Pictures at shutter blur speed, please.

falconeye · 12-03-2010, 04:33 PM

Originally posted by creampuff

Imo the shutter blur bunkum is just more pseudo-scientific crap. Unfortunately pseudo-scientific tests is a fav topic for some and the more it gets circulated, the more it takes a life of its own, needlessly scaring sensible people witless. Btw, I have never encountered any supposed issue with my K-5 or my previous K-7 for that matter.

I welcome this thread.

My shutter blur evaluation isn't pseudo-scientific or crap. But despite the fact that I said as clear as possible that the entire effect is a subpixel effect for the K-5 people won't notice in their work, people won't easily believe this. Of course, I wouldn't have done the work for the K-5 if the K-7 wouldn't have required it.

Also, I think I succeded to communicate that the K-5 has no "problem" here. I don't see a forum mill, not even over there at DPR where I didn't post on purpose.

Moreover, this thread is another good effort.

Nevertheless, bashing of my work should go in "my" thread. This thread would be better used for image examples.

In my study, I show an image where the effect is strong enough to see it with the naked eye, i.e. where the effect exceeds a pixel. Such images are the exception though and I don't expect to see them here in this thread.

So, let the images speak and rightly so

bats · 12-03-2010, 04:52 PM

Picture sharpness is overrated anyway.

Falk, thank you for your excellent investigations! I am very happy to see the K5 results.

My best regards,
Bob

**jackassp** · 12-03-2010, 05:05 PM

I'm old.
My tremor is worse than 2pixels worth of blur.

But my K-7 and K-5 fix it and make my photos look good (at least to me anyway).

ivoire · 12-03-2010, 09:03 PM

Testing is always a great idea and a lot of work. Kudos to falconeye or anyone else that spends the time to do an in depth study. Heres another addition DA40 at iso400, 1/80, f4

Last edited by ivoire; 05-05-2011 at 06:04 AM.

EyeofmyPentax · 12-04-2010, 02:37 PM

GimbaL and whoever is interested:
LumoLabs tested the K-7. When did they test the K-5? I found that there is a difference between the K-7 and the K-5 when using SR on a tripod. The K-7 needs to have SR disabled, even with FW 1.10, otherwise you add blurr to shots taken at under 1/180 speed. It also has real problems with LV on a tripod when SR is active. Not so the K-5. I do get actually sharper pictures in LV below 1/100 with the K-5 and telephoto lenses up to 500mm than in VF mode. I thought this was due to mirror slap. Now I read the LumoLab acrticle and they claim the mirror movement has nothing to do with it. I think it has for the K-5 and that it is 'masked' by a stronger shutter effect in the K-7, perhaps. I didn't do a scientific test, as LumoLabs did, but I can provide photos if anyone is interested. Bottom line, Pentax must have fixed something to reduce the shutter blurr in the K-5, but the 'mirror slap effect ' is now obvious at shutter speeds below 1/100, even with SR on, IMHO.

falconeye · 12-04-2010, 05:30 PM

Originally posted by EyeofmyPentax

but the 'mirror slap effect ' is now obvious at shutter speeds below 1/100, even with SR on, IMHO.

My LumoLabs article about the K-5 is discussed in a sibling thread. AFAIK, this thread (you are reading now and where you posted) is dedicated to photos.

K-5 mirror slap is measurable on a weak enough tripod. But not free hand. Further details via the other thread, please.

cbaytan · 12-04-2010, 08:58 PM

Originally posted by falconeye

I welcome this thread.

My shutter blur evaluation isn't pseudo-scientific or crap. But despite the fact that I said as clear as possible that the entire effect is a subpixel effect for the K-5 people won't notice in their work, people won't easily believe this. Of course, I wouldn't have done the work for the K-5 if the K-7 wouldn't have required it.

Falk, in my statistical knowledge I believe your tests weakness is not the method you are using but is the number of the sample size, statistically n:1 does not represent the universe (in statistical terms universe means the number of the K-7 or K-5 ever produced). With a sample is size of 1 you are assuming that all of the produced cameras are behaving same as the ones you are tested., which might not be scientific.. You have to perform an a-priori power analysis and calculate the sample size to report the mean difference with a precision (for 95.0% confidence level). Then you have to test minimum enough number of cameras to be able to report shutter shake levels of a certain camera model(s).

