Image-blurring in Shutter bounce & Mirror slap

Started Oct 14, 2012 | Discussions thread
Will1
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Re: Image-blurring in Shutter bounce & Mirror slap
In reply to PeterZheng, Oct 16, 2012

PeterZheng wrote:

Segment,

In film era, Nikon F80s was once a classical example. The F80s was a plastic mirror box framework built in, and a lightly weight body, so condition adversely to lesser vibrations. However, the shutter bounce and mirror slap the F80s was slightly lower than for elder brother F100. Nikon F100 was an alloy metallic box framework built in, and very lower vibrations, even below the half of the F90 vibrational acceleration value. (Nikon F90 was also an alloy metallic box framework built in).
Therein the Key, Nikon F80s was merely 2.5 fps, very lower mirror slap and the slower running of shutter blades, Secondly, the F80 shutter blades did not take the alloyed materials, but the mass of lighter synthetic materials. Thereby the F80 won so lower vibrations.

In currently, camera manufacturers are some duties ought to reinforce user-optional function onto a camera, wherein an optional low shutter bounce and mirror slap (3 fps/100ms lag), another optional fast fps and shutter lag (5 fps/60ms lag), to better suit dissimilar purposes. Maybe the mirror flipping might easily get a resolvent to the two speeds, but the shutter run with two speeds would be some difficulties.
We expect a camera can really be selected a mode with lower shutter bounce and mirror slap, whereas not sounds like more quiet, but is actually nothing lower vibrations helpful.

Also, we go back to again pay attention to the shutter with built-in lens. (a ring blades shutter, none a recoil).

The next writing is an originally comment on Pentax camera,  while also related to Nikon.  There are some common problems.

Image-blurring in Shutter bounce & Mirror slap
Another very nausea thing with Pentax K7, therein the shutter bounce blur degree is extremely graver of a worsening than k20d/k10d, even though you taken a MLU mode is also likewise worse, (MLU, mirror locked up, 2s delay). With third party the quantificational measured result to look at the k7 body, not only mirror slap blur and SR blur maybe you already heard, further, you can see that the k7 shutter bounce blur gotten a fearful worsening. (This type of image-blurring come from the shutter's recoil, the mirror slap blur is another type. The both of them are with problematic designs. ).

This is really too bad, looks like an inexperienced intern's design, and is also no enough technical equipment to test and measure to find problem. This makes us go back film era to look at eos1000 and eos888, with worse mirror slap blur and worse shutter bounce blur .However, nowadays is already 20 years later, and that the k7 is Pentax a topmost model, and not entry model.

Even though to go back 1995 - 1997, Pentax Z1p and MZ-3 never got like so worse, and the Z1p was a lower vibratory-blur than Nikon f90. Pentax MZ-5n was also a lower the mirror slap blur and the shutter bounce blur degree close to Nikon F80, (Nikon had a notably improvement on the camera vibrations late 1990s). However nowadays, Pentax did not suitably complete the least basal things, obviously, a patient as enterprise management, moreover Pentax camera division's technical management syatem is already a severe patient.

The shutter bounce blur degree at Pentax k5 gets a little improving, but is still not as near as the k20d/k10d. LumoLabs told us as follows, (Falk Lumo is Pentax camera a famed lover, from a teenager in 1977 and with a Pentax MX. He is yet no categorical to criticize Pentax, so take notice this point ),
"the K-7 has significantly more total shutter blur, about an increase from about 1.45 pixels to 2.9 pixels, a difference of 1.45 px with slightly larger 5.0 µm pixels". (the k-7 the worst blur up to 4 px, far larger than 5.0 µm).
"The K20D has around 0.2 pixels only, But blur widths don't add linearly. (Part of the K20D shutter blur is masked by the anti-alias (AA) filter). So, one way to put the result is that the K-5 is half way between the K20D and the K-7. All three cameras have a floating sensor shake reduction mechanism". (SR turned off in measuring)
"(k5) The absolute magnitude of the effect sits halfway in between a K20D which has almost no measurable effect and a K-7 which exhibits an effect large enough to make some people notice in their work."
"The matter may now have reached a satisfactory state with the K-5. But there remains work to be done for Pentax to fully understand and eliminate any unnecessary effects which compromise image sharpness." (LumoLabs/Dec 2010)

In March 2009, Japanese PIE 2009, The Nishi Lab and Tani Electronics introduced and demonstrated a measurement tool system, they developed a method to accurately measure the image-blurring effect of camera. Their system can accurately measure the blur offset of the every one pixel.

Further, the Nishi Lab and Tani Electronics demonstrated the measured result showing out a camera got a bad design that besides the mirror slap blur, even though you taken the mirror locked up mode is also some the image-blurring effects, which latter related the shutter bounce blur.

"There is no point in enhancing resolution unless we take some measures to reduce the vibration of a camera unit as a whole including a tripod," said Kazuki Nishi of UEC. (Nikkeibp/Mar 2009)
They also found once the vibrations in a camera significantly worsens, even if a 1.5 kg tripod used but the problem is still there.

