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03-31-2007, 05:23 AM   #31
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Just did a Test at 1600iso NO Banding What so Ever

QuoteOriginally posted by Harald Quote
Agreed.... if this "serious" phenomenon has to be pointed out with arrows, well.... I saw those spots, but thought they are some kind of reflections, or flare.

From monster car picture I couldnt find out any bands.... only band-like forms in shadows were windows (left upper corner).

Just came back home yesterday from two week trip to Japan. I photographed several hunreds of pictures in dim lighted dojos (kendo) and surprice, surprice, coudnt find from my pictures anything like this thing called VPN.

(thought VPN is "Virtual Private Network", but working at IT-industry makes me think oddly :-)
I have just posted a large file in the Photo Gallery Section in the Miscellaneous Photos File with a sample. I couldn't download the full size but:

Look. I took this shot handheld at 1600 iso specifically to highlight the fact that I have not experienced any VPN (Vertical Pattern Noise) I wanted extreme highlights next to extreme shadows to illustrate this point. Converted from RAW to JPEG Medium resolution for upload purposes using Native ACR color settings in Photoshop "ProPhoto RGB" as my color space. I see absolutely no banding what so ever and was quite impressed with how clean the image was at 1600 iso "Correctly Exposed".


Last edited by benjikan; 02-07-2013 at 06:03 PM.
03-31-2007, 05:48 AM   #32
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QuoteOriginally posted by benjikan Quote
I have just posted a large file in the Photo Gallery Section in the Miscellaneous Photos File with a sample. I couldn't download the full size but:

Look. I took this shot handheld at 1600 iso specifically to highlight the fact that I have not experienced any VPN (Vertical Pattern Noise) I wanted extreme highlights next to extreme shadows to illustrate this point. Converted from RAW to JPEG Medium resolution for upload purposes using Native ACR color settings in Photoshop "ProPhoto RGB" as my color space. I see absolutely no banding what so ever and was quite impressed with how clean the image was at 1600 iso "Correctly Exposed".
I agree that there is some patters in the pictures with severe underexposure (- 2-3 stops) and then "pressing" (as it was called here in old good film days :-) them to "correct" exposure + 2-3 stops at post processing.

Maybe I am fool, and have been some decades, but I systematically reject pictures (negatives) with so severe unintentional underexposure. Maybe this is reason why I cannot see this phenomena at all.

If the underexposure is intentional; you set ISO 1600 and there is not even then enough light and you take the picture underexposured -3 stops, then correct this in the PP with +3. Lets calculate: 1600, 3200, 6400, 12800 (+3 stops from 1600). You actually took the picture with 12800 ISO setting, correct? what were you expecting as an result?

Or if you made an mistake and underexposured your picture several stops at ISO 400 or ISO 200, as far as I can see, it is not your cameras fault that you cannot get good results. It is completely your own fault. Uncomfortable plain truth. I have to deal with this truth (and live with it) allmost every time I down load my memorycard.... and push the del-button.

How many correctly exposed pictures really have this phenomena? visible without any arrows or un-normal PP:ing?

This method was used in film days; 400 ISO film was exposed with 800 ISO or even 1600 or 3600 settings and then this was "corrected" in developing phase. It made photographing possible in difficult situations. Results were not near as good as they were at 400 ISO, but you got the pictures needed. Or this result was sometimes used as an effect... harsh big grain and high contrast.
03-31-2007, 06:26 AM   #33
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What the heck is film?

In the good old USA 'pressing' was something you did to uncurl prints and make dress slacks (pants) have a crease and look nice.

'Pushing' and 'Pulling' film are the techniques of underexposing/overdeveloping and overexposing/under developing to gain a pseudo-speed advantage and control excessive contrast/excessive saturation developed by photographers experimenting and expandingsimilar techniques from the work of White, Adams et al known as the Zone System.

Just as a point of reference the dSLR CCD (the chip itself) has a native or preferred ISO (speed) rating--a single number. Generally it's thought to be at or within one stop of the bottom end of the cameras range of ISOs. On the K10 that would be ISO/ASA 100.

The top of the range, at 1600 is therefore a 4 stop push! And correspondingly 3200, 6400 and 12800 are then 5, 6 and 7 stop 'pushes'. The rapid increase in digital noise when moving from ISO 100 to ISO 1600 seems to bear-out this assertion rather well.
03-31-2007, 06:30 AM   #34
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I also experenced some VPN at high ISO but in the shadows mostly. I got rid of the shot in question, but there were also some strange colors (not digital noise but some weird green pattern)
overall I would have to say I am dissapointed in my K10 high ISO performance (not always but most of the time)
My wife's K100 has less noise at 1600 then my K10 at even 600 ISO
I knew that the extra megapixels would push up the noise, but not as much as it did.

but in the grand sceme of things, the K10 high noise and vpn is much nicer then any film at the same high ISO

none of the above are major complaints, but just observations

cheers

randy

03-31-2007, 06:54 AM   #35
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QuoteOriginally posted by jfdavis58 Quote
What the heck is film?

