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Forum: Pentax K-1 & K-1 II
08-06-2016, 10:13 AM
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I have to say, that I find this post disappointing, as you personally don't know me, or how much time I have spent working on this type of photography. I have put in the time and for star trail photography, this is an issue that your mention of a manual dark frame subtraction won't fix. But needless to say, your points merit a response as I disagree with them.
This issue has been found before years prior and I would have hoped that Pentax would have taken similar steps to address it, which it appears they did not. Depending on your workflow and end result it can become problematic.
Don't really consider myself a noob, but will take it as you will. And for sure it's not "lack of user knowledge" sorry you feel necessary to take that approach. You can go to all the astro forums you want, and this particular issue will not be fixed as it's an issue that is different than traditional noise. I would also ask if you have tired this yourself? I have thousands of exposures and hours of time in stacking with various cameras. Only wanted to point out that this same problem existed in a different brand which uses the same sensor, the other company fixed it.
If you want to go through all the process of taking a dark frame and trying to manually subtract it that is fine. Net, there are plenty of cameras out there, basically all from Canon, Nikon, etc that can take such a exposure without creation of a white dot, which by the way is not that easy to remove even with a true dark frame ( I have tried it) and the white dots don't clean up as well as traditional dark noise, which tend to show up in red, red, or blue dots, which a dark frame subtraction can remove.
I had hoped that the K1 would at least equal the long exposure quality from other cameras I have used, none of which require taking a dark frame and manually removing the noise. again this is mostly for traditional stuck pixels, which are both larger and brighter than the dots. With any modern digital DSLR, you should be able to take a up to a 2 hour long series of stacks, anywhere from 30 seconds to 2 minutes to 3 minutes each and not have the dots, yes you will have noise, but most of that can be removed during the stacking process later on, as the dots will stay in the same place throughout the entire stacking process. The problem comes in when you combine the images.
Working with a intervalometer, you will always have a faint gap between the exposures, and I only know of one tool that will remove these in post, and that is "star tracer". By design it will move the stacked image in a series of controlled blurs, which will combine the gaps into complete trails, and help to give faint trails a brighter look, however this process of movement also moves the dots into dotted trails throughout the image that with a 36MP image will show up. Net, the dots have to be out prior to this final step, and manual dark frame in my experience will not remove them.
The in camera noise reduction, which you seem to feel is also noob feature, works well and in fact more than likely works better than any manual dark frame process, but it defeats the stacking process due to the gaping it creates.
As I already pointed out, Capture One can remove most of this in a raw file, but if you capture in jpg, then it will work on the dots.
Paul C
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Forum: Pentax Full Frame
09-21-2016, 07:22 PM
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Astrotracer, was one of the main reasons for my move to the K1 from Nikon. I did not want to purchase a tracking base, due to added weight, and setup times.
Overall, I have to say that it's a very impressive feature, and can produce some excellent images of the night sky.
Main limitation I have found is that the for my locations I need 15mm to 20mm for night sky and foreground. Mainly using the 15-30 in the 15mm to 20mm range, F 4 to F5. 1.5 to 3 minutes ISO ranges from 800 to 1600. The rectilinear nature of the 15-30 does force you to have the Milky Way in the center of the shot, or it will blur as you move to the edge. The stars of course trail also no mater what, but for my work, that just adds to the nature of the shot as the trails are not a long as a normal 2 minute exposure.
When in focus the details are amazing. Vastly superior to anything I captured with Nikon or Canon in the 20 second range at ISO 3200 up to 12K. Tried the stacking methods also, which helps on noise but just adds a lot more work and still can't beat a single 2 minute exposure. Plus this type of work requires a fast lens in the 1.4 to 1.8 range and most of these in the 14mm to 20mm range have coma issues. With the Astrotracer, you can now be in the F4 to F5 range, which also helps on over DOF and composition.
Have learned that you need to calibrate the GPS from the Astrotracer screen, not the GPS screen as the two calibrations don't seem to talk to each other. So far have not had any problems with the GPS locking and staying locked. Calibration is always something that is a bit tricky as doing it with a camera strap on is impossible (at least for me).
Results just keep improving, my only issue is the dark band I get at times at the top of the frame. Not a light leak, but appears to be a known issue on some K1's. But the fixes I have seen make the band look even worse at times, so I will just live with it for now.
