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04-21-2018, 08:05 AM   #121
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QuoteOriginally posted by MJKoski Quote
I found out what happens, at least with DNG files. Not yet camera RAW support for PEF files. The effect is very subtle but manifests itself with images where there are near-sharp details around sharp areas. ISO100-ISO400 are fine but after that, camera performs some form of edge enhancer function AND starts to blur out areas which are not 100% in focus.

Here is a crop from -3EV ISO100 exposure which is boosted 3 stops:.
Do you have the RAW?
I'm almost seeing a very subtle effect, but I wonder if it's indeed the camera or the RAW converter.

Anyway; fur is fur and stars are stars. Winter is not like summer, as one of our politicians used to say.

04-21-2018, 08:21 AM   #122
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QuoteOriginally posted by MJKoski Quote
The purpose of the comparison was based on the idea that no filtering happens at base ISO and when boosted one can use ISO invariance capabilities to crank up the exposure and avoid any damage done by overzealous filtering.
How did you establish that the result you got from underexposing 3 stops and boosting in PP is better than just shooting at 6400 ISO? Is that a practice you use in film?

How do you know Pentax has done the same thing Sony did? Different algorithms should produce different results.

Why did you consider 800 ISO to be the equivalent of "base ISO." (Hint base ISO is 100 ISO.)

You are trying to safe-guard against over-zealous filtering based on your experience with Sony. But surely you need to show that used correctly such an effect exists with Pentax. If you ask me, I always shoot and 100 ISO where possible, because according to every curve ever published, that's where you get the best resolution, Dynamic Range and colour depth. So given that you should always use the lowest ISO in any circumstance, I'd suggest you're just stating the obvious.

In simple terms, you gotta do what you gotta do. When I go to 800 ISO it's because there are reasons why I won't get any acceptable image at 400 ISO, ditto for 400 ISO and 200 ISO, then 200 ISO and 100 ISO.

So if because you need a faster shutter speed, or more depth of field or whatever, even if an 800 ISO image isn't the best possible in terms of IQ, you still have to evaluate your trade offs and go with it. It may be better than a subject with motion blur. It amay be better than really narrow depth of field. I don't see how this changes that. And that has nothing to do with what Sony, Nikon, Canon or Pentax did. That's just photography 101. The same across all platforms, digital and film.

Last edited by normhead; 04-21-2018 at 08:26 AM.
04-21-2018, 08:21 AM   #123
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QuoteOriginally posted by MJKoski Quote
My standard print size is 1 meter wide and up from there and this looks like something that actually will show up
if someone stands 0.49 meter away.

I guess we differ philosophically. My view remains that the photographer has captured a scene, and the entire scene is important {or s/he would have captured less of it}, so it should be viewed from a point where the entire scene can be observed at the same moment. From that perspective, this subtle effect would never be noticed.
04-21-2018, 08:31 AM   #124
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QuoteOriginally posted by MJKoski Quote
My standard print size is 1 meter wide and up from there and this looks like something that actually will show up. Now I know I will use max ISO400 in any case, also in astrophotography with this new mk2.
Hmmmm....1 meter and up, even if it is on the long side? Without any uprez? That's something I would consider for my 645Z, but if I was having to use my K1 to do this I would be very dialed in, at base iso or just up from it, PS, tripod, delay, no wind or vibration, & etc. Really, I think that's getting into medium format territory for something very exacting, like hair fibers. I might do that with the K1 for less "stringent" subject matter, or in a shot the subject/content/presentation mix does not require high sharpness/acuity. It has been suggested by others here that you are pushing the equipment to its limits. I'm thinking that's true, based on what you are saying.

This thread has become more interesting than just a mere comparison between cameras (which we still don't have, that I can see). It has ventured into post processing territory and comparisons thereof, considerations of the "purity" or raws, conceptions of usability in the field against ultimate output, and more. Quite the salad....

04-21-2018, 08:40 AM   #125
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QuoteOriginally posted by Class A Quote
Personally, I do not like any massaging of RAW data. If Ricoh believes they have good image improvement algorithms, they should (optionally) apply them to JPGs and offer them as part of DCU. If such algorithms are applied to RAW data (as in DNG or PEF files), they should be strictly optional, in my view. Having said that, I understand that all data in RAW files has been "treated". All manufacturers do it to some extent and sometimes users or sites like DxOMark find proof of it
Pentax has been tweaking RAW files at high ISO for ages. On my K-5ii this cuts in above ISO 1250. Using an 'accelerator' chip just does it faster.
04-21-2018, 09:00 AM   #126
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QuoteOriginally posted by MJKoski Quote
Switching back and forth between the two the effect reveals itself. Boosted ISO100 exposure has tiny amount of more noise but keeps fur details intact in out-of-focus areas. ISO800 exposure starts to melt the areas almost in-focus but not fully so.
Thanks for coming back with additional interesting information. To be honest, a difference in results is what I would expect. The exposure (EV) may be the same, but different ISO is, well, different ISO (3-stop different LV)*. Your results confirm the emerging wisdom that intentional underexposure with pull in post may provide better quality with some cameras.

I would be curious about a comparison of ISO 400 with -3 EV vs. ISO 3200 where color noise starts to assert strongly.


Steve

* How the three-stop ISO boost above base is accomplished determines how "fake" the data will be compared to base "fakeness".

Last edited by stevebrot; 04-21-2018 at 09:17 AM.
04-21-2018, 09:11 AM   #127
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QuoteOriginally posted by MJKoski Quote
Above crops have LR detail module turned off. If something still happens by Adobe, then it is Adobes fault too.
This is very likely, IMHO. Color rendering for ACR works on a perceptual model dictated by the camera profile (embedded in this case). Those profiles may provide brightness-dependent rendering which I suspect may significantly impact edge treatment.

