|
Forum: Pentax K-1 & K-1 II
09-05-2016, 05:48 AM
|
| |
Yes, that is what I explained above. And long exposure sensor heat up does not create random noise. Stacking without DFS just removes random noise and keeps the heat induced static noise pretty much exactly as it is. The hot pixels do stay where they are on each shot. The average of ten shots which all show 255 or 16000 on one pixel is what? Zero? ;)
Only you will see the heat noise much better because everything around it has been flattened by stacking but they remain shining as they did before.
That is why the Astro pros use dark frame subtraction.
It is extremely easy to understand if you think about what you are doing.
|
|
Forum: Pentax K-1 & K-1 II
09-04-2016, 09:46 AM
|
| |
I fear, it is just normal.
On this page here somebody has compared a load of cameras includig the K-1 and its peers:
The Sensor Noise DB. – Brendan Davey Photography
You can see them in comparison by selecting them sequentially in the drop down field at the end of the page.
It is even giving statistical analysis data on the noise beyond subjective view with MEAN, STANDARD DEVIATION and MEDIAN.
That is the best resource for this topic I could find at least. If you find better ones, go ahead, that would be interesting.
|
|
Forum: Pentax K-1 & K-1 II
09-04-2016, 07:19 AM
|
| |
Yes, the 100 ISO is not related to the last shot. The previous shots in this thread are at a lot higher ISO. That is what I was referring to.
If they were shot at the exact same conditions and if they are viewed at the same size, the should be about same. If you compare at 100% view, the K-1 should show x36/24 as much chroma noise. But that assumes the sensor heat-up is the same, which can be a totally different one due to construction.
As already noted: We currently can't see the actual sensor temperature, like we can on a K-3.
|
|
Forum: Pentax K-1 & K-1 II
09-04-2016, 06:43 AM
|
| |
Well. You should think again.
a) Clarity
That is meant to boost microcontrast. That is the worst you can do to anything with noise. Boost clarity and noise goes up.
What is worse in this case is the fact that microcontrast boosting does automatically turn somewhat brighter pixel into glaring bright pixels, the ones you call "white".
So good way to create an issue where there was none.
b) Stacking images from warmed up sensors
How does the oldfashioned dark frame subtraction work? Night shooters do know that long exposures heat up the sensor in a very reproducable way. Some hot pixels will show up and very specific places. Because those places do not change at all, you can take a dark frame and subtract it. It will not kill any other detail, because it has the exact same hot pixels at the exact same locations.
Now imagine what happens if you stack this scenario. All other random noise because of higher ISO will be averaged away. But the long exposure heating noise doesnt go away. It will remain in full strength, because those pixels will shine in each of those shots.
That is actually the best way to exaggerate the heat noise and make it appear as an issue, while it is none.
So bravo to consolidate all ways to get to a maximum of long exposure noise:
- warm sensor
- very long exposures
- high ISO
- sharpening
- clarity boosting
- stacking
- avoiding darkframe subtraction prior to stacking
The only thing I would add to maximise noise is to chose a raw converter software which is worse than others at removing the available noise. Usually LR is a good bet here, as it is really not very capable in noise reduction. Rawtherapee would have reduced our valuable noise a lot more.
I don't think there is any better noise way to maximise the effects and visibility of heat noise. You seem to love it.
|
|
Forum: Pentax K-1 & K-1 II
09-02-2016, 02:57 PM
|
| |
I might add the body temperature for both K-1/K-3 starts at 25°C with the ISO 100 shots and ends at 26°C with the high ISO shots. For the K-3 we also have the actual sensor temperature which is already 27°C for the high ISO shot (the sensor heats up much faster than the whole metal body).
It's sad we don't have that sensor temp readout from the K-1 available.
MJKoski can now do a comparable shot to any of these and then you can compare the raw files.
|
|
Forum: Pentax K-1 & K-1 II
09-02-2016, 09:12 AM
|
| |
In order to learn something from comparing, you and Zegaby should first do the exactly same lens-cap-on shot: same exposure parameters, same temperatures. Interestingly your raw file at -14 degrees (beyond spec of the camera) has more bright noise spots than the one at 25 degrees.
Currently samples are too different.
|
|
Forum: Pentax K-1 & K-1 II
09-02-2016, 05:22 AM
|
| |
There is nothing wrong with using any software you want. Only if you want to check if a camera sensor produces things you do not want you have to look at raw data as raw as possible, because afterwards you only assess software design.
And the two tools I mentioned are by far the best tools to analyse raw data as they do neither presharpen nor denoise by default. A raw file must look soft, otherwise it's already been manipulated.
Looking at the same file with 4 different softwares I can say the noise impression in these files varies a lot. Even more so when having presharpening active plus different types of denoising. Those interestingly create the bright pixels.
|
|
Forum: Pentax K-1 & K-1 II
09-01-2016, 02:21 PM
|
| |
If you want to see the actual raw content without software presharpening and other effects, use rawdigger or fastrawviewer.
Both can be used as testversions.
There is no white in there. Chroma noise is absolutely normal.
|
|
Forum: Pentax K-1 & K-1 II
09-01-2016, 08:54 AM
|
| |
ZeGaby has just uploaded two sample files which don't show a single white dot, so there you have your sample file.
A lot of noise, but for a body heated up to 27 °C at ISO 12800 using along expsoure and no DFS that is not surprising.
Sadly we currently don't get the sensor temperature from the metadata as well, which usually is a couple of degrees higher than the body temperature when it is being used.
