Dirt on the sensor?

[Mito]

A little up from the centre and to the left there is a grey "splodge". Is this a dirty sensor? The two photos were taken with two separate lenses, one a DA 18-55, the other a Sigma 28-200. The splodge appears at all focal lengths and appertures. Both lenses were cleaned before taking the photos and no PP apart from resizing and a bit of sharpening to accentuate the splodge.


Sigma




Pentax

[Manfred M]

Sure looks like it. Try running two or three cleaning cycles on your camera to see what happens.

[Geoff F]

Rather looks like one of those hard to shake off bits of debris though.

You could try a blower brush on your sensor; but if that fails, you will need a sensor cleaning kit and wipe over the sensor with a swab.

Plenty of cleaning kits available and quite easy to use. Just follow the instructions that come with the kit and your camera manual.

[Manfred M]

Rather looks like one of those hard to shake off bits of debris though.

So far I've managed to get rid of similar sized contaminants with just the repeated cleaning cycle, but you are quite right, if the cleaning cycle does not work, then the next step in investing in a cleaning kit or taking the camera in to have it professionally cleaned.

[DanK]

Yes, I think almost certainly. My approach:

1. Cleaning cycles, as suggested
2. CLEAN (not canned) air--I use a rocket blower
3. Static brush (available from Copper Hill)
4. Wet cleaning

I only go as far down the list as I have to. I use the Copper Hill materials for wet cleaning too. They have good tutorials on line. To find out at each stage whether you have solved the problem, take a shot of this screen at f/22 or smaller (smaller aperture, higher f-number).

[Mito]

Thanks, I'll have a go in the morning. Out of interest do you know what the cleaning liquid is?

[Manfred M]

Thanks, I'll have a go in the morning. Out of interest do you know what the cleaning liquid is?

The kit I used to clean the sensor on my brother-in-law's camera used isopropyl alcohol.

[HAZZA]

Hi Brian,

I had almost the same thing recently and was becoming frustrated in getting rid of it. Eventually I found in my manual a way of closing the mirror which then allowed me to use a blower on the sensor - this solved my problem. The instrucitions were under Senor, Manual Cleaning, in my Canon manual

Hope this helps

[Mito]

Hi Brian,

I had almost the same thing recently and was becoming frustrated in getting rid of it. Eventually I found in my manual a way of closing the mirror which then allowed me to use a blower on the sensor - this solved my problem. The instrucitions were under Senor, Manual Cleaning, in my Canon manual

Hope this helps

Thanks. I've got the instruction manual which explains reasonably well how to clean the sensor.
I've used the anti-dust facility several times and it seems to be getting better. This camera has a self test that checks the sensor for dust and displays an white image with black spots should there be dust. I've tried it and nothing shows up on the camera screen. I'm not going to clean the sensor at the moment, just shake it every now and then to see if it improves. On second thoughts I'll use a blower to see what happens.
Manfred, I've got a bottle of isopropy alcohol so if necessary I'll use that with some lint free swabs.

[DanK]

IMHO, it is worth buying a kit from one of the specialist firms, such as Copper Hill (there are others) because you get an appropriate liquid, truly lint free pads, and an appropriately firm swap to use the pads. The solution Copper Hill uses is Eclipse. The solvent is methanol, rather than isopropyl alcohol, but I assume that probably makes little or no difference.

[Manfred M]

Mito - the kit I used included an illuminated magnifier and I found that to be a necessary tool. Even with lint free swabs there was enough "crap" in the camera's mirror chamber that fell on the sensor (actually the AA filter) and it took some time to get it clean.

Dan - I suspect you are right; the reason to use alcohol is that it evaporates quickly and it does help dissolve some contaminants.

[drjuice]

I discovered, completely accidentally which I will explain momentarily, that a small bump to the camera will sometimes dislodge the bits that seem to be "stuck" to the sensor such that running a couple of cleaning cycles afterward will make the bits truly disappear.

I actually dropped my camera hard enough to mash the UV filter hard enough that I had to use sueded garden gloves to remove it so that I wouldn't cut myself on the shards of glass that the filter had turned into.

