DSLR Sensors and Dust

snerkler said:
Well every article I've just looked at suggests that the image will be flipped upside down and left to right. How do you explain it flipping one way but not the other then? If light from the top passes through and ends up at the bottom then surely the same happens from the sides?
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Doh.... have I humbled myself prematurely? Hold a lens to a well lit subject and you will see left/right top/bottom inversions :)
 
Well out of curiosity I decided to soak it, 3 swabs to really be sure and it's still there. I can see it! Can't be dust, I've been cleaning my sensors for years.

Thing is, was it there before I sent it to Nikon for a repair? Can't be sure, I haven't got any very recent images shot at a small enough aperture. Seems to be a little cursed this particular camera.
 
chuckles said:
Doh.... have I humbled myself prematurely? Hold a lens to a well lit subject and you will see left/right top/bottom inversions :)
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I don't know, that's why I'm asking. I've looked at several articles all saying upside down and flipped left to right, several with diagrams that I vaguely remember from physics back in my school day. But typically I've just seen one article that says upside down only. It's very difficult to get a definitive answer. My guess for the confusion is a number are stating basic physics, single converging lenses and pinhole cameras and maybe light in a DSLR etc is not captured the same way?
 
Livin The Dream said:
Seems to be a little cursed this particular camera.
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And thus a dilemma. Do you clone out the spot from every image that you keep? Or do you decide to give up the battle by selling the camera - and if so do you disclose the problem?
 
snerkler said:
My guess for the confusion is a number are stating basic physics, single converging lenses and pinhole cameras and maybe light in a DSLR etc is not captured the same way?
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It passes through the lens in exactly the same way as most other cameras. The lens is the only intervention between subject and film or sensor. Think of the light path as a diagonal.
 
snerkler said:
I don't know, that's why I'm asking. I've looked at several articles all saying upside down and flipped left to right, several with diagrams that I vaguely remember from physics back in my school day. But typically I've just seen one article that says upside down only. It's very difficult to get a definitive answer. My guess for the confusion is a number are stating basic physics, single converging lenses and pinhole cameras and maybe light in a DSLR etc is not captured the same way?
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Yes, the image is inverted and laterally transposed by the lens, but you reverse the transposition when you, in effect 'turn your back to the subject' and look directly at the sensor. In doing that, right and left become reversed. (And to repeat, you're not looking 'through' a piece of film.)

I did say not to think about it too much - just try that little experiment and all will become clear.
 
HoppyUK said:
Yes, the image is inverted and laterally transposed by the lens, but you reverse the transposition when you, in effect 'turn your back to the subject' and look directly at the sensor. In doing that, right and left become reversed. (And to repeat, you're not looking 'through' a piece of film.)

I did say not to think about it too much - just try that little experiment and all will become clear.
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I think we're saying the same thing in essence. The image is captured inverted but the image is only flipped upside down from this to give us the final image, therefore dust on the left will be on the left on the displayed image? However, is that looking at the sensor from the the front of the camera, or from the bac of the camera ;) :p
 
snerkler said:
I think we're saying the same thing in essence. The image is captured inverted but the image is only flipped upside down from this to give us the final image, therefore dust on the left will be on the left on the displayed image? However, is that looking at the sensor from the the front of the camera, or from the bac of the camera ;) :p
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Apology accepted :)
 
Let me clear all this up. Speaking as an expert with more than 30 years experience in this field, I'm not one, but I can put on the patronising voice. When you take a picture of, say, your lady friend, and you get your pictures back from the chemist, your lady friend is, as you'd expect, the right way up. But what you probably don't realise is that, in the camera, the picture is actually, what we, scientists call, arse backwards. Now, to the untrained eye, this may all sound unbelievable. But that is actually how it works. So when the chemist develops your pictures, they are in fact upside down and backwards. But here comes the trick that may surprise you. When he hands the pictures to you, he turns them the other way up! Amazing, I know. Dashed clever those chemists.
Anyway, how does it work for digital pictures, I hear you ask. You can't turn you PC screen upside down can you? And this is where those cunning Japanese boffins are one step ahead of you. When they actually assemble the cameras, the sensor, or "magic eye" of your camera if you will, now pay attention to this bit, is put in.. upside down! Brilliant! Yet so simple.
 
