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05-01-2009, 03:21 PM   #16
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I had a fair amount of blue "glow" at the top and bottom of the frame on my K20D (bought when they were brand new.) It was mainly visible at 3200-6400 and especially with a tungsten white balance. After 9-10 months, I sent it in to Pentax and they replaced the sensor. The new one is maybe slightly better but still shows some of this at high ISOs (3200+).

From what I've seen, the K20D's certainly able to match the D300/A700 sensor in terms of resolution and noise levels at 3200-6400 ISO, but I don't know that they have this blue glow. If Samsung could clean that up a little and maybe improve noise levels even more for the K-7, I'd be extremely happy.

05-01-2009, 04:02 PM   #17
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QuoteOriginally posted by Groucho Quote
I had a fair amount of blue "glow" at the top and bottom of the frame on my K20D (bought when they were brand new.) It was mainly visible at 3200-6400 and especially with a tungsten white balance. After 9-10 months, I sent it in to Pentax and they replaced the sensor. The new one is maybe slightly better but still shows some of this at high ISOs (3200+).

From what I've seen, the K20D's certainly able to match the D300/A700 sensor in terms of resolution and noise levels at 3200-6400 ISO, but I don't know that they have this blue glow. If Samsung could clean that up a little and maybe improve noise levels even more for the K-7, I'd be extremely happy.
Like this; Oppp's that's a Canon.....
Purple periphery of 5Dmk2 images: Canon EOS-1D / 1Ds / 5D Forum: Digital Photography Review
05-01-2009, 06:02 PM   #18
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No, not like that... like this. (ISO 6400.)





It's harder to tell with the white background here - it's more obvious on my site with the black background.
05-02-2009, 12:53 AM   #19
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QuoteQuote:
If the sensor is upgraded then I would expect a usable ISO6400. But as the K10D proved it might not be the sensor at fault.
The K10D was the only camera ever with this sensor type to produce VPN.
D200, D80, D40X, D60, A100, A200, A300, K200D, K2000/K-m.

The K20D is a different beast altogether.
Really no bands until Iso 2000-2500. Even then it was faint.
Another problem with High Iso on the K20D was a Magenta cast that came on like mist from all four corners of the frame.
However, none of these problems I think are that important compared to the biggest K20D problems.
The AF in tungsten or low lights. I am not talking about the speed
If you are required to shoot at High Iso (1600 +) then you will most likley use shalow DOF lenses. And I must say. almost every lens I own behaves differant under tungsten compared to daylight.
In daylight my F50 1.7 needs a +3 adjustment for perfect focus. Under tungsten it requires a -7 !!!!!!!
Now. The AF assist light will help a lot but I would rather they fixed this. Also the larger viewfinder will help to spot out of focus shots before they happen.
Anyway. The orizontal bands which appear on underexposer should be fixed a bit, also the magenta cast and hopefully the AF. If my K20D had all of these then there would be no point in my wishing (covoting) the K-7
Actually when I am referring to the banding issues of k20D, I am referring more to the random banding issues due to electronics interference and the like, rather than the banding issues that resulted from high ISO shots or under exposed shots.

05-02-2009, 02:41 AM   #20
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QuoteOriginally posted by Groucho Quote
It's harder to tell with the white background here - it's more obvious on my site with the black background.
Hmmh. I see blue stray light from the window. Is it this what you mean?
05-02-2009, 05:15 AM   #21
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QuoteOriginally posted by Groucho Quote
No, not like that... like this. (ISO 6400.)



.
Top one, same difference to the Canon image, only top to bottom instead of L,R.
anyways pushing sensors (yes iso 6400 and small amount of exposure IS pushing it to it's limits) to there max will usually lead to some odd behavior.
there is no iso 6400 sensor. Just a very low exposure amplified (via amp or software) a LOT.........
K10 had a red l left side, blue right side on poorly exposed high iso then pushed images.......

As to banding. seems to be a problem w/ black point correction on the sensor columns. Theory was w/ the k10 there were not enough "dark" samples at the ends of the sensor columns to correct the black point offsets (at least at low exposure, high boost).
this type of banding seems to be an individual sensor problem so some can have none to horrible.
Using my old D as an example, I had really clean high iso till it was repaired and the sensor swapped out. Now it bands a bit at high iso/exposure boost images.
If you notice banding is just inherent in the tech. why else would generic software have "fixes" for it.....
05-02-2009, 07:54 AM   #22
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QuoteOriginally posted by falconeye Quote
Hmmh. I see blue stray light from the window. Is it this what you mean?
No, there's no stray light here - those are taken on a very dark theme park ride (Pirate of the Caribbean) - not my best photos by far but pretty good at demonstrating the blue "glow" that I'm talking about. (The shots that suffer most from it don't end up getting uploaded!) Take a K20D shot at ISO 6400 where most of the frame is black and you'll probably see some of the same behavior, especially if you move the white balance towards tungsten or similar.

I have a collection of shots that I gave to Pentax when sending the camera in, where the blue is very apparent.

Last edited by Groucho; 05-03-2009 at 08:39 PM. Reason: corrected garbled sentence
05-02-2009, 03:18 PM   #23
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Amazing. The camera isn't even out yet and here I find people discussing the faults of the camera.

The K-7 will undoubtedly come with an improved sensor.

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