Beginner dust on photos but not visible on sensor ?

Messages
10
Name
Michal
Edit My Images
Yes
#1
Hi
I have dark spots on photos. Always in the same places. I will try to attach an example photo of a blue lion. You can see the spots all over top and left edge.
After reading some, I am convinced that they are sensor dust.
However, after locking the mirror for cleaning (Nikon D3500) and inspecting the sensor under bright light, there is none there. The entire square is spotless, perfectly clean without even tiniest particle on it.
What can I do?
https://photos.google.com/share/AF1...?key=dFBQOUpuZUphNkh1dmZySS1xY0lnbkhQYjRZX0JR

This is frustrating because blue lions are quite rare and my photos are ruined... ;-)
 
Last edited:
Messages
33,634
Edit My Images
No
#3
Just looks like 'dust bunnies' on the sensor to me ... needs a more effective clean.
Of course the marks can easily be cloned out of the picture.
 
Messages
3,815
Name
Terry
Edit My Images
Yes
#6
It'll be the sensor and it's right you won't see them with the naked eye.

Do a wet clean on the sensor.

It's not difficult or expensive to do it yourself.
 
Messages
20,523
Name
Alan
Edit My Images
No
#7
I'll assume this is a serious post and that I'm not wasting my time typing this...

Again, the sensor is flipped top to bottom but not right to left so a dust bunny in the top right of the picture is on the bottom right of the sensor.

I've found that you often can see dust bunnies on the sensor with just your unaided eye but you have to get the light and the angle of view just right and they can be easy to miss. All in all I think it's best to believe what you're seeing on the photo and assume they're there even if you can't see them by unaided or even aided eye. I have had contamination on the back of the lens cause this but in those instances they were relative boulders and it's much more likely that bunnies appearing in pictures are caused by contamination on the sensor.

The first thing to do IMO is to activate the cameras sensor cleaning system, if it has one. The next line of attack should be a rocket blower and if that doesn't do the job a wet clean is next. I use a drop of eclipse fluid on a pec pad wrapped around a slice cut from an old credit card.

Hope you can sort it.
 
OP
OP
M
Messages
10
Name
Michal
Edit My Images
Yes
#8
Thank you very much!
I did not realize that the dust pieces can be so small that I would not be able to see them.
Also, I was focusing at the wrong part of sensor.
I looked again at the sensor and can see nothing on it.
I will acquire the blower and give it a go.
Thank you for now. Will get back to you.
 
OP
OP
M
Messages
10
Name
Michal
Edit My Images
Yes
#9
looks like the lens is dirty to me :(
I thought so. There was quite a bit of visible particles on glass. I cleaned the front and back of the lens with damp cotton cloth.
Glass was looking spotless then but outcome on photos did not change.
 
Messages
2,122
Edit My Images
Yes
#11
It's unlikely to be the lens, the sensor cleaning routine should be try a blower and the inbuilt cleaning cycle if present, then think about swabs.
It's not something to be scared of provided you have reasonable eyesight and steady hand.
Even if not changing lenses regularly a wet clean is likely to be required at least couple of times a year unless you like cloning.
A common sticky 'dust' particle is pollen which is gong to be very hard to see.
 
Messages
23,194
Name
Phil
Edit My Images
No
#12
I thought so. There was quite a bit of visible particles on glass. I cleaned the front and back of the lens with damp cotton cloth.
Glass was looking spotless then but outcome on photos did not change.
It won’t be the lens;
The surfaces of the lens are well out of focus on your image.
It’s on your sensor, and of course they’re tiny
 
Messages
6,064
Name
Terry
Edit My Images
Yes
#13
I thought so. There was quite a bit of visible particles on glass. I cleaned the front and back of the lens with damp cotton cloth.
Glass was looking spotless then but outcome on photos did not change.
Even a heavily dirty lens does not show as spots in the image. Tt the worst it just lowers the contrast a tad, or makes them look a little smeary. in most cases it is not even noticed.
Even the smallest dust on the sensor shows as spots in the image.
 
Messages
6,064
Name
Terry
Edit My Images
Yes
#14
Some thing to be wary of with a dusty lens, especially in the inside of the back of it. is that the lens can act like a blower when zoomed and focused (some sorts worse than others)
And then deposit that dust inside the camera and on to the sensor. so from time to time, spend time cleaning your lenses.
Older lenses from the film days are often the worse for that, as it was not an issue then.
 

Nod

Krispy and Kremey
Messages
32,601
Name
Nod (NOT Ethel!!!)
Edit My Images
Yes
#15
It’s on your sensor, and of course they’re tiny
If you take an old 6MP sensor (just because the maths is easy!) which is 2000 pixels/photosites deep and 3000 wide. The physical measurements are 24mmx16mm (6MP and the mm dimensions are marginally different - I've rounded them for easier maths). 16mm divided by 2000 means that each pixel is just 0.008mm square. Now have a look at an affected image at 100% and see how many pixels are affected per spot and multiply the width by 0.008 and that's the size of the particle causing the problem.
 
OP
OP
M
Messages
10
Name
Michal
Edit My Images
Yes
#16
If you take an old 6MP sensor (just because the maths is easy!) which is 2000 pixels/photosites deep and 3000 wide. The physical measurements are 24mmx16mm (6MP and the mm dimensions are marginally different - I've rounded them for easier maths). 16mm divided by 2000 means that each pixel is just 0.008mm square. Now have a look at an affected image at 100% and see how many pixels are affected per spot and multiply the width by 0.008 and that's the size of the particle causing the problem.
i am actually using the S setting which is probably 6MP. mu photos are 3000 pixels wide.
the spots are 30 pixels across. (0.25 mm?)
as 4wd mentioned pollen, i must say that my favorite subject is blooming flowers so perhaps contamination occurred.
 

Nod

Krispy and Kremey
Messages
32,601
Name
Nod (NOT Ethel!!!)
Edit My Images
Yes
#17
Pollen can be a PITA to get rid of too. It tends to be sticky so a blower often can't shift it so a wet clean could be the only solution.

TBH, I'd expect 0.25mm specks to be visible with the naked eye as long as the eyesight's good enough (with correction if needed). A loupe will almost certainly let you see the dust.
 
Messages
7,365
Name
Jeff
Edit My Images
No
#19
Best way to see the dust on the sensor is to stop right down f11 or f13 and take a shot of a blue or grey sky . This will really blow your mind ,then do a wet clean
 
Top