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05-11-2011, 12:54 AM   #1
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Pentax K-7 to K-5...is the K-7 shutter blur enough of an issue to warrant it?

Is the shutter blue issue documented by falconeye and others enough of an issue with the K-7 to make one steer clear of this camera? How can I best test mine for this issue? I was hoping to be happy with the K-7 for around 3 years before going to the K-5, but reading all the threads of various circumstances inducing this defective trait sounds like a good shot at 1/100 with the K-7 could be ruined as a result. Thanks all for any input


Last edited by Loren E; 05-12-2011 at 11:22 PM.
05-11-2011, 01:51 AM   #2
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I have had a k-7 for almost 2 years, [2 different bodies] and have never noticed the problem. (I have read about it though). It appears maybe to be individual body related.

This is no help to you though because you cannot tell if the body has a problem till you check it out.
05-11-2011, 07:34 AM   #3
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It's best to assume they all have this problem, even though I have only noticed it until recently with the purchase of the DA15mm f/4 limited - And I chalk that up to the fact that I typically use lenses with greater mass which would have a dampening effect on these vibrations. For years I have shot hand-held at 1/125th with focal lengths up to 450mm with no observable degradation of IQ due to shutter vibrations. I use 1/125th shutter speeds quite a bit, it is the last shutter speed that ends in 5.
05-11-2011, 07:42 AM   #4
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I get really sharp images at slow shutter speeds with mine. 1/2 of the time when I get a blurry image it is because I am not use to having to wait on the SR to spool up. My Canon 5D did not have it, and the Olympus E-3 was much faster.

I shoot primarily with a Sigma 50mm f/1.4 and 90% of my images are taken at f/2.8 or wider. I'm sure it does effect some of my images. I would like to blame the camera for all my bad images.

05-11-2011, 07:46 AM   #5
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My hunch is that such issues are caused by SR not being ready. While it this can happen, I don't think it's a problem at all in practice.
05-11-2011, 08:03 AM   #6
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QuoteOriginally posted by Adam Quote
My hunch is that such issues are caused by SR not being ready. While it this can happen, I don't think it's a problem at all in practice.
actually I don't use the SR all that much, my technique is more than up to the task of hand-holding a 50mm f/1.2 at 1/4th and still achieve critical sharpness. using SR is a bit pointless with the DA15 f/4 on a bright sunny day. And still I see the blurring pop up from time to time when the shutter speeds hit 1/80th~1/160th zone. My solution to this is to take two images - that way you can make an immediate comparison on the rear LCD on the K-7 whether the image is blurred or not, and if they are both blurred it will still show up because of the slight differences in direction of the blurring.
05-11-2011, 08:14 AM   #7
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Prior to Falk Lumo's report, nobody thought or even suspected this was an issue with the K-7. However in the weeks leading up until that time, there some people reporting a problem with mirror slap / shutter induced blur on their K-x. And yet most people claimed they were not able to replicate the problem with the K-x (or afterwards on the K-7). In other words, it wasn't an issue for most folks at any shutter speed on either of the two cameras.
05-11-2011, 08:15 AM   #8
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The issue is not actually related to SR at all. It is a shutter induced blur that is visible primarily around shutter speeds of 1/100 second. I think all cameras have it to a certain extent, but for some reason it was more pronounced in the K7, causing up to 2 1/2 pixels of blur. The K5 also has it, but only about half the effect (1 1/2 pixels of blur at 1/100 second).

The question about SR was whether it could compensate for this shutter blur and at slower shutter speeds it does -- at really fast speeds it doesn't need to and in the middle it struggles.

All that said, I think it isn't a reason to avoid the K7, by any means.


Last edited by Rondec; 05-11-2011 at 08:41 AM.
05-11-2011, 08:21 AM   #9
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QuoteOriginally posted by Adam Quote
My hunch is that such issues are caused by SR not being ready. While it this can happen, I don't think it's a problem at all in practice.
You're probably right... some people release the shutter before the SR indicator comes on, however I doubt that would be the case with Falk.
05-11-2011, 08:22 AM   #10
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QuoteOriginally posted by Rondec Quote
I think all cameras have it to a certain extent
the pentax 67II definitely had it at 1/8th.
05-11-2011, 09:09 AM   #11
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I have not experienced any such issue with my K-7.

As a general observation on human nature, though, and without reference to anyone on this or other photography forums, there exist in this world people who aren't happy unless they have something to be unhappy about. Just sayin'.
05-11-2011, 12:35 PM   #12
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Every camera has its problems, I would not worry to much about it honestly. I think this problem was less so on both K20D and K-5 though.
05-11-2011, 11:50 PM   #13
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Thanks for your input all.
05-12-2011, 11:08 PM   #14
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After very extensive testing, there is no inherent problem

I bought my K-7 at the height of the concern. Being a measurement sort of person I set about measuring the effect of Shake Reduction.
More than 1000 tests later I came to the conclusion that there is no inherent design problem. See the graph below. In fact I would say that the K-7 has a very effective shake reduction system.

You can see my full report on Scribd (pdf)
Study of the Effectiveness of Shake Reduction in the Pentax K7
05-13-2011, 03:24 PM   #15
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QuoteOriginally posted by labnut Quote
More than 1000 tests later I came to the conclusion that there is no inherent design problem.
Nice work ! It confirms my practical experience that there is no problem with the K-7 as long as one waits for the SR to lock in before taking a shot.
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