LumoLabs: Shutter induced blur (or not) with the Pentax K-5 camera

falconeye · 12-02-2010, 03:59 PM - **1 Like**

Originally posted by nanok

i think falk has explained several times that sr has nothing to do with it, this is shutter induced blur, and it can happen just as well on film cameras.

I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters.

janneman · 12-02-2010, 04:54 PM

Originally posted by falconeye

I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters.

sheeshs...

nanok · 12-02-2010, 05:11 PM - **1 Like**

Originally posted by falconeye

I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters.

you are very gracious, as always. i will refrain from rephrasing your above statement

. thanks for the excellent work btw, and for taking the time to explain it to us mere mortals in plain english (though you might need a.. ahem.. "translator", as it seems by now.. no, i'll be quiet, i promised)

secateurs · 12-02-2010, 06:00 PM

Sorry everyone, i was misled by previous posts and by the out-of-context quote of K-7 literature.

Abstract · 12-02-2010, 09:56 PM

Sorry was tired when was searching about that, my mistake....I got worried myself.

SteveM · 12-02-2010, 10:40 PM

Originally posted by ogl

K-5 is between K-7 and K20D now.

A mans word needs to hold the test of time....it could be questioned.

Abstract · 12-02-2010, 10:45 PM

Originally posted by smc

A mans word needs to hold the test of time....it could be questioned.

I guess its a small price to pay, I mean if its not very noticeable(If at all) unless you go crazy zooming into the picture...I can't see this being a huge problem.

The other topic floating around here proves that well and good enough.

ogl · 12-02-2010, 10:47 PM

Originally posted by falconeye

I understand ogl is disappointed. What else?

I'm not disappointed at all. It would be silly.

shuie · 12-03-2010, 08:18 AM

Just out of curiosity, does anybody know who makes the shutter in the K-5 and K-7? I just wonder if there are other camera brands using the same shutter assemblies, and if they show similar shutter induced blur. I suspect this problem may be more difficult to correct if indeed it is the a combination of the shutter mechanism, mirror, sensor, and body, as all of these components are not made by the same company.

Just my random thought for today.
Shuie

falconeye · 12-03-2010, 09:52 AM - **1 Like**

Originally posted by shuie

Just out of curiosity, does anybody know who makes the shutter in the K-5 and K-7? I just wonder if there are other camera brands using the same shutter assemblies, and if they show similar shutter induced blur.

Shuie,

I don't know if anybody ever took notice.

But I always make a subtle distinction between shutter blur and shutter-induced blur.

I imagine K-5 and other cameras of similiar caliber have about the same shutter blur.

Shutter blur is a direct effect caused by the shift of center of gravity while the shutter curtains move. It is unavoidable (well, sort of) and maxes at around sync speed, i.e., 1/180s. Itcan be a problem and if you can "feel" the shutter when holding the camera it probably is. It's not an issue for the K-5 as it is half a pixel only maybe. Old books on photography already teached you about it and how to avoid it.

Shutter-induced blur is a delayed response to the shift of center of gravity, maybe because something vibrates or because the SR drive needs a couple ms to accomodate. It is completely avoidable, yes, with the SR mechanism too. This effect is now smaller than direct shutter blur for the K-5 which is why I'm not worried anymore. It wasn't for the K-7. For the K-5, the combined effect is still a subpixel effect.

Mirror slap is another possible problem which causes blur in many cameras. Due to vibrations caused by the heavy mirror hitting the upper stop. For the K-5, mirror slap adds zero blur which is a great thing. Because it means that the combined effect of shutter[+induced] blur and mirror slap still is a subpixel effect.

All what Pentax needs to do to turn shutter blur into a great spec is to find and fix that damned reason for vibration. There is no genuine reason for it to vibrate as shown by the K20D. The K-5 is good as it is. But I don't want to worry (and waste my time measurebating) every time Pentax releases another camera. They better "fix" it once and forever

Dan · 12-03-2010, 10:06 AM

Originally posted by falconeye

...
But I always make a subtle distinction between shutter blur and shutter-induced blur. ...
...
All what Pentax needs to do to turn shutter blur into a great spec is to find and fix that damned reason for vibration. There is no reason for it to vibrate as shown by the K20D. The K-5 is good as it is. But I don't want to worry every time Pentax releases another camera. They better fix it once and forever

Thanks for the helpful explanation, both here and in your blog. Your careful and objective analysis of this issue is extremely useful. Based on your analysis, I have no concerns about the K-5 with regard to vibration-induced blur (from the shutter or mirror). I agree that it would serve Pentax well to identify the source of the remaining shutter vibration so as to prevent it from becoming a significant problem in future cameras.

