All Forum Comments
Actually I had this day planned to be still on holiday but my father called me yesterday if I could help him out with work so...
But I'm glad I returned since the release of the K-5 is sooner than I thought so earned some money towards it
But I'm glad I returned since the release of the K-5 is sooner than I thought so earned some money towards it
Comment by Anvh posted on Voting competition #3 - "But soft. What light through yonder window breaks.....?" at 20/09/2010 - 20:16
Just see the typo
It must be: turn off DFS on your K20D and K7
It must be: turn off DFS on your K20D and K7
Comment by Anvh posted on turn off DFS with your K20D and K7 at 20/09/2010 - 20:09
The 645D is a very different camera than the K5, no way you can compare those.
About the focus speed, that also really depends on the lens.
It's quite safe to say that the bigger the focus throw the slower the AF will be, but that doesn't have to always be the case though.
Don't know if the SDM effects preformance?
About the focus speed, that also really depends on the lens.
It's quite safe to say that the bigger the focus throw the slower the AF will be, but that doesn't have to always be the case though.
Don't know if the SDM effects preformance?
Doug, I haven't read it though but the pictures does apply that that is the problem.
http://www.falklumo.com/lumolabs/articles/k7shutter/index.html
Very cool 1000fps movie from the K7 shutter http://www.falklumo.com/lumolabs/articles/k7shutter/K7-Shutter-Hispeed.mp4
This their conclusion.
http://www.falklumo.com/lumolabs/articles/k7shutter/index.html
Very cool 1000fps movie from the K7 shutter http://www.falklumo.com/lumolabs/articles/k7shutter/K7-Shutter-Hispeed.mp4
This their conclusion.
Quote:
When an SLR takes an image, it opens it's focal plane shutter. While it gets fully open, the shutter curtain accelerates and decelerates dramatically and then typically hits hard into the shutter box. As a result of this, the whole body accelerates significantly for a rather short moment in time (it gets a few„micro-kicks“). In the case of the Pentax K-7 camera, the shutter accelarations are a bit high and its floating sensor must then slip by a small amount (which isn't a bad thing as it counteracts the body movement due to shutter operation). But as a result of this, the camera electronics may struggle to get the floating sensor back into tight control. Or the imaging board may swing a little bit. Either effect magnifies blur to a level that it may become visible to the naked eye.
When an SLR takes an image, it opens it's focal plane shutter. While it gets fully open, the shutter curtain accelerates and decelerates dramatically and then typically hits hard into the shutter box. As a result of this, the whole body accelerates significantly for a rather short moment in time (it gets a few„micro-kicks“). In the case of the Pentax K-7 camera, the shutter accelarations are a bit high and its floating sensor must then slip by a small amount (which isn't a bad thing as it counteracts the body movement due to shutter operation). But as a result of this, the camera electronics may struggle to get the floating sensor back into tight control. Or the imaging board may swing a little bit. Either effect magnifies blur to a level that it may become visible to the naked eye.
Quote:
1. The K-7 has a heavier and/or faster shutter than the K20D, creating about 50 % larger body accelerations.
2. A sloppy, unstable, weak, ill behaving non-linear image sensor position controller magnifies the effect (for selected shutter speeds between about 1/180 s to 1/60 s) by another 100 %.
Or an equivalent non-linear effect is responsible for this, triggered by body acceleration (like a swinging imaging sensor board but not vibration alone!).
3. Combined, we see a 200 % extraneous blur effect increase compared to the K20D (3x its magnitude) leading to additional image blur in excess of 10 µm (on average). Which can be up to almost 4 pixels in worst cases (portrait orientation wide angle 1/80 s).
1. The K-7 has a heavier and/or faster shutter than the K20D, creating about 50 % larger body accelerations.
2. A sloppy, unstable, weak, ill behaving non-linear image sensor position controller magnifies the effect (for selected shutter speeds between about 1/180 s to 1/60 s) by another 100 %.
Or an equivalent non-linear effect is responsible for this, triggered by body acceleration (like a swinging imaging sensor board but not vibration alone!).
3. Combined, we see a 200 % extraneous blur effect increase compared to the K20D (3x its magnitude) leading to additional image blur in excess of 10 µm (on average). Which can be up to almost 4 pixels in worst cases (portrait orientation wide angle 1/80 s).
Comment by Anvh posted on Shutter Blur on K7 at 20/09/2010 - 19:21
johnriley wrote:
Not quite a focal plane shutter, but thanks for the link - it's ages since I saw that bit of film.
Funny enough the newest bridge in Rotterdam had the same problem but than with the cables.Not quite a focal plane shutter, but thanks for the link - it's ages since I saw that bit of film.
At certain wind speeds they started to vibrate, they have solved the problem though
Comment by Anvh posted on Shutter Blur on K7 at 20/09/2010 - 19:15
Don wrote:
if that were the case you'd think the sr could be programed to offset it.
Don't think so, if you think that the force of the shutter is always the same than you're right.if that were the case you'd think the sr could be programed to offset it.
The problem is that the effect change depending on the weight of the camera (lens weight, flash, battery grip, ect.) and how a person holds the camera.
Therefore the movement of the camera is different every time.
Newton's second and third laws are in action here.
II. The relationship between an object's mass m, its acceleration a, and the applied force F is F = ma.
III. For every action there is an equal and opposite reaction.
Comment by Anvh posted on Shutter Blur on K7 at 20/09/2010 - 19:12
Pentaxophile wrote:
How is this fixed Stefan?
I said that it was not really a problem easily fixed. How is this fixed Stefan?
The problem is that the first curtain moves and stops creating motion and there is a second curtain doing the same and if they move just in the right way they "amplify" the motion.
It's roughly the same as with certain cars when you drive a certain speed they vibrate a lot and when you go over it the vibration gets less.
This the same thing almost but than with a bridge link
It only did that with winds of around 40 mph (64 km/h)
Maybe they can change the weight, move it faster or slower or mount it differently?
Another way is to have the same amount of force travelling in the other direction of the shutter, that would cancel out the force.
Or use a different kind of shutter like a diaphragm shutter.
Pentaxophile wrote:
But after a few days of being rather horrified, I've chilled out a bit as the camera is just so nice apart from this little 'glitch.' I have 'bonded' with it... lol. I just hope the K5 has a slightly more dampened - or completely new - shutter.
It's not a glitch, it's in all camera's after all it's just an engineering mistake it happens to be at 1/125th and they should have know better But after a few days of being rather horrified, I've chilled out a bit as the camera is just so nice apart from this little 'glitch.' I have 'bonded' with it... lol. I just hope the K5 has a slightly more dampened - or completely new - shutter.
The K5 has a higher FPS so the shutter is most likely different.
Comment by Anvh posted on Shutter Blur on K7 at 20/09/2010 - 18:34
Thank you mike
Well it's true though.
cabstar wrote:
I love the explanation of the difference between 12 bit raw & 14 bit raw on that video. It's better because you have more...
I love the explanation of the difference between 12 bit raw & 14 bit raw on that video. It's better because you have more...
Well it's true though.
Comment by Anvh posted on Official K-5 specs !!! at 20/09/2010 - 18:06
be sure to press "enter" when you finish with the less line of codes and leave the battery door open.
Those where the problems most K10D user had when trying to get the AF adjustment to work.
Those where the problems most K10D user had when trying to get the AF adjustment to work.
Comment by Anvh posted on turn off DFS with your K20D and K7 at 20/09/2010 - 18:02
And before anyone asks I have no Idea why they jumped from K10-20