Dust spots

GeoffColl

GeoffColl

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Geoff
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I've had various Fuji cams, from the S3Pro to X series and I can honestly say there's been very few images taken that display dust spots, providing I keep the lens and/or filter clean.

I've had a Sigma Quattro SD for just about a year, initially intending to use it for IR, but it seems to have become my goto for Landscapes.

However, in spite of not changing lens, I seem rather plagued with dust spots on the sensor. Given my Fuji experience I inadvertently thought the Foveon sensor was faulty! Comments on another website were telling!

Question, therefore, if I might ask - what are your software tips for identifying said spots in your images. I use SPP and Affinity Photo, but any tips are sought.

Many thanks

Geoff
 
I do regular out of focus test shots of a white door at minimum aperture. If anything shows up I might then take a series of shots gradually opening the aperture and then decide if it's worth cleaning the sensor or not.

I prefer testing and cleaning to cloning out contamination in pictures.
 
One way to do it Alan, thankyou.
Except I did that once I discovered there was a problem, first dozen shots were clean then gradually the motes started appearing, perhaps the sensor needed a bit of charge to make the motes popup?
 
GeoffColl said:
One way to do it Alan, thankyou.
Except I did that once I discovered there was a problem, first dozen shots were clean then gradually the motes started appearing, perhaps the sensor needed a bit of charge to make the motes popup?
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I've never heard of that happening before.

Years ago I remember reading that most sensor contamination is generated internally by the cameras moving parts and I suppose that's easy to understand with flappy mirror mechanisms. I also remember Nikon had an issue with mirror mechanisms spraying oil onto the sensor. These days the only moving part is I suppose the shutter but I suppose your Sigma could be a worse than usual camera for this?

My mirrorless cameras are Panasonic and Sony and they rarely show contamination despite me doing multiple lens changes and often when out and about and I'd expect other mirrorless cameras to be good in this regard too.

Maybe Googling the issue might shed some light on if the Sigma is particularly bad for this or not?
 
There were a few comments made after the camera had been out a while, that it might be flecks shedding from the shutter mechanism. But it's certainly caught me by surprise.

Now just need to find a sensible software trick that can show them up.
 
Shoot a couple out of focus pictures of a pale surface at the narrowest aperture possible. Once the file is in the computer, ramp up the contrast as high as possible and compare the files. Any blobs in the same place will almost certainly be dust bunnies (or similar).
 
SFTPhotography said:
100% - soon as I have 1 or 2, I get mine cleaned. I cannot abide sensor dirt and truth be told it's one of the reasons I am reluctant to go mirrorless.
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With canon mirrorless the problem is less bad as when you switch off the camera to change lenses, a protective shutter comes over the sensor.
 
SFTPhotography said:
100% - soon as I have 1 or 2, I get mine cleaned. I cannot abide sensor dirt and truth be told it's one of the reasons I am reluctant to go mirrorless.
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I was a bit worried about this but I suffer much less contamination than in my DSLR days but having said that I think that sensor coatings have probably got better throughout the industry so maybe todays DSLR's are better than the old Canon DSLR's I had. I have to say that the 5D in particular was just awful for contamination.

One thing to possibly consider could be that mirrorless cameras don't have the mirror mechanism with all the possibility that brings for shedding material and spraying oil about. When I get the time for photography I do a lot of lens changes and I'll change lenses anywhere but even so I very rarely need to clean a sensor.
 
woof woof said:
I was a bit worried about this but I suffer much less contamination than in my DSLR days but having said that I think that sensor coatings have probably got better throughout the industry so maybe todays DSLR's are better than the old Canon DSLR's I had. I have to say that the 5D in particular was just awful for contamination.

One thing to possibly consider could be that mirrorless cameras don't have the mirror mechanism with all the possibility that brings for shedding material and spraying oil about. When I get the time for photography I do a lot of lens changes and I'll change lenses anywhere but even so I very rarely need to clean a sensor.
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That is true - but the mirror acts as a gaurd when the camera is off and when the lenses are being swapped. But yes - oil spots etc on DSLR's happens. I've seen it on my D850, 645z, D610 and D810 (once).

Extending barrel zooms, even some internal zooms, pump dust into the sensor area. The mirror helps offset that.

Feedback from workshop clients with mirrorless bodies is that this is an issue. The Nikon Z9 with it's sensor gaurd will probably offset the problem. Basically there is a blind over the sensor except when you are taking pictures.
 
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SFTPhotography said:
Nikon are getting there with this on the Z9 - Sony nowhere and Fuji GFX not sure.
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The Sony A7iv shutter can be set to come across when lens is removed, in my opinion it makes things worse, I think there is a bit of static on the blades which attract dust and then it is thrown about inside later.
 