Interestingly the JPGs do show some bright artifacts, where there is nothing (not even a lighter green oder blue) in the raw data. Looks like a funny software issue. Maybe sharpening combined with weird demosaicing and noise reduction?
|
|
Forum: Pentax K-1 & K-1 II
08-25-2016, 04:36 AM
|
| |
Is this a clown-show? :lol:
LE noise "compared" with two completely different images? Completely ignoring even the -10°C versus +30°C environment? . Different light levels. ISO 3200 versus ISO 100. :lol:
Did you start shooting yesterday or did you just not learn at all for a longer time?
What do you think where the noise comes from on any LE? What do you think why do astrophotographers like cooling their cameras?
I can show JPG images with any noise type and level I desire from any camera and claim whatever I want.
Comparable raws are needed, all carefully set-up to avoid beginner errors such as yours.
|
|
Forum: Pentax K-1 & K-1 II
08-25-2016, 12:19 AM
|
| |
What is your issue, MJKoski? You claim comparisons but don't present solid proof.
Unless you actually provide raws to support your claim you seem to be an incompetent liar / troll only, thanks to your underskilled opening post. If you lack the "motivation" to show you didn't lie and it's just your lack of skill that is behind it, fine. If you don't present raws of the exact same scene taken side by side with same exposure parameters and camera temperatures to support your claims you automatically prove you lied. It's that easy.
It's already telling you did not do so without external reminder in your opening post.
If you consider LENR a "trick" you should go back and start to learn the basics.
It is not any news that a tiny bit of noise happens in long exposures in all cameras and it is far from being any issue aside from the normal issue between the ears of users. That is what dark frame subtraction (= LENR) is for: for removing white and red and blue and green hot pixels.
If we ever see any camera which does not produce noise in a long exposure we know the manufacturer has screwed around in the raw data. It's super easy for them to do that, but it is clearly unwanted.
So far all we see is JPGs of people claiming things with no comparison data available. The failure apologists could claim the earth is flat based on some JPG "proof" just as easily.
---------- Post added 25th Aug 2016 at 09:23 ----------
DFS is supposed to do just that.
To compare to a K-5 the K-1 image part has to be resized otherwise you only compare different magnifications.
|
|
Forum: Pentax K-1 & K-1 II
08-24-2016, 10:41 AM
|
| |
Which files do you have to show you are neither a liar nor a troll?
You need to post your raw files of all the cameras mentioned to substantiate your laughable claims.
And obviously the shots need to be using the same subject, taken at the same time with the same exposure settings.
Canons white noise issue:
 Quote: The new Canon 5Ds/r with 50MP on the other hand doesn’t perform at all for long exposure photography. From the various long exposure testshots I’ve seen taken with this specific camera, here’s a review by renowned long exposure photographer Cole Thompson for example, the noise is already a huge issue with very short long exposures. As long as Canon doesn’t acknowledge and tackle this issue I would simply not recommend this camera if long exposure photography is an important part of your style of photography. Quote: while at 240 seconds the noise is completely unacceptable. I only have a few shots to judge this by, but all of my longer exposures have this noise and so I’m sorry to report that my first results with the 5DSr are disappointing from a long exposure perspective. Canon 5DSr Noise Issues | Cole Thompson Photography
Here is what you get on Canon (twice the price of a K-1):
http://www.photographyblackwhite.com/wp-content/uploads/2015/07/Spiral-Jetty-240-sec.jpg
Canon 5DSr = White noise. |
|
Forum: Pentax K-1 & K-1 II
08-06-2016, 10:59 AM
|
| |
You claim this, but have not yet provided any meaningful proof of it being any "issue" at all.
Until we can inspect the raw file of the exact image you showed per screenshot there is not "issue", there just is a non-convincing claim.
If you read my post carefully, you'll find that I just said, dark frame subtraction is the key. For the easy approach you do not need to do it manually, even though I am under the impression most users serious about it do it. But it seems you have not even used the automatic DFS in camera, or am I wrong?
If there are unusual "white dots" I'd like to see them in a raw file when using DFS. Take a shot with DFS and share the raw if it shows "white dots".
That is more to the point. For your application you do not want to use the normal procedure for removing this type of noise. Fine. But then don't complain about it and call it funny names.
You do not want to use noise reduction. You do not want use raw. Fine again. But : Calling the result an "issue" is a pure user issue.
Generally you might want to read the following sentences:
Quote: Although such “thermal” pixels are very common in digital camera sensors and are supposed to show up when shooting long exposures, camera manufacturers usually clean them up, whether you shoot in RAW or JPEG format. This clean up happens in the image processing pipeline, before RAW and JPEG files are generated. https://photographylife.com/nikon-d810-thermal-noise-issue
So the "issue" at worst is that the Pentax K-1 is not pre-cooking the "raw"s as much as Canikon.
If you prefer pre-cooked raws, fine. Most users don't.
|
|
Forum: Pentax K-1 & K-1 II
08-06-2016, 08:41 AM
|
| |
That is very normal behaviour and the very reason why for ages there has been the concept of dark frame subtraction and that is the case for special astro cameras as well.
http://starcircleacademy.com/2012/10/darkframes/
https://www.dpreview.com/forums/thread/3617190
If you want to do it properly you not only have your light frames in raw, but also bias, flat and darkframes - the latter are required per focal length, per ISO, per sensor temperature.
The lazy noob approach is to just switch on the in-camera dark frame subtraction called "long exposure noise reduction". This is automatically at the right focal lnegth, ISO and temperature.
No issue at all, other than lack of user knowledge.
Go to a astro forum and let them teach you, how to approach this.
|
