Site Sponsors
Results 1 to 17 of 17

Thread: K1 and astrotracker--a bit disapointed!!

  1. #1
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    K1 and astrotracker--a bit disapointed!!

    I have seen over and over the excellent results from Pixel shift files, and had been waiting to get out at night when I could try the astrotracker feature, needless to say, at least on the 15-30 @ 15mm, the feature appears to be a bit broken at least on my camera.

    At 2 minutes, which is not even half the total time which can be used (5 minutes is the total), I found that the Astrotracker can only track well in the center of a shot and as you move out towards the edges of the image, you will start to see traditional star trails, to full 2 minute trails at the edge. And the Milky way is not tracked correctly (since there are trails) and it's blurred against the trails.

    I have attached some screen shots from C1, the image on the left is a 25 second Pixel shift shot and the one on the right is from a 2 minute Astrotracker shot. As you can see, the right edge is basically not captured at all. Not sure if this is due to the 15mm lens? which is so is a huge surprise as most landscape work involving the M way is going to use a ultra wide lens, 14mm to 20mm. My GPS was calibrated, (you have to do a calibration each time anyway as prompted) and it actually correlated very close to what my Garmin showed, so don't think that was the issue. Anyway, will try again, but I worked up several shots during the evening and all showed the same thing.

    Here are a few screen shots.
    Image on right is a pixel shift (taken to see if noise levels would be lower) and image on right is 2 minute astrotracker

    Image 1 shows a side by side 25 sec on left and 2 min on right, basically almost full star trails on the astro tracking image
    Image 2 show a crop from dead center and if anything the astro tracker shot is a bit out of focus
    Image 3 shows a crop from top middle, and here the stars are sharp, and no trails
    Image 4 shows full images, mainly to show the dark color band toward top of all files, this appears on all images taken in either astro tracker or Pixel shift @ 25", did not try traditional stacking to see if band still shows. This is bigger show stopper than anything as it has to be corrected each time. in the side by sides, I have already worked on the band so it's not as evident.

    Also note that the Milky way is blurred in the 1st screen shot, so basically astro tracker failed 100% here. GPS was fully calibrated and confirmed to be so.


    Images worked in Capture One.

    Paul C


    Click image for larger version. 

Name:	Astro tracking failure 1.jpg 
Views:	62 
Size:	542.8 KB 
ID:	120367Click image for larger version. 

Name:	Astro tracking failure 2.jpg 
Views:	31 
Size:	554.7 KB 
ID:	120368Click image for larger version. 

Name:	Astro tracking failure 3.jpg 
Views:	49 
Size:	703.6 KB 
ID:	120369Click image for larger version. 

Name:	Astro tracking failure 4.jpg 
Views:	35 
Size:	406.9 KB 
ID:	120370

  2. #2
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    From some feedback from other sites, it appears that 15mm with a rectilinear design can't work with the Astrotracer feature. The distortion of the lens towards the edges can't be accommodated by the Pentax algorithm. Looking back, I have seen this in star trail work also, where the trails towards the edge of the frame are extended more, but did not consider it for the Astrotracer feature.

    Will have to look for a fisheye style lens or closer to a 50mm, where that focal will work or attempt a stitch.

    Paul C

  3. #3
    Member
    Join Date
    Dec 2009
    Location
    Big Island, Hawaii & Utah
    Posts
    125
    Post Thanks / Like
    Images
    11

    Re: K1 and astrotracker--a bit disapointed!!

    The AstroTracker feature is interesting and sometimes works in some fashion. I gave up on it when I owned a Pentax K3. My solution was, and still is, the iOptron Sky Tracker. Using aps with my iphone, I can set it up and align it in a couple of minutes. I've attached two shots from the other evening with about a 1/3 moon, so the sky has some blue in it as is normal with lots of moonlight. One is the full frame shot and the other is a crop, same frame, from the center of the Milky Way, 81 seconds at ISO 800, Rokinon 14mm @6.3, Pentax K1.

    There were clouds and thin cloud cover, so it was merely test shooting. I am now convinced that the iOptron has tracking accuracy that will allow me to use Pixel Shift for night sky work and I'm looking forward to trying that when we have some clear nights here.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Nightsky FF.jpg 
Views:	12 
Size:	595.2 KB 
ID:	120512   Click image for larger version. 

