Any examples of long exposures or star trails from K-x?

ambienthousewife · 12-09-2009, 06:45 AM

After lots of muttering, threats and indecision, I have a date with my credit card and my local photo shop (which luckily, has Pentax in the flesh

). I am still interested in long exposure performance and I have had a search around, but I have not been able to find any examples of long (5 - 30 minute or more) exposures at ISO 200 or 400 from the Kx. I have seen some from the K7 and loads of high iso, but not slow and long from the Kx. Would anyone be able to help or point me in the right direction? Full size raw or jpgs preferred, I am interested to see how it would do for use with an ND110 filter, star trails etc (although the subject is not so important for this test, I want to see hot pixels and noise).

rawr · 12-09-2009, 07:05 AM

Did you manage to have a look at this thread:

https://www.pentaxforums.com/forums/pentax-dslr-discussion/77684-k-x-king-lon...ighlight=astro

ambienthousewife · 12-09-2009, 07:22 AM

Hi rawr, yes thanks, I trawelled that one (and the similar K7 thread) and they were very informative (and pretty stunning really). Lots of short stacked exposures, but nothing I could find that was a single exposure over a minute. I recognise that it is also getting to the time of year here when only the very rugged venture out for this sort of thing!

rawr · 12-09-2009, 07:35 AM

Originally posted by ambienthousewife

I recognise that it is also getting to the time of year here when only the very rugged venture out for this sort of thing!

Indeed!

Where I live for the last several days it has been 41 degrees Celsius in the shade during the day, and as I type this at 1:34 am at night it is 30 degrees Celsius in my study.

Is that what you mean?

ambienthousewife · 12-09-2009, 07:57 AM

Not quite the same here, not too bad actually as it is still about 2 or 3 degrees at night and we dont get too much snow - unlike Canada or northern Europe. I can live with the cold, but I always dread getting a heatwave like that when I go back to Australia.

ambienthousewife · 01-17-2010, 11:02 AM

I was just posting a new thread related to this and it has disappeared. Strange. Anyway, I did buy the Kx in the end, and it is miles better than the K100d for long exposures. I tried it out with a couple of long exposures of 6-10 minutes, no probs. I also did a stack using 130 30 second exposures (no long exposure noise reduction, jpeg, f4.5, iso 800, fisheye 10mm) which I was very happy with. See here Kx Star Trails I used picolay and startrails to stack them, but startrails produced a grid pattern on the image:

This was not visible with the default settings of picolay (but it did appear with higher settings for 'minimum contrast' and 'weighted average' processing). Is this common for other cameras? I am delighted with the results for a first attempt, the Kx does indeed succeed!

er1kksen · 01-17-2010, 04:28 PM

While hiking in the Colombian andes, I did a couple 20-minute star trails at ISO 100 (trust me, although it's an "artificial" ISO with the K-x, ISO 100 is absolutely a very useful setting on the K-x and I use it more than 200) around camp. These were accomplished by wrapping a strap around the grip and jamming a twig between the strap and camera to hold down the shutter button. I did use the dark-frame NR option with this (not sure if it was necessary or not) but the results are excellent. Processing the jpegs in-camera in such a way that should exxagerate noise produced no noise whatsoever when viewing at full magnification. I haven't gotten to play with the files on the computer yet, however... I'm getting home tomorrow. I'll put the star trails at the top of my qeue of files to work on and get back to you as soon as possible. You can see an OOC jpeg here: Star Trails over la Valle de Cocora. Some of the trails seem to be "interrupted" here and there, probably by the clouds that kept drifting through the field of view.

milesy · 01-18-2010, 04:59 PM

hi all

sorry couldnt help but jump into this thread.......here is a startrails done with the K7........about 160 exposures of around 28 seconds (to make sure no DFS happening)

quite please with the result

rRnt · 01-20-2010, 12:18 PM

I tried startrailing with my K-x a few weeks ago. Because it was about -12 degrees celsius I spent only about 15 minutes exposing the image but I was happy with my first try altough it was not shot towards the North and so on. But my next one shall be.

