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04-06-2007, 06:33 PM   #61
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QuoteOriginally posted by scg Quote
Ray,

If I am reading your statement correctly that is precisely the problem. Low key, to me and most others, does not involve the elimination of midtones or even some highlights. IT does mean, however, that the predominant mood and tones will fall into the sub midtone and visible shadows for delivery of mood and visual impact.

If the minimal midtones and remaining highlights are intact, VPN/HPN should not be present in the shadow. These very real problems are unfortunately encountered by a fair number of forum members.

Contrary to the thoughts of some forum experts, the vast majority of the worlds camera owners do not live in sparkling lands of endless sunshine. Occasionally, we have clients who want moody shots that reflect the ambience of evening, shade or the play between sun and shade. I recently saw a beautiful evening image wherein a major Railway company wanted a beautiful valley shot of their train yards. The light grey colored grain cars, showed clear VPN @ 100 in the normal evening light found in the valley.

Now, granted, maybe these are isolated camera sensors that diverge from the norm, but even on a digital this type of imaging should easily be handled without VPN or HPN.

Stephen
I guess we have differing definitions of low key and that may be the problem. Low key, as I understand it, means predominantly similar tones, mainly darker, with few, if any, highlights. High key is just the opposite.

Google Low key definition and you will find any number of definitions that pretty much match this definition.

I also have several photographic texts with the same or similar definition.

What is clear is that play between sun and shade is most definitely NOT low key and is beside the point I was making altogether.

Moody shots also do not have to be crammed into the last 3 stops of DR at the low end of the sensor range to be moody and dark at the final result.

Sparkling sunshine is also not germane to the issue of shooting low key images as far to the right on the exposure histogram as possible in order to avoid excessive noise.

I do not know about you, but when faced with less than sparkling sunshine, in many cases I can simply use a slower shutter speed or a wider aperture. This is not always possible (like with action shots), but there is nothing new about that in the world of photography.

The bottom line is that one can often expose to use as much of the full DR as possible so to avoid noise issues. If you leave 2 stops of room under the right side of the histogram when exposing your low key image, you are simply limiting your DR and inviting noise problems. Many, if not most, of the "VPN" images I have seen posted are muddy, seriously underexposed scenes shot at high ISO and pushed significantly.

If you have VPN problems at 100ISO, you should send the camera to Pentax with sample images and ask for a repair or replacement. People that claim to have such problems and choose not to send the camera back puzzle me. I guess as far as I am concerned there is a growing credibility gap when these folks continue to hammer on how bad VPN is with the K10D but refuse to make a warranty claim.

As for VPN at 100 ISO in my images, I have yet to see that in either of my K10D bodies. I can see VPN in deep shadows (maybe zone 1 or perhaps 2) at ISO 1600 in areas with little detail, more so if I push the image more than one stop.

While I believe that all K10D's behave this way, perhaps some worse than others, this is not an issue for me as I never expected a 10mp APS-C camera to be usable at high ISO. I reach for my K100 for those shots.

Ray

04-06-2007, 10:46 PM   #62
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I am not a computer guy so I tried to answer this post by topic. Just to let you know...no hostility in my words...just explanations. I'm not big on confrontation so please don't take my comments as such.


QuoteOriginally posted by Ray Pulley Quote
I guess we have differing definitions of low key and that may be the problem. Low key, as I understand it, means predominantly similar tones, mainly darker, with few, if any, highlights. High key is just the opposite.

Agree, I'm not sure why you think I think otherwise. My intentions were to say that low key images usually have a (to varying degrees for effectivness) a modest midtone element and, rarely, a high key element to set off the overiding low key theme...not that low key mixes evenly with average and certainly not high key imaging.

Google Low key definition and you will find any number of definitions that pretty much match this definition.

We don't disagree on the definition. I lecture on photography so perhaps the misunderstanding is in my trying to say too many different things in one short post.

I also have several photographic texts with the same or similar definition.

Diddo.

What is clear is that play between sun and shade is most definitely NOT low key and is beside the point I was making altogether.

