When I went over to Micro Four Thirds around 5 years ago, there was one unexpected bonus. Dust and dirt on the digital sensor ceased to be a problem. I was very happy about that. It had always irked me a bit with my DSLR, that dark blobs would appear on my pix, particularly noticeable on large plain areas such as a clear blue sky. I had the sensor professionally cleaned now and again but it annoyed me forking out £40 or more each time.
With film, of course, every frame is a new sensor and freshly installed in position from the cassette, so dirt and dust isn’t a visual problem at all.
On a DSLR there’s a mirror and shutter between the sensor and the world so I reckoned that muck would be a headache with my new Micro Four Thirds bodies, given that the sensor faces the elements directly when the lens is changed. Plus, any particles on the rear of a lens when fitted on the body can just fall straight on to it .
I was pleased to find I was wrong and that a dirty sensor was, judging by my results, a thing of the past. I didn’t know why and put it down to the automatic sensor cleaning routine operating on start-up and the extra care I took when changing lenses. In particular air dusting the lenses frequently and holding the camera maw facing downwards during the un-bayonet/ bayonet routine.
But then I bought an Olympus macro lens, of necessity stopping it down to f/22 for depth of field sometimes – and hang the diffraction. And suddenly there they were, the little bas****s, the devil’s blobs. I was about as pleased to see them as I was a scratch on a new Steely Dan album in the 70s.
I bought some very expensive swabs and paddle things but was loath to use them because of all the dire warnings of terrible damage to the sensor. Then I read that that the sensor itself was covered with glass for several reasons, among them presumably, protection
It all seemed a little less dangerous so I used a blower, swabs and paddle thingies now and again to budge the stuff the built in high frequency sensor cleaning routine didn’t shift. It never got rid of everything but it made a reasonable job of it. I’m not a fussy person and I rarely open up a lens beyond f/4 anyway. Nonetheless, it niggled me that I couldn’t clean it properly. Having seen cleaning being done in a camera shop, there’s nothing magic to it. They didn’t have any special equipment that I didn’t, apart from a loupe with LEDs built in.
Then, while fitting the 12-40mm Olympus Pro lens to my little GM1, I lost my grip on the camera and it slipped out of my hands – with no lens on it, of course. I caught the GM1 one handed as it dropped. Being one handed, I clawed at it to stop its fall. My thumb went to the back and one finger finished my pincer movement neatly and luckily gently. Excellent! I had caught it. Less excellent, I had caught it by the back and…..sensor.
I could see my paw mark with my naked eye. A beautiful clearly delineated 3rd finger print worthy of Scotland Yard itself. Smack bang on the GM1’s delicate little sensor. Great! Now I would be shooting pictures with an £800 piece of state of the art optical design – but focused onto what looked like the greasy bottom of an unwashed frying pan.
I tried to clean it with those paddle things and a drop of cleaning fluid. It worked ok but still didn’t look right, certainly not perfectly clean. And I’d run out of paddle swabs and cleaning fluid. So I put a cap on the camera body and sent for an LED equipped loupe like the big boys have. I was a bit shocked by what it revealed. There were a few little dots of dust or pollen or whatever, nothing to particularly worry about. But there were also smears to be seen. The beauty of the loupe is that you can clearly see all the grease and grunge on the sensor. It’s not a pretty sight.
So , another professional clean then? After all, the swabs and paddles hadn’t done the job and I wanted the sensor spotless. Then, trawling around the net for ideas, I saw someone who swore by Q Tips, generically, cotton tips or buds and isopropyl, which I use for cleaning lenses and electrical contacts. Since I was going to send the camera away anyway, if I didn’t use violence on the sensor, I wasn’t going to do anything that couldn’t be undone by the professionals. So I gave it a try.
I put a tiny amount of the isopropyl cleaning fluid on a cotton bud and went for it. Using the loupe, seeing what I was doing was easy and light rubbing removed the grease and the spots very effectively. I was very pleased to see the spots go, because I think they were probably sticky pollen and the camera’s sensor cleaning routine has no effect on that at all.
My cotton bud did, however, leave a few streaks. A light to and fro with a fresh dry cotton bud got rid of those without trouble leaving one tiny fibre which a quick blow from my Giottos Rocket Blower made short work of, leaving me with a sensor with two tiny spots visible only lightly at f22 on a white surface. I contemplated running the GM1 through the dishwasher to be certain of eradicating them but it seemed a bit extreme. Maybe the Karcher pressure washer? A new GM1? That’s a it like changing your car because the tyres need pumping up. Maybe just live with it?
I wonder if it is possible to get a completely and utterly clean sensor? Maybe there’s a point at which you have to say that good enough is good enough? Certainly, a sensor which looks pristine to the naked eye is less so when looked at through a loupe(UK)/(USA).
It’s like pixel peeping. You have a razor sharp lens, you’re delighted with it and then you look at 100%. Or even 200%. OMG! If I make a print 6 feet across it won’t be razor sharp viewed from 6 inches! I’m reminded of an old Tommy Cooper joke where he goes to the doctor and tells the doctor “doc, it hurts when i do this”. And the doctor replies, “well, don’t do that!”.
If you stop a lens down to f/22 and then photograph a sheet of out of focus white paper and g and there are a few dust bunnies to be seen, maybe the answer is, as the doc says, “well, don’t do that”. Certainly, the spots I’m talking about aren’t visible in normal use. Do they matter? I suppose not. Trouble is, thanks to the loupe, I know they’re there.
The funny thing is that film negatives regularly got scratched in handling and filing. The answer to that was the pole opposite to cleaning a sensor. You’d rub your finger over the top of your nose and then rub it over the scratches. Hid them beautifully. Don’t try that on your E-M1, though.
Like all good stories (and this one), there is a moral point to it. As happens so often, Confucius put it well – “Wise photographer never look at sensor through loupe”.
And please, please note – I am not recommending my method. Using cotton buds and isopropanol comes in at about 1/1000th the cost of professional cleaning. It is only for cheapskates and chancers like me.