Just a (relatively) quick explanation about what seems to cause the bits to attach themselves to the sensors in the first place. Back in the day before I got my DSLR, I had two Minolta Maxxams which use the same lenses as my DSLR and I never had this particular problem with those camera bodies. Upon investigation, it turned out that having the camera body with the lens mount face up even for a couple of seconds while you're switching lenses can allow the dreaded blob to appear. However, I've since done two things. First, I got spare front and rear lens caps (I had to get several different front caps because the diameter of the six lenses differs somewhat). Second, when I'm ready to change lenses, at the very least I get in my car with ALL the orifices closed (windows, fresh air vent, etc., anything that might result in dust being blown inside the car, then let any little dusties already in the car settle down for 5-10 minutes without opening up my camera.

Then, I get the spare lens caps unscrewed from each other and place them with the inside of each one nearest to the surface of the car's console.

Then, I place the lens to be mounted on the camera with the back lens cap removed and the back of the lens nearest to the surface of the car's console. The rear lens cap is placed on the console with the inside closest to the surface of the console.

Next, I push the button and unscrew the presently mounted lens, screwing the spare rear lens cap onto the lens. The cap that covered the front stays on the lens when it is put into its storage case.

While this is going on I keep the camera with the open lens mount face down on the console until I'm ready to mount the "new" lens on it. When I get ready to mount the "new" lens, both it and the camera body are perpendicular to the ground so that the two mounts will be parallel and can't easily get dust inside. It usually takes me less than 2-3 seconds to screw the two units together.

Then, I put the spare lens caps back together and into their pocket. By now, you're probably asking why the extra lens caps. Good thought, it's because sometimes I'll accidentally bump one off the console and onto the passenger seat. I don't want to take the chance of picking up dust from the velour fabric of the seat and introducing it into the camera body.

Since I worked out this procedure, I can't recall having any blobs like the ones you submitted for demonstration purposes.

Hope this helps.

virginia

[Val Mansfield]

A couple of way off comments, if I may.

Firstly I have never attempted to clean a sensor and I hope that I never will. But, if you are going to clean a sensor it sounds odd to me to use a blower that just moves the duct around, some of which may well find its way onto the sensor. Surely it makes more sense to use a vacuum cleaner of some type, though that too may attract dust. I have a little vacuum cleaner that runs off a USB and is designed to clean keyboards, something similar might work.

Like Virginia, I am very particular about how and when I change lenses, as I result I have missed some good shots because I have refused to change lenses in the prevailing conditions. One point Virginia didn’t mention is to turn the camera off before changing lenses. Otherwise the sensor can be charged which will attract dust particles. Obviously, with Virginia’s technique the camera will have switched itself off before the lens is removed.

Which brings me to my second thought. Those of us who go back to film will remember the old black bag that enabled one to open the back of the camera and check on the film etc. The camera went in through a zippered and lightproof opening and the hands went in through holes with elastic cuffs. It seems to me that something similar would be ideal for changing lenses. Not, of course, one made of a dust filled material, but perhaps one made from clear plastic that would allow the coupling marks to be lined up? With that, lenses could even be changed in the rain. I am thinking of having one made up before our forthcoming South American trip, but maybe some entrepreneur type would like to consider producing one?

[Glenn NK]

Dirt on a sensor is part of life - like dirty dishes and underwear, they all need cleaning now and then. One needs to accept it, get on with photography, and stop missing shots.

The newer built-in sensor cleaners will remove some crud, but not always all of it (the first ones were useless).

One can take endless precautions to avoid dust when changing lenses, but it may not do any good because the sensor is not exposed during this process, and the kind of dust that floats in the air might not even stick to a sensor surface, but would be removed by the cleaning mechanism. On another forum, someone said they hold their camera facing downward when changing lenses to keep dust out - I wonder which way the rear element of the lens must be facing.

Lubricant from the mirror bearings being flung onto the sensor surface is probably the most sticky. With a new camera, this is likely to be more problematic until the excess lubricant is "taken care of". And it will likely require a few wet cleanings. And it won't blow off.