Vertical shots work great also.
Paul C
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Forum: Pentax K-1 & K-1 II
11-16-2016, 03:25 PM
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Astro tracer, works great on exposures where you are attempting to capture a static image, example Milky Way. Here you want no movement i.e star trails as the trails will blur the shot and the Milky Way itself will blur with just a normal exposure much past 25 seconds. Astro tracer will allow much longer exposures, up to 5 minutes, brining in a lot of more light on distance astro features. On average I will expose in the 1.5 to 2.5 minute range. Note, that with a wide rectilinear lens, (like the 15-30), the edges of the image will still blur (or trail) since astro tracer can't accommodate the wider lenses. So keep the feature of your shot as centered as possible if you are using a wide lens.
Astro tracer, to me, is one of the main reasons I moved from Nikon (D810/D750) to the K1, as I can expose night shots at a much lower ISO, thus less noise and more details. Overall an excellent feature, when combined with the GPS.
Make sure you have a green signal on the GPS, and I always go ahead and re-calibrate the GPS if I move more than 15 feet. If your image is still showing movement in the center at 1 to 2 minutes then you should consider re-calibrating the GPS.
For star trails, you really don't want astro tracer, as it will defeat them.
For star trails, I would recommend you stack multiple exposures, instead of one long exposure. Stacking will allow you to pull in a lot more of the fainter stars and give you a better over image especially if you work with partial moonlight to help illuminate your foreground (something I always do).
Here is a short article I wrote several years ago, but it can give you some ideas on setup/capture and post processing on the star trail type of photography.
So far I have gotten about 1.5 hours on a single K1 battery, which is not quite long enough for a good star trails session, so I will use the grip with another K1 battery. The grip with AA NiMh, does not perform well at all. The K1 does not see the batteries with a full charge and only gives you around 30 minutes before you get a low battery warning, whereas with another K1 battery, you can easily get 3 hours.
You will need to use a intervalometer to stack. The K1 has a intervalometer, but I am not sure it if allows a timer function, (most DSLR's will only go to 30 seconds max with an internal intervalometer. There as many 3rd party ones on the market, that plug into the mic port on the K1.
09/23/14 Using Stacking for better Night Photography results @ Photos Of Arkansas
Paul Caldwell
Here is a vertical shot from late summer and you can see slight movement towards the top of the frame, again since I used a 15mm lens. Illumination done with a lantern.
[IMG] Roark Bluff at Midnight on the Buffalo River by paul caldwell, on Flickr[/IMG]
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Forum: Pentax K-1 & K-1 II
10-08-2016, 07:52 AM
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One from last weekend. Had no choice but to shoot with the M Way towards the top of the shot, thus trails occurred due to retro-focus lens and Astrotracer issues. It's interesting to note that it's possible that iOptron traced shots may not have this same problem as I have seen several from MF and the 28mm F 4.5 lens (17mm 35mm equivalent) which seem to handle the edges better. This is actually a combination of several files, Astrotracer for the sky, then a series of long exposures, non traced for the Bluff illuminated with a single lantern.
Paul C
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Forum: Pentax K-1 & K-1 II
10-02-2016, 01:27 PM
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From a few nights ago, K1, 15-30 ISO 500, 46 seconds total. Astrotracer. As Milky Way is off center, there were some trails through the Milky, but not enough that I felt it mattered. Other option was trying to wade out in waist deep water, but at night felt it was not the best idea.
Paul C
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Forum: Pentax K-1 & K-1 II
09-30-2016, 04:14 PM
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It is a very well designed feature. I mainly use the 15-30 which trails about the same as the 14mm Rokinon. Below is a work in progress still need to pull in the non tracked base.
Key with ultra wides is frame shot with Milky Way in the center of possible.
Paul C
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Forum: Pentax Full Frame
09-21-2016, 07:42 PM
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The White dots, are a form of noise, unique to the Sony 36MP sensor. Was not a problem on the D800, was a problem on the D800e, (fixed on later models silently) Was an immediate problem on the D810 and fixed with a recall. I have used all of said cameras for long exposures at night. The fix for the D810 allows the Nikon to operate up to around 10 minutes before the dots become problematic. With Nikon the dots were throughout the files evenly, with Pentax, they only seem to show in the shadow areas. At least for me.
With Astrotracer, the dots can become a bit more problematic especially after operation over 30 minutes.