In the good old USA 'pressing' was something you did to uncurl prints and make dress slacks (pants) have a crease and look nice.
Old? good? weird..... :-9

Nice to hear you explanation about word "pressing". It is correct translation and in our language it means just what you described, besides that it means also something you call "pushing", what actually means in our language something you do if gasoline were run out.... :-)

QuoteOriginally posted by jfdavis58 Quote
Just as a point of reference the dSLR CCD (the chip itself) has a native or preferred ISO (speed) rating--a single number. Generally it's thought to be at or within one stop of the bottom end of the cameras range of ISOs. On the K10 that would be ISO/ASA 100.

The top of the range, at 1600 is therefore a 4 stop push! And correspondingly 3200, 6400 and 12800 are then 5, 6 and 7 stop 'pushes'. The rapid increase in digital noise when moving from ISO 100 to ISO 1600 seems to bear-out this assertion rather well.
I depends.... as far as I know it is called "amplifying" when it is done by circuitry and "pushing" if it is done in PP.... and results are quite different too.
03-31-2007, 07:16 AM   #36
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See, you have just verfied my point. The VPN is so slight, you really have to look for it. I will take a look at your NN technique though. I have not attempted to isolate noise by color channel.
Thanks
03-31-2007, 07:28 AM   #37
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Much Ado about Nothing

The Bard said it centuries ago!
03-31-2007, 07:32 AM   #38
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Maybe, maybe not. I think as Jonas points out, some people are more sensitive to it then others. There may in fact be some sample cameras that do produce more VPN than others.

I do agree that the issue is WAY over blown.

03-31-2007, 12:15 PM   #39
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Low noise = avoid ACR

QuoteOriginally posted by slipchuck Quote
I also experenced some VPN at high ISO but in the shadows mostly. I got rid of the shot in question, but there were also some strange colors (not digital noise but some weird green pattern)
overall I would have to say I am dissapointed in my K10 high ISO performance (not always but most of the time)
My wife's K100 has less noise at 1600 then my K10 at even 600 ISO
I knew that the extra megapixels would push up the noise, but not as much as it did.

but in the grand sceme of things, the K10 high noise and vpn is much nicer then any film at the same high ISO

none of the above are major complaints, but just observations

cheers

randy
Randy - for high ISO shots avoid using ACR as your RAW converter. PhotoLab and SilkyPix both remove much more noise. I use ACR primarily for people shots (slightly better highlights and healthier skintones) but PhotoLab for all high ISO work.
03-31-2007, 12:36 PM   #40
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Acr Photolab

QuoteOriginally posted by *isteve Quote
Randy - for high ISO shots avoid using ACR as your RAW converter. PhotoLab and SilkyPix both remove much more noise. I use ACR primarily for people shots (slightly better highlights and healthier skintones) but PhotoLab for all high ISO work.
My native color setting in ACR is Photolab, so is my color space in PS. The results since doing so have been outstanding. I could not believe the improvement in rendition on all levels. I was surprised as I expected a subtle difference, but not at all. I keep everything in 16 bits right up to the end of the PP process.

Last edited by benjikan; 03-31-2007 at 12:45 PM.
03-31-2007, 12:52 PM   #41
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Good heavens - I remember film and we used to "push" process because we wanted the effects of "Grain" - we used to exploit it. The nice thing about film is that the silver halide crystals are very close to being truly random - while digital the photo sites are in a highly regular pattern. It seems now that with the advent of digital - "photographers" and I use the term loosely - now prefer to see the world as if it had no - grain, texture, finite features - and smoothing has become the "gotta have". Just for your information - the real world is not made out of porcelain, texture exists, noise is out there – learn to exploit it not b*tch about it.

I remember taking ASA 125 film and pushing it with POTA developer to 400 and Tri-X to 800 and up to 1000. I remember spending hours in the darkroom dodging and burning – interestingly enough the effects of dodging and burning are reversed in digital – and I still want PP software to give me measures in f stops not percentage.

I remember “seeking the grain” shooting to “enhance” the characteristics of the inherent grain of the media. If you take film and underexpose by 4 f stops – you will spend days trying to get a decent image. If you are using one of the “canned” modes or are shooting in a mode where you --- the photographer --- has minimal input as to the exposure (think green settings here) then good luck, you have a 800 USD P&S – live with it.

