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Forum: Pentax Camera and Field Accessories
10-27-2015, 08:00 AM
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you can play with the blend mode of your layer and sometimes it works out perfectly with little or no extra work. Try "lighten" and "lighter color" as long as the trees/leaves are darker than your stars, you may not have to worry about a messy selection.
i am almost positive for this marsh house shot, i just used lighten for the blend mode and the stars came right through the trees with no extra work:
 John Marsh Stone House & Stars by Mike Oria, on Flickr
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Forum: Pentax Camera and Field Accessories
10-26-2015, 07:54 PM
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Thanks Rondec. Yes Rob, the usual technique is to shoot a star exposure with the OGPS and then switch it off to capture the terrestrial shot and then blend layers. Works fine unless the selections are tricky such as lots of trees with leaves, etc.
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Forum: Pentax Camera and Field Accessories
10-06-2015, 06:19 AM
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Noticing my 3.5 year old thread has been recently bumped, I thought I would share this album of my Astrotracer shots and say that over time, I have gotten the hang of using the OGPS1, even advanced techniques such as multi-stack pano shooting (ie, 10-frame pano using 3 stacked exposures each = 30 images combined). Two of these images have since been printed full page in magazines, so I am happy using the device now.
My Astrotracer album: https://www.flickr.com/photos/mikeoria/albums/72157649944280914 |
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Forum: Pentax Camera and Field Accessories
10-11-2013, 08:20 AM
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slightly off topic but interesting regarding EM interference and the O-GPS, I was shooting scouting shots directly underneath a giant wind turbine and had the O-GPS on to record the coordinates and compass direction to the images and noticed that every time the blades rotated, the compass polarity read by the O-GPS would reverse nearly 180 degrees. For instance, it read N, then S, then N, then S, alternately. Very cool effect.
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Forum: Pentax Camera and Field Accessories
10-10-2013, 08:33 PM
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Hmmm, sounds a little superstitious...
...but I will give it a try just in case!
:p
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Forum: Pentax Camera and Field Accessories
10-10-2013, 10:37 AM
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Agreed, even when the astrotracer is showing a max exposure if 4 to 5 minutes, I find keeping it under 2 minutes is still a good idea.
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Forum: Pentax Camera and Field Accessories
10-07-2013, 10:55 AM
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Well, I put the device in a drawer for over a year and just pulled it out again over the weekend to try for a Milky Way shot.
Results were good using a short-ish exposure time of 80 seconds. No visible trailing.
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Forum: Pentax Camera and Field Accessories
07-23-2012, 11:36 PM
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another composite, 1 with the moving sensor for the stars, a 2nd shot with the tracer off for the shed. This is 2min at 10mm. Note, at very wide angles, you are bound to see star trailing due to the extreme distortion from the lens. Likewise, the moving clouds here look like rays emanating from the structure for the same reason.
Heavenly Shed
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Forum: Pentax Camera and Field Accessories
07-23-2012, 11:04 PM
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got out under clear skies (still lots of light pollution though) and got this shot using the O-GPS for a 2 minute exposure at 10mm. Though the device indicated I could go to 5min max time, i found anything over 2 minutes started making streaks.
Night Glow
composite of 2 images, 1 with the tracer on and one with it off.
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Forum: Pentax Camera and Field Accessories
06-16-2012, 11:48 PM
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i enter the correct FL. i will try with my shorter manual lenses, ie 28mm and see if i still get the problem.
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Forum: Pentax Camera and Field Accessories
06-16-2012, 03:46 PM
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ok, so when using A lenses, calibration carries out just fine. When using M lenses, after a couple of tilts, the LCD screen goes black and if i press menu, i am back at the main menu page (ie out of the GPS page). My workaround for this is to change to an A lens to calibrate and then mount the manual lens. very aggravating.
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Forum: Pentax Camera and Field Accessories
06-16-2012, 11:18 AM
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were you able to calibrate using the manual lens? I cannot calibrate with any manual lenses mounted as the accellerometer ends calibration and dims the screen when the camera is tilted even a little. must have something to do with the contacts??