My average exposure with Astrotracer is 2 minutes, longest 3.5 shortest 1 minute. Iso ranges from 400 to 3200 average is 1600 at F4.0.
With star trail stacks up to 2 hours, of 2 minute exposures with moonlight adding illumination, the dots are not a problem in the night sky or areas lit by the moon, only in shadows.
With Astrotracer, my skies seem fine but again the darker areas can become problematic, but since they are blurred anyway, I don't worry about it, and just take one exposure for the foreground non traced with LEN on. This takes care of the vast majority of the dots and noise.
Warmer outdoor temps make this issue worse as does high humidity.
In normal use, I limit LEN, as it's wasteful in that you are locked out of the camera for the same time of the previous exposure. This is draining battery life, possibly adding more heat, and for sure can cause you to miss a shot due to changing conditions.
Still overall very impressed with the entire K1 camera and the Astrotracer feature. Image below is a 2 minute exposure on the night sky, at F 3.2 or 4.0, can't remember. Prefer not to have to use F 2.8 as the shallower DOF will be problematic. Sky shot combined with a 1.5 and 1 minute non traced image for the bluff and river. Since I was using a 15mm lens, I should have centered the M Way in the frame, but didn't think of that on that night.
Paul C
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Forum: Pentax K-1 & K-1 II
09-22-2016, 01:49 PM
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It's fair to say, Pentax has not made a big in road in the current full frame market. It's too bad the K1 came out this year, instead of mid 2015. But the bigger issue is the flange focal distance issue. As Nikon, and Canon glass can't be adapted to the K mount, lots of photographers have just passed. Where as the Sony A7 series is much easier to justify.
Me, the benefits were worth it and I am slowing moving all of my Nikon gear except a view lenses and a D810.
IMO it help Pentax a lot if they could get Adobe to improve on their current pixel shift conversion and or get Phase One to add it to their Capture One software (only standard K1 raw are supported)
The current software that supports pixel shift, besides LR, is pretty limited in feature function and none of them offer the cataloging features of C1 or LR, or the tools sets which I use a lot.
Silkypix developer Studio Pro does an OK job, but it's workflow is a bit odd to me and their masking needs improvement (in the way you draw or create a mask). But Developer Studio pro gets an excellent pixel shift conversion.
Paul C
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Forum: Pentax K-1 & K-1 II
09-20-2016, 12:20 PM
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Just wanted to thank you for this, it works!!. I thought I had read the manual on the green button, but did not realize in M mode the green button could be programed as such.
Thanks again for the help. Sadly I must add the Pentax support US folks I have spoken to, has no idea that this can be done, per my attempts to get help over the past few weeks on this.
Paul C
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Forum: Pentax K-1 & K-1 II
09-16-2016, 02:41 PM
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One other consideration,
When you open astrotracer, the 2nd option is to do a GPS calibration (this is from the main camera menu), not the info screen. You need to run the GPS from this screen, (it's the 2nd option), this seems to sync the calibration back to astrotracer.
If you don't and just turn on astrotracer, so that the app is on and showing "on" in your info display and then run a GPS calibration, you may not get a perfect sync between the 2 features. Thus you will still trail a bit even on center for the M way.
If you are seeing a bit of movement with the M Way centered in your shot, then I would recommend, turning off Astrotracer,, go back to the main camera menu, and turn it back on, them immediately select the calibration option. This has made a big difference for me, as when the app and GPS are in sync the results are truly impressive.
Also, remember if you are using anything wider than a 50mm, and don't have the M Way center, it's going to trail and blur anyway, just due to the retrofocus design of the Pentax wides, (true with all brands), the wider the lens the greater the issue will become. I use the 15-30 mostly @ 15mm, and the M way must be centered with this lens to get the best possible results.
These two crops are from a single 2 minute shot @ 1600 ISO, F 4.0. Still need to work in the corrected bottom.
Paul C
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Forum: Pentax K-1 & K-1 II
09-14-2016, 12:06 PM
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Least some feel I am down on Pentax, trust me I am not.
