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Forum: Pentax K-1 & K-1 II
01-18-2019, 08:28 AM
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No I did not use 50kg rig or 5 ton beach rock. Certain shutter speeds, as I wrote (from my own tests 0.5s to 1/20sec) are problematic no matter how you secure the camera. If the shutter mechanism resonates with the lens/tripod it just blurs the image. 100mm WR Macro has always been the one causing this and to lesser extend Zeiss 50MP (you can feel shutter activation when holding the metallic lens barrel). As soon as this resonance is taken care of, blurring is reduced significantly but not always completely. These single exposures are the problem, not the stacking itself which just used these problematic shutter speeds. Thus, I began to investigate why the stack was blurred and found out how to avoid the problem. So I do not use these certain speeds and stacks are sharp, and there was no poltergeist camera movement phenomenon. I wish fully electronic shutter could be used more as it goes all the way up to 30 seconds when using pixel-shift so it is not something that cannot be done technically.
I had very heavy duty carbon-magnesium Benro tripod which completely killed the resonance issue with tripod but did not remove occasional issues with the lens. Benro now rests in pieces and current Manfrotto carbon tripod is a bit less secure (going to be replaced at some point) causing minor vibrations.
So, in this order:
-avoid nasty shutter speeds, if not possible, then...
-stop any lens resonance and finally
-check for possible tripod resonance issues
Lenses I found problematic (metallic barrel):
-100mm WR Macro
-Zeiss 50MP
Lenses having no issues (composite construction):
-IRIX 15mm f/2.4 Firefly
-Samyang 35mm f/1.4
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Forum: Pentax K-1 & K-1 II
01-17-2019, 04:33 PM
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You can mount the camera on 50kg rig or 5 ton rock on the beach and shoot away. You will get shutter shock either with single frames or an averaged stack. It does not matter. Stack is ruined when it is ruined by single frames blurred somewhere in between and that will happen with correct shutter speed. Exact same story as with D800E, D810 or A7R1 which I used extensively before K-1 bodies. Shutter mechanism is not dampened properly and it resonates with some lenses and most tripods. If one messes up a stack by moving the camera body during stacking, it is completely another issue. K-1 mk1 or 2 is not immune to shutter shock but it has good option to avoid it - EFCS in live view. It is real shame that fully electronic shutter utilized by PS is not allowed when shooting multiexposure stacks where it would really shine.
There is a trick to dampen shutter shock at certain shutter speeds which works with all cameras mentioned above. One needs to put some mass straight on the lens or tie it to the tripod by using a heavy rubber band. Or, if nothing else helps, get a grip on the lens and push down the tripod towards the ground with another hand.
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Forum: Pentax K-1 & K-1 II
08-10-2018, 09:10 AM
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Yes it is. If I hold the lens (Zeiss 50MP) tightly by hand and fire away with MLU I can still feel the shutter resonating thru the lens body (or tripod legs). Multiexposures cannot be used with electronic shutter (plain dumb feature) and firing away 256x exposures with MLU is even more hassle should it cure something (it does NOT). I have workaround for this - ND filter to make exposures long enough but not too long. Combining few second exposures with multiexposure averaging is superb technique for smooth IQ.
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Forum: Pentax K-1 & K-1 II
08-10-2018, 12:34 AM
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Oh the shutter shock is there with MK2. Just use shutter speed between 0.5s and 1/20sec, put camera to multiexposure average mode and shoot the stack. Output is more or less messed up. Much less of an issue towards faster speeds or longer exposures.
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Forum: Pentax K-1 & K-1 II
08-08-2018, 04:37 AM
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I just wrote that the same cast is present in all ISO100 exposures when pushed. This again suggests that RAW conversion fails or ISO100 is not the real base ISO of MK2 but something higher. Have to do ISO100 vs 200 comparison using multiexposure averaging which allows huge boosting of moderately high ISO value images. It will not remove the cast but shows it very clearly.
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Forum: Pentax K-1 & K-1 II
08-08-2018, 03:22 AM
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How do you explain this: Mark I vs Mark II ISO Comparison Plus Files - Page 3 - PentaxForums.com
Nothing special done except exposure push. All my ISO100 exposures look like that when pushed beyond 4EV. Trying to adjust tint to get rid of the magenta results in very weird looking images. Are there again some uncalibrated sensors or similar issues in some models while others are good?
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Forum: Pentax K-1 & K-1 II
08-08-2018, 01:12 AM
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AFAIK they do not have any magenta issues. I have owned D800E, D810 and A7r1 which all use the 36MP chip and no issues with current Adobe converters or Capture One. Or RawTherapee (which had a bug BTW when handling black level which caused magenta cast with D810). It does not require very long exposure to get the cast with MK2 - I posted two examples with ~2 second ISO 100 exposures in SirTomster's thread.
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Forum: Pentax K-1 & K-1 II
08-03-2018, 01:57 PM
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It all depends how you look at it. Few past weeks have been optimal for hanging out inside air-conditioned car stuck in local traffic jams due to insane heat wave. Usually that is not much fun. I have only few uses for digital camera - ultimate pixel level quality and ability to work in hard weather conditions. Former is like 3 steps backwards (ISO100 pushes magenta, ISO800+ have useless NR applied, Pixel-Shift multiplies damage done with NR-ridden ISO values) and zero forwards for the mk2 model.
Why is baked-in NR useless? Well if I take 5 exposures in average per shooting I can work the NR on my own. Current ISO100 handling for pushing shadows reminds me of old Canon sensor tech and Pixel-Shift then...combining blurred images for extra sharpness is like knitting mittens made of one's own hair. They look like mittens BUT do not keep you warm in cold.
For some mk2 works, for some it does not. It is possible that few firmware fixes could do wonders.
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