Name:	Nightsky crop.jpg 
Views:	15 
Size:	759.4 KB 
ID:	120513  
    Likes 2 Member(s) liked this post

  4. #4
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Hello Charles:

    I tried the pixel shift for night work, at ISO 3200 to 6400 but the noise was still pretty heavy, compared to the Astrotracer feature. As far as I can tell the pixel shift will not work with bulb and only works to 30 seconds max exposure. I was hoping that from other tests where pixel shift at high ISO vs normal shots, where the high ISO pixel shift files are considerable cleaner would hold true for this night work. It might have been the ambient temp or humidity or both, but the noise still became pretty harsh. C1 still did a good job on the sky and I ended up using LR for the foreground part.

    The astrotracer does blur the foreground considerably, and merging the sky and foreground take a while, but it can be done OK.

    Overall the astrotracer, minus the issue with the 15mm and trails at the edge, is a very nice feature. The GPS locked every time I used it and the center center third of the files are perfect. Being able to hold the exposure open for 2 minutes makes a huge difference, in noise and needed ISO as the sky in the shot below was at ISO3200, which kept things very clean. Still need to try a pano with like a 35mm vertically and see how all that works, but it's going to be a lot of work for sure.

    Paul C

    Click image for larger version. 

Name:	3 Milky Way over Buffalo Point.jpg 
Views:	26 
Size:	960.3 KB 
ID:	120517

  5. #5
    Member
    Join Date
    Dec 2009
    Location
    Big Island, Hawaii & Utah
    Posts
    125
    Post Thanks / Like
    Images
    11

    Re: K1 and astrotracker--a bit disapointed!!

    Hi Paul,

    I been fighting two problems. I have a very difficult time achieving Calibration in the Astrotracer mode. I can get calibration periodically here at my home. However, I have had 0 success in the field. There is lava, both solid and liquid kind on this island. I went out to the lava flow the other evening, could not achieve calibration. I've actually wondered if the flowing lava at the site affected the compass that is part of the calibration process. As I own an iOptron tracking mount, my thinking is now that I will use it in conjunction with pixel shift at ISO 1600, and see what I can achieve.

    My other issue has been white spots/hot pixels against dark backgrounds on high ISO, long exposures. I tried pixel mapping, didn't cure it. Long shutter speed noise reduction did but I'm distressed that my K1 has this issue. I've never noticed it on any other Pentax or Canon digital camera that I've owned.

  6. #6
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Hi Charles,

    The White dot issue, is a problem for sure.

    K1 and white dot issues (Same as the D810)

    I tried to bring this issue up in the forums on www.pentaxforums.com, but was shot down pretty quick by one of the usual "rocket scientists" on that site that claims to know everything, but actually knows nothing about the subject.

    The white dot issue is known problem with the 36MP chip, and started with with the Nikon D800E, for some reason the D800 did not have the issue. Nikon fixed the problem internally on the D800E. By that I mean no recall was done. But later versions of the camera did not have the problem. I know this as I owned 2 of them. When the D810 was released, within 3 weeks, Nikon recalled all shipped cameras to have a fix made for this issue. Nikon's fix did involve sending the camera to a service center, so it was more than just a firmware fix something was also replaced on the camera.

    Here is a link to the Nikon announcement:

    http://www.nikonusa.com/en/service-a...ikon-D810.html

    Pentax I know very little about their company. In the past they have done very good development work, and on the K1 they seem to have done a good job, but they did overlook the white dot issue. Which is a unfortunate, if as a photographer you want to use the K1 for long exposures for astro work, where the in camera long exposure noise reduction is not a good tool as it create a gap. This mainly effects star trail work, but I do love to work with star trails also.

    Here is link to an article I wrote about the D800e, but you can see the dots are the same:

    http://photosofarkansas.com/2013/08/...-dot-problems/

    With the K1 I noticed the white dots, almost immediately with 2 minute and 1 minute exposures, and a few others on the Pentax forum did let me know that they had seen them, but were not sure what they were, as they don't look like normal long exposure noise, (red, blue, green pixels). As the camera gets hotter, the white dots become much more frequent. The good news is the that in camera long exposure noise reduction will remove this noise, but it does take the camera off line for the same time frame as the previous exposure. So Pentax and Nikon both do this in real time and not in the buffer in the background like Canon does. Kudos to Canon.

    For star trails, the white dots are a disaster. Star trails are best shot in stacks, time lapse with a intervalometer. Then you combine later on in photoshop. Even if you just shoot 1 long exposure, for some reason you will get faint gaps, not even clean line. With stacking, you will get a faint gap after each separate exposure. As the dots don't move as star do, the combination in photoshop will leave them alone. But if you use a program like "Star Tracer" to move the image to take out the gaps, then the single dots, become a dotted line. So there is the problem and you will have potentially thousands of these dotted lines to remove.