QuoteOriginally posted by MJKoski Quote
I can share the RAW files tomorrow when I get back home. In DNG format (straight from camera ofc). Then you can play with them as you wish.
Thanks!


Steve
04-21-2018, 10:28 AM - 1 Like   #128
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I'm not sure why normhead has a problem with MJKoski's examples.

The point being made as Stevebrot pointed out is that the camera may be using a different processing path when ISO 800 is chosen over something like 400/200/100. If that's the case then it's significant if image detail is being manipulated in both positive or negative ways.

04-21-2018, 10:30 AM - 1 Like   #129
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QuoteOriginally posted by MJKoski Quote
Firmware update would be nice with on/off setting for this magic chip. Post-processing easily produces as good or better results with right tools.
The theory behind an 'accelerator'/'coprocessor' is that it contains logic which cannot fit on 'the other' chip. For example, as already mentioned, Intel had the 8087 for their 8086, and the 80287 for their 80286, but from the 80386 onward they have integrated floating-point math into the main processor. I have heard that Sony integrates this kind of functionality as just another layer on their sensors. From the way Pentax talks, most likely they consider this to be an extension of the sensor, enabling the sensor's output to be 'cleaner' ..... and not the sort of thing that you turn off or on {just as they wouldn't connect or disconnect resistors or capacitors on the leads between the sensor and processor}

---------- Post added 04-21-18 at 01:40 PM ----------

QuoteOriginally posted by HarisF1 Quote
I'm not sure why normhead has a problem with MJKoski's examples.

The point being made as Stevebrot pointed out is that the camera may be using a different processing path when ISO 800 is chosen over something like 400/200/100. If that's the case then it's significant if image detail is being manipulated in both positive or negative ways.
If I understand correctly, MJKoski is shooting at ISO 800 and then boosting exposure 3 steps, and normhead is asking a very logical "why?" - why not shoot at the 'correct' ISO in the first place? - why not shoot at ISO 100 and then boost exposure 6 steps. At another photography forum, an artist regularly "over exposes" shots on purpose and then retards most exposure, because he says light is the enemy of noise ..... I see the OP doing the opposite of that.
04-21-2018, 10:48 AM - 2 Likes   #130
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QuoteOriginally posted by reh321 Quote
If I understand correctly, MJKoski is shooting at ISO 800 and then boosting exposure 3 steps, and normhead is asking a very logical "why?" - why not shoot at the 'correct' ISO in the first place? - why not shoot at ISO 100 and then boost exposure 6 steps. At another photography forum, an artist regularly "over exposes" shots on purpose and then retards most exposure, because he says light is the enemy of noise ..... I see the OP doing the opposite of that.
I believe the OP has taken two shots... one at ISO 100, which he's then boosted by three stops in post processing, and a second actually at ISO 800 (not boosted). Comparing the two, the boosted ISO 100 shot shows a little more noise but no obvious loss of image detail, whereas the ISO 800 shot has less noise but shows very slight loss of fine detail.
04-21-2018, 11:06 AM - 1 Like   #131
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QuoteOriginally posted by BigMackCam Quote
I believe the OP has taken two shots... one at ISO 100, which he's then boosted by three stops in post processing, and a second actually at ISO 800 (not boosted). Comparing the two, the boosted ISO 100 shot shows a little more noise but no obvious loss of image detail, whereas the ISO 800 shot has less noise but shows very slight loss of fine detail.
If this is the case this is the first time I have seen pentax using NR on one of its cameras below iso 1600. From what I can find the K1 did not use NR




Input-referred Read Noise versus ISO Setting
04-21-2018, 11:13 AM   #132
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QuoteOriginally posted by BigMackCam Quote
I believe the OP has taken two shots... one at ISO 100, which he's then boosted by three stops in post processing, and a second actually at ISO 800 (not boosted). Comparing the two, the boosted ISO 100 shot shows a little more noise but no obvious loss of image detail, whereas the ISO 800 shot has less noise but shows very slight loss of fine detail.
Correct. This has nothing to do with underexposing on purpose but instead emulating shooting ISO800 by using ISO100 and by doing that bypassing whatever filtering might happen at ISO800. And the result so far supports this.
04-21-2018, 11:27 AM   #133
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QuoteOriginally posted by Ian Stuart Forsyth Quote
If this is the case this is the first time I have seen pentax using NR on one of its cameras below iso 1600. From what I can find the K1 did not use NR
Yes, but now Pentax using it (actually it also happens with Pentax KP), and that is the reason for this debate/thread...
04-21-2018, 11:33 AM   #134
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QuoteOriginally posted by aikaarska Quote
Yes, but now Pentax using it (actually it also happens with Pentax KP), and that is the reason for this debate/thread...
I have a feeling that a lot of the improvements we see with the KP really has to do with the newer sensor and might not be even NR done after the sensor output. If we look at the time frame of when the KP was released we see newer sony sensors with DCG technology that gives us better high iso performance.
And one of the reason why we see much better images at higher iso with the KP is that with this reduction of noise (from DCG) above iso 400 most companies using this new tech don't apply NR to images below iso 3200
This has a 2 fold benefit one less noise and two better detail because of less NR

Last edited by Ian Stuart Forsyth; 04-21-2018 at 11:42 AM.
04-21-2018, 11:51 AM   #135
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KP is weird one. Just get it and try extremely long exposures. Results are as good if not better than K-1 mk1. No way it is only the new 24MP Sony crop sensor doing that. KP sensor is also in Fuji X-T20 which I had for few months last year and it is nowhere close with long exposures (very noisy after 30 seconds).
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