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PostPosted: Thu Sep 04, 2008 8:27 pm 
Hello all.

When I turn my a200 on, the lens makes always makes a sound that I don't really think sounds "healthy." All three lenses I've tried have done this, although they make slightly different sounds. It also makes a sound on power off, which I think sounds even worse. I figure that when the camera is powered on, the camera goes through a routine of checking the lens focus range, but I don't know what good that would be.

Is it normal? Do other brand DSLR cameras go through similar power on and power off routines that make similar sounds? Can it affect the lenses in a bad way?

Thanks in advance.


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PostPosted: Thu Sep 04, 2008 8:37 pm 
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Assuming it's the same as on the A350, the power on sound is the camera moving the lens focus to infinity.

When you turn off, I think that's the dust reduction shaking the sensor.

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Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
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PostPosted: Thu Sep 04, 2008 8:40 pm 
Is there a reason it changes the focus to infinity rather than leaving it wherever it was? Is it because I had it in AF with a cap on it?


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PostPosted: Thu Sep 04, 2008 8:45 pm 
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It does it regardless of if the body is in AF or MF mode. I don't know why, but one reason is most lenses are shortest when focused to infinity and it may be a requirement of the AF mechanism to start there.

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.


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PostPosted: Fri Sep 05, 2008 4:31 am 
Here are my thoughts:

When switched on/off, the sound from the...

...camera is the sensor being shaken to remove dust.

...lens is the focus being altered to make the lens at its physically shortest position.

I've never tried an internal focusing lens for Sony (if it has one anyway)

SnS 8)


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PostPosted: Sun Sep 07, 2008 12:31 pm 
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SCREAMnSHOUT wrote:
I've never tried an internal focusing lens for Sony (if it has one anyway)

Lots actually, there are quite some lenses with IF (internal focussing). The Zeiss 16-80mm is just one example. That also focusses to infinity when switched on and off, for the reasons mentioned above.

- Bjorn -

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PostPosted: Sun Sep 07, 2008 1:52 pm 
The Sigma lens I'm using is an internal focusing lens as the frontal element doesn't move when focusing (w00t, I can use a polarizer now!). It also focuses to infinity when powered off.


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PostPosted: Sun Sep 07, 2008 2:31 pm 
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To clear up, when you don't have IF, the front might move forward and back, but it may or may not rotate. Lack of IF does not mean the front rotates!

_________________
Canon DSLRs: 7D, 5D2, 1D, 600D, 450D full spectrum, 300D IR mod
Lenses: EF 35/2, 50/1.8, 85/1.8, 135/2+SF, 28-80 V, 70-300L, 100-400L, TS-E 24/3.5L, MP-E 65, EF-S 15-85 IS
3rd party: Zeiss 2/50 makro, Samyang 8mm fisheye, Sigma 150 macro, 120-300 f/2.8 OS, Celestron 1325/13
Tinies: Sony HX9V.


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PostPosted: Mon Sep 08, 2008 1:14 pm 
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Good to know, thanks popo! I want to buy prime lenses some time, which often do not have IF and I'd prefer the front elements not to rotate.

- Bjorn -

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Leica M9-P (my article on Camera Labs) | Leica D-Lux 5 | 50mm Summilux


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