Are these stuck pixels?

Started 5 months ago | Discussions
HappyBlack
HappyBlack Regular Member • Posts: 363
Are these stuck pixels?

Hello.

I bought a new camera on eBay this week and finally found a while to test it.

Upon close examining the photos, I noticed some strange 'blobs'.

100% crops:

Are these stuck pixels?

They are on every photo I took, always in the same place.

However, when I took a body cap photo, I couldn't spot them no more. The photo is pitch black.

Both camera sensor and lens are clean, they have no dust, scratches, etc.

As you can see, I didn't drag the shutter. The blobs appear even at 1/250th

I performed a couple of Sensor Cleaning in-camera, didn't notice any difference.

Followed this thread: https://www.dpreview.com/forums/thread/3911003 - no help, at all.

Any ideas?

Thanks.

bclaff Veteran Member • Posts: 8,735
Re: Are these stuck pixels?
2

Probably; but if you want an objective test I can analyse a particular image from you and report back.
I'll contact you by Private Message (PM).

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

bclaff Veteran Member • Posts: 8,735
Re: Are these stuck pixels?
1

HappyBlack wrote:

Hello.

I bought a new camera on eBay this week and finally found a while to test it.

Upon close examining the photos, I noticed some strange 'blobs'.

100% crops:

Are these stuck pixels?

They are on every photo I took, always in the same place.

However, when I took a body cap photo, I couldn't spot them no more. The photo is pitch black.

Both camera sensor and lens are clean, they have no dust, scratches, etc.

As you can see, I didn't drag the shutter. The blobs appear even at 1/250th

I performed a couple of Sensor Cleaning in-camera, didn't notice any difference.

Followed this thread: https://www.dpreview.com/forums/thread/3911003 - no help, at all.

Any ideas?

Thanks.

I tested the files you provided and my analysis located quite a few bad photosites (over 150).

The number is so high and they are distributed in such a way that I don't think these are typical "hot" pixels but something more like laser damage.

Here's an example:

This is a cluster of 20 bad photosites.
Normally there would only be one (or maybe two) and the effect on the jpeg would look like a cross.

If you can return or exchange the camera I definitely would!

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

bclaff Veteran Member • Posts: 8,735
Re: Are these stuck pixels?
1

In case you're curious this is the type of output I get from my analysis:

This shows the bad photosite and indicates how many standard deviations away from the expected value it is. By default the program considers anything more than 8 standard deviations away as bad.

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Bill ( Your trusted source for independent sensor data at PhotonsToPhotos )

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