I have a K10D (love it) and the TAv mode is freedom itself!
I wanted to understand noise throughout the ISO range better so I could adjust the auto ISO function. I wanted the most flexibility I could get but I didn’t want photos too noisy to use. So I set up a quick test shot (sorry for the lack of wow factor) and I wanted to post my results and get a discussion going.
I am posting the ISO 100 version of the complete test shot and a series of crops of the test shots with higher ISOs up to 1600. All photos where shot RAW with K10D, A series 50mm f1.4 lens at f2.8 with camera noise reduction on. No corrections made to the images.
The noise steadily increased in the out-of-focus areas but the in-focus areas of the photos hold up quite well.
Can anyone explain this?
Any magical hints on limiting noise?
Comments on TAv for President?

be well,
joe

The comparison shots are too small to see any difference, at least for me.

Thanks for the shots but I have to agree with Deni... bigger samples would be better.

Personally I'd also be inclined to turn camera noise-reduction off. Since you ask for hints on limiting noise, mine is: Leave camera noise-reduction off to keep as much detail as possible, then use software (NoiseNinja, NeatImage etc) which usually can do a better job.

I have always left my camera noise reduction on. Have you had experience with using NN or NI without the camera noise reduction? Does it really make a difference? I use NI on some of my shots but that's with NR already having been applied in camera. Thanks.

Paul... yep, I use NeatImage with my K100d and did briefly with a K10d... my experience has been that it is often better than the in-camera solution (assuming you get a good profile)... though I'm not saying that the in-camera reduction is poor, or that other software will always do a better job...

But the main advantage of having camera noise reduction off is that you start off with more detail, and can then try different noise reduction programs and settings in order to get the best results. So I feel it having camera noise reduction off gives you more control and choice, a bit like shooting RAW instead of Jpeg.

I also keep my cameras NR on, unless I do fireworks pictures, then it should be off. I wouldnt be surprised of NN was better, but the way it works is different since in camera NR works by taking a second frame and doing a subtract. Tho I have not made a comparison, I tend to like things that are done automatically in camera better.

As for the noise in the test, noise will manifest itself more in dark areas so I dont think it has as much to do with focus as with the metering, if the background was bright and the in focus object was dark then more noise would be visible there imo.

Hi All

I normally tend to stick with using jpegs for the majority of general run-of-the-mill shots, but imagined that noise-reduction probably had no effect whatsoever when shooting RAW images, although I'm probably talking through my hat as usual ?
I'd like to find out definitely one way or the other and await a response from those more knowledgeable than I ??

Best regards
Richard

I think there's at least two reasons why you're seeing more noise in the out of focus areas.

1. There is generally more noise in shadow areas and less in the highlights. This is because the shadow areas get amplified more in the conversion from linear raw data. To see this effect, try taking a picture at ISO 1600 during the day and another at night. You should see more noise in the night picture, because there's more dark areas. Unfortunately, this means high iso quality is much better when it's not needed.

2. Noise is more visible in smooth areas than areas with a lot of detail, even if the amount of noise is the same in both. Out of focus areas are smooth, so you eye picks up even low levels of noise fairly easily. Because of this you can usually use higher iso's on your cat (noise isn't very visible in the fur) than your wife, but only if they're about the same brightness.

If you repeat your test with some black tape on top of the wood, I think you'll find just as much noise in the tape as in the background.

See https://www.pentaxforums.com/forums/general-pentax-photography/13261-barts-te...st-loving.html for a magical hint on limiting noise.

It is my understanding that Pentax noise reduction means making a second dark frame exposure after the original shot, and then use the resulting exposure to clean hot pixels from the first exposure.
I doubt it also does "traditional" noise reduction like Noise Ninja does.
Anybody have a definitive answer on this?

You are correct. the NR filter doesn't need to be on for short exposures and is most useful for long exposures like night shooting. NR adds a 'dark' frame to map out any hot pixels in a long exposure shot. I've heard it said in shorter exposures that it can add unwanted artifacts to a shot although I haven't seen that in my pictures. So I leave it on most of the time. You can also try Neat Image which works very well and is freeware.

baw, you're absolutely correct.

Pentax "Noise reduction" found in custom menu doesn't have anything to do with high ISO noise reduction.

I leave Noise Reduction ON, simply because I don't want to add yet another step to my postproduction process.

That being said: Why leave NR OFF for fireworks? (Apart from avoiding the annoying several seconds-long dead time due to dark frames.) How about for star trails?

Folks
I will say this...The thing with the K10D is that it is NOT a point and shoot...The K100D's for the most part are point and shoots..The K10D is meant to be tailored for your personal preference...Yes, I do know that it has a green mode, but that green mode does not have different scenes to choose from so the pictures do not look as nice as say the K100D does while both are in green mode...Now in saying that, I have my K10D adjusted pretty good and when I get home will post some high ISO pics inside of a dark chapel...The iso settings can also be fine tuned in the K10D..
Example 200 / 400 / 800 / 1600 std settings.
100 / 200 / 320 / 400 / 520 ETC...
I know these numbers are not exact, but the illustration is..This feature is not available in the K100's...So when you set the K10D to this custom setting and raise the available auto settings for the ISO, The camera is smart enough to choose the right setting and noise is really none existant..Another thing, I have found is that by moving the sharpness setting all the way + it produces some very nice sharp pics and is especially noticeable in low light conditions...This also works well with the K100's

Hi Folks..
Here are some pics I took last week with my K10D at the mission in Santa Barbara...
The lens I was using that day is my 28mm to 300mm Tamron lens..So it was not my best lens by any means...Had I used my 70 f1.8 I am sure I would have got better results...

This picture is at ISO 400..@28mm....I show this one so you may see the dark conditions..


Here is the same shot at ISO 1600 (max on a K10D) @28mm


Here is a similar shot still at 28mm but allot closer and ISO is only 1100


If you would like to check out the details, download the images and check out the properties or exif info....

I get great ISO shots with my K110D and MY100D super, but not nearly as nice as the K10D...Those extra MP make a difference... hope this helps...