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Forum: Pentax K-5 & K-5 II
09-13-2016, 04:04 PM
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Yes, the K-1 can be tethered to a laptop. You will have to purchase the appropriate software then if my understanding is correct.
And yes, the flucard will also work with a laptop. I have tried the following browsers wit success: Firefox and Chrome. I am sure a mac with Safari will work too.
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Forum: Pentax K-5 & K-5 II
09-13-2016, 02:07 PM
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The difficulty with liveview focusing of the Moon is that (to me) annoying auto-gain of the LCD liveview image in all still image shooting modes. However, there is a work-around for that:
Set you camera to Manual Video Mode and adjust exposure time and aperture until you see the Moon properly exposed. Now, focusing using magnified liveview and Focus Peak is easy. Once you have established your shooting parameters, you can either do a video as set or return to single image shooting in Manual Mode using the settings you have found.
Since you have the K-3: I have the Pentax FluCard and sometimes use that for quality control in the field. Transfer of jpg-images to a smart phone or a tablet with either Safari or Chrome browser is reasonably fast and efficient. However, the card is quite power hungry so I rarely use it for astrophotography purposes.
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Forum: Pentax K-5 & K-5 II
09-11-2016, 09:40 AM
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For me, this has never been a real problem, neither with my K-5 nor with my K-3. I just find a bright star in a convenient wieving angle, use liveview and 8-10 x magnification for critical focusing. Once I have nailed focus, I can then confidently go to my targets elsewhere in the sky. You may use tape, if you want to fix that focus position and you can further do the focusing during the day-time on remote objects.
You can also try to autofocus on such brighter stars. You might get a surprise when you see how efficient Pentax low-light autofocus really is. OK, here K-3 AF excels over that of the K-5, but I do use AF on both cameras with my faster telephoto lenses.
Finally, you could try pktether - works fine with the K-5. Again, lt's a matter of nailing focus first and keeping it there before you go hunting for your targets.
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Forum: Pentax K-5 & K-5 II
04-18-2016, 05:06 AM
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True; less than perfect seeing will smear out and distort objects in the sky - both visually and photographically. This is the rationale behind adaptive optics. But even in empty space, with a large aperture telescope you will find that brighter stars forms larger images, as this Hubble image demonstrates:
Hubble Space Telescope Images | NASA |
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Forum: Pentax K-5 & K-5 II
04-17-2016, 05:53 AM
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Stars are point-like sources of light, but photograps of these are not 'points'. They are images of diffraction patterns, consisting of concentric bright and dark circles whith a diameter that depends upon the absolute aperture (size of entrance pupil) and focal length of your optics. The larger the f-number, the larger the image of the diffraction pattern.
The bright circles decrease rapidly in brightness with the distance from the center, and we often only capture the innermost central part, but he brighter the star, the more of this diffraction pattern you may/will actually capture.
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Forum: Pentax K-5 & K-5 II
11-01-2015, 01:10 PM
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Congratulations from me too - that honour is well deserved!
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Forum: Pentax K-5 & K-5 II
12-12-2014, 04:12 AM
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Thanks for an excellent overview.
I live at 56 degrees North and normally don't see large variations in positioning - position is more often than not correct within some + 10 meters. But I have made it a habbit to regularly check the electronic compass headings found by the O-GPS1 against the true headings as can be assessed with Geosetter (: freeware). Variations over short periods of time can be quite astonishing on certain days/nights.
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Forum: Pentax K-5 & K-5 II
12-09-2014, 10:48 AM
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Beautiful pictures SirTomster - I wish I had that kind of a sky!
And in continuation to our answer to Suhndog: Vintage MF-lenses can be used for atro photography but the probelm with them can be, that many of the wider ones (say, from 50mm FL and shorter) suffer from annoying coma. Therefore, a modern, aspherical design like the Samyang/Rokinon seems a better choise.
If you on the other hand favour the longer focal lengths (300mm being about the sensible and 200mm the "safe" upper limit in O-GPS1 context) there are many cheaper Takumar, smc Pentax, Tamron adaptall-2 etc. lenses available). You can see my results with various lenses here:
DSLR Astophotography: Astrotracer Images with Pentax GPS Unit O-GPS1 |
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Forum: Pentax K-5 & K-5 II
12-07-2014, 08:00 AM
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Firmware for the O-GPS1 js embedded in the camera firmware - so just have your camera updated.
As far as I recall, there have been just two updates for the K-5 specifically mentioning the O-GPS1. First was to allow operation at all and second was some sort of 'general stablity issue' if I remeber correctly.
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Forum: Pentax K-5 & K-5 II
11-07-2014, 02:49 PM
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Thanks for sharing your interesting pictures with us stanzhou.