SFTPhotography said:
Feedback from workshop clients with mirrorless bodies is that this is an issue. The Nikon Z9 with it's sensor gaurd will probably offset the problem. Basically there is a blind over the sensor except when you are taking pictures.
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I don't know how much a sensor guard will help as if anything lands on it the chances are that when you attach the lens and the camera starts working again whatever was on the guard will be flying around inside the camera unless it's stuck and stays on the guard but even then it could I suppose detach and work its way onto the sensor.

It's a genuine mystery to me why some people have a lot of problems and some like me who'll change lenses anywhere and everywhere don't. For example I've done multiple lens changes on Saltburn beach and in the countryside where I live with vastly fewer issues than I had with those old Canon DSLR's.

I suppose there could still be cameras that suffer more and cameras that suffer less and I suppose being brutally honest lens changing and gear handling technique could be an issue for some people.
 
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My Sony A7III collects much less dust than my D610 did, presumably a different coating.

To answer the OP, there's a feature in the spot removal tool for revealing dust spots. The only real weakness is that it doesn't work for mono.
 
woof woof said:
I don't know how much a sensor guard will help as if anything lands on it the chances are that when you attach the lens and the camera starts working again whatever was on the guard will be flying around inside the camera unless it's stuck and stays on the guard but even then it could I suppose detach and work its way onto the sensor.

It's a genuine mystery to me why some people have a lot of problems and some like me who'll change lenses anywhere and everywhere don't. For example I've done multiple lens changes on Saltburn beach and in the countryside where I live with vastly fewer issues than I had with those old Canon DSLR's.

I suppose there could still be cameras that suffer more and cameras that suffer less and I suppose being brutally honest lens changing and gear handling technique could be an issue for some people.
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I think most spots are actually skin flakes from house dust and pollen so maybe less of those on a beach.
But I have rarely need to touch my Sony mirrorless whereas 5dii needed full wet clean about once a month.
A blower helps if you have it and use it around the mount before opening..
But above all get everything ready and positioned to swap in like 5 seconds or less, keeping the opening pointing down.
Get the marker spot visible so there is no delay or fumbling.
 
My daughter mentioned the curtain on the R7. So the curtain won't shed onto the sensor....:exit:
 
4wd said:
I think most spots are actually skin flakes from house dust and pollen so maybe less of those on a beach.
But I have rarely need to touch my Sony mirrorless whereas 5dii needed full wet clean about once a month.
A blower helps if you have it and use it around the mount before opening..
But above all get everything ready and positioned to swap in like 5 seconds or less, keeping the opening pointing down.
Get the marker spot visible so there is no delay or fumbling.
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I turn the camera off and get the replacement lens ready by loosening the end cap. I turn away from any breeze, point the camera downwards and take the lens off the camera and put it straight down or in the bag, pick up the replacement and fit it and then sort out the lens I've just taken off. Being able to change lenses is perhaps a part of the reason we buy this kit so it's a shame to limit lens changes or even dread it.
 
woof woof said:
I turn the camera off and get the replacement lens ready by loosening the end cap. I turn away from any breeze, point the camera downwards and take the lens off the camera and put it straight down or in the bag, pick up the replacement and fit it and then sort out the lens I've just taken off. Being able to change lenses is perhaps a part of the reason we buy this kit so it's a shame to limit lens changes or even dread it.
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I would have thought it's better to change lenses outdoors? When I look through a sun ray across the rooms in my house, it's full of floating tiny house dust that you can't see usually.

I would have thought the outside air was "cleaner" in this respect ?
 
Just to expand on what other people have said about taking a test shot(s) of a pale surface. At a small aperture and the lowest ISO you will probably have a long shutter speed, so move the camera during the exposure and any sensor dust spots will show up while any spots that are on the pale surface will blur out and not be noticeable.
 
Crotal Bell said:
I would have thought it's better to change lenses outdoors? When I look through a sun ray across the rooms in my house, it's full of floating tiny house dust that you can't see usually.

I would have thought the outside air was "cleaner" in this respect ?
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Yes, I suppose there's a lot for floating dust indoors but outdoors there may be more sticky stuff so I suppose the dangers could balance out?

Just to be safe I always take the same precautions no matter where I am.
 
Suvv said:
Just to expand on what other people have said about taking a test shot(s) of a pale surface. At a small aperture and the lowest ISO you will probably have a long shutter speed, so move the camera during the exposure and any sensor dust spots will show up while any spots that are on the pale surface will blur out and not be noticeable.
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Yup. I go for a speed of several seconds and I wave the camera about whilst the shutter is open to prevent the camera recording any detail present on the surface. I also make sure that the camera is focused at infinity whilst the camera to surface distance is short, again to lessen the chance of detail being recorded at small apertures.
 
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