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04-28-2015, 11:01 AM   #31
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QuoteOriginally posted by K David Quote
I use a flash RF trigger. They're about $15 on eBay. The receiver fixes to the flash's hot foot and there's a hot shoe transmitter for your camera. The transmitters have an override so you could hold that in your hand and push the override button when you're in the foreground. I do this a lot with light trails and dark room portraiture.
How do you determine exposure? If I understand corrrectly, the camera-assisted exposure determination implemented through P-TTL is separate from any RF trigger mechanism.

04-28-2015, 11:23 AM   #32
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QuoteOriginally posted by Spodeworld Quote
I've been wondering the same things you were. Maybe the waterfall would be OK. If it is a long exposure, it would stack the blurs. Maybe that wouldn't be bad. It might be worse though if there is a breeze and there is some leaf movement. That is a problem anyway with long exposure shots: this would exacerbate that

It seems things like foilage, etc. would be the problem if there is even the slightest breeze in any landscapre attempt.

Maybe if you are in the US Southwest and photographing canyons it would work.
Using pixel shift will be similar to HDR. Windless days will be best for landscape photography. When shooting an HDR scene with a waterfall I usually stack the processed HDR image in layers in photoshop on top of the best single exposure of the waterfall. Then I just erase out the blurry HDR waterfall. So I end up with a crisp waterfall with an HDR background. You will have to use workarounds sometimes with pixel shifting just like with HDR. It's true there will be some drawbacks but pixel shifting will still be a very valuable tool in the right hands. I strongly disagree with people here who say that it just a gimmick for tech geeks.


.....but don't get me started about no onboard flash. I will really miss that little bugger!!!!!
04-28-2015, 11:30 AM   #33
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QuoteOriginally posted by RonHendriks1966 Quote
This is One of the issues I have with Ricoh Imaging. They are a tech-company that serves geeks and isn't a photography company that has his eye on photography and being creative.
It's the photographer's job to be creative. The camera only needs to provide its user with the necessary tech to make that shot possible. No matter how hard you tried, Foveon sensors always added a 'wow' on top of everything you would get with a Bayer. Hopefully this is no longer true. Whether it is for geeks or photographers, for a lot of people (including me) pixel shift is groundbreaking.
04-28-2015, 11:37 AM   #34
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QuoteOriginally posted by reh321 Quote
How do you determine exposure? If I understand corrrectly, the camera-assisted exposure determination implemented through P-TTL is separate from any RF trigger mechanism.
I know my flash's guide number, calculate exposure based on distance and aperture. I set the flash's power manually if I want to control power. With my el-cheapo units, which only flash at full, I adjust lighting with aperture, flash distance, bounce, or physical modification (such as diffusers and ND filters.)

04-28-2015, 12:24 PM   #35
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I believe the inaccuracy displayed by the O-GPS1 is mostly due to the recalculation necessary when a satellite disappears from view and it needs to regain sync with a new constellation. Every GPS unit has this problem. As for use with astrophotography, the new K3 model will likely be a boon for some types of tracking mount work. After all, the background stars can be considered motionless for the possible exposure ranges.
04-28-2015, 12:25 PM   #36
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QuoteOriginally posted by Winder Quote
The more I read about the K-3II the less impressed I am with the new features. None of them appear to be designed to work together. Its like Ricoh just took a bunch of different technologies and put them together without integration.
Well, that's true as far as it goes ... the built-in GPS and the pixel shift don't work together.

But the astrotracer and a built-in flash wouldn't really work together, either.

A camera includes a selection of tools. It's nice to have a bunch of different tools so you can "fix" a variety of "problems." Just like it's nice to have both a hammer and a wrench, even though one might rarely use them together.
04-28-2015, 02:42 PM   #37
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QuoteOriginally posted by K David Quote
I know my flash's guide number, calculate exposure based on distance and aperture. I set the flash's power manually if I want to control power. With my el-cheapo units, which only flash at full, I adjust lighting with aperture, flash distance, bounce, or physical modification (such as diffusers and ND filters.)
So you go "old school" with an RF link? I don't mean to sound disparaging - I am quite familiar thru experience with those methods - but a lot of people here seem to really like the automation provided by P-TTL.
04-28-2015, 03:20 PM   #38
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Regarding astrophotos, while deep sky / long focal lengths may not be doable, I'm betting a fairly wide, fast lens (my 35mm f/1.4 for example) added to the camera taking photos in dark skies without the astrotracker on could prove amazing because it would be essentially quadrupling the effectiveness of the fast aperture. It would essentially be doing a 4-image stack in-camera for you.

04-28-2015, 03:56 PM   #39
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QuoteOriginally posted by Pete_XL Quote
Yeah! I wished the Pentax engneers would apply some pragmatic calibration routine to their software. That would help us along!!!


