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06-05-2015, 10:03 AM   #1
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K-3 ii & Pixel Shift: How still is still?

Deciding between a K-3 and a K-3 ii. With respect to the Pixel Shift feature, how still does the scene have to be for it to work?

Would pixel shift work for:
1) Portraits, if the person is standing still?
2) Landscapes? There's been talk about wind vs. no wind, but I'm guessing that also depends on distance and field of view, i.e., wind hitting a tree far away in your picture might work vs. wind hitting a tree right in front of you.

How long does it take to snap a photo in pixel-shift mode? Is it basically 4x shutter speed? I.e., if you set shutter speed to 1/1000, it'd take 4/1000 seconds (1/250)?

06-05-2015, 10:12 AM   #2
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QuoteOriginally posted by ahw Quote
Deciding between a K-3 and a K-3 ii. With respect to the Pixel Shift feature, how still does the scene have to be for it to work?

Would pixel shift work for:
1) Portraits, if the person is standing still?
2) Landscapes? There's been talk about wind vs. no wind, but I'm guessing that also depends on distance and field of view, i.e., wind hitting a tree far away in your picture might work vs. wind hitting a tree right in front of you.

How long does it take to snap a photo in pixel-shift mode? Is it basically 4x shutter speed? I.e., if you set shutter speed to 1/1000, it'd take 4/1000 seconds (1/250)?
This is a question for the new K-3 II users....
06-05-2015, 10:18 AM   #3
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If one has the expertise and the time, I expect that with a little extra work you could shoot K3II on a windy day with moving subjects.

I do lots of HDR. Also I do some "focus stacking". You run into the same problem with shooting moving objects with these methods, even more so.

If the moving object, or the wind effect is localized, you simply use "layers" in PhotoShop to brush in the optimum image part from a single layer onto your finished layer.

Or, with pixel shifting (PS), take an extra photo not in the pixel shifting mode, and use a layer mask to blend the sharp part of the non-PS image onto the PS image!

I just received my K3II and will soon be testing this theory on a photo safari that will sure to have some windy days...

Stay tuned a couple of weeks and I'll post right here how the above theory works in real life.

---------- Post added 06-05-15 at 10:26 AM ----------

Also, when shooting RAW, I read somewhere that some RAW developers simply recognize a multi image pixel shifting image as just 1 image. So, there may be no need to shoot a second shot in the non=Pixel shift mode = rather, just open the PS image in a RAW developer that sees only one of the 4 PS images.

I'll be trying this method too. Looks promising , but give me a few weeks to see if it works...


Dave in Wisconsin
06-05-2015, 10:30 AM   #4
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A single pixel on that sensor is so slight I have trouble imagining it can *ever* do it just because of camera vibrations, even on a tripod, but I guess it does...

06-05-2015, 11:21 AM   #5
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I can probably shed some light on this topic to a degree. I don't have a K3II nor am I going to order one, but have read the II's user manual, and inadvertently done some similar imaging to a degree.

Last weekend I was re-post processing a set of images from a couple of years ago. Sunset and Sunrise images shot at ISO 80 for the best image quality I could get, and bracketed (5 images +/-2ev). The problem was that the object I was shooting had some slight movement to it. She was a square rigged ship tied up to a pier. She did not appear to be affected by wind or the tide, but the images showed otherwise. Also, when the ship was stable, the rigging was bouncing around like a banjo string, just moving a cm or so - not much, but just enough.

Stacking the images (using a HDR utility) produced a blob, however quickly sequencing through them (cartoon mode) showed the ship ever so slightly moving around. Going into each individual image (especially the -1 and -2 ev frames) showed on some the rigging slightly moving - a fraction of an inch - essentially producing a "halo" effect around the line. Other times, one of the masts was moving and had a blur to it.

On others, you could clearly see the surrounding structures, the dock, the buildings, etc. were rock solid perfect, but the ship was ever so slightly in motion. Now out quite a few images taken, some were just total losses (in particular the over exposed +1, +2 ev frames). Others were mostly OK, but had isolated problems. Finally, there were about a dozen (out of several hundred), where I caught the ship just right, with everything still for that moment. Those were the keepers that I was able to really rescue. The more I post processed - especially the really under exposed ones (obviously with the shortest shutter speed), lighten up, adjust the lights, darks, shadows, highlights, contrast and over all exposure a bit, the various problems popped out - or didn't show up.

So, in terms of capturing the images using Pixel Shifting, the manual says the physical shutter opens, and then using the electronic shutter capability, 4 images will be taken with the same exposure, then combined producing a fifth, then all five saved to the "new" file format. The supplied Pentax software will un-bundle the "new" file format and provide the individual files for what ever further processing you desire.

If there is some movement in one area of the image, you are just going to have to judge if its acceptable or not. If it's way in the background with a touch of blur - most will never see it, and if you and they do, does it detract sufficiently from the overall image to render it not useable. In the end, it's your call. You are the photographer.

06-05-2015, 12:21 PM   #6
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In theory, if a subject moves in the frame, that portion of the photo is bound to look distorted. So portraits are almost certainly going to be out of the question.

With that said, it's certainly worth testing in real life.