If one is concerned about changing lenses in the rain (a completely different problem), then there are solutions; the one I use:

https://www.box.com/s/qf2e1drq6d4rrv5kq9gv

I live near the rainforest - it rains for three months in the winter - and my camera keeps dry.

Glenn

[martinp2502]

I had this problem a while back but fortunately the Auto cleaning on my Canon did the trick. I've tried buying a cleaning kit over here but to no avail so I'll have to wait until I go back to the UK in April. Taking the camera into a dealer over here is not an option, they'd probably use a scouring cloth or hammer and chisel.

[drjuice]

Good point, Val.

I guess I forgot about that because I work with electronics all the time and I always make sure the electrical source is turned off or removed before I fiddle anything on the insides.

ANY TIME I change the configuration of the physical parts of any piece of equipment, I make sure the electricity is off. For example, I have a couple of flash units that I sometimes attach in lieu of using the built-in flash with diffuser attached and the electricity is off for that. Same for removing the memory card when leaving the electricity switched on sometimes makes it necessary to reset the date/time information - this is my version of ultimate tedium!. Certainly, before removing the battery, even if just to put in a fully charged battery, the camera needs to be turned off.

Thanks for the reminder.

virginia

[Manfred M]

Of course, everyone is forgetting the little "air pumps" we install on our cameras called lenses. With the exception of some internally zooming lenses, they push air through the back end of the lens (i.e. blowback), stirring up things inside the mirror chamber while zooming in and out. Several of my lenses have end-to-end travel distances of several centimeters, when I look at the back element assembly . That means that there is a fair volume of air that gets pushed around blowing around and stirring things up, with no guarantee that things will have settled down when I press the shutter release.

[Glenn NK]

Of course, everyone is forgetting the little "air pumps" we install on our cameras called lenses. With the exception of some internally zooming lenses, they push air through the back end of the lens (i.e. blowback), stirring up things inside the mirror chamber while zooming in and out. Several of my lenses have end-to-end travel distances of several centimeters, when I look at the back element assembly . That means that there is a fair volume of air that gets pushed around blowing around and stirring things up, with no guarantee that things will have settled down when I press the shutter release.

Manfred:

Very good point - it is significant. Every time the lens increases in length (volume), it draws in a fresh batch of outside air.

I have three zoom lenses:
17-55: changes length by 28 mm, and the rear element moves in and out approx. 15 mm.
24-105: changes length by 32 mm, and the rear element moves in and out approx. 15 mm.
70-200: doesn't change length and the rear element doesn't move.

Assuming that a sensor has a static charge, turning the camera off may not help - static charges don't dissipate quickly.

Electronic flashes utilize a capacitor on which a static charge is built up an is stored - turning the switch off doesn't release the charge.

The type of dust that is everywhere (what one sees in a sunbeam) doesn't fall - it floats freely in all directions - pointing an open camera downward won't help to keep it out.

A self-cleaning sensor is the first line of defense; being able to manually clean a sensor is essential.

Strangely enough, I haven't found anything in the camera manuals that suggests turning the camera off during lens changes. Changing cards or batteries is an entirely different matter.
Glenn

[xpatUSA]

Of course, everyone is forgetting the little "air pumps" we install on our cameras called lenses.

Yes, just discovered this wonderful effect on a Nikon D50 with an 18-55mm kit lens. After shooting inside and outside a house for sale, involving much zooming in & out, I now have a big dust speck inside the viewfinder "penta-mirror" assembly - completely impossible to remove by normal means.

My solution - it's up on eBay, with full disclosure of course.

BTW, is "penta-mirror" the correct term for that cheap-skate viewfinder mirror arrangement?

[Manfred M]

Strangely enough, I haven't found anything in the camera manuals that suggests turning the camera off during lens changes.
Glenn

Glenn - Nikon certainly recommends turning of the camera before changing lenses. Pg 25 on my D800/D800E manual says: "Be sure the camera is off when removing or exchanging lenses". I seem to remember the D90 manual having a similar statement.

I don't know about static charge build up on the sensor. That would be something that the manufacturers would want to eliminate in their design work; having a sensor acting as a dust magnet would not be a brilliant piece of engineering. Electronic circuits are easily damaged by static discharge, so I suspect that this is a non-issue.