But this calibration must be repeated from time to time because (as I also heard from other users) astrotracer sometimes suffers from changing data supplied by the camera and/or O-GPS1. As an example you see in the following picture of the data of one photo series of M51 that the metadata of the pictures show a variation of shooting positions and directions during the session (I did not move the tripod, just followed M51 a few degrees. The transparant Zone with the red line shows the FoV of the 200 mm lens). The variation is an indication to the "inaccuracies" I mentioned before. Without knowing exactly where you are and in exactly what 3-D-direction relative to the Rotation axis of the earth the lens is pointing you can not calculate the compensation of the star movement with the precision necessary for new high-res pixel shift.



What you are seeing here is the accuracy at which the receiver is calculating the global position of your setup. With this kind of GPS the accuracy that we would see is in the ball park of 10m.
04-28-2015, 04:03 PM   #40
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QuoteOriginally posted by gazelle01 Quote
Well that's disappointing. I can't think of too many landscapes that don't have something moving in them: leaves on a windy day, almost any type of water, clouds, etc.
You could take the one landscape shot of the waterfall using the high resolution method, and then take a second shot using a normal exposure for the water fall. You should be able to blend them using layers in photoshop. Just using the water from the second image to replace the water in the high resolution image.
04-28-2015, 04:52 PM   #41
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QuoteOriginally posted by Sagitta Quote
Regarding astrophotos, while deep sky / long focal lengths may not be doable, I'm betting a fairly wide, fast lens (my 35mm f/1.4 for example) added to the camera taking photos in dark skies without the astrotracker on could prove amazing because it would be essentially quadrupling the effectiveness of the fast aperture. It would essentially be doing a 4-image stack in-camera for you.
Nothing written about pixel shift suggests it will align the images, so star trails would be a problem unless you use the same *total* exposure to time. Instead of one 4-second image with pixel shift, you'll combine 4 1-second subframes. If pixel shift won't work well with the astrotracer because the tracking isn't accurate enough, things will be even worse without any tracking. Pixel shift is not magical.

Pixel shift *might* be usable for astrophotos with a good equatorial mount and an autoguider. If you're already carrying all that equipment into the field, though, just use the usual stacking techniques.
04-28-2015, 05:44 PM   #42
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QuoteOriginally posted by reh321 Quote
So you go "old school" with an RF link? I don't mean to sound disparaging - I am quite familiar thru experience with those methods - but a lot of people here seem to really like the automation provided by P-TTL.

So... I actually don't know how to use a TTL flash since I don't own one.

---------- Post added 04-28-15 at 05:49 PM ----------

QuoteOriginally posted by Sagitta Quote
while deep sky / long focal lengths may not be doable
I used my O-GPS this weekend for the first time. I found two factors to be important in image success -- focal length and lens size. The wider the better, obviously, just like an exposure with a 200mm has to be a lot shorter than with a 10mm due to magnification and all that jazz that everyone understands.

What surprised me was that my astrotracking images with my 31mm FA Limited worked better than with my 10mm Samyang. I figured out that the reason was lens size. Even though there was NO wind and not even a breeze the one clear night we had, the Samyang's weight and size affected the astrotracker's ability to track accurately. So two rules for lenses: wider and smaller.
04-28-2015, 06:07 PM   #43
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QuoteOriginally posted by K David Quote
the Samyang's weight and size affected the astrotracker's ability to track accurately.
I'm a little confused by this, can you explain why this is causes problems? I thought only the sensor moved, not the lens. What am I missing?
04-28-2015, 06:40 PM   #44
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QuoteOriginally posted by jatrax Quote
I'm a little confused by this, can you explain why this is causes problems? I thought only the sensor moved, not the lens. What am I missing?
Considering what one does to calibrate the device for their location, and the gps capabilities of the device, I don't think the image through the lens(other than the focal length) makes any difference in the performance at all. I think one could point the camera at a non-moving wall, turn on the device and by the end of the exposure, the wall would be fully moved/blurred.

Not saying that i read this anywhere, its just my best guess.
04-28-2015, 07:07 PM   #45
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QuoteOriginally posted by K David Quote
What surprised me was that my astrotracking images with my 31mm FA Limited worked better than with my 10mm Samyang. I figured out that the reason was lens size. Even though there was NO wind and not even a breeze the one clear night we had, the Samyang's weight and size affected the astrotracker's ability to track accurately. So two rules for lenses: wider and smaller.
QuoteOriginally posted by jatrax Quote
I'm a little confused by this, can you explain why this is causes problems? I thought only the sensor moved, not the lens. What am I missing?
QuoteOriginally posted by philbaum Quote
Considering what one does to calibrate the device for their location, and the gps capabilities of the device, I don't think the image through the lens(other than the focal length) makes any difference in the performance at all. I think one could point the camera at a non-moving wall, turn on the device and by the end of the exposure, the wall would be fully moved/blurred. Not saying that i read this anywhere, its just my best guess.
Motorized tracking mounts move the entire camera, but I think all 3 of you are talking about the Pentax O-GPS1 which only moves the sensor. If a heavy lens is causing problems, you might need a heavier duty tripod head.
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