[Michael Piziak]

I think I'd rather have noise if caused by things like higher ISO. To turn this off, should I turn off both "High ISO NR" and "Slow Shutter Speed NR" BTW, what does it do, apply some post processing or digital filter to achieve this?

Are there any other settings where the camera fiddles with the image using post processing or filtering ?

BTW, when my K-S2 was just returned from a warranty repair, it was set to factory defaults. Anyone that can help me with 2 settings, the link is:

Need some help with a few settings on my K-S2 - PentaxForums.com

[mattt]

Its for Dark Frame subtraction. It makes the frame, then makes a second frame with the shutter closed and substracts the noise from the first. It's effective, but if you are making long exposures it takes twice as long to make an image. In astro this can be hugely detrimental as conditions change, and exposures can be quite long.

[DeadJohn]

What image format do you use, JPG or raw DNG? What's the maximum ISO you normally use?


"High ISO NR" is applied to JPG files. It can make images look less grainy at the expense of losing some detail. The effect is similar to applying noise reduction during post processing.

"Slow Shutter Speed NR" applies to both image formats. I don't recall exactly how slow the shutter speed has to be to trigger this feature, but if you take a 30 second photo the camera will take another 30 second "dark frame" with the shutter down, then use that 2nd dark frame to erase noise from the 1st photo.

"Slow Shutter Speed NR" can be helpful for city skylines at night or astrophotography. If you are taking a lot of photos, though, you might find you're wasting too much time for dark frames. An alternative is to take all of your light frame, then take a single manual dark frame of your own with the lens cap on, then use that dark frame with Photoshop. The dark frame needs to be at the exact shutter speed, exact ISO, and near the same sensor temperature as the light frames to be usable.


I suggest starting with both settings off. If noise becomes objectionable then turn one or both features on.

[mikesbike]

In order to use "M" lenses not featuring an "A" setting, you just have to go into menus- in this case, the last category, "C", and section 4. Down at the end, line 28, you will then access the aperture ring usage setting. Just select "Enable" so you can set aperture using the lens's aperture ring, and the shutter will fire.

[Michael Piziak]

Its for Dark Frame subtraction. It makes the frame, then makes a second frame with the shutter closed and substracts the noise from the first. It's effective, but if you are making long exposures it takes twice as long to make an image. In astro this can be hugely detrimental as conditions change, and exposures can be quite long.

Thanks for the info/input !

---------- Post added 01-07-23 at 01:41 PM ----------

What image format do you use, JPG or raw DNG? What's the maximum ISO you normally use?


"High ISO NR" is applied to JPG files. It can make images look less grainy at the expense of losing some detail. The effect is similar to applying noise reduction during post processing.

"Slow Shutter Speed NR" applies to both image formats. I don't recall exactly how slow the shutter speed has to be to trigger this feature, but if you take a 30 second photo the camera will take another 30 second "dark frame" with the shutter down, then use that 2nd dark frame to erase noise from the 1st photo.

"Slow Shutter Speed NR" can be helpful for city skylines at night or astrophotography. If you are taking a lot of photos, though, you might find you're wasting too much time for dark frames. An alternative is to take all of your light frame, then take a single manual dark frame of your own with the lens cap on, then use that dark frame with Photoshop. The dark frame needs to be at the exact shutter speed, exact ISO, and near the same sensor temperature as the light frames to be usable.


I suggest starting with both settings off. If noise becomes objectionable then turn one or both features on.

I shoot in .jpg mode & much of the time I shoot with an ISO of 800...

What you typed is my understanding.

I'm going to turn them off. I actually enjoy the "noise" in some images & also don't like the idea of losing some detail in images because the camera is post processing noise out...

Thanks...

[mikesbike]

If you like the grainy look of noise, then fine- but that itself is destructive of fine detail! In fact, the edges of objects can come apart from the noise factor!

