do agree that an OOF penguin is not an example

Thanks Chris, I'll have a look at what they did later.

Just look at our common starling for example. At first glance they look a drab black with some white spots, but look closely and all myriad of iridescent colours can be noted. Take a patch of black oil leaked in a puddle, look closely and with that too the rainbow colours can be seen in the right light. Nothing at all to do with camera sensors!

John K

We'll have to agree to disagree on this particular Penguin, the poor thing It seems that we are still to find a common consensus on how to define moire exactly, and how it differs from colour noise, or indeed colour iridescence.

As I said before, I'm not wanting to overplay the effect here, its not going to ruin the image except when viewed closely, but I would not want it. I see it as exactly the sort of thing that an aa filter simulator is intended to deal with. I find it difficult to accept that in real life this birds head has those colours on it.

Its the unpredictable nature of moire that is the concern - so efforts to 'induce' it may be futile, as it may well strike where we won't be looking In any case, having a few common guidelines on using the aa filter simulator would surely be a good thing. (And before anyone says it, no, I don't think we can rely on shooting without it first, then checking the LCD screen to spot problems - thats not practical in real shooting situations).

Many birds have iridescent feathers Nigel, including the humble pidgeon. It can be quite spectacular when the light catches the back of its neck.

Now that will be something to watch out for, definately - if I throw some bread down I might get one hopping around a bit and carry out a thorough test of the K7's AF tracking abilities!