#21  
Old 29-08-2011, 10:27 PM
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midnight (Darrin)
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Originally Posted by Bassnut View Post
Well, I dont know if this helps, but I remember haveing banding problems like this on a cam a long time ago and it was due to a faulty power supply smoothing capacitor allowing 60hz ripple to occur. If your game, open the back of the cam and see if any of the larger caps (round al tubes) are bulging at the top. Thats a sure sign of a failed cap. Easy and cheap to replace if your a tech.....
My 40D had vertical banding a few months ago. I did some calculations based on read out time etc and came up with about 100Hz. A full wave rectified AC signal (which is 50Hz) has rippling at 100Hz. This is a characteristic of FW rectification. I noticed this only when I was on the AC adapter for the Canon. For comparison, I went back to battery power and the banding was gone completely. An LC snubber cct was built and has reduced the effects but not eliminated them. The internal camera amplifier must be very prone to such interference.

Darrin...
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  #22  
Old 29-08-2011, 11:06 PM
ptc (Richard)
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Originally Posted by midnight View Post
My 40D had vertical banding a few months ago. I did some calculations based on read out time etc and came up with about 100Hz. A full wave rectified AC signal (which is 50Hz) has rippling at 100Hz. This is a characteristic of FW rectification. I noticed this only when I was on the AC adapter for the Canon. For comparison, I went back to battery power and the banding was gone completely. An LC snubber cct was built and has reduced the effects but not eliminated them. The internal camera amplifier must be very prone to such interference.

Darrin...
while that may be true for the 40D let's not confuse your result with a well known anomaly that is common in improperly designed cameras based on the KAI series.

the jailbar patterns are readily observed in KAI based cameras that don't do the clocking correctly as is obvious with the STL11K

Kodak is aware of this anomaly and that is why they put out the application note explaining how to change the clocking

please note that they do not blame it on operating temperature and there is an existence proof that temperature is not to blame: FLI's ML and PL series DO NOT exhibit this problem, but many many STLs do....

it is a weak design in my opinion and I personally think that unless you get one really really cheap they aren't worth wasting your time and money to use when there are cameras using the same sensors that do not have the list of "excuses" one has to accept when using SBIG.

Sorry to bust your bubble if I did that, but sometimes the truth is difficult to accept. but the sooner you do the sooner you can put forth a corrective action plan: ie ASTROMART!!!

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  #23  
Old 30-08-2011, 02:03 AM
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Peter Ward
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Originally Posted by ptc View Post

please note that they do not blame it on operating temperature and there is an existence proof that temperature is not to blame: FLI's ML and PL series DO NOT exhibit this problem, but many many STLs do....
I would not normally respond to commercial subjects such as this on IIS....but...

Even a white pointer wouldn't swallow this.... Richard have you forgotten an early post you made elsewhere using a FLI 39000 series image that had more vertical bars than Long Bay gaol ????

There is more to this that simply clocking. The vast majority of STL11k's have zero problems.

Raki. I have been in touch with SBIG and will contact you with options when I get back to Sydney later this week.

Rest assured you will be looked after !
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