Canon EOS 20D - Busy after bulb exposure

[subha]

<p>I am getting BuSY signal every time I have a picture in BULB mode. <br>

What I have is: EyeFi Mobi SD card inside CF adaptor. <br>

The BuSY time is exactly the same amount as bulb exposure. <br>

So if I take a picture for 300 seconds, the BuSY is about 300 seconds. <br>

I do remember when I took long exposure shots using my 10D the BuSY was not this long. <br>

Any suggestions?</p>

<p> </p><div></div>

[JDMvW]

<p>Without actually looking it up, I seem to remember that the 20D has a noise reduction procedure for long exposures that can be turned on or off in the parameters somewhere.<br>

Look in the manual under noise reduction.</p>

[subha]

In the custom function I have noise reduction

turned on

[fmueller]

<p>In that case it would seem it takes that long for the camera to process the noise reduction routine. If you want to test that, switch noise reduction off, and see if you still get the BuSY.</p>

[alan_bryant1]

<p>I believe it's doing "dark frame subtraction"; essentially after a 300 second exposure it's taking another 300 second exposure with the shutter closed, and using that to find the bad pixels to remove them from the image. </p>

<p>It's a pretty common surprise for people who take long exposures. Another link,</p>

<p>http://www.photo.net/canon-eos-digital-camera-forum/00Ce9S</p>

<p>I would just turn off the custom function. Modern software has gotten quite good at noise reduction.</p>

[paddler4]

<p>I don't have a 20d, but most Canon cameras have two noise reduction functions. one affects only in-camera jpegs. The other is the long-exposure subtractive noise reduction that you had turned on. They behave very differently.</p>

<p>I don't agree with Alan. I do some long-exposure night photography, and unless I can't accept the longer time the camera is locked up, I always leave long-exposure noise reduction turned on, even though my cameras are much newer than yours and therefore produce less noise. The reason is that subtractive noise reduction does not damage the quality of the image. While other noise reduction programs have gotten much better, they necessarily will damage image detail. </p>

[akocurek]

<p>Nice lightning capture!</p>

[Marcus Ian]

<p>Now that you know what is going on, you can choose whether or not to turn it off. Remember that your 20D has both an extremely noisy sensor (by today's standards), <em>and</em> only has an 8MP sensor. Combined, this will <em>severely</em> limit the capabilities of most NR software.</p>

<p> Subtractive LENR is not a panacea, as a good portion of the noise is, in fact, random - so will not be affected. However, it is by far the single most effective way to reduce noise in B exposures.</p>

<p>If you want a rude shock, turn it off, and shoot some RAWs. You will be shocked at how fast those dark frames turn into utter garbage. But of course standards, as well as subjects, composition, individual units and even ambient temperatures can all drastically affect the imagery you get. I think I'd try it if I were you...at least once.</p>