From EXIF data:
Model: PENTAX K-x
Exposure: 94348/100
Aperture: f/3.5
Focal length: 3750/100
ISO: 100

12-09-2009, 06:45 AM	#1
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38	Any examples of long exposures or star trails from K-x? After lots of muttering, threats and indecision, I have a date with my credit card and my local photo shop (which luckily, has Pentax in the flesh ). I am still interested in long exposure performance and I have had a search around, but I have not been able to find any examples of long (5 - 30 minute or more) exposures at ISO 200 or 400 from the Kx. I have seen some from the K7 and loads of high iso, but not slow and long from the Kx. Would anyone be able to help or point me in the right direction? Full size raw or jpgs preferred, I am interested to see how it would do for use with an ND110 filter, star trails etc (although the subject is not so important for this test, I want to see hot pixels and noise).

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12-09-2009, 07:05 AM	#2
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Did you manage to have a look at this thread: https://www.pentaxforums.com/forums/pentax-dslr-discussion/77684-k-x-king-lon...ighlight=astro

12-09-2009, 07:22 AM	#3
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38 Original Poster	Hi rawr, yes thanks, I trawelled that one (and the similar K7 thread) and they were very informative (and pretty stunning really). Lots of short stacked exposures, but nothing I could find that was a single exposure over a minute. I recognise that it is also getting to the time of year here when only the very rugged venture out for this sort of thing!

12-09-2009, 07:35 AM	#4
rawr Veteran Member Join Date: Jun 2009 Posts: 11,913	Originally posted by ambienthousewife I recognise that it is also getting to the time of year here when only the very rugged venture out for this sort of thing! Indeed! Where I live for the last several days it has been 41 degrees Celsius in the shade during the day, and as I type this at 1:34 am at night it is 30 degrees Celsius in my study. Is that what you mean?

12-09-2009, 07:57 AM	#5
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38 Original Poster	Not quite the same here, not too bad actually as it is still about 2 or 3 degrees at night and we dont get too much snow - unlike Canada or northern Europe. I can live with the cold, but I always dread getting a heatwave like that when I go back to Australia.

01-17-2010, 11:02 AM	#6
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38 Original Poster	I was just posting a new thread related to this and it has disappeared. Strange. Anyway, I did buy the Kx in the end, and it is miles better than the K100d for long exposures. I tried it out with a couple of long exposures of 6-10 minutes, no probs. I also did a stack using 130 30 second exposures (no long exposure noise reduction, jpeg, f4.5, iso 800, fisheye 10mm) which I was very happy with. See here Kx Star Trails I used picolay and startrails to stack them, but startrails produced a grid pattern on the image: This was not visible with the default settings of picolay (but it did appear with higher settings for 'minimum contrast' and 'weighted average' processing). Is this common for other cameras? I am delighted with the results for a first attempt, the Kx does indeed succeed!

01-17-2010, 04:28 PM	#7
er1kksen Veteran Member Join Date: Oct 2008 Location: Forestville, NY Photos: Albums Posts: 1,801	While hiking in the Colombian andes, I did a couple 20-minute star trails at ISO 100 (trust me, although it's an "artificial" ISO with the K-x, ISO 100 is absolutely a very useful setting on the K-x and I use it more than 200) around camp. These were accomplished by wrapping a strap around the grip and jamming a twig between the strap and camera to hold down the shutter button. I did use the dark-frame NR option with this (not sure if it was necessary or not) but the results are excellent. Processing the jpegs in-camera in such a way that should exxagerate noise produced no noise whatsoever when viewing at full magnification. I haven't gotten to play with the files on the computer yet, however... I'm getting home tomorrow. I'll put the star trails at the top of my qeue of files to work on and get back to you as soon as possible. You can see an OOC jpeg here: Star Trails over la Valle de Cocora. Some of the trails seem to be "interrupted" here and there, probably by the clouds that kept drifting through the field of view.

01-18-2010, 04:59 PM	#8
milesy Veteran Member Join Date: Jan 2009 Location: Melbourne Photos: Gallery Posts: 379	hi all sorry couldnt help but jump into this thread.......here is a startrails done with the K7........about 160 exposures of around 28 seconds (to make sure no DFS happening) quite please with the result

01-20-2010, 12:18 PM	#9
rRnt Forum Member Join Date: Dec 2009 Photos: Gallery \| Albums Posts: 88	I tried startrailing with my K-x a few weeks ago. Because it was about -12 degrees celsius I spent only about 15 minutes exposing the image but I was happy with my first try altough it was not shot towards the North and so on. But my next one shall be. From EXIF data: Model: PENTAX K-x Exposure: 94348/100 Aperture: f/3.5 Focal length: 3750/100 ISO: 100