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11-10-2010, 07:45 PM   #1
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K5 Startrail, what am I doing wrong

Tried the startrail as a test of the K5 this evening. Set the camera on tripod bulb mode, left it with shutter open for an hour and three quarters. Is this picture what you would expect f 5.6 infinity focus. I did not do a dark frame as I have no idea how to do one and subtract it from the image. Any ideas considered!

It was a bit windy which is why the tree is not in focus, plus I did focus at infinty.

Have added a 100% crop of the original raw so you can check out the noise level.


Last edited by telfish; 01-30-2011 at 10:17 AM.
11-10-2010, 07:50 PM   #2
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So what's the problem?
11-10-2010, 07:54 PM   #3
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Looks friggin amazing to me. What were you expecting?
11-10-2010, 07:54 PM   #4
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looks pretty good to me.

11-10-2010, 07:57 PM   #5
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This is the first time I have ever tried one and as I did not do a DFS I thought it might have come out better.

I was pleased that the K5 seems to work fine with long exposures. It seems to have picked up a shed load of stars I could not see with my naked eye.

So how do I do a DFS and will it improve these sort of images. I want to do more when I can get the right location and a starry dark night sky.
11-10-2010, 08:06 PM   #6
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QuoteOriginally posted by telfish Quote
This is the first time I have ever tried one and as I did not do a DFS I thought it might have come out better.

I was pleased that the K5 seems to work fine with long exposures. It seems to have picked up a shed load of stars I could not see with my naked eye.

So how do I do a DFS and will it improve these sort of images. I want to do more when I can get the right location and a starry dark night sky.
I don't really understand DFS but there doesn't appear to be any noise in the image, hence DFS probably won't do anything

I once did a 30minute exposure with my ist DL- end picture looked like white noise on a TV. If that's what you're getting SOOC then it must be applying DFS automatically?
11-10-2010, 08:09 PM   #7
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You only need to do a DFS if there is a lot of noise. It looks like you have pretty dark skies you might even want to try a larger aperture next time. What lens did you use?
11-10-2010, 08:11 PM   #8
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What's that thing in the bottom right? Power lines?
Otherwise it looks pretty cool to me

11-10-2010, 08:13 PM   #9
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DFS doesn't occur until After the exposure is made. The big complaint about not being able to turn it off since the K10d is that to do a photo like yours (looks great btw), one might desire to do several exposures and stitch them together. DFS takes as long to perform as the exposure and while it is doing so, the camera is completely inoperable. So if you wanted to stitch together 50x 1 minute exposures, you would have 50x 1 minute gaps in each trail. By being able to turn off DFS, that procedure becomes much more simple and manageable.

11-10-2010, 08:16 PM   #10
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QuoteOriginally posted by dtra Quote
What's that thing in the bottom right? Power lines?
Otherwise it looks pretty cool to me
Could be a plane navigation lights or a satellite I guess. Or a UFO
11-10-2010, 08:17 PM   #11
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That was my guess...

11-10-2010, 08:19 PM   #12
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QuoteOriginally posted by krp Quote
You only need to do a DFS if there is a lot of noise. It looks like you have pretty dark skies you might even want to try a larger aperture next time. What lens did you use?
I used a Da 15 Limited, so I might get better results at say f16? And do I focus on infinity to get the stars to show as a clean line? I ask because I want to get buildings in focus with the startrails behind.
11-10-2010, 08:21 PM   #13
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QuoteOriginally posted by JeffJS Quote
DFS doesn't occur until After the exposure is made. The big complaint about not being able to turn it off since the K10d is that to do a photo like yours (looks great btw), one might desire to do several exposures and stitch them together. DFS takes as long to perform as the exposure and while it is doing so, the camera is completely inoperable. So if you wanted to stitch together 50x 1 minute exposures, you would have 50x 1 minute gaps in each trail. By being able to turn off DFS, that procedure becomes much more simple and manageable.

Thanks Jeff, so it looks like with the K5 I don't have to concern myself with doing a dark frame at all?
11-10-2010, 08:52 PM   #14
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QuoteOriginally posted by telfish Quote
Thanks Jeff, so it looks like with the K5 I don't have to concern myself with doing a dark frame at all?
Not unless you're doing multiple long exposures that you intend to layer together..

11-10-2010, 09:06 PM   #15
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QuoteOriginally posted by telfish Quote
Thanks Jeff, so it looks like with the K5 I don't have to concern myself with doing a dark frame at all?
You can turn on DFS in camera. It's called long exposure NR. For your photo, it will take another 1h45, so you would come back after 3h30 if the battery can sustain that long. I believe we are all curious to see the difference, if there is any.

BTW, with the amazing DR of the K-5, it should be possible to expose at ISO 80 and later apply some tone mapping to bring up the many dark stars w/o burning the bright ones
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