LCD Hot Spots

[TME]

Fortunately I don't see it all the time. Just have to live with it and be careful when using certain settings I guess.

If u do not see the spots all the time, it simply means there's likely to be nothing wrong with your camera's sensor or LCD screen. The hotspots at longer exposure times (i.e. shutter speeds) are due to overheating of the CCD sensor. That's common to digital cameras and as tankm has pointed out, once your shutter speed is 1s or greater, the camera does a dark frame subtraction automatically. It's unusual for hotspots to occur at 1/2s shutter speed but it's not impossible.

As for why your P&S does not exhibit these hotspots, the immediate reason is that the CCD in your 5D is substantially larger than that in the P&S. The amount of heat generated is also substantially greater leading to heat-induced hotspots on the 5D's sensor. Secondly, at 15s, with such a small sensor in a P&S, the signal to noise is very small and the noise generated is so great that the hotspots are lost in that noise... so u do not seem to observe it. On the other hand, with the larger sensor in the 5D, the cleaner image results in these hotspots standing out very clearly... so u tend to notice them... u can try shooting at ISO1600, 15 s (use bulb mode) and see if u can see the hotspots on the LCD of the 5D... the noise will be quite substantial such that the hotspots will be rendered non-obvious.

 

[blueayz]

If you only see hot pixel during long exposure, those are not hot pixel. For long exposure turn on the noise reduction and when you trigger the shutter make sure it's on single frame or timer mode. Continuous mode will disable the noise reduction. When noise reduction is enable during exposure longer than 2 sec, the camera will take another dark frame of similar exposure time and remove those long exposure hot pixel.

For shorter shutter speed for example 1/200s, if you see hot pixel/dead pixel those are faulty pixel. Happens in all camera, just some of them handle it better than others. For KM case, they do the remap once a month. After remap the hot pixel will be replaced with a computed value based on surrounding value.

After the service, is the viewfinder much better ?

The noise reduction is in the Menu Settings I presume. Don't have my camera with me now, but will try it once I get back.

As for the remap and the hot pixel is "replaced with a computed value based on surrounding value", I guess you mean it will take on a computed value of its surrounding neighbour pixels and hence it will blend in and not be as visible. Thats great cos it means it can be salvaged.

The viewfinder is cleaner now. Didn't notice anything else. I had tried to use a standard camera kit blower to blow off the dust, which i cant see, on the penta-mirror and also blown on the sensor to try rid of the dust but it didn't work. So I had to go SSC. Its great now. Not a single speck I can find yet.

 

[blueayz]

If u do not see the spots all the time, it simply means there's likely to be nothing wrong with your camera's sensor or LCD screen. The hotspots at longer exposure times (i.e. shutter speeds) are due to overheating of the CCD sensor. That's common to digital cameras and as tankm has pointed out, once your shutter speed is 1s or greater, the camera does a dark frame subtraction automatically. It's unusual for hotspots to occur at 1/2s shutter speed but it's not impossible.

As for why your P&S does not exhibit these hotspots, the immediate reason is that the CCD in your 5D is substantially larger than that in the P&S. The amount of heat generated is also substantially greater leading to heat-induced hotspots on the 5D's sensor. Secondly, at 15s, with such a small sensor in a P&S, the signal to noise is very small and the noise generated is so great that the hotspots are lost in that noise... so u do not seem to observe it. On the other hand, with the larger sensor in the 5D, the cleaner image results in these hotspots standing out very clearly... so u tend to notice them... u can try shooting at ISO1600, 15 s (use bulb mode) and see if u can see the hotspots on the LCD of the 5D... the noise will be quite substantial such that the hotspots will be rendered non-obvious.

Hi TME. I understand a bit better now. Will try that ISO 1600, 15s on my 5D and see how it turns out. Thanks for your explanation. ;p