In this regard, Pentax DSLR engineering is especially good- definitely a cut above Canon and Nikon. This has been shown in independent lab tests of numerous models over time. Your K-S2 is very capable of handling noise generated at higher ISO while preserving detail. The NR kicks in gradually as ISO goes up, so as to have minimum effect on the image. The NR technology or method Pentax uses is a different one than those of other major brands. Theirs might remove more noise but theirs also smears detail while the Pentax type does not, or when it does, it only effects detail in one or two colors.

Based on my own experience, as I too shoot mostly highest-quality jpeg images, and the findings of a number of lab tests, I recommend the following for any Pentax DSLR- Go into the Custom Image menus to set up the Sharpening levels, and to set up "Fine Sharpening". Especially in the most often-used default "Bright" category. Avoid having your camera's mode dial set on the "Auto" mode, as this blocks access to most controls and adjustments. If you wish automatic setting of exposure, and both the aperture and shutter speed by the camera, use the "P" mode instead, which will not interfere with your making adjustments, etc.

Use the info button to bring up the quick link page to access the Custom Image menus. When you shoot jpeg images, you are using the camera's processor to convert the RAW file to a JPEG image instead of using your own chosen software to do this yourself. What you would be doing here, is fine-tuning the camera's processor. Pentax has designed this access for you to do so. I have used these settings on a number of Pentax models over time, and have seen these exact settings recommended by some lab tests in the past. Once you bring up the Custom Image section, usually by default it is already set to the "Bright" category, or if not, tab over to it. Then open it and tab down to Sharpening. You will see, the sharpening level is already up by one notch (+1), since this is shown in green as "Normal" for this category. But go ahead and up it by one more, so now it is at +2. Then (important) implement "Fine Sharpening", using your thumb dial. I think it best, over "Extra-Fine". Then hit "ok" and your are done. Just shut off the camera which will then kick back to the regular screen.

You can also do the same in other Custom Image categories as well. I have the "Natural" category adjusted the same way- Sharpening at +2 and "Fine Sharpening" implemented, as well as a couple of other categories. I leave the "Portrait" category on standard, because when photographing many subjects, revealing too much detail does not always make for the most desirable result. You want a good, sharp picture, but not every skin blemish or wrinkle to be in etched revelation!

If having any trouble getting into and making these adjustments, I would be glad to walk you through.

The K-S2 is especially good at handling noise at higher ISO, one of the very best before the KP and K-70 came along. In fact, it is sort of at a toss-up with the K-5 IIs. Only at or above ISO 3200 does the K-S2 begin to become more aggressive with NR, but still not really overly so. At this point on, when compared to the K-5 IIs, that camera will preserve edge sharpness and detail a little better, while the image from the K-S2 will lose a bit of detail but will have a smoother overall image. Take your choice, because each has its own merit!! Wirth the K-5 IIs you can always add more NR on your own, but with the K-S2 your image out of camera might look better- hard to call.

You can see these effects and judge for yourself. Just bring up the Imaging Resource "comparometer" where you can compare the same images taken by different cameras. They use highest-quality jpeg images all at default settings by various cameras right out of the box. The regular set-up to select cameras will only give you more current models. But you can click on "all cameras" at the top of the column to get past models included.

Be sure to use the "still life" image of various bottles, fabrics, numerical scales, and other objects. This is the best one. You have to click the image a couple of times to get the biggest blowup! Look at shadowed areas to evaluate noise. Then in realizing the images are taken at different times, the same area might not have the same depth of the shadow, so look for a comparable degree of shadow. Then look for detail and contrast in images on the bottles, as well as printing on labels, etc.

In dealing with Pentax models, however, you have to be careful in making judgements, because Pentax has been shown by lab tests, compared to others, to under-employ sharpening by their in-camera processors for jpeg images to a varying degree between their models. I believe the thinking is to leave further adjustment up to the individual, more like doing their own post-processing, and having leeway to do so. There often appears to be even less default sharpening done with flagship models.

This means jpegs right out of the camera often are somewhat softer compared to other makes or even other Pentax models. So be sure to take this into account when making these visual comparisons, and that the means are there to make such adjustments.