For instance a Power analysis sample

unless explaining to us (at least to me) why would you expect all K-7's or K-5 will behave (in the shutter shake levels of course) exactly same as you are tested.

I have to mention that I would like to thank you for your tests here once more.

falconeye · 12-05-2010, 04:11 AM

Originally posted by cbaytan

unless explaining to us (at least to me) why would you expect all K-7's or K-5 will behave (in the shutter shake levels of course) exactly same as you are tested.

Wrong thread (again).
Moreover, I commented about sample variation in my study and the appropriate thread, already.

Originally posted by cbaytan

I have to mention that I would like to thank you for your tests here once more.

You have a strange way to say thank you

cbaytan · 12-05-2010, 06:30 AM

Originally posted by falconeye

Wrong thread (again).
Moreover, I commented about sample variation in my study and the appropriate thread, already.

Why wrong thread Falk? I've quoted you. In fact I am not aware the thread you are mentioning, would you point us please?

falconeye · 12-05-2010, 07:13 AM

Originally posted by cbaytan

Why wrong thread Falk? I've quoted you. In fact I am not aware the thread you are mentioning, would you point us please?

https://www.pentaxforums.com/forums/pentax-k-5-forum/124523-lumolabs-shutter-...-5-camera.html

It's on the same page of thread listings as this one, has 4x #replies and a clear title. Is it really this difficult to find?

Anyway, I may post pictures at shutter blur speed here but otherwise won't respond anymore.

12-04-2010, 02:37 PM	#20
EyeofmyPentax New Member Join Date: Oct 2010 Location: Lilburn, Georgia Photos: Gallery Posts: 6	Shutter blurr GimbaL and whoever is interested: LumoLabs tested the K-7. When did they test the K-5? I found that there is a difference between the K-7 and the K-5 when using SR on a tripod. The K-7 needs to have SR disabled, even with FW 1.10, otherwise you add blurr to shots taken at under 1/180 speed. It also has real problems with LV on a tripod when SR is active. Not so the K-5. I do get actually sharper pictures in LV below 1/100 with the K-5 and telephoto lenses up to 500mm than in VF mode. I thought this was due to mirror slap. Now I read the LumoLab acrticle and they claim the mirror movement has nothing to do with it. I think it has for the K-5 and that it is 'masked' by a stronger shutter effect in the K-7, perhaps. I didn't do a scientific test, as LumoLabs did, but I can provide photos if anyone is interested. Bottom line, Pentax must have fixed something to reduce the shutter blurr in the K-5, but the 'mirror slap effect ' is now obvious at shutter speeds below 1/100, even with SR on, IMHO.

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12-03-2010, 04:33 PM	#16
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by creampuff Imo the shutter blur bunkum is just more pseudo-scientific crap. Unfortunately pseudo-scientific tests is a fav topic for some and the more it gets circulated, the more it takes a life of its own, needlessly scaring sensible people witless. Btw, I have never encountered any supposed issue with my K-5 or my previous K-7 for that matter. I welcome this thread. My shutter blur evaluation isn't pseudo-scientific or crap. But despite the fact that I said as clear as possible that the entire effect is a subpixel effect for the K-5 people won't notice in their work, people won't easily believe this. Of course, I wouldn't have done the work for the K-5 if the K-7 wouldn't have required it. Also, I think I succeded to communicate that the K-5 has no "problem" here. I don't see a forum mill, not even over there at DPR where I didn't post on purpose. Moreover, this thread is another good effort. Nevertheless, bashing of my work should go in "my" thread. This thread would be better used for image examples. In my study, I show an image where the effect is strong enough to see it with the naked eye, i.e. where the effect exceeds a pixel. Such images are the exception though and I don't expect to see them here in this thread. So, let the images speak and rightly so

12-03-2010, 04:52 PM	#17
bats Senior Member Join Date: Sep 2010 Location: San Francisco Photos: Gallery Posts: 102	Picture sharpness is overrated anyway. Falk, thank you for your excellent investigations! I am very happy to see the K5 results. My best regards, Bob

12-03-2010, 05:05 PM	#18
jackassp Site Supporter Join Date: Apr 2010 Location: Adelaide, South Australia Photos: Gallery Posts: 813	I'm old. My tremor is worse than 2pixels worth of blur. But my K-7 and K-5 fix it and make my photos look good (at least to me anyway).