To put it in somewhat crass monitory terms – You do not make money while sitting in front of the computer – You make money when the client is paying you to shoot. In plain terms – shoot more (by understanding the limits of your equipment and its medium) process less. Get it right the first time --- and you will find time to capture a usable image from another angle. If you want just P&S and spend hours on a marginal shot in PP – I suggest you get a el-cheapo P&S or video camera – and get out of my way.

PDL
03-31-2007, 12:56 PM   #42
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I meant PhotoLab RAW converter

QuoteOriginally posted by benjikan Quote
My native color setting in ACR is Photolab, so is my color space in PS. The results since doing so have been outstanding. I could not believe the improvement in rendition on all levels. I was surprised as I expected a subtle difference, but not at all. I keep everything in 16 bits right up to the end of the PP process.

as bundled with the camera, rather than the colour space. However I also agree you should use 16 bit and a wide gamut colour space during the editing process
04-01-2007, 06:02 PM   #43
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QuoteOriginally posted by jfdavis58 Quote
We can avoid the shouting and abrasive behavior of 'over there' if we stick to the facts and pertinent related issues.

Pattern Noise, vertical or horizontal is a well know and reasonably well understood physical phenomena (Google 'Vertical Pattern Noise' and scan for proceedings of IEEE--i.e. technical papers). Most of these authors and all of the reviewers of such proceedings are experts in the field.

There are two solutions: hardware remodeling (preferred), and software re-write(probably necessary for legacy equipment--i.e. that camera in the consumers hand). The software solution is problematic: is there sufficient memory to hold the required code? Is the camera CPU sufficiently fast to execute the code without a noticeable increase in lag time between shot and writing to card/reviewing on LCD?

Currently the assumption is that enough space exists and the CPU is sufficiently fast. (Read the GordonBGood thread at DPR; he appears to have the requisite knowledge of the subject to effect a software solution, independent of Pentax).

That pretty much covers the facts, so what are the issues?

Two issues remain that matter: "Should V/HPN be addressed by the camera manufacturer?" and "does every user require the fix?"

The answer to the first question will be based strictly on market conditions: Do enough users operate their camera in a manner that will cause them to experience V/HPN? In this regard, it's counter productive for either side to 'shout down' the other as such shouting cheapens the argument with useless and meaningless human noise.

Common sense says that if you need a solution to V/HPN then a direct approach to the manufacturer will be more productive than any forum rehash of the issue. Following onward: a loud, persistent, demanding mob outside the front door will gain more than a single dilettante whispering in some minor functionaries ear over cheese and crackers.

The answer to the second question is simple logistics and a method exists for rapid deployment; common sense says that if a fix is developed then it should be made available to everyone.
Perfectly put and exactly what I was saying "over there" at the other forum, especially the part where you say "a direct approach to the manufacture will be more productive than any forum rehash of the issue."

As much as VPN is a problem it was the constant threads on the matter which I thought was overdoing it especially where the same old issues were addressed by the same people with many of the same photos. My point is that Pentax are the one's who ultimately have to fix the problem, not the forum, and the multitude of rehashed threads were achieving little if nothing other than to create a heated debate about the fact that it was being done to death, and in some eyes, overstated. Unfortunately, A simple request like this labelled me a "fanboy".

The fact of the matter is, there are quite a few people directly attached to Pentax that read and contribute to the forum, like Ned B, John C and Mark Dimo and I am sure that Pentax are very much aware of the issue and are addressing it.

Maybe it needs to be "put to bed" unless someone actually comes up with something constructive about a actual *fix* for the problem, rather than another whinge about the matter.

If it were a Canon or a Nikon I would say the same thing.
04-01-2007, 06:16 PM   #44
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QuoteOriginally posted by jfdavis58 Quote
See photo fragment:
Off topic... I'm noticing your signature, are you a Dylan fan? I love Dylan!


Does this issue only affect the K10D or does it extend to K100D and K110D also?

I've never seen anything of the sort with my K110D.
04-01-2007, 06:59 PM   #45
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QuoteOriginally posted by Buschmaster Quote
Off topic... I'm noticing your signature, are you a Dylan fan? I love Dylan!


Does this issue only affect the K10D or does it extend to K100D and K110D also?

I've never seen anything of the sort with my K110D.
Just a k10 sensor/adc thing. Equivalent type noise in a k100 would be horizontal pattern noise (HPN ) due to that's the read direction on the 6mp sensors.
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