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Old Jul 28, 2006, 7:55 AM   #1
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I'm leaving out for a trip very soon and don't have time to buy a Gitto rocket blower. I was adjusting my XT's diopter last night with focusing on my laptop screen with eye chart like word documant. Then I thought I'd check to see if there was dust on my sensor (the camera is about 1.5 months old and I've changed lens a couple times for testing purposes, maybe 4 times total and have tried to be careful).

Anyway at F13 which is about the diffraction limit of the camera the dust is visible on a complete white shoot (laptop screen w/ paper infront of it and flash). At F32 I can clearly see the dust. I would say I have about 1 or 2 dozen (tops) very small dust particles on the sensor. About 2-4 of these are modestly big.

It doesn't look all that bad and I wouln't use F32 for sure. F13 is about as small as I would ever want to go due to diffraction and hopefully that will be enough DOF.

My question is how much of an issue will this be in real life shots? I realize that it will show in the blue sky shots but what about the rest of the image, if a landscape, such as trees, grass, buildings, lakes, etc. Is it easily visible?

I will not have the equipment or time to clean the sensor before my 2 week trip. I just want to anticipate how much PP work I may have to be doing when I get back. I plan to have around 1400 photos (120 a day for 12 days) when I get back.

I have not noticed the dust in any of my realife shots yet, but then again these were mostly f2.8-f5.6 anyway. On my trip I plan to do some street, city, and landscape shoots and thus will be in the f8-f13 range. Anyone with experience on the dust issue that can help me will be appreciated. Should I worry or not? BTW, I will NOT be changing lenses. I only have the tmron 17-50 2.8 lens. Thanks.
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Old Jul 28, 2006, 11:26 AM   #2
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The reality is you're not likely to notice it unless you're doing very large prints or pixel peeping 100% crops. Absolute worst case scenario you'll have a dust spot or two that will show up on some of your images (depending on colors, aperture etc..) and you can fix them in PP.

In general you want to clean the camera as infrequently as possible. So, after the trip, get a blower and cleaning kit and clean ONLY WHEN you start to notice an impact to your actual shots. It's like cleaning a lens - every time you touch it you risk doing more harm than good. Overcleaning poses a greater risk, IMO, than in leaving the dust there until it's noticable on prints. Now, if you shoot a lot at lower apertures it will become noticable earlier on - but I still say don't touch it until you have to.
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Old Jul 28, 2006, 12:16 PM   #3
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That's what I was thinking too. In fact I bet that at any given moment most sensor have some dust on them (even after they are clean). I wasn't suprised to find it but nonetheless knowing it is there is a tad bit iritating (I'm a bit of a perfectionist).

You mention cleaning should be done infrequently? I am not planning on doing any method that requires me touching the sensor. Especially since it isn't covered under warently.

I figure the Gitto Rocket Air at B&H will be the best choice for me and to use a tripod and and tilt the camera down to blow out the dust would work best. In this senerio is the a big risk of damage with frequent cleaning? I"m just curious as nothing is touching. Although, I could see a chance to get more dust in every time cleaning is attempted.

But for now there isn't much I can do sense I'll be leaving for vacation. PP work is expected as I shoot RAW anyway.
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Old Jul 28, 2006, 2:49 PM   #4
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My 2 cents - if you aren't noticing it on your pictures, don't worry about it at the moment. If you are, then do you have a baster? They can be used to blow air in a pinch, only takes a couple of seconds. I wouldn't think that using a bit of air to blow off dust would cause problems if done somewhat frequently, though I could see a cleaning kit might affect things (don't know that it really would, it just sounds logical).
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Old Jul 28, 2006, 4:05 PM   #5
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Just to add my 2 cents:

Not changing your lens is NOT a guarantee that you will not get (more) dust on your sensor. Assuming you are using a zoom lens, the lens itself is not sealed, so each time you zoom in and out you are exchanging air inside the film chamber. And lets not forget that flapping SLR mirror each time you take a photo.

The Giottos Rocket blower is also not a total solution to cleaning your sensor. You can get dust that is sticky (maybe a bit oily or greasy) clinging to the sensor and no amount of blowing will dislodge it. And then there is dust attracted to the sensor through a static charge. Blowing on this may simply move it around, but not necessarily dislodge it.

The bottom line is that, sooner or later, you will need to perform a physical cleaning of your sensor. That's a fact and you should prepare yourself for it.

Your sensor is not super fragile, so don't be afraid of it. Get the right tools and learn to clean it yourself. The first time will be the worst, but you will soon get used to it and be able to do in about 10 or 15 minutes.
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Old Jul 28, 2006, 6:06 PM   #6
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Well said, amazingthailand!

Cleaning the filter covering the CMOS sensor is scary the first time but it is easily done providing that you use the correct tools and the proper technique. There are numerous websites devoted to cleaning the sensor, such as copperhill, so I will not go into that in detail.

As amazingthailand said, cleaning the sensor filter is a fact of life in the DSLR world. Accept that and enjoy your camera.

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Old Jul 28, 2006, 11:22 PM   #7
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I've had my 300D for over two years now and my 20D for over a year. I've never used anything but a bulb blower (mine is made by promaster, but like a rocket.)Be sure to get a quality blower, one withthe valve that keeps the blower from sucking dust inside the bulb. I use it before every major shoot, it only takes a couple of minutes and you're done. But I alsoprepare my lenses when I change them by losening the rear cap so when I pull one lens off the other one is on in a matter of seconds. I also hold my camera with the sensor facing down. I check my sensor by putting on a wide angle lens and stopping down to about f/11 and taking a shot of my light bank then dumping the photo into photoshop elements. and click on auto levels. If there is any dust on your sensor believe me it will show up. Also when I clean my sensor I hold my camera with the sensor facing down so the dust just doesn't settle back down in a different spot. If you do this as a regular habit, chances are you will never need to do any other type of sensor cleaning.
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