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The thread to end all VPN discussions....

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Joshua Hakin said:
Unfortunately there's a lot of people here who don't do low light
or high ISO photography. These are the ones who keep saying there's
no problem... so why do they comment?
Click to expand...
To temper the impression that everyone and his uncle has a VPN problem? All of us don't. This does not mean that your camera don't have the problem.

Here, an example:



This is shot at ISO1600 in starlight and the reflections from city lights 15km away. Go ahead, find the VPN. Here's the full-size image:
http://www.p-i-x.net/gallery2/d/4449-1/Cityglow.jpg

There are thousands of K10 images on PBase right now with lots of low-light areas and no VPN. Check out Sean Carpenter's images, for one. I saw what I think is a slight bit of the horizontal grip-stripes in a few of them, but no VPN. I can make my camera show VPN, but I still don't have a real-life problem with it. In fact, as I have searched a bit, I have found that all brands of cameras I've been able to test so far has had some kind of banding or striping artifact in low-light situations. My old Oly 2100uz has a diagonal pattern, the Canon 400D has horizontal stripes and the D80 has very similar VPN to the K10. It's apparently very difficult to engineer out of a digital camera. I'd be very happy if Pentax could do it, but I won't hold my breath and I won't stop taking pictures. YMMV.

But think of it this way, if all the people who don't have a problem keep quiet and this makes Pentax think that all cameras have the exact same problem, don't you think they'll look in the wrong place for a solution as opposed to knowing that only a large subset of cameras have it?
Joshua Hakin said:
For example, I've read sooo much about the jpeg quality being poor
on the K10D.... I dont shoot in jpeg, so I'm not gonna be able to
offer any comments on it! Maybe it is, maybe it ain't! But I'm not
gonna fight those people trying get Pentax to notice their problem
and fix what they need.
Click to expand...
That's a bad example. The correct example would be if you shot JPEG, thought they looked absolutely spiffy and mentioned that you had a differing opinion.

Now, I agree that some (on both "sides") have made very general remarks along the lines of "all cameras have the problem" or "it's not a problem with the camera" instead of the more correct "some, perhaps a great many owners have a problem with using their cameras as expected". This polarization of opinions is not conductive to finding a solution. I'm just saying. BTW, the exact same rhetoric can be seen in the Nikonian forums regarding the D80 amp glow...

/ Richie - http://www.p-i-x.net
 
I simply explained how my K10D works, behaves.
If you don't like this, then it is nothing I could do about it.
Why should I lie about the behavior of my K10D?

It does not help solving the issue to stop people from telling their true experiences.

If you can't accept that it does exist other experiences than your own, then you have a problem. And this problem isn't about your K10D. It is about you.
Some K10D has the problem, some don't.
Some has a heavy problem, some has a minor one.
On some K10D's the problem shows up at normal exposure at ISO 1600.
On others it doesn't.
The problem is inconsistent, not consistent.
And you don't help resolvoing the issue by denying those facts.
--
Take care
R
http://www.flickr.com/photos/raphaelmabo
 
True, it is of NO HELP trying to silence those who doesn't have the VPN problem.

I don't understand why some of those who has the problem refuses to accept the fact that not everyone is having it. It is bad that some has the problem yes, really bad.

But it's not helping the issue making false claims that every K10D has this issue and that the issue is consistent for all. Making false statements never helps solving an issue.
--
Take care
R
http://www.flickr.com/photos/raphaelmabo
 
Joshua Hakin said:
we know there is no problem in ISO 100-400
Click to expand...
No, we don't know anything of the sort.



Why do you keep saying there is no problem when I have clear VPN in ISO 100?

(OK, sorry. I just had to turn that particular table a bit)

Seriously, that image IS actually in ISO 100. VPN is not directly ISO-related, but you will need to push the exposure in PP a hell of a lot more to see it than in ISO1600. Hey, if I had kept quiet, Pentax might not have known to look in lower ISOs as well and wind up not solving the problem. See what I mean? More info on who has it and who doesn't and in what circumstances can only help with solving the issue.
Joshua Hakin said:
Rolando, if you don't regularly shoot at high ISO then you have no
experience or knowledge to add to this discussion. Leave it to
those of us who have experience in this area.
Click to expand...
Like I said, high ISO or not is irrelevant and excluding people from the discussion because they don't agree with you, or worse, don't have the same problem that you do is counter-productive, not to mention quite rude.