Never meant to imply that at all. Please read my post again for clarification. or better yet, perhaps it is explained better below.

Moody shots also do not have to be crammed into the last 3 stops of DR at the low end of the sensor range to be moody and dark at the final result.

That is the point I am trying to make. It shouldn't. But for some it is because there apparently is a problem with some sensors...not all...and probably not all that many either.

Sparkling sunshine is also not germane to the issue of shooting low key images as far to the right on the exposure histogram as possible in order to avoid excessive noise.

You missed my point once again. Sunshine has nothing to do with low key...I never meant to imply such. The issue I was trying to point out is this. In sunshine the sensor works fine. In the grey of a typical east coast winter (summer, fall and spring ) and in the shadows that line the valley bottoms around here when the sun is still shining or has set beyond the hills and the ambient light from the sky lights up the hillsides and river valleys, the camera is more than prone to some degree of VPN even at ISO 100.


I do not know about you, but when faced with less than sparkling sunshine, in many cases I can simply use a slower shutter speed or a wider aperture. This is not always possible (like with action shots), but there is nothing new about that in the world of photography.

True. But as you stated, this is not geramane to what I was talking about

The bottom line is that one can often expose to use as much of the full DR as possible so to avoid noise issues. If you leave 2 stops of room under the right side of the histogram when exposing your low key image, you are simply limiting your DR and inviting noise problems. Many, if not most, of the "VPN" images I have seen posted are muddy, seriously underexposed scenes shot at high ISO and pushed significantly.

Agreed. But, remember this...the camera wants to expose even a wholly shadowed valley (as in the explanation above) as if it were a normal exposure. Therein is part of the problem. You can open up the histogram but there is a cost required in PP and some of that low(er) key elements may not be recoverable due to VPN. Because it is also in opening up the shadows on the histogram that those limited # of cameras with this problem show an exacerbated case of VPN in midtones to low key area. I have tested a (not mine) K10D on a gray card in just this type of lighting and it was not a pretty sight. .

If you have VPN problems at 100ISO, you should send the camera to Pentax with sample images and ask for a repair or replacement. People that claim to have such problems and choose not to send the camera back puzzle me. I guess as far as I am concerned there is a growing credibility gap when these folks continue to hammer on how bad VPN is with the K10D but refuse to make a warranty claim.

I stated that I did not experience it to any real degree in my K10D. I stated that I have seen it in other peoples work. Even though I did not see it in my camera I don't close my eyes to the fact that other people have the problem and contrary to what some people want to believe... it is a problem for some. How much of problem?...I don't know...but it is still there. I did state however, that I did experience HPN. I worked with Pentax for 3 months on the issue and did send them a DVD full of examples that their engineers and personnel went over. They knew it was there. I did send my camera in. They ran tests and offered me a new camera. I turned them down. I'll find the answer to the issue some other way even if I have to bite the low(er) key images with this camera. The answer may lie in something as simple as a permutation of settings in the camera because even I cannot always induce the phenomenon. So now I write down all setting in case the situation arises again. When and if I find it I will glady share my findings with Pentax and the forum.

As for VPN at 100 ISO in my images, I have yet to see that in either of my K10D bodies. I can see VPN in deep shadows (maybe zone 1 or perhaps 2) at ISO 1600 in areas with little detail, more so if I push the image more than one stop.

I have never seen this in any of my other Pentax bodies either. The DL is a kick- A little camera that I have never had a problem with. The K100D has never let me down at all. The K10D is a wonderfully built and engineered camera with very few faults.

While I believe that all K10D's behave this way, perhaps some worse than others, this is not an issue for me as I never expected a 10mp APS-C camera to be usable at high ISO. I reach for my K100 for those shots.

