Sensor hygiene....

molested_cow

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Sounds like a sensitive topic for the camera's most sensitive spot...

Well I clean my sensor myself with the swab and stuff, but what makes me wonder is if the mirror is down while swapping lens, which is pretty much the only reason why it will be exposed to begin with, where do all those oil spots come from? The shutter mechanism?

My D700 probably has 40k clicks already, so it's not like the newish D600 issue. Mystery?
 

Gavjenks

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Some of the newest Nikons have been known (as in, reported by dozens and dozens of people on Amazon reviews, for instance) to have mirrors which fling oil onto their own sensors as they activate, for the first several hundred or thousand activations or so.

Fun times!

There is a possibility that this might be solved in the near future (or maybe has been already), and that Nikon may be able to fix it for you. You might do well to call and ask.
 

cowleystjames

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I have the D800e and so far have around 18,000 shutter activations. Thankfully no spots on sensor have appeared as yet! So perhaps Nikon have got on top of this problem.
But I also use a Giotto puff blower up into the lens mount cavity whilst holding camera downward, when I change lenses. Along with vibrate sensor on start up on shutdown, I'm hoping this regime will keep me clear of dust spots for a while. :)

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The mirror has to be up before the front shutter curtain opens.
When changing lenses, not only is the mirror down, the front shutter curtain is between the image sensor and the mirror box.

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Gavjenks

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Hm, good point. Well maybe it is the shutter mechanism then. I don't know, but something about the act of taking pictures is known to fling oil. Without the lens having been removed in between, etc. It's not from an external source (or it's unlikely)
 

Kolia

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Who knows what kind of fluid dynamics are involved in a small enclosed space with one of its wall is swooshing up and down ?

I think that if there is oil anywhere in the camera, it is susceptible to eventually fly unto the sensor.

As for the front curtain, mine is always down, so my sensor is exposed at all time when the camera is ON. I find the delay needed to raise it before coming back down for each shot to long. I'm assuming all DSLR offer the option of keeping it down ?
 

Gavjenks

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Who knows what kind of fluid dynamics are involved in a small enclosed space with one of its wall is swooshing up and down ?

I think that if there is oil anywhere in the camera, it is susceptible to eventually fly unto the sensor.

As for the front curtain, mine is always down, so my sensor is exposed at all time when the camera is ON. I find the delay needed to raise it before coming back down for each shot to long. I'm assuming all DSLR offer the option of keeping it down ?
Not sure what you mean by front curtain. The term "front curtain" usually refers to flash lighting that fires as soon as the entire shutter is fully open (as opposed to rear curtain that fires just before part of the shutter begins to close again). The curtain being referred to simply being the shutter (although the shutter is usually 2 pieces). A physical front curtain, I dunno, but maybe. Could be a sony thing?

My Canon cameras only have the mirror and the shutter in between the sensor and the outside world (assuming no lens, obviously).

There is an option to lock up the mirror so it doesn't have to swing each time, but the consequence of this is that you can't look through the viewfinder, and AF is slower. Also, it doesn't speed up the camera's firing rate. Rather, it just helps prevent camera shake for precision tripod work.
 

Kolia

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Front curtain.... Front shutter... I'm sure you have more imagination than you let on.

Let me rephrase. On my camera I have the option of leaving the front shutter down (ie open) and only the second shutter actually moves to cover the sensor when I take a picture.
 

Gavjenks

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Front curtain.... Front shutter... I'm sure you have more imagination than you let on.

Let me rephrase. On my camera I have the option of leaving the front shutter down (ie open) and only the second shutter actually moves to cover the sensor when I take a picture.

I am still not sure what you're talking about. Your camera has TWO shutters? Why? I'm not saying you're wrong... I've just never heard of such a thing, and cannot understand why it would be beneficial to have two shutters. Here is a high speed video of a Canon 60D taking a photo:

As you can see, the mirror moves out of the way, then the single shutter in the entire camera opens and closes (it has two halves, but they are top and bottom, not "front" and "back," both being at the same distance from the sensor).

If a Sony a65 has two shutters, I would be very interested to know where the "front shutter" is and what its purpose is.
 
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dl4449

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I have one of the D600 with the spots on the sensor .I sent it to Nikon for repair and they replaced the shutter mechanism. Apparently the shutter wasent sealing properly and letting dust in and getting on the sensor
 

table1349

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Front curtain.... Front shutter... I'm sure you have more imagination than you let on.

Let me rephrase. On my camera I have the option of leaving the front shutter down (ie open) and only the second shutter actually moves to cover the sensor when I take a picture.

I am still not sure what you're talking about. Your camera has TWO shutters? Why? I'm not saying you're wrong... I've just never heard of such a thing, and cannot understand why it would be beneficial to have two shutters. Here is a high speed video of a Canon 60D taking a photo:

As you can see, the mirror moves out of the way, then the single shutter in the entire camera opens and closes (it has two halves, but they are top and bottom, not "front" and "back," both being at the same distance from the sensor).

If a Sony a65 has two shutters, I would be very interested to know where the "front shutter" is and what its purpose is.


Read and learn Grasshopper, read and learn. How A Typical DSLR Shutter Works
Monk_Emote___Meditate_by_Kitrakaya.gif
 
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Gavjenks

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Yes I am aware. That's why I said it is in two halves (which are much closer together than those diagrams suggest).

Maybe this is what he is talking about, but it doesn't seem like it. He mentioned "having the front [curtain?] left open for speed." Unless I am missing something, this would make little sense, since both curtains moving is not any slower than one moving and then returning to its original position again. In fact, if you only have one shutter, you are limited to SLOWER shutter speeds, since anything faster than your shutter sync speed (1/200th or whatever) would require both curtains.

And either one or two shutter curtains moving would both be so much faster than the mirror and the data transfer bottlenecks that none of it would effectively speed up your shooting FPS or lag time by any reasonable amount.

So why would the Sony have an option of only using one of the two halves of your shutter? I don't see any advantage, but do see multiple disadvantages (limited to sync speed, more complicated mechanism to have the shutter work multiple ways, "whiplash" of a single curtain reversing direction very quickly that might reduce lifespan, etc.)

If instead, there is something sort of like a dust screen or something in between the mirror and the lens, then it might make more sense, but that would be unexpected.
 
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Gavjenks

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Aha, so it is indeed a "Sony thing." That's kinda cool. What disadvantages might there be?
 

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