    On my post in the www.pentaxforums.com site, I was deemed a noob and as someone who really doesn't know what there are talking about, and that a simple lens cap dark frame solution would fix this issues. But as you pointed out it won't as the dots being white won't be removed with classic dark frame subtraction. But even if it did work, the amount of extra time involved would be a huge issue for me.

    Capture One, will remove the vast majority of the white dots, without hurting the stars or star trails, with the single pixel noise reduction slider moved to close to 100%. LR will do nothing with them or will Silkypix. If you have not tried C1, give it a try and see what you think.

    But for star trail work, I will have to keep the Fuji or Nikons around as I prefer to use LR many times.

    Paul C

  7. #7
    Member
    Join Date
    Oct 2011
    Location
    Kraków
    Posts
    52
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Thank you Paul. I will make some test tonight as I want to make some photos of falling stars. Today will be peak in intensity of meteors from 109P/Swift-Tuttle.
    I will check if I have similar effects.
    If so I', planning to send my K1 to service we will see what will be the answer from them.
    As you wrote problem is quite big.
    Best!

  8. #8

  9. #9
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Just a bit more feedback after several more trips.

    1. I have to give Pentax a real thumbs up, as the technology in astrotracer, is really very impressive overall.

    2. If you are using a ultra wide, say 15mm to even 30mm, you need to make sure the best part of the Milky Way is in the center of your frame. This allows it to track perfectly no trails. This is not due to the astrotracer feature, but just the retrofocus design of a wide lens. You can see the same issue in normal star trail photography, as your trails towards the edge will always be longer than those in the center, especially if you are centered on the north star.

    3. If you can't frame it in the center then try to keep your exposures in the 45 second to 1 minute range as this will limit the trails.

    4. Astrotracer allows you to use aperture ranges of F3.5 up to 5, which in astro night work is unheard of. This allows both better performance in the sky but most importantly the foreground will not be as soft and may not require a second shot.

    5. I still at times get a dark/different color band at the top of the frame. This was first attributed to light coming in from the viewfinder, but I have shot the the viewfinder blacked out totally and at time still get the color band. It's worse with longer shots, say 2mm or longer. Most times you can resolve it in post (raw). I need to try a 2nd body sometime to see if I get it there also.

    6. White dots, (see my previous post on this), are much worse for some reason in Astrotracer mode, not sure why this would be? Since Astrotracer by design moves your foreground you need to shoot a non traced frame to merge later. Most times I have done this with long exposure noise off and the non traced frame shows some white dots, just not as many thousands. However as the night wears on, I tend to go ahead and shot one frame with the LEN on just to make sure as this will allow me to work in LR with Raw. C1 still does by far the best on removing the dots with the least amount of image loss. (thankfully). The main issue with LEN, is you are doubling your exposure time, and running down the battery just that much faster.

    7. I have compared shots taken with iOptron setups and really can't see much difference, at least on the Milky Way. The iOptron will allow much longer tracing, but really with the K1, you can get what you need for the Milky Way in 3 minutes or less due to the camera's excellent performance with the higher ISO ranges. Plus you don't have to find the north star to calibrate as has to be done with the iOptron as I understand it.

    8. The GPS, in the K1, is excellent, I have been out in the woods now 12 times and so far have not had any problems getting a lock. HOWEVER, there is no way you can calibrate the camera with a camera strap on as it will tangle around your neck. Since getting a lock requires rotation of the camera, you need to really be careful at night not to drop it. Once lock is obtained, you are good unless you move more than 12 feet, then I would recommend re-calibration.

    9. Make sure to re-calibrate each time you turn on the Astrotracer function for the first time. If the GPS has been on before, the Astrotracer, will not flag you to re-calibrate, and thus you may not get a perfect fix resulting in trails. I forgot this a few times during the first few shots, and the difference is pretty noticeable.

    10. The real wonder of this tool, is that now the need for expensive F 1.2 and 1.4 glass is really not required as a F 2.8 will easily get the job done. I still would love to see Sigma make their wonderful 20mm 1.4 for the K mount!!.

    Paul C

  10. #10
    Member
    Join Date
    Dec 2009
    Location
    Big Island, Hawaii & Utah
    Posts
    125
    Post Thanks / Like
    Images
    11

    Re: K1 and astrotracker--a bit disapointed!!

    I have a difficult time obtaining a calibration with the Astro Tracer function quite a lot of the time and it is impossible in some locations here where I live in Hawaii. I've discussed this with Pentax and the person I spoke with concurs with my opinion, that the high iron content in the lava here affects the internal compass within the K1, that is part of the calibration process along with GPS.

    I have no problem obtaining compass readings with my iPhone and I use tilt meter and level apps and with the compass reading set for true north rather than magnetic north, I don't have to bother trying to align with the north star with the iOptron. With the mount pre-set for elevation for my location, once the tripod is leveled, the compass alignment is merely seconds and the set up is complete.

