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HotPixel Again.. (Maybe dead); help!
Topic Started: Jan 1 2009, 04:41 PM (611 Views)
montoyasg
Alpha Elite Member
quote from dpreview

Quote:
 
OK, so for those not in the know, Minolta and Sony A100 bodys remap hot pixels. I did some more detailed looking into this matter for my own benefit (and to post findings here for the community). Here is what i found:

- Remap occurs on shutdown where the month has changed (doesn't have to be the 1st of the month, i.e. you can just bump the month and cycle power).

- Remap occurs twice if you count changing the date back and cycling power again.

- Remap is based on a 6 second black exposure taken at camera power-down (you can tell because the access light remains lit for 7.5 secs vs. the normal .5 sec). I came to the 6 second conclusion because manual only allows for 6 or 8 seconds, and 6 + 1 sec processing + .5 second normal shutdown = 7.5.

- Remap is just that - a REMAP. It does a good job at catching those which appear during the 6 second capture, but by analyzing 6 and 30 second lens cap exposures, while everything is basically caught at 6, longer exposures amplify the effect. Those which are mapped may still show up at 30, and some which were not caught at 6 appear at 30 (and much brighter to boot). From the 30 sec samples I noted a different set of hot pixels with each remap.

Finally, I am not sure what the deal is, but my A100 has no hot colors at all. Only the luminosity goes up. White pixels on a black shot. In normal shots the pixel is just a brighter version of whatever color was captured. I'm not sure if the remap is catching and eliminating the hot colors first and allowing the overall (bright) pixels by, or what.

I figured this info is a good starting point, especially for those that shoot sky / star / moonlight / bulb shots.
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hktan
Alpha Newbie
Today is Febuary 9th and I am doing the lens cap shoot again..
shoot taken at 6s and 30s. Long exp NR off, SSS Off, ISO100, MF
No suprise.. the hotpixel still there.. there is no 6s REMAP.. even i change the date to mac or april.

Conclusion : A200 don have REMAP
well Can't expect too much when getting an entry level camera..

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montoyasg
Alpha Elite Member
actually i encountered the 6sec remap on the A200 before. after i installed the battery the 'busy' indicator lights up for the 6-7secs before powering on.
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hktan
Alpha Newbie
Then what I have is a lemon set lor... :'(

Just get a F58 recently.. Shooting in my fren wedding, I suspect there might be some focussing issue also..
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