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Forum: Pentax Camera and Field Accessories
06-16-2012, 07:43 AM
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so it looks like switching to firmware 1.13 got rid of the tracking issue. I am ready to try this again.
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Forum: Pentax Camera and Field Accessories
05-31-2012, 11:29 PM
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well, i tried it last night with firmware 1.13 & no other changes and the curves are gone. This is a 3.75 minute exposure with still slight trailing. The device was telling me i could get a max exposure of 5min but apparently not.
The Big Dipper (O-GPS testing) | Flickr - Photo Sharing!
Another issue i noticed last night when switching to my manual lenses is that when I try to calibrate O-GPS, the calibration screen goes black when the accellerometer detects that the unit has been tilted. It happened every single time with all the manual lenses i mounted and thus will not allow calibration to occur. The only workaround i found was to calibrate using an auto lens and then mount the manual lens.
Has anyone experienced this and is there a fix??
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Forum: Pentax Camera and Field Accessories
05-30-2012, 10:56 PM
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i didnt know there was a ver 1.13 firmware. just updated and will try again tonight in case that has any effect.
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Forum: Pentax Camera and Field Accessories
05-30-2012, 10:23 AM
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regarding SR, i have a hunch the astrotracer disables it anyway in order to function, but havent tested that.
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Forum: Pentax Camera and Field Accessories
05-30-2012, 10:22 AM
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yes,
firmare 1.12 is installed (K5)
and the SR is disabled when 2-sec lockup timer is engaged.
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Forum: Pentax Camera and Field Accessories
05-30-2012, 10:02 AM
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i'll to go out tonight and run some shutter time brackets to see if perhaps the streaking is beginning after a specific elapsed time. The shortest exposure i took last night was 106 sec (astrotracer suggested a max exposure of 165 sec BTW), and the image is all curved streaks similar to what i posted. If i were to reduce my time to say 60 sec, that seems to defeat the whole purpose of buying this device IMO.
so far, i am quite unhappy with this unit.
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Forum: Pentax Camera and Field Accessories
05-30-2012, 08:19 AM
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i don't know if this has any bearing on the astrotracer function but my electronic level in the K5 is out by 3-4 bars; could the misaligned sensor be affecting it tracing ability??
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Forum: Pentax Camera and Field Accessories
05-30-2012, 08:16 AM
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thanks for the replies, i will try to respond to each point below...
yes, i do the simple calibration and then the precise calibration often and am getting the "OK" confirmation for both. Additionally, using the compass feature gives real time compass motion suggestiong it is tracking location as well.
i am doing all of this.
i have it set to 2-sec timer to bring up the mirror and am using a cable release to start the exposure. ive tried it just as 2-sec timer or as cable release only and get the same result, however.
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Forum: Pentax Camera and Field Accessories
05-30-2012, 03:23 AM
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here are a couple of crops that have been processed to add contrast. there is light pollution because i shot them from my front porch with some streetlights in the neighborhood - no more driving 45 min out of town to have all the pictures be crap anyhow, lol.
Dogleg Nebula
Comma Constellation
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Forum: Pentax Camera and Field Accessories
05-30-2012, 03:06 AM
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Hi,
tonight was my 5th opportunity to practice using the O-GPS unit for astrophotography and I still am not getting clean looking stars.
I will process some pics tomorrow to show but in general I am getting comma shaped star trails on pretty much all shots. I have tried a few different lenses and the issue is not apparent with the wide lenses, but my intent is to use my 70-200 to shoot constellations and all of those result in curved streaks.
i am performing precise calibration and getting the "OK" confirmation right before shooting. I also reduce my exposure time to about 30% less than the max exposure computed. i've tried shooting dirrerent areas of the sky, low and high and don't notice any improvement. I am low to the ground on a 4-point stable tripod and there is no wind at all.
this thing is frustrating for sure.
any suggestions would be appreciated. thanks!
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