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Wednesday, February 09, 2011

K-5 Mirror Slap Blur Issue

http://www.pentaxforums.com/forums/pentax-k-5-forum/127267-k-5-shutter-blur.html

Have a look at the above test. The test is clearly described and the results are self-explanatory. See:-



So, it can be quite safely concluded from the above that the mirror slap is an issue for the K-5 and it causes obvious blur in the final images, especially when a longer focal length is used. And, against what Pentax camera operation manuals always advise for turning off the SR when mounting the camera on a tripod, turning on the SR could reduce the effect somehow, but however the problem and the adverse effect is still not totally eliminated, unless the mirror is locked up.

Do note that it is the mirror slap that causes blur but not the shutter vibration, otherwise even locking up the mirror cannot help.

All in all, the K-5 has a higher pixel count for an APS-C DSLR, but without a more accurate focusing system and a more gentle mirror slap that cause less vibration, most of the effective resolution of the sensor is actually wasted and the image quality suffers. And, if the higher fps is the cause of all those mirror slap problems for the latest Pentax DSLRs (i.e., K-7, K-x, K-5 and K-r), I would rather have a 3 fps rate in the old days for all those Pentax digital bodies! >:-[

Comments (17)

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that's why Sony's SLT isn't that bad idea :) Yes you lose some light (only visible effect at very high ISO), but in usual everyday usage, there is no moving mirror.
2 replies · active less than 1 minute ago
True mirrorless could be even better, as the AF is achieved via LiveView.
Split the difference.
Use a pelicile mirror in place of the standard mirror and shoot through the mirror for video and make a user selectable function whether to flip or lock the mirror up, or shoot through it...
That's why no mirror is good idea too. But i would choose to use mirror up function and live view.
This might be the reason why all dslrs have such a setting as mirror lock up, because all brands have this problem, and like TTB says a Sony SLT isn't a bad idea, but then nobody has compared the rolling shutter of the slt against an EVIL camera and they don't have any moving parts. EVIL is the future. (just kidding)
1 reply · active 434 weeks ago
Not exactly. True flagship models of C and N have minimal mirror slap effect but yet a very short system lag time.
This issue is known (but always interesting to see). I guess, that K-7 was worser at bigger pixels.
You should know this: http://falklumo.blogspot.com/2010/12/lumolabs-pen...
BTW: At the 645D it's the same. You can't make sharp, clear pictures slower than 1/100s.
I will now use more the mirror-up function in future under some circumstances ;)
6 replies · active 737 weeks ago
MIRROR lock-up does NOT prevent blur caused by SHUTTER vibration!
Just lock up the shutter as well :)

More seriously, given all the problems with this, can't Pentax just get a shutter from somebody else, e.g. Sony? If it can get Sony sensors and probably some other parts from other manufacturers, why not this ^&%# shutter that caused so much headache? and maybe some motor drive from others, like Sigma or Tamron, for its lenses? And in fact anything mechanical, since its QC is so poor?
Michael A.'s avatar

Michael A. · 737 weeks ago

Sounds you are going to make your own camera..btw, Seiko makes shutters, not Pentax, they buy them..similar applies for motors (don't remember the maker now)
How about Copal? Do they still exist?
Michael A.'s avatar

Michael A. · 737 weeks ago

Pretty sure they do, because a new stock is still available. They are usually LF #0, #1, #3 or old #3S & electronic. Have first 3 sizes myself, but don't know if they make other styles besides leaf though..they might...
I came across a few articles long ago and learnt that the focal-plane shutters used in some old film Pentax SLRs were made by Copal.
Good for you! You've discovered what photographers have known for decades, which is to use MLU for maximum sharpness.
The thread title is misleading. Please, take the fact into account that the 2s timer doesn't delay exposure from the shutter.
1 reply · active less than 1 minute ago
The 2s timer delay exposure by two seconds, it does not lock the shutter of course, but only the mirror!
Pentax K5's documentation says than the SR have to be shut down when you use a camera on a tripod, it can generate blur.
Don't you read the doc ?
1 reply · active less than 1 minute ago
Don't you see the *actual* results then?

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