Dan

ogl · 12-03-2010, 10:10 AM

Originally posted by falconeye

Shuie,

I don't know if anybody ever took notice.

Falk, I've converted PEF from K20D and K-5 yesterday and it seems to me that K20D has just a bit thicker AA filter than K10D and K200D or K-x. The photos are really sharp.
K-5 has stronger AA filter than K20D. Can you test it more carefully?

falconeye · 12-03-2010, 10:25 AM

Originally posted by ogl

Falk, I've converted PEF from K20D and K-5 yesterday and it seems to me that K20D has just a bit thicker AA filter than K10D and K200D or K-x. The photos are really sharp.
K-5 has stronger AA filter than K20D. Can you test it more carefully?

ogl, you confused the threads. This isn't your favourite AA filter thread

But let me give you this one reply in this thread since you asked.

From what I've seen and heard, the K10D has an AA filter which only blurs vertical lines (anisotrop AA filter). K20D seems to blur both directions (isotrop AA filter). The K-7 seems to have a slightly weaker isotrop AA filter than K20D. K-5 seems to have the same physical AA filter as K-7 which may make a measurebators difference because the pixel pitch is 5% smaller. All four AA filters do not blur away Nyquist frequency patterns, ie., they belong into the class of so-called weak AA filters. I cannot compare K20D and K-5 directly.

But I can say that without some sophistication, all four cameras with a good lens, are sharp enough to measure focus accuracy rather than camera resolution. So, results will be random. I get best results around f/4 because diffraction already hurts at f/5.6 and focus at f/4 is .... an untamed beast

If everything is setup in an optimal way, at f/4.5 the K-5 MTF22 "resolution" equals Nyquist with a LR-sharpening of 50% and 0.5px only, which happens to be the mathematical value from an ideal lens from a Foveon sensor w/o AA filter. So, LR-sharpening of 50% and 0.5px (LR 2.x) seems to invert the AA-filter pretty well. The real reason for a weaker AA filter is that natural blur can replace part of it...

Actually, the shutter-induced blur between 1/160s and 1/40s would be able to replace a good part of the K-5's AA filter in the horizontal direction. But only for free hand photography and not for faster, slower or flash photography

Nevertheless, I wonder if Pentax didn't suspect shutter blur for the K10D to be larger than it actually was

ogl · 12-03-2010, 10:45 AM

Originally posted by falconeye

ogl, you confused the threads. This isn't your favourite AA filter thread

But I can say that without some sophistication, all four cameras with a good lens, are sharp enough to measure focus accuracy rather than camera resolution. So, results will be random. I get best results around f/4 because diffraction already hurts at f/5.6 and focus at f/4 is .... an untamed beast

I've downloaded DNG from DA21 + K-5...
WebFile - 0212
I'm a bit shocked. No any sharp photos at all.
Pay attention at time of exposure

qtopplings · 12-03-2010, 10:58 AM

Originally posted by ogl

I've downloaded DNG from DA21 + K-5...
WebFile - 0212
I'm a bit shocked. No any sharp photos at all.
Pay attention at time of exposure

Who else is tired of OGL? *raises hand*

Seriously man, give it a rest. You sound like that guy who's name starts with a Rice and ends with a High.

12-02-2010, 04:54 PM	#47
janneman Veteran Member Join Date: Sep 2006 Location: Netherlands Photos: Gallery Posts: 908	Sheesh Originally posted by falconeye I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters. sheeshs...