/ Richie - http://www.p-i-x.net
 
I see a few verticals out towards the right-hand side of the image that appear typical of VPN. If this is a problem to you, well only you can tell us that.

I'd enjoy that image either way, it's a great shot.
--
/ Richie - http://www.p-i-x.net
 
BTG308 said:
To temper the impression that everyone and his uncle has a VPN
problem? All of us don't. This does not mean that your camera don't
have the problem.
Click to expand...
I have never said everyone has the problem. But I have said that people can't see it... meaning the posted examples of photos that clearly have the problem.
BTG308 said:
Here, an example:
http://www.p-i-x.net/gallery2/d/4450-2/Cityglow.jpg
This is shot at ISO1600 in starlight and the reflections from city
lights 15km away. Go ahead, find the VPN.
Click to expand...
I quite honestly see the problem in this photo. In the sky area, which you have tried to hide with NR software or some PP.

I have seen some images without VPN from some people. And my camera may very well be worse than others. In fact, my first K10D was quite bad so I returned it for another. The second one was better, but not great.

Joshua Hakin Photography
http://www.hakinphoto.com
 
No grip,
Never been over 400 ISO (rarely over 200)

Just over 6000 shots, every single one viewed at 100%, lots of user errors :) , plenty of underexposure, never seen vpn

Phil
 
Roland Mabo said:
I can make 1000 shots if you like and you will still refuse to
believe me and then you surely will ask me to take 1000 shots
more... I can spend all my life taking shots and you won't believe
me. I can nothing but feel sorry for you.
Click to expand...
Ok. You don't need to take 1000 shots.
Just one.
A photo of a grey card, filling the frame at ISO1600, no post processing.
Post your result please.

--
Joshua Hakin Photography
http://www.hakinphoto.com
 
1. Yes all K10d cameras have the VPN problem. No on poor quality control. VPN arises from an erroneous algorithm in a circuit in the NuCORE data acquisition circuits, PENTAX's much-touted ADC that PENTAX ASO said would give the K10d un unmatched dynamic range (DR). Not so much. Ironic that the very ADC meant to expand DR has resulted in reducing it because of VPN.

2. PENTAX ITSELF pushed the K10d's ability to go into low light, including ISO 1600. I'm not comparing the K10d to film, I'm comparing it to what PENTAX said it would allow me to do as a photographer.

3. Yes, I all too well remember the aftermath of Phil's review. And yes, talking does shape attitude and perception. But VPN and HPN are hardware problems, not problems of perception. Take the K10d onboard flash for instance. Many, too many, K10d flashes have failed. Don't know why. And because I NEVER use the onboard flash, should I MYSELF care about my fellow K10d users? If you yourself like the results of your VPN, great. Enjoy. But I'd think twice about saying the VPN discussion has gotten out of hand just because of your one camera, which you yourself say has VPN.

4. "We do create our own reality with our minds. This is what modern quantum physics says, so it is scientifical approved." I hope you're saying that tongue in cheek. If you really believe such nonsense, have your mind create world peace or the best camera ever. Go to work, man! Start creating by simply thinking! Quantum Mechanics makes no such claim, never has, as you would/do know if you ever studied/have studied it in a serious way. The relation of QM-level events to Macro-events is still hotly debated and far fromn settled, but a physcist who claims QM means "If you think it, it will come into being" would be laughed out of the profession.

Cheers.
Roland Mabo said:
1. All cameras has VPN. You won't be able to find a camera that
hasn't got it. It is normal. On some samples, like yours I guess,
VPN is more visible than on others. This is more about poor quality
control at the factory rather than an effect of poor design.
2. I only discovered VPN because I looked really hard for it, I
wouldn't have noticed it otherwise - because it is so minor (and
ONLY happens in heavy underexposed shots at ISO 1600, now how often
do I take 4-5 stops underexposed shots at ISO 1600??? And why
should a camera behave perfect with 4-5 underexposure at ISO 1600?
Not even film did it!!!)
I did notice it because the forum is filled with it. In this sense
talking about something makes a problem larger than it is, and
suddenly people are seeing things they didn't did before. Remember
Phil's review of the K10D? Before his review, many here was amazed
about the fantastic image quality of their K10D. They praised it,
applaud it, and then Phil came along and those who were so pleased
suddenly wasn't pleased any more. The images was the same, but
their interpretation of the images was different. This shows how
things can go out of hands like VPN has done here.
3. But we do create our own reality with our minds. This is what
modern quantum physics says, so it is scientifical approved.
--
Take care
R
http://www.flickr.com/photos/raphaelmabo
Click to expand...
 