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ianp5a said:
Let me clear all this up. Speaking as an expert with more than 30 years experience in this field, I'm not one, but I can put on the posh BBC voice. When you take a picture of, say, your lady friend, and you get your pictures back from the chemist, your lady friend is, as you'd expect, the right way up. But what you may not realise is that, in the camera, the picture is actually, what we, scientists call, arse backwards. Now, to the untrained eye, this may all sound unbelievable. But it is actually true. So when the chemist develops your pictures, they are in fact upside down and backwards. But here comes the trick that you probably didn't realise. When he hands the pictures to you, he turns them the other way up! Amazing, I know. Dashed clever those chemists.
Anyway, how does it work for digital pictures, I hear you ask. You can't turn you PC screen upside down can you? And this is where those cunning Japanese boffins are one step ahead of you. When they actually assemble the cameras, the sensor, or "magic eye" of your camera if you will, now pay attention to this bit, is put in.. upside down! Brilliant! Yet so simple.
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^^^^^ Bit radical isn't it? ^^^^^
 
ianp5a said:
Yes. It's amazing what science can do.
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Yeah.... it's also amazing how useless Google is in trying to find an image of a plate camera with a view including the subject AND the ground-glass screen!
 
I've not read through the entire post so forgive me if this has been covered, this is just a reply to the OP. I've had my 6d now for 2 years and not once felt the need to wet clean! Its still dust free, I only ever have to use a rocket blower if I see any.

There's a lot of paranoia about sensor cleaning and quite often people wet clean when they don't really need to, which is dangerous as you could cause damage to the sensor / filter.

Thats not to say sometimes it won't need it, professionals changing lenses multiple times every day will need to, but the average amatuer should be able to just blow the dust off.
 
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odd jim said:
I've not read through the entire post so forgive me if this has been covered, this is just a reply to the OP. I've had my 6d now for 2 2 years and not once felt the need to wet clean! Its still dust free, I only ever have to use a rocket blower if I see any.

There's a lot of paranoia about sensor cleaning and quite often people wet clean when they don't really need to, which is dangerous as you could cause damage to the sensor / filter.

Thats not to say sometimes it won't need it, professionals changing lenses multiple times efery day will need to, but the average amatuer should be able to just blow the dust off.
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Well, excuse you for getting the thread back on track ;)

The only time I've found a wet clean necessary is when the "dust" is, in fact, sticky pollen grains!
 
Gaz J said:
I just clean the whole sensor. No thought required and my brain doesn't hurt. :)
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Likewise, I don't need to know exactly where a dust spot is. If I've cleaned the sensor properly it doesn't matter :p
 
Right, here's against the white ceiling. Not sure what is to be gained from this Bill, looks quite similar but somehow there are some dust spots for reference which clearly look a little more solid. The mark seems to have a little less body. It blows out before the dust. This shot was taken after a swab last night as you can still see residue on the bottom of the frame. I have cleaned all the dust out just with the eyelead but this mark still persists.

 
realspeed said:
As I have said before A loupe should be an essential part of a photographers kit.

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But if you already know exactly where the dirt actually is, how is it helping?
 
Livin The Dream said:
Right, here's against the white ceiling. Not sure what is to be gained from this Bill, looks quite similar but somehow there are some dust spots for reference which clearly look a little more solid. The mark seems to have a little less body. It blows out before the dust. This shot was taken after a swab last night as you can still see residue on the bottom of the frame. I have cleaned all the dust out just with the eyelead but this mark still persists.

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Looks a bit of an oily spot to me that. I had one similar on delivery and my sensorklear pen did the trick.
 
snerkler said:
Looks a bit of an oily spot to me that. I had one similar on delivery and my sensorklear pen did the trick.
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Just ordered a sensor pen. I literally must now have every device ever invented for cleaning sensors, apart from a loupe ha! I guess it could be oil, hope so.
 
Livin The Dream said:
I guess it could be oil, hope so.
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If it IS oil (which I'm surprised is still there if you've wet cleaned it) those `dabbers` can spread it around & make a mess.

This was the result after a mate tried cleaning oil from his D7000 sensor. tbh there was more than 1 oil spot, but they were smeared/spread, not lifted.

(contrast & colour adjusted to show how bad it was)

2nbg2tz.jpg
 
Did wonder about the smear effect and, like you, surprised a wet swab didn't move it around at least. Getting desperate so try this as a last resort before contacting Nikon. Mine body has spent more time with them than me, or so it seems,
 
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OldCarlos said:
If it IS oil (which I'm surprised is still there if you've wet cleaned it) those `dabbers` can spread it around & make a mess.

This was the result after a mate tried cleaning oil from his D7000 sensor. tbh there was more than 1 oil spot, but they were smeared/spread, not lifted.