12-03-2010, 09:03 PM	#19
ivoire Veteran Member Join Date: Mar 2007 Photos: Gallery Posts: 3,381	Testing is always a great idea and a lot of work. Kudos to falconeye or anyone else that spends the time to do an in depth study. Heres another addition DA40 at iso400, 1/80, f4 Last edited by ivoire; 05-05-2011 at 06:04 AM.

12-04-2010, 05:30 PM	#21
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by EyeofmyPentax but the 'mirror slap effect ' is now obvious at shutter speeds below 1/100, even with SR on, IMHO. My LumoLabs article about the K-5 is discussed in a sibling thread. AFAIK, this thread (you are reading now and where you posted) is dedicated to photos. K-5 mirror slap is measurable on a weak enough tripod. But not free hand. Further details via the other thread, please.

12-04-2010, 08:58 PM	#22
cbaytan Inactive Account Join Date: Nov 2008 Location: Trabzon/Turkey Photos: Gallery Posts: 1,010	Originally posted by falconeye I welcome this thread. My shutter blur evaluation isn't pseudo-scientific or crap. But despite the fact that I said as clear as possible that the entire effect is a subpixel effect for the K-5 people won't notice in their work, people won't easily believe this. Of course, I wouldn't have done the work for the K-5 if the K-7 wouldn't have required it. Falk, in my statistical knowledge I believe your tests weakness is not the method you are using but is the number of the sample size, statistically n:1 does not represent the universe (in statistical terms universe means the number of the K-7 or K-5 ever produced). With a sample is size of 1 you are assuming that all of the produced cameras are behaving same as the ones you are tested., which might not be scientific.. You have to perform an a-priori power analysis and calculate the sample size to report the mean difference with a precision (for 95.0% confidence level). Then you have to test minimum enough number of cameras to be able to report shutter shake levels of a certain camera model(s). For instance a Power analysis sample unless explaining to us (at least to me) why would you expect all K-7's or K-5 will behave (in the shutter shake levels of course) exactly same as you are tested. I have to mention that I would like to thank you for your tests here once more.

12-05-2010, 04:11 AM	#23
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by cbaytan unless explaining to us (at least to me) why would you expect all K-7's or K-5 will behave (in the shutter shake levels of course) exactly same as you are tested. Wrong thread (again). Moreover, I commented about sample variation in my study and the appropriate thread, already. Originally posted by cbaytan I have to mention that I would like to thank you for your tests here once more. You have a strange way to say thank you

12-05-2010, 06:30 AM	#24
cbaytan Inactive Account Join Date: Nov 2008 Location: Trabzon/Turkey Photos: Gallery Posts: 1,010	Originally posted by falconeye Wrong thread (again). Moreover, I commented about sample variation in my study and the appropriate thread, already. Why wrong thread Falk? I've quoted you. In fact I am not aware the thread you are mentioning, would you point us please?

12-05-2010, 07:13 AM	#25
falconeye Veteran Member Join Date: Jan 2008 Location: Munich, Alps, Germany Photos: Gallery Posts: 6,871	Originally posted by cbaytan Why wrong thread Falk? I've quoted you. In fact I am not aware the thread you are mentioning, would you point us please? https://www.pentaxforums.com/forums/pentax-k-5-forum/124523-lumolabs-shutter-...-5-camera.html It's on the same page of thread listings as this one, has 4x #replies and a clear title. Is it really this difficult to find? Anyway, I may post pictures at shutter blur speed here but otherwise won't respond anymore.