I can't say that I totally disagree with you, because I would also certainly not consider the O-GPS1/Astrotracer as a real replacement of a (good) equatorial tracking platform. Still, one should not totally dicard the O-GPS1 for the longer lenses. With today's sensors you can have great fun and get the "thrill of discovery" using the O-GPS1/Astrotracer for just some 20-40 seconds exposures even with lenses in the 200-400mm range:
Planetary nebula M27, Dumbell Nebula, in Vulpecula. Image taken with Pentax K-5 and smc PENTAX-DA* 1:2.8 200mm lens.
Five 20 second exposures at f/3.5 and ISO 1600 stacked in DSS and post-processed in PhotomImpact X3
Click to see non-resized 100% crop. |
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Forum: Pentax K-5 & K-5 II
06-16-2014, 04:13 PM
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If I remember correctly 31 seconds interval isn't enough when you have an exposure time of 30 seconds. Try intervals of 32, 33, 34.......seconds.
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Forum: Pentax K-5 & K-5 II
05-12-2014, 03:30 PM
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Yes, that's a K-3 function only - so far.
The Astrotracer menu on the K-3 is quite different from that of K-5 and many ways more convenient: Apart from turning the LED light on and off, one can change essential parameters and functions (aperture, ISO, delayed release with mirror lock-up a.o.) without having to leave and re-enter the Astrotracer menu.
On the down-side: With the K-3, exposure times can only be set at fixed 10 seconds and 1 minute intervals. To me, there can be a lot of difference between 10s and 20s.......
And then I miss the "simple navigation" optionon on the K-3. Well, that's not Astrotracer related and perhaps not the most useful feature of the O-GPS1, but it is fun to have anyway.
PS.: Glorious astro-landscape photo, Mike SF - as always from you!
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Forum: Pentax K-5 & K-5 II
02-22-2014, 10:11 AM
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I all originates from the same guy in Poland. Have you tried this version:
PK_Tether |
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Forum: Pentax K-5 & K-5 II
02-13-2014, 08:41 AM
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Forum: Pentax K-5 & K-5 II
02-04-2014, 03:08 PM
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Forum: Pentax K-5 & K-5 II
02-04-2014, 12:45 PM
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Hi dqniel and welcome to the fascinating world of astrophotography.
You have many, fully understandable questions -and there will be more than one "correct" answer to each of those.
To begin with your gear: You have ALL you need to get started, so do rush out under your light polluted sky and try out your gear with fixed tripod astrophotography. Get acquinted with your gear well in advance of your trip to Mexico. We all have our personal limits as to when star trails become objectionable; my limits are: Some 20 seconds max exposure with a 14mm lens; 8 seconds with a 35mm lens; 4 seconds with a 70mm lens. Try our your lenses at full aperture and stop downonly, if aberrations are very annoying at wide open apertures. Also, start out with high iSO - don't be afraid of ISO 3200 with a K-5 II.
Next comes post-processing: Don't expect to see an awfull lot with your images straight out of the camera. So, if you don't have it already, your next purchase should be a decent imaging software, where you can work with curves, levels and, preferrably also layers. Such software could be of the type PhotoShop Elelements or PaintShop. And then you will soon need a stacking program such as Deep sky Stacker, which can be downloaded for free.
Regarding tracking platforms: Now it becomes difficult to give solid advice! I have the O-GPS1, and I wouldn't be without it. It's portability and quick set-up procedure means an awful lot to me. Still, I consider the O-GPS1 a supplement and not a substitute for a more 'robust' tracking platform that will allow the use of longer lenses for significantly longer exposure times. The platforms that you mention all require accurate polar alignment to work properly, which can be quite time consuming and even frustrating for the beginner, but you will have to master it sooner or later anyway.
I hope, others may join and tell how the Polarie and the Skytracker compares.
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Forum: Pentax K-5 & K-5 II
01-23-2014, 02:54 PM
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Congratulations from me too to seti_v2. Clouds and noise or not, this IS a very fine capture!
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Forum: Pentax K-5 & K-5 II
09-27-2013, 02:27 PM
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I recently acquired the Rear Converter A 2X-S for my DA* 200mm f/2.8 lens. That lens needs to be stopped down to f/3.5 to produce reasonably round star images and thus, with my converter I now have a 400 mm f/7 system - not too far from the 500mm f/8 system discussed.
The other night, my (urban, light polluted) night sky finally cleared. Seeing was rather poor, but I still got some first results:
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Southern part of constellation Lyra with M57, the Ring Nebula.
Downsized stack of 5 + 5 images at 15 sec exposure time; f/7; ISO 2000 and 4000 respectively.
Click to see larger (1280 px wide) version.
As said, seeing was poor - the brighter stars were litterally boiling at 8X magnification in Live View, but the following 100% crops are good enough to demonstrate what can be achieved with Astrotracer and a 400mm system - up to 15s of exposure time:
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Star Beta Lyra and surroundings. 100% non-resized crop of the above image.
