farnz Posted January 31, 2009 Share #21 Posted January 31, 2009 Advertisement (gone after registration) As far as the banding is concerned there may be a 'non-photographic' explanation. Most of us carry mobile phones these days that have fairly strong transmitters, which regularly communicate with radio base-stations when we unknowingly move from one base-station area to another. This transition is invisible to us but not to the phone that has to register with the new base-station and it's quite possible that the M8 is picking up RF which is interfering with the M8's processor writing to the SD card and showing up as banding. (If you really want to see evidence of your mobile phone's RF interference hold your phone close to your monitor while making a call but be warned: you may need to de-gauss your monitor afterwards if you end up with areas of block colour on it.) The answer may be to keep your phone well away from your M8 or to simply turn it off. It might pay to see if you can replicate the banding by holding the phone near the camera while making a call and taking a picture. Don't get the phone too close to the LCD though, just in case. Pete. Link to post Share on other sites More sharing options...
Advertisement Posted January 31, 2009 Posted January 31, 2009 Hi farnz, Take a look here Increased noise since firmware update. I'm sure you'll find what you were looking for!
stunsworth Posted January 31, 2009 Share #22 Posted January 31, 2009 If you really want to see evidence of your mobile phone's RF interference hold your phone close to your monitor while making a call but be warned: you may need to de-gauss your monitor afterwards if you end up with areas of block colour on it. If I put my iPhone too near my mouse cable at work, the mouse pointer jumps all over the place from time to time - presumably when the phone's communicating with the base station as this happens even when I'm not taking a call. Link to post Share on other sites More sharing options...
farnz Posted January 31, 2009 Share #23 Posted January 31, 2009 If I put my iPhone too near my mouse cable at work, the mouse pointer jumps all over the place from time to time - presumably when the phone's communicating with the base station as this happens even when I'm not taking a call. Steve, Radio's not my field, but I expect that from time to time the base station sends out an "Are you still there?" message to all the registered mobiles in its area, to which the mobiles reply "Yep." and the base station de-registers the ones that don't reply to make room for new mobiles entering its area. It sounds like your mouse cable's acting like quite an effective aerial. Pete. Link to post Share on other sites More sharing options...
stunsworth Posted January 31, 2009 Share #24 Posted January 31, 2009 It sounds like your mouse cable's acting like quite an effective aerial It does indeed. It totally locked up the PC a couple of times before I realised what was happening. Link to post Share on other sites More sharing options...
pgk Posted January 31, 2009 Share #25 Posted January 31, 2009 I'm unsure of the shutter accuracy/precision but it does vary in any shutter and it may be yours is poor at low speeds. My first reaction was that there had been an exposure difference for some reason but the exif data say it was shot on manual. A varying shutter speed might be responsible (is a power fluctuation a possibility?) but I also wonder about the conversion down to 8 bit with slight differences in the histogram being visible in the final output - especially with a 'mildly' varied image. Given that few others have noted increased noise after a firmware update then this does seem somewhat unlikely to me. Link to post Share on other sites More sharing options...
sbelyaev Posted January 31, 2009 Share #26 Posted January 31, 2009 I don't know much about electronics, but it looks like in order to extend dynamic range the camera increase gain in darker areas if the images. It leads to disproportionately increased noise. Link to post Share on other sites More sharing options...
Rick Posted January 31, 2009 Share #27 Posted January 31, 2009 Advertisement (gone after registration) Quotes: (If you really want to see evidence of your mobile phone's RF interference hold your phone close to your monitor while making a call but be warned: you may need to de-gauss your monitor afterwards if you end up with areas of block colour on it.) The answer may be to keep your phone well away from your M8 or to simply turn it off. It might pay to see if you can replicate the banding by holding the phone near the camera while making a call and taking a picture. Don't get the phone too close to the LCD though, just in case. Rest assured, you will not ruin your LCD screen or your monitor (non CRT) one iota by holding your cell phone next to it. Electromagnetic energy will effect a CRT television but not an LCD. I doubt if your cell phone could even create enough energy to effect a CRT enough to need degaussing. It is an interesting thought though, that the electromagnetic signal is getting into the M8 circuitry and causing banding. This could be possible but, I'd put my money in the software. It will be interesting to see if someone can get a cell phone to cause noise in the M8 circuitry. Is this a reported phenomena with other cameras? Link to post Share on other sites More sharing options...
farnz Posted January 31, 2009 Share #28 Posted January 31, 2009 Rick(?), Not trying to pick a fight with you and I agree that theoretically LCDs shouldn't be affected by EMI but the technical world seems split on the subject, hence the availability of EMI shields for LCD monitors and I recall seeing a paper on the subject some time ago. I'd also agree that it's unlikely that a mobile phone should interfere with an electronic camera because in the UK their emissions are legally required to comply with BS EN 55014, which limits their effect on other equipment, and the M8's metal body will further limit EMI by acting as a weak Faraday cage. On the other hand, typical mobile phone field strength is around 20 Volts per square meter at 1 meter from the phone, which is powerful enough to have "an" effect so it's not beyond the realms of possibility. Sorry to all for the technobabble, back on topic ... Pete. Link to post Share on other sites More sharing options...
sfokevin Posted January 31, 2009 Share #29 Posted January 31, 2009 A Faraday Cage in action... (Complements of Sabrina's MySpace) Link to post Share on other sites More sharing options...
ho_co Posted February 1, 2009 Share #30 Posted February 1, 2009 Looks like my kind of chick. Link to post Share on other sites More sharing options...
stunsworth Posted February 1, 2009 Share #31 Posted February 1, 2009 Looks like my kind of chick. You seem to need balls to do that experiment. Link to post Share on other sites More sharing options...
chris_livsey Posted February 1, 2009 Share #32 Posted February 1, 2009 And perhaps a tripod for the camera next time Link to post Share on other sites More sharing options...
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