IQ4150 Hot Pixels getting worse

[JamesJetel]

I've had this back for a little over 4 years now, and it's been in for service once just on a port. I've noticed, however, that in the last 2 years the hot pixel presence has gotten increasingly bad. Not only are there more, it's not just long exposures anymore. 1/8s 1/4s and I'm sure faster shutter speeds, I could dig into archives to confirm how fast they appear. I wanted to see if any other long term owners have seen this happen. I don't know much about sensor technology, but to my mind, it's degrading in some capacity.

I'm going to send it in shortly. Last time I brought this up Phase said "just pull the hot pixel slider in C1" which I thought was a low-effort, flippant response.

 

[Boinger]

I have had hot pixels from the get go. Are you using the factory black frame? I find its almost always necessary.

 

[JamesJetel]

I've not been using the black frame because it puts such a handicap on the speed at which I can shoot, good to think about though.

 

[Boinger]

I mean the pre recorded black frame. Not to create one.

Page 98 from the manual:

You toggle it on and off by tapping on the Black Frame Calibration icon (see the illustration on the top left). If there is no blue dot by the icon, the IQ4 is using Prerecorded, while the blue dot indicate the use of a traditional black frame calibration.
You can also enable it in the menu by selecting File Settings > Black Ref. > Prerecorded.

 

[tcdeveau]

I noticed hot pixels getting a little worse over time on mine (it's an achromatic though) but also realized I've had the prerecorded black frame option checked for, oh, idk probably the last year or so. I went back to black frame creation and it seemed to do a better job.

 

[cunim]

Interesting point and something I will have to keep an eye on with my own back. There is a lot of circuitry in that little box and any of it could be degrading. Or it could be unrelated to electrical component failure. For example, if the cooling efficiency is reduced by dirt accumulating over time, the noise floor would rise because the back is running warmer. However, hot pixels are a special case. Theoretically, they should be flaws in the sensor array and, unless you are being targeted by cosmic rays, the number of hot pixels should be fairly constant - though they more will tend to appear if the noise floor rises. I think component failures tend to kill columns or rows, as opposed to individual pixels, but I may be wrong.

Do you mean your hot pixels are getting hotter or there are more of them? Actually, never mind. Best solution is the one you have chosen. Send the back in with a description of the problem and a request that the back be returned to the original quality control spec for noise and hot pixels. They would probably just create a new black frame to hide it all, but they would also need to confirm the sensor is meeting spec before they do that. Please let us know what happens.

 

[f8orbust]

A lot of sensel level issues are caused by our old friends heat + time. Using live view for extended periods on a large sensor is a bit of a recipe for failure(s), so it's just one of those things we have to live with. Trying to physically 'fix' it is the digital equivalent of playing whack-a-mole, and all that P1 will do is map any faulty pixels and simply 'hide' them, something you can do yourself for certain backs using the IIQRemap utility. And of course, like others have said, there's always the single pixel noise reduction slider in C1.

 

[Digitalcameraman]

I've not been using the black frame because it puts such a handicap on the speed at which I can shoot, good to think about though.

James,

Those hot pixels have a lot to do with using the look up table that is built in to IQ4 150 back with the pre recorded black calibration frames. For years Phase One backs always forced you to create that black calibration frame during the exposure. With the ability to turn that off, comes these hot pixels that have to be filtered out via that slider in Capture One you mentioned., which works very well.

I just wanted to add the heat plays a huge roll in this. I live in Florida and we can see these hot pixles even on a 2 sec exposure when we have the back set to not create a fresh frame during each exposure.

A little article my team published on Hot Pixels in case you have not seen this one, We see it with the Fuji GFX100s as well. https://www.captureintegration.com/the-quick-fix-to-fujifilm-hot-pixels/