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The Ring Nebula, M57. 100% non-resized crop of the above image.
As I have said before, I belive that 400mm and some 15-20 seconds of exposure time is about the upper sensible limit for Astrotracer. But, of course, there is only a little way to go up to the 500mm.............
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Forum: Pentax K-5 & K-5 II
09-17-2013, 01:21 PM
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I wouldn't expect too much with any 500mm lens. The Tamron mirror lenses have fine, aberration free and sharp optics, (I use the 350mm f/5.6 , Model 06B myself), but for the 52B and 52BB lenses the long focal length as well as their relatively small f/8 aperture ratio speak against use with Astrotracer.
My own experiences are that success rate remains acceptable - just - up to some 300 - 400 mm focal length, (somewhat depending upon what one will accept as "acceptable").
https://www.pentaxforums.com/forums/pentax-camera-field-accessories/195236-pe...l-lenghts.html |
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Forum: Pentax K-5 & K-5 II
08-13-2013, 04:30 AM
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Great shower show tonypysm!
You can really se them (most of them) radiate from the Perseus region.
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Forum: Pentax K-5 & K-5 II
08-04-2013, 11:47 AM
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The Perseid meteor shower should peak around 12 August. But as luck would have it, a rather large forerunner showed up last night, just as I had begun some wide field Milky Way panorama shots (at my place, this time of the year the sky is still very bright around midnight):
.JPG)
Pentax K-5 with smc Pentax DA 18-135mm f/3.5-5.6 lens at 18mm FL. 40 second exposure at ISO 1600 and f/3.5.
Tracking by means of the Pentax O-GPS1 unit.
And to better show the colours of the meteor trail itself, here's a closer crop:
.JPG)
Rotated crop of the above image. Here, the horizon is to the right side of the image. |
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Forum: Pentax K-5 & K-5 II
06-28-2013, 12:27 PM
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Hello Jeff, congratulations with your new K-5 and O-GPS1. Something tells me that you are very new, as we all were at some point in time, to astrophotography, so be warned: A good camera and a tracking device do not alone secure good astrophotos. May I suggest that you browse a few tutorials such as the 'Quick Start Guide 1 and 2' here:
Astrophotography Techniques
Now to your specific questions: The O-GPS1 does not set the exposure time depending upon lens focal length unless you ask it to, and it isn't really a setting you can trustfully use. It is rather a recommended maximum exposure time before you will get excessive star trails - and that in your full, uncropped image! Regarding aperture, ISO setting, mirror lock-up and everything else it is not set by any automatics. You have the freedom to set it as you wish, and that's the way it should be.. Because no tracking device will "know" the brightness of your local sky (seasonal and light pollution), the quality of seeing, what it is that you want to capture on this particular night (e.g. dim nebula vs. bright constellation stars vs. meteors or what ever).
So, learning by doing and by looking at what others have done with similar equipment (provided that they also provide their exposure details!) is the best advice I can give you. As far as my suggested camera settings are concerned, you may find a compilation here:
Camera Settings for Astrophotography |
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Forum: Pentax K-5 & K-5 II
06-14-2013, 03:46 AM
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@tonypysm and mattb123: Just want to join in on the praise of your pictures. Truly beautiful and stunning!
tonypysm: You speak about high-level light pollution. Well, everything is relative but can you describe your observing site a bit closer. I don't think I could produce anything like your pictures (granted that I had your skills) anywhere near where i live.
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Forum: Pentax K-5 & K-5 II
06-02-2013, 02:40 PM
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Coma or not, I think this is an impressive and very good-looking result. Hmmm....need to see, what Nebulosity can do for me!
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Forum: Pentax K-5 & K-5 II
05-27-2013, 07:41 AM
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After about a year of ownership and very frequent use of the O-GPS1 (as frequent as the lousy Danish weather permits), I should say that I get fairly consistent results. So, my experience is that as long as you have the most recent firmware update and get confirmation on 'Precise Calibaration OK' there is little more you can actually do and to my experiences there are only the following three issues to observe:
1. The magnetic sensor seems to be by far the largest source of inaccuarcy. By all means do the Precice Calibration and use the astrotracer safely away from very localized magnetic disturbances, be they man-made or geological.
2. As GPS satellites change their positions the quality and number of signals received may change. A short break followed by a renewed Precise Calibration may be required from time to time during a night's session.
3. There remains a certain element of "black magic" to the operation of the Astrotracer function. On any night do try to use it at different azimuth and altitudes. Chances are that on any night, some directions will work better for you than others. On those nights where everything seems to conspire against you, try using your widest lenses only.
If problems persit, I would suspect that errors would most likely, though not exclusively, be found in the camera body sensors and/or actuators. I know of no other way of checking that than trying out your O-GPS1 unit on another K-5 body.
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