Though possibly isolated VPN can be seen at 100 ISO on some cameras. Even a 30 year Pentaxian like me can't put his head in the sand and say the issue does not exist. I, for purely selfish reason, want Pentax to become a tour de force in photoography and the sooner the better. The legitimate complaints of those that wrote about their problems should not be shouted down or photographic skills insulted. Though Pentax denies they read these forums we all know that they do. If some degree of disatisfaction with certain aspects of production did not reach their ears the next product would be no better than the product you have in your hands now. The need to correct errors (no matter how rare or pervasive) is what drives good companies to do better. I'm sure that ever so silently, Pentax will correct this problem in a future firmware update without having to admit diddly.
And that's OK by me

Ray
Thanks for the comments. Cheers.

Stephen
04-06-2007, 11:10 PM   #63
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QuoteOriginally posted by Ray Pulley Quote
-snip-
As for VPN at 100 ISO in my images, I have yet to see that in either of my K10D bodies. I can see VPN in deep shadows (maybe zone 1 or perhaps 2) at ISO 1600 in areas with little detail, more so if I push the image more than one stop.
Hi Ray,

I don't think I would feel that concerned by seeing VPN in deep shadows in Zone 1. I could live with that and sometimes I might decide to use my DS instead.

Everything else you say makes sense. In the thread here:
Test: Are you VPN sensitive?
In which picture(s) do you see VPN?

I ask as I have some problems grasping the problem. Perfectly normal members at this and other forums don't see it, while just as perfectly normal but other individuals have no problems seeing it and also describes it the same way independently from eachother.

To that we can add some reports VPN from their cameras while others "never" have seen it. All this make me wonder if Pentax already fixed the problem with later items (without telling anyone). Tracy's Epsom salt picture can hardly be said to be underexposed. Nor is it pushed. Still, in reality her kitchen wall doesn't look like that.

Maybe I just have to buy a K10D and find out by myself what it is like.

regards,
04-06-2007, 11:28 PM   #64
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Here's a question from someone who has yet to embace digital capture (tho' that is due to change shortly) but has scanned a few thousand slides and negatives.

Q. Is the banding appearing in printed format as well as on screen?

I ask this because, just sometimes, my scanned images display wierd effects on screen which disappear with a change of scale and/or do not appear in prints.
Moire effects in particular seem often to be generated on screen by the very nature of its pixellation only to resolve themselves with a change of magnification.
I got to wondering if, perhaps, some monitors are exaggerating the effects of 'banding' in the camera whereas others are tending to cancel them out.

Clues, anyone?

04-07-2007, 12:21 AM   #65
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In some different threads over at DPR, yes, the monitor question has been discussed. It seems as LCD monitor owners can see some of the striped patterns more easy. But the opposite exists as well. Here is the answer:

Above: A photo of my fridge door some time ago where my print, post card size, of Tracy's Epsom salt package can be seen.

A small print, a photo of it, processed for the web, pretty small here, and the VPN can still be seen despite the reflections.

I understand your question but think that when you say "Moire effects in particular..." you mean "Moire effects" not followed by the "in particular". This is pretty much natural. If colors, noise patterns, noise, details and what more magically disappeared or showed at different print sizes we would never get what we expected when clicking Print.

regards,

Jonas

ref:
Re: So should we print in blue channel also?
04-08-2007, 01:28 PM   #66
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John, as you don't stand behind your post I think I don't comment on it. It is a lot of irrelevant stuff you have put in there and a pretty scary post in general but I'll leave it at that.
04-09-2007, 03:06 AM   #67
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Jonas I know you pretty well & we've had several converstions regarding the VPN on the K10D. I guess the problem for you is that you have to rely on the photos you see posted by others to make a judgement.

The problem for me is that VPN isn't easy to predict - sometimes you'll get it in a particular shooting situation, sometimes you won't. I've never seen it in a well exposed photo, even at high iso. Sometimes you don't nail exposure though, especially in those split-second captures, & it would be nice to have a decent image to fall back on.

B&W conversions often show the pattern up better, but as I found shooting high ISO last night, using Daylight white balance can improve things dramatically (maybe because the exposure is greater due to higher red content?). Other than the VPN, shooting at high ISO is actually a joy - other than deep shadow noise, the actual noise performance is great.