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06-05-2015, 12:58 PM   #7
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I think everyone can test that with whatever camerea they currently have - after all it is just a brust of four pictures in a row. That the 24mpx sensor moves also 1px with each frame probably does not change the end result too much (for the motion blur).

My guess would be if the scene/situation can be captured sucessfully with a single long exposure of about 1.5 sec it will work for pixel shift as well.
06-05-2015, 01:18 PM   #8
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I found this re: Hassleblad using pixel shifting. Very interesting, really the same process as Pentax but they use 4 or 6 shots rather than just 4 and they get 200 or greater mob files! They also talk about using it with flash??

The company says that the switch from CCD to CMOS makes its multi-shot cameras more flexible, and allows photographers to use them in a wider variety of settings. The CMOS sensors offer ISO sensitivity up to 6400, while the previous CCD models could only manage ISO 800. A Hasselblad spokesperson explains that while the 200 million-pixel multi-shot feature will mostly be used for fine detail recording in flash-lit indoor conditions, such as a museum’s reproduction department, the fact that the camera can also be used at ISO 6400 and in single shot mode means it can then be used in low light outside or to boost flash impact when lighting larger areas or with moving subjects.

06-05-2015, 01:23 PM   #9
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This movement concerns me, not least because I often bracket a shot for aperture, focus, etc. With pixel shift, I'd not be sure exactly what I had till I got back home. Probably then I'd end up adding pixel shifted versions to my other bracketed shots. Would get through a few cards and batteries too with the extra processing.
For fixed subjects its tempting. Probably pixel shifting in k3 ii is a test bed for the technology in the ff. If so the resulting pixel counts are likely to be astronomical. More memory required. Not sure where this is going ...
06-05-2015, 01:59 PM   #10
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I think someone calculated that it is at minimum 1/2s of exposure? I've seen sharp portraits at that shutter speed, so I think it should be ok if planned properly for.
06-05-2015, 02:33 PM   #11
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Handheld (braced) is doable, check out my post & pictures here: https://www.pentaxforums.com/forums/172-pentax-k-3/296605-post-your-k-3-ii-photos-here.html
06-05-2015, 05:57 PM   #12
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QuoteOriginally posted by npc Quote
I think everyone can test that with whatever camerea they currently have - after all it is just a brust of four pictures in a row. That the 24mpx sensor moves also 1px with each frame probably does not change the end result too much (for the motion blur).

My guess would be if the scene/situation can be captured sucessfully with a single long exposure of about 1.5 sec it will work for pixel shift as well.
Minor movement (trees and leaves) in a single 1.5 sec exposure will show as a tiny bit of blur if you zoom in. Pixel shift creates pixelated artifacts around the movement, which to me is far more objectionable than blur. I expect someone out in Pentax land to find a solution but so far the pixel shift looks limited to indoor studios. It can be used outdoor for buildings as long as no people or trees are in the scene.

---------- Post added 06-05-15 at 09:01 PM ----------

QuoteOriginally posted by longbow Quote
Handheld (braced) is doable, check out my post & pictures here: https://www.pentaxforums.com/forums/172-pentax-k-3/296605-post-your-k-3-ii-photos-here.html
I assume those samples are a downscaled image, not 1:1 crops that show the full impact of pixel shift. Please correct me if I'm mistaken.
06-05-2015, 07:02 PM   #13
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Okay this is what I have seen so far with my K3II. Handheld braced a must. I have hand held a SMC Pentax A 70-210 4.0 at 1/10th Second 1/2 way out though with many other Pentax DSLR cameras with success and with hand held Pixel Shift I get mixed results. I just took a 1/60th of a second of our Cat a moment ago with a 50-20mm DAL 4-5.6 Ed Wr and it looked fine as he was sleeping. I won't post the photo as it shows my messy office. The shot took appox 1.5 seconds, I braced myself on a chair. The first Sat I had the camera I went out and took some landscape shots with moving water and grass for a test here are the results . This was a windy day, fast flowing stream, I was Tripod mounted. The original file is 152.94 MB raw and all I did was shrink it down to 2mb. I have done no other adjustments just converted it to JPG. Which has become another issue as my After Shot Pro 2 will not recognize the DNG but my Fastone, Pentax and Corel Paint Shop Pro X6 will. If you pixel peep you can see the grass has some issues. When loading these in the Pentax Lab you can hear the hard drive whine for a bit which is something as this computer I had built 4 months ago to meet all my future photography needs. Have fun with this, I will post some better shots once I am done all my testing.
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06-05-2015, 07:10 PM   #14
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QuoteOriginally posted by DeadJohn Quote
I assume those samples are a downscaled image, not 1:1 crops that show the full impact of pixel shift. Please correct me if I'm mistaken.
Not cropped, I downloaded directly from slot 2 (JPEG side for RAW+) with no changes on my part.
06-05-2015, 08:12 PM   #15
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For portraits, hyper resolution is not very flattering, because every small hair which we can't usually see with naked eye on the skin will became very clear. More about blemish, nostrils hair, and other things that we don't like to be seen. Normal 24Mp is already big for a close up in my opinion.
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