12-03-2010, 09:52 AM - 1 Like	#55
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871 Original Poster	Originally posted by shuie Just out of curiosity, does anybody know who makes the shutter in the K-5 and K-7? I just wonder if there are other camera brands using the same shutter assemblies, and if they show similar shutter induced blur. Shuie, I don't know if anybody ever took notice. But I always make a subtle distinction between shutter blur and shutter-induced blur. I imagine K-5 and other cameras of similiar caliber have about the same shutter blur. Shutter blur is a direct effect caused by the shift of center of gravity while the shutter curtains move. It is unavoidable (well, sort of) and maxes at around sync speed, i.e., 1/180s. Itcan be a problem and if you can "feel" the shutter when holding the camera it probably is. It's not an issue for the K-5 as it is half a pixel only maybe. Old books on photography already teached you about it and how to avoid it. *Shutter-induced blur* is a delayed response to the shift of center of gravity, maybe because something vibrates or because the SR drive needs a couple ms to accomodate. It is completely avoidable, yes, with the SR mechanism too. This effect is now smaller than direct shutter blur for the K-5 which is why I'm not worried anymore. It wasn't for the K-7. For the K-5, the combined effect is still a subpixel effect. Mirror slap is another possible problem which causes blur in many cameras. Due to vibrations caused by the heavy mirror hitting the upper stop. For the K-5, mirror slap adds zero blur which is a great thing. Because it means that the combined effect of shutter[+induced] blur and mirror slap still is a subpixel effect. All what Pentax needs to do to turn shutter blur into a great spec is to find and fix that damned reason for vibration. There is no genuine reason for it to vibrate as shown by the K20D. The K-5 is good as it is. But I don't want to worry (and waste my time measurebating) every time Pentax releases another camera. They better "fix" it once and forever Last edited by falconeye; 12-03-2010 at 10:04 AM.

12-03-2010, 10:06 AM	#56
Dan Pentaxian Join Date: Dec 2007 Location: Pacific Northwest Posts: 325	Originally posted by falconeye ... But I always make a subtle distinction between shutter blur and shutter-induced blur. ... ... All what Pentax needs to do to turn shutter blur into a great spec is to find and fix that damned reason for vibration. There is no reason for it to vibrate as shown by the K20D. The K-5 is good as it is. But I don't want to worry every time Pentax releases another camera. They better fix it once and forever Thanks for the helpful explanation, both here and in your blog. Your careful and objective analysis of this issue is extremely useful. Based on your analysis, I have no concerns about the K-5 with regard to vibration-induced blur (from the shutter or mirror). I agree that it would serve Pentax well to identify the source of the remaining shutter vibration so as to prevent it from becoming a significant problem in future cameras. Dan Last edited by Dan; 12-03-2010 at 10:11 AM.

12-03-2010, 10:25 AM	#58
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871 Original Poster	Originally posted by ogl Falk, I've converted PEF from K20D and K-5 yesterday and it seems to me that K20D has just a bit thicker AA filter than K10D and K200D or K-x. The photos are really sharp. K-5 has stronger AA filter than K20D. Can you test it more carefully? ogl, you confused the threads. This isn't your favourite AA filter thread But let me give you this one reply in this thread since you asked. From what I've seen and heard, the K10D has an AA filter which only blurs vertical lines (anisotrop AA filter). K20D seems to blur both directions (isotrop AA filter). The K-7 seems to have a slightly weaker isotrop AA filter than K20D. K-5 seems to have the same physical AA filter as K-7 which may make a measurebators difference because the pixel pitch is 5% smaller. All four AA filters do not blur away Nyquist frequency patterns, ie., they belong into the class of so-called weak AA filters. I cannot compare K20D and K-5 directly. But I can say that without some sophistication, all four cameras with a good lens, are sharp enough to measure focus accuracy rather than camera resolution. So, results will be random. I get best results around f/4 because diffraction already hurts at f/5.6 and focus at f/4 is .... an untamed beast If everything is setup in an optimal way, at f/4.5 the K-5 MTF22 "resolution" equals Nyquist with a LR-sharpening of 50% and 0.5px only, which happens to be the mathematical value from an ideal lens from a Foveon sensor w/o AA filter. So, LR-sharpening of 50% and 0.5px (LR 2.x) seems to invert the AA-filter pretty well. The real reason for a weaker AA filter is that natural blur can replace part of it... Actually, the shutter-induced blur between 1/160s and 1/40s would be able to replace a good part of the K-5's AA filter in the horizontal direction. But only for free hand photography and not for faster, slower or flash photography Nevertheless, I wonder if Pentax didn't suspect shutter blur for the K10D to be larger than it actually was Last edited by falconeye; 12-03-2010 at 10:46 AM.

