Dead pixels

[Simon Wyndham]

Quite frankly I think what we are seeing here is the limitations of current technology. It'll be improved over time, but on existing equipment hot pixels remain pretty much an expected thing.

http://www.visuals.co.uk/pixelproblems.asp

[Alister Chapman]

I've taken cameras with no hot pixels on transatlantic flights and landed with 12 or more hot pixels. Cosmic rays are certainly a major cause. Watch almost any video footage shot on the Space shuttle or ISS and you'll see lots of pixel damage. It only takes a few days in space to write off a CCD camera. I've seen hot pixels on Panasonic, Canon, JVC and Sony cameras. I had a Sony 700 digibeta camcorder and I had to get the optical block replaced after 18 months of flying around the world filming various sporting events.

[Eelco Romeijn]

We've also experienced a hot pixel issue after the first weeks of filming with our F330. It was checked at the dealer's workshop and send to Sony UK.

Verywel fixed. Camera back in two weeks time. If you have Premium Support Sony supplies you with an exchange cam after 7 or 8 days.

I also use a DXC D30 wich recently showed it's first dead pixel after 8 years of maintenance free operation.

I guess that the smaller individual pixel size of HD CCD's also makes them more sensitive.

[Alister Chapman]

There does seem to be a tendency for the F350/F330's to develop a few hot/dead pixels during the first few weeks of use, however regular black balancing and masking should sort these out.

My F350 developed 3 or 4 hot pixels when I first got it nearly 2 years ago. Since then I have taken it on at least 20 trans-atlantic flights and many shorter flights with only a couple more showing up. Black balancing has masked them except when using frame accumulation where I get 2 bright pixels. I use the CHV repair plug-in for FCP to sort these out.

[Joseph Anthony]

Greetings all,

I too have a 350 with a hot/dead pixel that I'm sending in for repair today. The camera is less than one year old. I've tried multiple times to mask it using the consecutive black balance method and it has not worked. It's going to Teaneck, New Jersey today and we'll see what happens.

JA

[Michael Rissi]

My F350 had hot pixels after less than three months of use.

Like other people here, I was very glad it was under warranty. I took to Sony here in Los Angeles and asked them to replace the pixel block. They didn't.

Sadly, I've been through this before. I had a DSR 300 which developed bad pixels as well. By the way, this is under normal working conditions. Normal corporate work.

Each of these cameras has been kept in pristine condition and used in mild temperatures here in Southern California. Never shipped anywhere.

Sony told me to keep black balancing to get rid of the bad pixels on the DSR 300, but they just got worse and worse and more and more visible.

Sony finally agreed the block on the DSR 300 had to be replaced. The rub? Unfortunately, by the time it HAD to be totally replaced, it was OUT of warranty by about a year, so it was a very expensive replacement repair. You can imagine how angry I was about the situation, but I remained a loyal Sony customer, mostly because all the rest of the gear I own is primarily Sony and I thought perhaps I just happened to get a "Dud" DSR 300 out of bad luck. Cut your losses sort of thing and move on, right?

Fast forward to this year. I purchased a brand new F350. Less than ninety days from purchasing the F350 brand new -- bad pixels! I explained all of the above to Sony which they verified, but even with my prior history, they did not replace the F350 pixel block.

After thorough testing, the repair dept. agreed that black balancing would not get rid of the hot pixels on the F350. However, the F350, unlike the DSR 300 apparently, can be programmed to use surrounding pixels around the bad ones to create a psuedo pixel from averaging the information of surrounding pixels. In essence, the pixel block remains defective, but they shut off the bad pixels and replace them with this "averaging" technology.

It's a workaround solution, but troubling. Because past experience tells me that this block is likely to only get worse, with new hot pixels developing over time.

After my experience with the DSR 300 pixel block which plainly only got worse over time, you can imagine that I'm not thrilled with the way Sony handled the new pixel problem I have with the F350. However, I have about 1 year and a half left on my F350 warranty, so I will monitor the pixel trouble carefully. I'm almost hoping it will get worse, simply so that I can get Sony to agree it should be replaced BEFORE the warranty runs out this time.

If I have to replace a bad pixel block at my own expense twice in a row, I am going to be one EXTREMELY unhappy customer.

I've never heard of other brands having this issue, but I've been a Sony customer for so long, I don't follow any other brand, so I can't say.

Nevertheless, I'd have to rate my situation as cautiously optimistic, but very disappointed that this has happened to me twice and that Sony essentially has given me a "band aid" solution.

I really DID expect Sony to go out of its way to provide me with a new pixel block on my F350 given my history with them and the past problem I had with the DSR 300 which became very costly.

To my fellow Sony owners, take this as fair warning, I guess, cross your fingers and hope for the best. At this point, unless I'm mistaken, I think that's about all I can do myself.

Best regards,
Michael Rissi

[Simon Wyndham]

Incidentally, have you tried holding down the black balance switch for a few seconds as opposed to just switching it quickly? I think I remember seeing something once from Sony about this with Digibeta cameras. Could be wrong though as my memory is seemingly getting worse!