I think it would be good for Pentax to acknowledge the problem & solve it as quickly as possible, much as Leica did with the IR on the M8.
04-09-2007, 03:31 AM   #68
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QuoteOriginally posted by benjikan Quote
Hello Rico;

I work with Adobe RGB in the K10D and in Adobe Camera Raw I use "ProPhoto RGB" The same goes for my color profile in CS2 "ProPhoto RGB"

I hope that answers your question.

Ben
Hi Ben

Setting the camera to Adobe RGB only affects the "in-camera" JPEG's. If you shoot in Raw, it has no colour space, so setting the camera to Adobe RGB will have no effect. Colour space takes effect when converting to another storage format (JPEG, TIFF etc.,).

You can choose what colour space you wan't to work in at the Raw conversion stage. Abobe RGB has more space than sRGB, and ProPhoto has more again. Also using 16 bit gives more colour "tones" as well and prevents posturisation when doing extensive PP work.

Provided you continue to work within a "colour managed" environment, you should retain colour fidelity and integrity, up to and including the print stage. As soon as you step outside of that controlled "colour managed" environment, all bets are off!

If you display on the web it is essential that you convert the image to sRGB and 8 bit to ensure a display to anything approaching the correct colours (depending on the users monitor calibration). The same usually applies to commercial (consumer) photo printing labs. Outputting anything other than sRGB to the web or general print houses will "guarantee" an incorrect colour balance.

Sorry if I'm teaching Granny to suck eggs here! I felt it needed clarification.

04-09-2007, 04:50 AM   #69
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QuoteOriginally posted by tinospiros Quote
Jonas I know you pretty well & we've had several converstions regarding the VPN on the K10D. I guess the problem for you is that you have to rely on the photos you see posted by others to make a judgement.

The problem for me is that VPN isn't easy to predict - sometimes you'll get it in a particular shooting situation, sometimes you won't. I've never seen it in a well exposed photo, even at high iso. Sometimes you don't nail exposure though, especially in those split-second captures, & it would be nice to have a decent image to fall back on.

B&W conversions often show the pattern up better, but as I found shooting high ISO last night, using Daylight white balance can improve things dramatically (maybe because the exposure is greater due to higher red content?). Other than the VPN, shooting at high ISO is actually a joy - other than deep shadow noise, the actual noise performance is great.

I think it would be good for Pentax to acknowledge the problem & solve it as quickly as possible, much as Leica did with the IR on the M8.
You are guessing right. As you know I'm selling the 5D and some stuff as it is a bit too much camera to me. So, what should I replace it with? I'm now a bit spoiled with a camera I can trust, that actually meters the light (going back to the DS can be okay but then I will have to bracket pretty often and check that stupid lum. histogram and guess what it tells me) and don't give me nasty surprises when I think I have a nice picture on the card.

I think you saw the VPN in the test series, picture 3, didn't you? I understand what you mean about predicting the presence of VPN. A bit annoying. How cool is it with a camera responding fast, having SR and a lot of features if you need to use ISO100 and ISO200 all the time to be sure you can use the picture? Hence my endless questions and my hope that Pentax has fixed this in later items.

Then it is not reassuring with the response some members here provide; not standing behind their post, or just not comment on replies. I didn't know I was that provocative but I guess I can be. I wonder what makes it so hard.

Have a look at this:
Not remotely sharp: Pentax SLR Talk Forum: Digital Photography Review
Sean hasn't responded yet so I don't know if the picture is pushed or not. If it is not I can see quite some of my possible fututre pictures being a waste of time.

B&W is very important to me. I have been impressed by the tonality I have seen in many K10D pictures. They would be good starting material for B&W conversions. Then what if this accentuates possible patterned noise?

You are right again - I don't know really where I stand right now. Maybe I should just buy an Oly, knowing there will be noise but at least random noise.

regards,
04-09-2007, 04:53 AM   #70
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QuoteQuote:
VPN...What Gives?
It gives/results in concerned customers, present and future. It results in defensive owners shouting they have never seen it. It has once made me jump ship.