(contrast & colour adjusted to show how bad it was)

2nbg2tz.jpg
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It does sometimes spread but you just go over it again, no different to getting fingerprints off a lens ;) Mine was absolutely crystal clear afterwards but of course YMMV.

One thing I've found is that the sensorklear does leave carbon? deposits after you cleaned with it so you always need to give it a good blow with a rocket blower after using it.
 
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Livin The Dream said:
Did wonder about the smear effect and, like you, surprised a wet swab didn't move it around at least. Getting desperate so try this as a last resort before contacting Nikon. Mine body has spent more time with them than me, or so it seems,
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Just make sure it's the sensorpen and not lens one ;)
 
Livin The Dream said:
Yes, definitely the sensor one. I have a lens one already.
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Like any time you use something that touches the sensor make sure you've give it a good blow with a rocket blower so that there's no debris that could potentially scratch the sensor.
 
snerkler said:
It does sometimes spread but you just go over it again, no different to getting fingerprints off a lens ;) Mine was absolutely crystal clear afterwards but of course YMMV.

One thing I've found is that the sensorklear does leave carbon? deposits after you cleaned with it so you always need to give it a good blow with a rocket blower after using it.
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I was referring to those gel-sticks, which won't really lift oil.

OldCarlos said:
If it IS oil (which I'm surprised is still there if you've wet cleaned it) those `dabbers` can spread it around & make a mess.
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StewartR said:
At LensesForHire, we make sure the sensor is dust free every time a camera goes out on hire. So that's a lot of sensor cleaning. My experience is that the on board sensor cleaning functions on Canon DSLRs are *much* more effective than those on Nikons.
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This is excellent to hear I've been think if hiring a second body maybe a D750 or D7200. It would be next year for the big air show at Fairford but will be in contact before then!
 
I use my rocket blower to suck and blow away the dust on the lens and body sensor. I remember one time I was taking some sample images at home and I realise I'm getting a big black dot on the image. At 2.8 it does not appear but f4 onwards it is very obvious and I thought my sensor had problem. After detaching the lens and put the camera in cleaning mode I realise some carpet material is on my sensor, so I sucked it out using the rocket blower and problem solve.
 
badboy1984 said:
I use my rocket blower to suck and blow away the dust on the lens and body sensor. I remember one time I was taking some sample images at home and I realise I'm getting a big black dot on the image. At 2.8 it does not appear but f4 onwards it is very obvious and I thought my sensor had problem. After detaching the lens and put the camera in cleaning mode I realise some carpet material is on my sensor, so I sucked it out using the rocket blower and problem solve.
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Just a note on this. Rocket blowers, eg Giottos, don't suck. They only blow, and have a valve in the other end for refilling with clean air.

However, they can suck up a tiny amount of dirt before the valve closes fully, if you're foolish as I was when blowing away some fine sawdust on a DIY job. I noticed it when cleaning a lens and it seemed to be getting more dust on it than less. So I pulled the blower apart and gave everything a good wash, then left it a couple of days to dry thoroughly.
 
HoppyUK said:
But if you already know exactly where the dirt actually is, how is it helping?
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With a loupe you don't have to think about reverse image and guess where the dirt is. It is where you see it in the loupe. Also having the LED lights really help in checking for anything else on the sensor. You don't have to keep going back and forward checking to see if dust has gone via the camera lens either.



A bonus is there is also a 7x magnification . I would add that if anyone is in East Sussex or near they are most welcome to come and use mine here and the Artic butterfly brush
 
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realspeed said:
I would add that if anyone is in East Sussex or near they are most welcome to come and use mine here and the Artic butterfly brush
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As long as there's no oil! :D

(I tried cleaning what turned out to be oil spots on my D7000 3 or 4 years ago, with the AB :rolleyes: Took a bit of cleaning in isopropyl to get the brush clean again)
 
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Update: so I got the sensor klear brush today and gave the mark a good going over, won't budge! Bugger! Now there clearly is a problem.
 
Hopefully not a serious problem/damaged sensor, but thinking back to what you said earlier;

Livin The Dream said:
It's been to Nikon recently but can't prove whether it was there before or not?
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What did you send it in for initially? (light bleed jobby?)

Also, not expecting it to be the case, but have you checked the serial #'s on the body since you got it back? (always a slim chance you got a different body returned)
 
I had that rectified on a separate occasion. I had the catch on my tripod fail and it fell no more than a metre, in my living room. Didn't think it would have done much but the weight of the 14-24 damaged the lens mount so had that replaced and AF realigned. £270!
 
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