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12-02-2010, 03:59 PM - 1 Like	#46
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871 Original Poster	Originally posted by nanok i think falk has explained several times that sr has nothing to do with it, this is shutter induced blur, and it can happen just as well on film cameras. I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters.

12-02-2010, 05:11 PM - 1 Like	#48
nanok Veteran Member Join Date: Sep 2007 Photos: Gallery Posts: 969	Originally posted by falconeye I think the confusion comes from the fact that shutter and shake both start with sh and the written report starts to be boring to read after the first two letters. you are very gracious, as always. i will refrain from rephrasing your above statement . thanks for the excellent work btw, and for taking the time to explain it to us mere mortals in plain english (though you might need a.. ahem.. "translator", as it seems by now.. no, i'll be quiet, i promised)

12-02-2010, 06:00 PM	#49
secateurs Senior Member Join Date: Oct 2010 Location: Adelaide, Australia Photos: Albums Posts: 250	Sorry everyone, i was misled by previous posts and by the out-of-context quote of K-7 literature.

12-02-2010, 09:56 PM	#50
Abstract Inactive Account Join Date: Sep 2010 Location: New York Photos: Gallery Posts: 388	Sorry was tired when was searching about that, my mistake....I got worried myself.

12-02-2010, 10:40 PM	#51
SteveM Veteran Member Join Date: Jan 2009 Location: Vancouver Island, BC, Canada Photos: Gallery Posts: 3,294	Originally posted by ogl K-5 is between K-7 and K20D now. A mans word needs to hold the test of time....it could be questioned.

12-02-2010, 10:45 PM	#52
Abstract Inactive Account Join Date: Sep 2010 Location: New York Photos: Gallery Posts: 388	Originally posted by smc A mans word needs to hold the test of time....it could be questioned. I guess its a small price to pay, I mean if its not very noticeable(If at all) unless you go crazy zooming into the picture...I can't see this being a huge problem. The other topic floating around here proves that well and good enough.

12-02-2010, 10:47 PM	#53
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Originally posted by falconeye I understand ogl is disappointed. What else? I'm not disappointed at all. It would be silly.

12-03-2010, 08:18 AM	#54
shuie Senior Member Join Date: Oct 2008 Location: colorado Photos: Gallery \| Albums Posts: 140	Just out of curiosity, does anybody know who makes the shutter in the K-5 and K-7? I just wonder if there are other camera brands using the same shutter assemblies, and if they show similar shutter induced blur. I suspect this problem may be more difficult to correct if indeed it is the a combination of the shutter mechanism, mirror, sensor, and body, as all of these components are not made by the same company. Just my random thought for today. Shuie

12-03-2010, 10:10 AM	#57
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Originally posted by falconeye Shuie, I don't know if anybody ever took notice. Falk, I've converted PEF from K20D and K-5 yesterday and it seems to me that K20D has just a bit thicker AA filter than K10D and K200D or K-x. The photos are really sharp. K-5 has stronger AA filter than K20D. Can you test it more carefully?

12-03-2010, 10:45 AM	#59
ogl Banned Join Date: Dec 2007 Location: Sankt Peterburg Photos: Gallery \| Albums Posts: 8,382	Originally posted by falconeye ogl, you confused the threads. This isn't your favourite AA filter thread But I can say that without some sophistication, all four cameras with a good lens, are sharp enough to measure focus accuracy rather than camera resolution. So, results will be random. I get best results around f/4 because diffraction already hurts at f/5.6 and focus at f/4 is .... an untamed beast I've downloaded DNG from DA21 + K-5... WebFile - 0212 I'm a bit shocked. No any sharp photos at all. Pay attention at time of exposure

12-03-2010, 10:58 AM	#60
qtopplings Senior Member Join Date: Nov 2009 Location: Marin, CA Photos: Gallery \| Albums Posts: 282	Originally posted by ogl I've downloaded DNG from DA21 + K-5... WebFile - 0212 I'm a bit shocked. No any sharp photos at all. Pay attention at time of exposure Who else is tired of OGL? raises hand Seriously man, give it a rest. You sound like that guy who's name starts with a Rice and ends with a High.