I would like to know if they have fixed it in later items or not. That simple.

Pentax.... Hello!?
04-09-2007, 05:42 AM   #71
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QuoteOriginally posted by Jonas B Quote
It gives/results in concerned customers, present and future. It results in defensive owners shouting they have never seen it. It has once made me jump ship.

I would like to know if they have fixed it in later items or not. That simple.

Pentax.... Hello!?
Hi Jonas, not sure they can completely fix VPN until they get the ADC, sensor, and prime working together as a happy set..gordon's thesis seems to imply that. First iterations of a product are bound to have minor annoyances. As to "where to next", how about a K100?
Though it's just 6MP, it seems to be the best of the 6mp group. They seemed to have tweaked the meter a bit since the D series . I is no 5D though.
04-09-2007, 06:11 AM   #72
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QuoteOriginally posted by Jonas B Quote
Have a look at this:
Not remotely sharp: Pentax SLR Talk Forum: Digital Photography Review
Sean hasn't responded yet so I don't know if the picture is pushed or not. If it is not I can see quite some of my possible fututre pictures being a waste of time.
I'll post back here when I know.

In the meantime, I might check out the tools used in this response:
Re: Test: Are you VPN sensitive?: Pentax SLR Talk Forum: Digital Photography Review
04-09-2007, 06:29 AM   #73
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QuoteOriginally posted by Richard Day Quote
You can choose what colour space you wan't to work in at the Raw conversion stage. Abobe RGB has more space than sRGB, and ProPhoto has more again. Also using 16 bit gives more colour "tones" as well and prevents posturisation when doing extensive PP work.
Since we're being pedantic I think it's a bit misleading to say that Adobe RGB has "more" space -- rather, it covers a larger range of colors by leaving more space between each one. you don't really get more until you go to more bits.

QuoteQuote:
If you display on the web it is essential that you convert the image to sRGB and 8 bit to ensure a display to anything approaching the correct colours (depending on the users monitor calibration). The same usually applies to commercial (consumer) photo printing labs. Outputting anything other than sRGB to the web or general print houses will "guarantee" an incorrect colour balance.
Also, unless you have a very new and expensive extended-gamut monitor, you literally can't see Adobe RGB on the screen to work with it (even if you're able to select it as a color profile somewhere in your application or OS). As mentioned in another thread, the only way to work with this is by adjusting based on histograms and other controls (fly-by-wire!), printing, tweaking, and reprinting.
04-09-2007, 07:42 AM   #74
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Unedited version

QuoteOriginally posted by Jonas B Quote
The version to which I linked was developed in ACR prior to the K10's "official" support, so my manual white balance in the posted shot is lost forever. (Grumble about this?) It had -1 exposure compensation and +126 brightness, so I'm not sure if that makes it ultimately pushed or not.

Here is the shot, opened in Adobe Camera Raw, all settings neutral. This is 0 exposure compensation, 5 shadows, 50 brightness, and 25 contrast. Noise reduction and sharpening are set to 0 (as with most of my shots).



This is a pbase-reduced version of a full-size image I posted in the following link (warning - this is a large 10MP image in the link):
Full-sized image here.
04-09-2007, 09:02 AM   #75
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Ok, thank you Sean - that explains a lot. I think about the "shadows" and "brightness" sliders in ACR as another version of playing with levels in Photoshop. Moving the handles in opposite directions is not always a good thing.

Your original post at DPR was this one:

That picture scared me, sittinghere contemplating if a K10D maybe can do it for me, or not.

I downloaded the big picture and loaded it into Photoshop. With just some minor color adjustment and then adjustments for levels I got this one:

Better but not finished really. We can however see the banding creeping there in the sky. So, I started over again but this time I used curves instead to avoid lowering the middle greytones before pushing them again:

Again better (imo), again not finished - this is just a quick check to see what can happen.

So, it feel better again. And I still like the picture. Btw: there were parts of the sky with strange noise, now I see you made a quick little editing there to get rid of the lens flare. That was puzzling at first when I saw the original post.

thanks again,
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