noise at iso100

If you google on ETTR or expose to the right you will with luck come across an interesting article about why EV +1 or even +2 can be helpful on some shots. I have tried this and it does seem to work sometimes but of course you have to avoid blown highlights.

Mike

If you look at the hair shadow in particular you can see the tones are uneven - they are posterised. This and the noise at 100 iso suggest that the image has been 'pushed' in development. could be your default settings are trying to be too helpful.

Personally, I would risk trading off some small blown highlights for a creamy bokeh and interesting shadows. Your raw processor will be able to find plenty of detail in apparently blown areas, without having to amplify the data.

BTW, the image on your monitor might be a lot better than the JPEG we are looking at.

Chris, it seems I need a new monitor, too! I concur with Darkmunk, I also see a slight noise in the two shots and no noise in other areas of the site.
My monitor is a 4-5 year old Samsung SyncMaster 171P.

I do see this, but it's not a lot. As I said earlier:

The thing is, underexposed areas (and especially, as you say, if they've been pushed a bit), will very frequently show a bit of noise.

This is very different from an overall noisiness, that I don't think is evident on these pictures, and certainly not enough to suggest that there's anything wrong with the camera or the lens.

I would suggest this:

If you're concerned about your camera's focusing, this thread may be useful.

Find out for sure whether the camera is focusing properly, and fix it if it isn't.

Then stop worrying about tiny amounts of noise in underexposed parts of photos, which is normal, and usually means you need to work on getting exposure right.

I agree with all that.

Oh...BTW my monitor is an ACER AL 1717 - no idea if it is any good but I am so pleased with it I have 6 of them in the office and one Sony (which is pants)

Well I have a jolly fine monitor

There are a couple of additional points here:
* The sample images are PNG format - they must have been converted from some other format. So it's difficult to tell what's happened.
* There is some posterization - looks like JPG artifacts to me. So I'd guess the image was RAW->JPG->PNG.

As I mentioned, the RAW converter you use can have a big impact on artifacts & noise (look up "Bayer filter" in Wikipedia).

I'd suggest the following:
* Take a sample RAW file
* Process in Lightroom and output as an 8-bit TIFF file
* Process in Pentax Photo Lab and output as TIFF

Compare the two at 100% in Photoshop/Elements/etc.

The deepest shadows will always have some noise - even at ISO 100. The further you push-process, the more noise you will "dig up" from the shadows. That's why the "ETTR" can be helpful.

To be honest, the images look absolutely fine to me (notwithstanding the JPG artifacts). You can get carried away with "pixel-peeping" - the real eye-opener is checking out the positively huge noise and grain on ISO1600 Fuji print film I might be able to dig a sample out - that'll put the K10D into proper perspective

Matt

All digital cameras produce SOME noise at all ISO settings because they use analogue to digital converters, and all analogue devices are affected by noise. It's just a question of how much.

The amount of noise looks minimal to me in the examples posted here. I can only see it when my eyeballs are right up to the screen.

Anyway, you could try processing the RAW images differently if you want the fine detail to appear differently.

The amount and type of sharpening makes a difference. Silkypix is very good as it provides lots of options and settings for this sort of thing.

I can see the smallest amount of noise in those images, but I had to zoom in to 200% to see it.

Wasn't it already at 100%?

Thanks again for your input. Re the above 2 images converted from raw to png, one raw to jpg. As for the pasturization theory oops posturization I think this is mainly the problem. Most of my images are under exposed and I have to adjust in processing but the problem with this theory is as I have said before these images have no processing except for the conversion from raw to png or the third one which from raw to jpg. Infact I checked the histogram for these images. The first one is under exposed and the others are 1/500 of a second bright sunny day blown highlights exposed. I will see what happens if I increase the ev value in camera.
Here are 2 more complete images. One again is unprocessed f2.4,1/2000,daylight setting. and the other is processed f6.7, 1/350,daylight setting which I found surprisingly fishy. Both taken in the same conditions.
[IMG]http://i266.photobucket.com/albums/ii271/kiwao/IMGP5695-1.jpg[/IMG]
[IMG]http://i266.photobucket.com/albums/ii271/kiwao/IMGP5686-1.jpg[/IMG]

Thanks again for all the comments

Mike

There is no such thing as an unprocessed RAW image, or a "straight" conversion, only unprocessed RAW data.

You might be using your RAW program's default settings, but it is doing lots of complex processing just to create an image at all. Different programs will create different results even if you don't play with any of their settings, and the conversions may not be as straight as you think.

So you can't say any of your pictures are "unprocessed". They are processed; automatically processed.

Here are 100% crops of these images. One has been adjusted sharpening etc but no noise adjustment. No adjustment to the other except for the Lightroom default adjustments, as correctly pointed out by the previous poster, this image has noise.
[IMG]http://i266.photobucket.com/albums/ii271/kiwao/IMGP5686-1crop.jpg[/IMG]
[IMG]http://i266.photobucket.com/albums/ii271/kiwao/IMGP5695-1crop.jpg[/IMG]
Thanks again for all your comments.

Mike

nothing wrong with these !
that fish is extraordinarily sharp for a small, distant, moving object.
And noise just isn't an issue.

Agree! Excellent camera and lens.