Pentax did not care for that above?

Most of the enthusiasts had no idea how serious the problem, in fact, the image blurring of the camera vibration could make your 20 MP camera equivalent to a 5 MP camera, and the image sharpness significantly worsened, worse imaging than for a 5 MP camera.

However, manufacturer did not talk thier own problem, some so-called the known websites are always no saying, and their "testing" have always reporting good and good, good to good. With the flash lighting source to shoot the resolution chart that makes you cannot know the difference. Even if they have used other lighting source, but the resolution chart merely read horizontal direction, the real worse vertical direction imaging-blurring was not reflected.

People hard to see the truth.

The mirror slap blur is main harmful to a shutter speed below the 1/50s, whereas the shutter bounce blur is harmfully all the whole open shutter of speeds, the affected speed range with Xsync and slower.
The shutter bounce blur has long been existing in the focal plane mechanical shutter system, ( along linear movement recoil), moreover, a mirrorless camera is likewise cases, if they got a bad design, except the shutter with built-in lens. (a ring blades shutter, none recoil).

You can use a B&K accelerometer equipment to measure a relevant vibration value from a slap of mirror flipping up, (non flipping down that moment), likewise measure on the shutter bounce vibration.
Using the 2s delay-mode (camera self-loading mirror lockup) can respectively measure to the vibration values from the mirror flipping up and the shutter bounce.
(a detailed measurement needs vertical/Y-axis and horizontal/X-axis, that is top, bottom and sides at a camera body. But nowadays a camera is usually vertical motion in shutter or mirror, thereby the vertical direction image-blurring to be easier discoverable).

With using a digital storage oscillograph then you can also observe the vibrational amplitude in waveform of a damping process. Here is not only about the vibrational amplitude, and controlling the vibrational duration is same important problem, that the vibrational duration length must be little, and the damping must be enough.

This point, an alloy (metallic) mirror box is always a better built-in than a plastic mirror box.

About the non-quantificational testing method to obtain a usefully comparing between cameras, for our camera lovers oneself.
a B&K accelerometer system is overly expensive, it planned goal on a corporation, not personal. Whereas, a generic digital storage oscillograph is not so expensive (200 - 500 USD, non famous brands), a piezoelectric acceleration transducer (sensor) module is around 20 - 50 USD, a low pass amplifier module (10 - 20 USD), a simple remote control device to synchronously trigger on oscillograph and camera, then you can observe the vibrational amplitude and waveform of a damping process, and compare in between cameras.

This low pass amplifier module can be replaced with an older Hi-Fi phono amplifier, a bandwidth -3dB/10Hz, 5-10 mV input and 1 Volt output.
The testing camera body must be putting onto an extra-soft of cushion, like a half full of a air pillow.

Worse Shutter bounce & Mirror slap related Faster FPS & Shutter lag
Someone who blindly cheered the faster fps and shutter lag, maybe you could thereby get in worse shutter bounce and mirror slap. The faster mirror flipping and shutter travel easier meant higher accelerated motion, in same costs and built framework, body weight. Are you a sports cameraman?

Some topmost cameras more focused for pressmen cameramen, the heavy camera body and expensive price, with faster fps and shutter lag but uncertain to get the shutter bounce and mirror slap the lowest.

For the goal non-pressmen's cameras, should never firstly consider the faster fps and shutter lag. Do a choice, the imaging quality is first, that is firstly the lesser shutter bounce and mirror slap.

In film era, Nikon F80s was once a classical example. The F80s was a plastic mirror box framework built in, and a lightly weight body, so condition adversely to lesser vibrations. However, the shutter bounce and mirror slap the F80s was slightly lower than for elder brother F100. Nikon F100 was an alloy metallic box framework built in, and very lower vibrations, even below the half of the F90 vibrational acceleration value. (Nikon F90 was also an alloy metallic box framework built in).
Therein the Key, Nikon F80s was merely 2.5 fps, very lower mirror slap and the slower running of shutter blades, Secondly, the F80 shutter blades did not take the alloyed materials, but the mass of lighter synthetic materials. Thereby the F80 won so lower vibrations.

In currently, camera manufacturers are some duties ought to reinforce user-optional function onto a camera, wherein an optional low shutter bounce and mirror slap (3 fps/100ms lag), another optional fast fps and shutter lag (5 fps/60ms lag), to better suit dissimilar purposes. Maybe the mirror flipping might easily get a resolvent to the two speeds, but the shutter run with two speeds would be some difficulties.
We expect a camera can really be selected a mode with lower shutter bounce and mirror slap, whereas not sounds like more quiet, but is actually nothing lower vibrations helpful.

*************************************************

Also, you can also read here,

www.falklumo.com/lumolabs/articles/k5shutter/index.html

*************************************************

a measurement of the motion of a body equal to the product of its mass and velocity.

Therefore, when you divide by the mass to get the acceleration, the response of different bodies is inverse to the mass.

Uh - say again?

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