[Michael Rissi]

Hi Simon,

I couldn't tell if your last post was directed at me or someone else.

If you are asking me, yes, I held down the black balance switch for several seconds. Black balancing did NOT solve the problem.

Sometimes pixels on these cameras simply go bad. Period.

Sony's repair technicians determined that the block on my F350 had to be re-programmed in order to hide the defective pixels. The pixel block itself is no better than it was when I brought it in for repair.

My previous post explains in more detail.

Thanks,
Michael

[Alister Chapman]

Bad pixels isn't a Sony specific problem. I've seen large numbers of defective pixels on Panasonic Varicams, Ikegami and Canon cameras. It is a CCD fact of life. On HD cameras the problem is more pronounced simply because there's a lot more pixels to go wrong.

[Michael Rissi]

Hi Alister,

I believe you.

The ironic aspect of this to me is that I have only had defective pixels develop on the higher end video cameras I've owned.

I've had a Sony PD100 for years as well as several other Sony consumer level video cameras which have been all over the world on vacations and what not, and these cameras never developed any bad pixels.

I understand your point that the problem is more pronounced on cameras with a higher number of pixels. Higher probability of trouble from higher number of sensors.

But somehow when you spend upwards of $25000 on a camera, you expect it to behave better than your handheld consumer camera. Call me idealistic.

I grumble for good reason about Sony due to some frustrating experiences with their equipment, but you notice I haven't jumped ship to a different manufacturer. Not yet anyway. All in all, I still feel Sony trumps the competition for overall design and format longevity.

I've shared my experiences here in the hopes that it will shed some light on the subject for other forum members who will come to their own conclusions. My concern about the defective pixel problem stems from my experience that it can get worse over time. That's what happened with my DSR 300. As long as I'm under warranty, no worries. But unlike similarly priced Panasonic models which include five year warranties (last time I checked), Sony gives you two years. For the vast majority of HD professionals out there, if defective pixels turn out to be equally common on all cameras, this may turn out to be of some interest.

Best regards,
Michael Rissi

[Joseph Anthony]

I sent our F350 in to Teaneck NJ for hot pixels that would not reset using the black balance method. The repair description states that "RPN management performed." So it looks like electronic management was used to mask/blend the offending pixels and no block replacement was performed.

I must give kudos to Sony for the turnaround time, though. I shipped on Tuesday and had it back on Friday. Can't complain too much about that.

[Alister Chapman]

Don't get me wrong. I don't believe that it is acceptable to have hot or dead pixels spoiling your pictures at 0db gain within the first year of ownership of an expensive piece of kit.

I wish I knew why this seems to be a problem that affects high end cameras more than cheap consumer cameras.

I don't have a problem with pixel masking or re-mapping as long as it is transparent in use, which in most cases it appears to be. RPM (residual pixel noise) masking improves all the time. Older digibetas could only mask about 32 pixels, newer cams many more. AFAIK Sony have 2 layers of RPN mapping. One that is done using the Black Balance method which has a limited amount of memory and then a second bank that can be programmed by the factory or repair center. When you send a camera in for RPN work they copy the data from the user memory to the hard memory so that the user memory can then mask a further batch of pixels. At some point however you run out of memory and then you may be looking at a new block.

[Greg Boston]

Originally Posted by Alister Chapman

I don't have a problem with pixel masking or re-mapping as long as it is transparent in use, which in most cases it appears to be. RPM (residual pixel noise) masking improves all the time. Older digibetas could only mask about 32 pixels, newer cams many more. AFAIK Sony have 2 layers of RPN mapping. One that is done using the Black Balance method which has a limited amount of memory and then a second bank that can be programmed by the factory or repair center. When you send a camera in for RPN work they copy the data from the user memory to the hard memory so that the user memory can then mask a further batch of pixels. At some point however you run out of memory and then you may be looking at a new block.

That's a bit different than the explanation I got while training at Sony last year.

Black balancing does nothing to mask stuck pixels. Black balancing observes the output from each pixel site in a total blackness scenario, and zeros the gain for any pixel still producing residual current. This will not resolve a pixel that is truly stuck on (defective). Black balancing gets rid of residual thermal noise where the pixel should be producing zero output current. Thermal noise would be incorrectly interpreted as image data.

RPN is done in the service menus and has both a normal memory and a separate memory for slow shutter RPN data. Pixel masking shuts off (or ignores) the stuck pixel site and uses nearest neighbor interpolation to approximate the disabled pixel's data. The interpolation will work fine up to a point. Too many approximations will start to noticeably degrade resolution. I like that it has a dedicated RPN routine for slow shutter since many of those pixels aren't really stuck on and will be just fine under normal operation and shouldn't be shut off unnecessarily. They just have a tendency to ramp up too much if allowed to accumulate a charge for too long. Almost like a thermal runaway condition.

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