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Long Exposure with DSLR


kenghor

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Tried shooting star trail with the 300D and the result is disaster!

Extremely noisely at ISO 100. Battery died and camera shut off by

itself before the intented time.

Well, I guess this is one area where film still rules.<div>008YyM-18402084.jpg.f01aa67f78e8adef174e709dd815bafc.jpg</div>

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"More digital bashing based on ignorance."

 

Geez, instead of flame the guy, why don't you be helpful Chuck? Comments like that are what is wrong with internet discussions.

 

I didn't read the post as digital bashing per se - did you see the "I guess" part? Give him the benefit of the doubt, I don't interpret the original post as that provocative.

 

Bah.

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The March, 2004 issue of Sky & Telescope has an article on capturing star trails with digital cameras that might be helpful.

 

I haven't tried star trails with my 300D, but I have taken comet images from a tripod and long-exposure astrophotos using a telescope. Noise is definitely an issue for longer photos. You can take a dark frame (cover the lens cap and make an exposure of equal length as the star trail photo) and then subtract the dark frame from the main exposure to get rid of some of the noise.

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Actually, it is a bashing post, no doubt about it, complete with esclamation mark. I don't see any questions in the post either. Had there been it would be a different story. And, the conclusion "this is one area where film still rules" reveals the user inability to use his own tools and seals the bashing :)
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I can't find my post on this but I did include comments on this photo I took here <A href"=http://www.photo.net/photo/2369022">http://www.photo.net/photo/2369022</A><BR><BR>

<img src="http://d6d2h4gfvy8t8.cloudfront.net/2369022-md.jpg" hspace=10 height="435" width="616" border="0"><BR>

<h4>I don't know about the D70 for star trails</h4>

Star trails can be done as it is in the above photo <b>but I can't recommend the D70 for doing this.</b><BR><BR>There are 3 major issues:

<br>1. Noise

<br>2. Noise Redution Processing

<br>3. Battery life<BR><BR>

This is a 20 minute exposure. It takes 40 minutes until the camera is ready for the next shot. Noise Reduction (NR) Processing takes as much time as the original image exposure. Yikes! So this shot is 20 minutes of exposure + 20 minutes of NR = 40 minutes. Now you must use NR (according to everything I've read, but not tested). The resulting image has noise artifacts. It was fairly difficult/tedious to clean these up and I'm very proficent with PS. I can get large prints out of the D70, however I've given up on anything larger than 12x18 inches on long exposure shots due to noise. <BR><BR>Battery Life: 40 minutes is a lot of battery time. I did have a battery die while processing a picture and I lost the image. I wouldn't trust the battery life for this in cold weather, it was about 65f/18c this evening and the batteries were new and broken in.

<br><BR>So Mine is a Nikon and his is a Canon. Still the same problem for long exposures.

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Is my post considered as digital bashing?

I've been shooting digital exclusively ever since I bought the 300D. I've never touched film since. I've been selling away almost all my film based camera and systems.

I've just stating my observations. Did the shot inside my hotel room. My shot was at least 1.5 hours because I felt asleep after that. Woke up 2.5 hours later and realised that the battery is dead. Loaded in a fresh battery and was glad that the image was saved. But the image is extreme noisy.

 

Seems that some of u have managed to get some pretty nice exposure with shorter exposure duration. Perhaps a cold environment can help to reduce the noise.

 

But if I were to do a star trail shot again, I'll choose film over digital.

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I am shooting both but you guys jump on this guy right away saying it's digital bashing. That only shows your insecurity about the whole issue.

 

 

The truth is: Long exposure requires a lot of battery life and in many cases it is not enough for DSLR to handle. A camera with manual remote release cable is obviously more practical. The only practical way about this is to run an extension cord from your house directly to the camera or perhaps utilizing your car battery or another alternate power source. That's a lot of hoops to jump through as opposed to using a film camera.

 

The time it takes to process the picture in the camera and to CLEAN it afterwards on a PC is time you don't have to deal with when using a manual film camera. Let's face it. DSLR's aren't there yet for very long exposures.

 

Now that I said it please do not jump on me for bashing digital. What percentage of people will be doing 2 hour exposures? The margins are slim so let's not get all defensive about it.

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Good point Rene. Basically, the right tool for the right job. Right? I love my DSLR. I'll make sure I toss my my SLR and a few rolls of film in my bag next time I'm out as I sometimes never know where I'll end up - like Delicate Arch at 2am.

Very interesting comment about noise and temperature. The big 22mp sensors for medium format have cooling systems on them to reduce the heat/noise.

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There is an interesting way to make long exposures with digital cameras. For some subjects (including star trails) you can make a series of shorter exposures and stack the resulting images. The shorter exposures reduce the noise/image and the stacking tends to average out the noise. For examples see http://www.tawbaware.com/maxlyons/cgi-bin/image.pl?gallery=8

 

Wally

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The star trails are about 15 degrees per hour; thus the exposure for Wee's image are known by measuring the arc in degrees; about pole; ie center of the circles. <BR><BR>Also Wee appears to be close to the equator; maybe +/- 5 degrees is my guess; based on the pole to horizon appearance.<BR><BR>Both film and digital "work better" in cold.
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