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09-06-2021, 01:55 PM   #1
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Pentax IST DS distortions on photos below and around lights when photographed

I was at a music event at the weekend, took lots of pictures of bands in various light levels at 3200 ISO to avoid using flash. On processing my photos on the computer I noticed distortions under lights which appeared in the photos. My camera has never done that until now. So I took a couple of test photos of my dining room light at home at 200 and 3200 ISO for comparison. The 200 ISO photo is simply awful resulting in a central light that looks like a chandelier (its only a small single fluorescent bulb). The 3200 photo improved the result but the light still shows unacceptable distortion that looks like a vertical 'rocket trail' underneath the bulb. Just wondering if anyone else has experienced this and if this is a readily fixable problem or whether camera needs to go in for repair. This is the first time I have noticed this after a period of not using the camera for a while. 2 are the test pics of my home light ISO 200 maximum distortion, ISO 3200 smaller level of distortion with a few examples of band shots ruined by this effect. Any suggestions as to how to correct this would be most welcome and thanks.

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09-07-2021, 05:18 AM   #2
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Are these processed RAW's or straight out of camera Jpegs?


Personally I think it might be time for you to get a new camera, considering what is happening to those highlights. A possibility is that LED lights are well known for causing artifacts due to the monochromaticity of the light they generate, but I have never seen LEDs cause anything quite like this.
09-07-2021, 05:40 AM   #3
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If it can't be resolved by a hard reset then I don't think it can be economically repaired even if parts were available. If it doesn't have the latest firmware installed you could try that.
09-07-2021, 06:02 AM   #4
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The effect is called "blooming" and happens when too much charge accumulates in a CCD pixel and it spills into the neighbouring pixels, usually down the column and sometimes into the neighbour's in the same row and down their columns. When it happens on a colour sensor, with the Red Green Green Blue (RGGB) Bayer Matrix, it's why you get the excess of green. Some sensors have anti-blooming gates that mitigate it.

This is the worst I've ever seen and I suspect a failure.
Try it in normal lighting conditions (eg outside).

09-07-2021, 07:42 AM   #5
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Well, I grabbed the *istDS, pulled the curtains and turned on the single low-power non-LED light, and the camera took perfectly "normal" pictures, 1/500 @ ISO 3200 and 1/4 @ ISO 200, with no streaking or other distortion, so, unless there's some weird filter fitted to the lens that has not been noticed, I'd suspect the OP's camera has "gone the way of all good things"
Any risk the camera was stored without a lens or body-cap fitted, thus allowing an accumulation of unwanted material in the body?
Another vote for "trying it normally" to see if it works at all.
Even make a few dozen "normal" exposures to see if things "settle down", assuming the camera was stored without batteries and there may be some capacitor somewhere that needs a little "re-forming" to get it back into working order. Unlikely I know, but if it's broke anyway there's no harm done in trying.
In the very worst case scenario, the body can be cannibalised for "white" solenoids for fixing aperture block failures on some later cameras
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aberration, anomaly, bulb, camera, chandelier effect, distortion, distortions on photos, ds distortions, iso, light, pentax ist ds, photos, rocket trail effect, spotlight, stagelight, test
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