Never said you said VPN was a problem. I merely pointed out you claim your K10d doesn't have VPN and then say that it does have VPN. Can't have it both ways. ALL k10d cameras have VPN, but not all K10d owners find VPN a problem, and you apparently fall into the latter camp.
Roland Mabo said:
Yes, if I look very carefully on shots that are underexpoed by 5
stops in ISO 1600!
And how often do I underexposes my shots so heavily at ISO 1600? I
have ZERO VPN on ISO 1600 correctly exposed, I don't even see it at
3 stops underexposure. I need to go down even further to be able to
discover it at all. So for normal shooting, VPN never happens. So
it is not a problem.
--
Take care
R
http://www.flickr.com/photos/raphaelmabo
Click to expand...
 
Yes it is. We can see some banding sort of noise, common noise and also VPN. The green colored blotches are easy to spot on both the left and right side of the comet (?) trail.

If you try to remove the noise, using any method, the blotches will still remain.

imho,

Pretty cool picture!

imvho,

--
Jonas
 
River0 said:
Jerry--
Would you mind posting your "properly exposed" twilight photos to
show the problems? And the same shot overexposed to avoid VPN?

Like you, I've discovered the K10d is terrible for low light
photography. I should have never fallen for those low-light photos
in the K10s sales brochure, shots that show no signs whatsoever of
VBN, VPN, HPN, or any other -PN.

Thanks.
Click to expand...
Here's a recent shot, exposed so as to hold detail in the capitol dome:

http://www.pbase.com/jthirsty/image/75848110/large

It is most obvious just above the skyline to the right of the smokestack, but extends all the way across and down into the ice. Looking at the channels, the red channel shows a nasty mottled pattern, while the green and blue channels have just a hint of it. One sort of work-around is to set the white balance to tungsten; that produces a very blue image, minimizing the effect, but if a blue image isn't what you want then you're stuck with it.

Here's the same shot overexposed by two stops to overcome the noise pattern:

http://www.pbase.com/jthirsty/image/75848596/large

At this point all detail is pretty much gone from the dome.

I recently started using a second computer that has a CRT (my main computer has an LCD monitor). One thing that I discovered is that the noise pattern is virtually invisible on the CRT unless I know to look for it, while on the LCD it stands out like a sore thumb. Nonetheless, it is also readily apparent on prints.

--
Jerry Thirsty
 
Roland Mabo said:
Again, I don't have it in my k10D. My K10D works as I have stated.
I can look hard day and night, I can spend endless hours of pixel
peeping, I don't find it! It only exists at 4-5 underexposure at
ISO 1600. That is how my K10D behaves, that is how it works.
Why are you refusing to believe me?
Some has the problem, some don't.
Click to expand...
I don't refuse to believe you; if you don't see any VPN you don't see any VPN.

Now that wasn't exactly what my question was about.

--
Jonas
 
Jonas B said:
What do you think about Alexandra's pictures here:
http://forums.dpreview.com/forums/read.asp?forum=1036&message=22440440
How many stops underexposed are they?
Click to expand...
They doesn't seem that much underexposed... the lady is perhas only slightly underexposed, and the other one is pushed 1 stop. Looks rather fine from an exposure point of view. So?

It is VPN in them. And I see them, yes. So what? What is your point? I have never claimed that others don't have the problem. I was talking about my K10D, not others. Those images says nothing about my K10D, but they do tell about her. So what are you trying to say?
--
Take care
R
http://www.flickr.com/photos/raphaelmabo
 
BTG308 said:
I see a few verticals out towards the right-hand side of the image
that appear typical of VPN. If this is a problem to you, well only
you can tell us that.

I'd enjoy that image either way, it's a great shot.
Click to expand...
Thanks, Ritchie. I must say I don't give a rat's rse about it. It was before the firmware upgrade, so it may be better now. I've shot sport under lights @iso 1600 with good results since then.
--
Thommo
http://www.flickr.com/photos/jthommo101/

 
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