The k1 has offered some really amazing opportunities, period. The tech they have with GPS and Astrotracer is quite impressive. I have tried all the tricks over the years besides purchase of a D810A. All the cameras I have tried, can't touch the DR you can get with a 2 minute or so shot on the Milky Way. Sure, not NASA grade, but huge improvement over anything else. The stack method can come close but it's a lot more work in post at least to me. This gives you a lot more license to move around, setups etc. The files are amazingly clean and the stars just pop. I use a 15mm understanding that I have attempt to keep the M way centered or I will trail and blur the M Way, but the images just keep impressing me. Hoping to get somewhere out west next year where a 50mm will work as that should work much better with the edges and not trailing.
Here are two quick screen shots. Should have paid a bit more attention to foreground as I let that blow out, but can be fixed in post. 2 minute series. Had some faint clouds that night, but lucky on this shot they were out of main subject.
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Forum: Pentax K-1 & K-1 II
08-06-2016, 12:43 PM
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Thanks again to all the replies. I have seen this in star trail work, just for some reason did not expect it. I fully realize the effect the rectilinear lenses have especially at the edges. I may try the fisheye and will move up to 24mm or even 35mm to see if I can get a better result. The images are very clean from noise as I had hoped.
Paul C
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Forum: Pentax K-1 & K-1 II
08-06-2016, 08:21 AM
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I bet you are right on light leakage. Where I was shooting dos have a street light behind me. I will bring some gaffers tape to cover the eye piece next time.
And thanks for the explanation I figured it was as much which is unfortunate. But I can try a vertical pan next time with the Sigma 35mm.
Paul C
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Forum: Pentax K-1 & K-1 II
08-05-2016, 10:49 AM
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Attached screen shot, shows the problem quite well. This is from LR, which can't ever handle any stuck pixel noise anyway, but the problem manifests itself just like the D810. The image on the left was shot with in camera noise reduction ON, the Right it's off. So for Astro work of the M Way you can go that way, but it's a NO GO for any star trail work, due to the dots. When you stack, all the dots will create dotted lines thus ruining the shot. I had hoped Pentax would have done their home work on this, but obviously they did not as the problem was found by Nikon over 2 years ago on the same chip. Can't get the attachment large enough to really show it, but the dots are there.
Edit, it shows up much better here:
http://www.getdpi.com/forum/pentax/59293-k1-white-dot-issues-same-d810.html#post701089
Paul C
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Forum: Pentax K-1 & K-1 II
07-19-2016, 01:29 PM
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What I would like to see:
1. A much better raw converter, other than the software that ships with the camera, which IMO is terrible. Pentax could at least include a coupon for the full version of Silkypix software, to help defray the cost of having to add full Silkypix. Adobe's current attempt to work on pixel shift files, is less than stellar, and their track record on fixes is not very good. I also don't see Phase One coming out with a pixel shift solution either.
2. Much faster buffer or processing algorithm for Pixel shift, as currently it takes about 12 seconds for the camera to write a file which is way way too long. Pentax should have been able to send some of that processing to a buffer that would free up the camera to shoot again in more like 5 seconds.
3. Vastly improved AF, Coming from Nikon, the K1's current AF is lacking but I expected that.
4. Lenses it would be nice to see more D FA primes, or a better partnership with Sigma so that more of the newer Art lenses can be made in the K mount. Pentax could use a much faster super wide in the 14mm to 20mm range, even a F 2.8 would be great.
5. Battery life, Pentax could possible produce a battery with a great milliamp life. Current battery life is about 1/4 less than other comparable brands.
6. Improvements to pixel shift, which allows the photographer to work with motion. Currently even with the motion selection on, you really can't work with outdoor subjects that have much wind movement. Not sure if this is possible, but it would be a nice feature.
7. Consider moving the remote port to the left side of the body? Only camera I have used that has it on the right.
8. Better balance on highlights, as I have found the K1 much less forgiving on highlights, i.e. you really have to meter your clouds as they can go pure white very quickly.
9. Allow full bracketing control in M mode, as currently in M mode, bracketing (brackets) both aperture and shutter speed, something again I have never seen before. This forces you to Av mode as
you don't want your aperture to change during a bracketing sequence.
Overall a great camera, and it has enough potential that I have started leaving my Nikon's at home. Pixel shift is a true game changer, but needs a lot more focused attention by Pentax, both in raw software (Ricoh needs to work closer with Adobe and Phase One) and buffer/processing speed. 12 total seconds of being locked out of the camera, needs to be dropped by at least 1/2 of that, to more like 5/6 seconds.
Paul Caldwell
Photos Of Arkansas |