  11. #11
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Hi Charles:

    Interesting issue on Hawaii, and a bit sad, as you should have some great views of the night sky!!

    I still may invest in the iOptron in the future, which model are you using? And I see from you previous post, you don't have to find the north star to calibrate it, but just have the device level?

    It's pretty clear now that the white dots seems to manifest only with 1. long exposures using pixel shift in the 30 seconds to 15 second range and 2. With most astrotracer shots, more in the landscape area, than sky. The Astrotracer also puts a darker bar at the top of the frame i most shots I have taken. Other seems to see this also, not sure if Pentax is aware of it or working on a fix. But it's not from light coming in from behind as some have stated on other forums. I have shot with the camera basically in a black bag so to block all light and the bar is still there.

    I have used the K1 now on two different nights for standard stacking for star trails and the images are extremely clean, up to ISO 1200, shooting as long as 3 hours.

    Paul C

  12. #12
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    But when it works, it's really amazing technology.

    This is 1 shot, 2 minutes ISO 1600. Had some clouds moving around that night, and I screwed up and blew out my foreground, but can fix that later. The depth of the color and stars just pop. This is at F 4.0, something you just can't do with any other DSLR as you are in need of a F 1.4 lens and they have their own set of issues (don't I know it). Plus here you are still stacking for the stars and yes that works, but I would still rather use a 1.7K camera which has more use in the field than spend the extra for a D810A which will have other issues in daylight, not to mention it's ISO base is too high for a lot of work I do. Once again Kudo's to Pentax.

    Have to remember to center the M Way if at all possible as that eliminates the trailing/blur that will happen if the M Way is towards the edge due to the ultra wide lens 15mm. One day hope to get out west and use 50mm or so as that should tracer very evenly. But I like the effect anyway. The center is tack on.

    Paul C

    Click image for larger version. 

Name:	M way K1 no1.jpg 
Views:	29 
Size:	641.7 KB 
ID:	121131Click image for larger version. 

Name:	M way K1 no2.jpg 
Views:	13 
Size:	596.2 KB 
ID:	121132

  13. #13
    Member
    Join Date
    Dec 2009
    Location
    Big Island, Hawaii & Utah
    Posts
    125
    Post Thanks / Like
    Images
    11

    Re: K1 and astrotracker--a bit disapointed!!

    Great images and excellent post work.

    The K1 was just tested by DXOMark. https://www.dxomark.com/Reviews/Pent...l-frame-marvel
    Likes 1 Member(s) liked this post

  14. #14
    Senior Member Quentin_Bargate's Avatar
    Join Date
    Oct 2008
    Location
    Saffron Walden, UK
    Posts
    1,803
    Post Thanks / Like
    Images
    58

    Re: K1 and astrotracker--a bit disapointed!!

    Quote Originally Posted by Charles Wood View Post
    Great images and excellent post work.

    The K1 was just tested by DXOMark. https://www.dxomark.com/Reviews/Pent...l-frame-marvel
    I was an early adopter of the K1 for a reason; it seemed obvious to me when I tested it that the K1's image quality was of a very high order, and its design, features and size made it highly desirable. Add in pixel shift, and it becomes an even more compelling proposition for studio food, product and still life work.
    Quentin Bargate
    Co-Founder of Ajuve, Director of Bargate Murray, Law Firm of the Year 2012 - 2016, Photographer
    Likes 1 Member(s) liked this post

  15. #15
    Member
    Join Date
    Jan 2011
    Posts
    130
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    Ouentin,.....the Sony a99II is about to dock now and has vastly better spec than the now obsolete pentax K1,.....so, when you unceremoniously toss it over your shoulder could you make an OAP very happy by making sure that it describes an arc into my waiting hands please?

    ......Got my hands in the 'catch' position so thanks in advance!
    Likes 1 Member(s) liked this post

  16. #16
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    I wish I could get Bob to change the title, as I am NOT disappointed with Astrotracer!

    K1 15-30 50 second single exposure, (for some reason the tracer did not blur the bridge), ISO 500.

    Paul C


  17. #17
    Senior Member
    Join Date
    Dec 2007
    Location
    Little Rock AR
    Posts
    1,624
    Post Thanks / Like

    Re: K1 and astrotracker--a bit disapointed!!

    As an update to this thread,

    Pentax released firmware 1.4 today. One of the aspects of this firmware was to fix the white dot issue (which means that Pentax admits they have an issue). However the firmware only effects jpgs not raw files. So for me a total waste of time.

    Paul Caldwell

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •