350xt - grey spots on pictures?

Hi , this is my first message on this forum so i introduce myself, this is Benny from italy, after many here of powershot (G1) just bought few days ago a DRebel 350xt and read many of your threads, all very interesting and all with beautiful pictures!!

Anyway this first message is because...sigh, i found a little issue making some tests with the camera, specially if taking pictures in shutter priority Tv and specially with slow shutter and light uniform backgrounds (like skylines), i see some grey spots on the pictures , always localized in the same points :-(.

When taking pictures in other modes i thought the spots were not there but watching in details, i think they are just lighter softer....

What can be the problem, kit lenses ? (i cleaned the lens but the thing doesn't change) or i already got dust on the sensor ??

Here are the pictures, first in shutter priority, with the spots visible, they are near the center, near the top right angle and in the bottom right, the second in aperture priority, they are very soft, almost invisible.





Please tell me if any of you had the same kind of problem or have an idea of the cause.

Thanks all

B e n n y F i ò

http://www.webalice.it/bennyfio/index.html

Looks like you have dirt and dust on your sensor, either that or major dirt on the lens or scratches. I would suggest getting the sensor inspected by the store you bought the camera from, or just look at it yourself. But if this is your first DSLR, please, don't try to clean the sensor yourself. Take it to a professioinal and have it cleaned. Or try to blow out the dust with a puffer, not your mouth or canned air.

http://194.100.88.243/petteri/pont/How_to/a_Brush_Your_Sensor/a_Brush_Your_Sensor.html

I recently read this article and I am considering it. I use the copperhill method that works great.

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http://www.mike-j.smugmug.com

Zoom in to 400x, if the spot is exactly one pixel then it is a hot or bad pixel. If it looks like a small slightly blurry dust speck than that's what it is. You should not have any bad pixels at normal conditions like 1/10 second shutter speed or faster and iso 400 (they should have been mapped out at the factory). See the threads on cheap alternatives to the sensor dust brush for info on cleaning off dust spots. You shouldn't need to clean your sensor so soon but it is a skill you will probably need eventually anyway.

Definately looks like sensor dust.

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Dave Lewis

You have two shots there, one at f/14 which shows the dust and one at f/6.3 which doesn't. This is normal. The smaller the aperture the more pronounced the dust will become.

Try a shot at the blue sky at f/22. Put the lens to manual and adjust the focus so the shot will be out-of-focus. At f/22 you will clearly see the dust on your sensor.
No problem, its just time to give it a clean.

Cheers,
Mred32
--

For most PC troubleshooting, a .22 will do the job.

ah, thanks a lot for the technical explanation, i will test it tomorrow with the same bright sky.
Great thanks also to Mike J for the link

so it's just 5 days i got the camera and i already have to clean it.

How often do you notice new dust and clean it?

from the link given by Mike J

http://194.100.88.243/petteri/pont/How_to/a_Brush_Your_Sensor/a_Brush_Your_Sensor.html

i read that over the sensor there is a glass filter, so it should safe cleaning it with a classic brush like the one sold for film camera, right?
Or should i definitely order the sensorswap/copperhill
http://www.pbase.com/copperhill/image/39083486

?

Be sure to read that paper carefully - I think that standard photo brush you are talking about would not work. I would not even use that on my lenses (let alone the sensor).

You need to use a high quality synthetic brush that has all the size (glue used to keep the bristles together during shipment) removed. I went to the local art supply store and found brushes that would work fine for $5 ea. I just haven't actually tried them out yet, but it shouldn't be a problem. The brushes also seem like a good idea because you can clean out the camera chamber as well.

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http://www.mike-j.smugmug.com

Yoohoo, my first dust dust was catched, i didn't have the swab spatula so i did it with a cotton swab, i covered it with a sheet of silicon treated paper (classic lens cleansing paper) similarly to what suggested in the copperhill method, but dry without any drop of solution, and i was lucky to see the main dust so that i moved or removed, don't know, anyway it's not there anymore.

For the next time i have just to find some better quality of silicon paper cause this is too delicate, for the rest the cotton swab was ok, maybe something more near to the spatula tip but still soft is better of course.

Also a small high quality brush as suggested by Mike probably would have been ok so my next stop will be at the art store.

Now just hope to make some good picture to post it here.

thanks!

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B e n n y F i ò

http://www.webalice.it/bennyfio/

I have read about (and sort of ignored) the need to clean the sensor on the Rebel. I assumed that, since I only have the kit lens and never open the camera, there was no way I would ever get my sensor dirty.

I have recently realized that, somehow, a curly hairy blurry thing must have found its way in because it appears in more or less the same spot in a couple of pictures.

This absolutely petrifies me because I am afraid to harm my camera.

Since I can't come up with some other explanation as to what this artifact might be, can you give me some reassuring pointers as to what I should do, and what I shouldn't touch?

I am hoping for a low-cost process, but if I have to spend money to do it really well, I guess I will.

Also, any ideas on how that could have gotten inside a sealed camera? I'm stumped!
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Kate

Kate Street said:

I have read about (and sort of ignored) the need to clean the
sensor on the Rebel. I assumed that, since I only have the kit lens
and never open the camera, there was no way I would ever get my
sensor dirty.

Click to expand...

That's good logic, so I wouldn't rush to clean it until you're sure you need to. I'm frequently swapping lenses and have just specifically blown some dust off my sensor for the first time since getting the camera 18 months ago. I suspect it depends on location and number of gentle bumps.

Kate Street said:

Since I can't come up with some other explanation as to what this
artifact might be, can you give me some reassuring pointers as to
what I should do, and what I shouldn't touch?

Click to expand...

There are heaps of threads offering advice on sensor cleaning, but what I would strongly recommend is reading the manual ( under " cleaning the Image sensor " p 34-35, including footnotes ) and going through the steps to lock the mirror up. Instead of actually cleaning the sensor, look carefully at it to see if you can see the dust.

I only cleaned mine once I could see something. Note that we exhale lots of moisture, so don't allow your breathe to enter the camera, and our hair holds a lot of dust, so don't lean over it. I tend to place the camera on a table near a desk lamp and slowly rotate it so I can see if there is any dust.

Kate Street said:

I am hoping for a low-cost process, but if I have to spend money to
do it really well, I guess I will.

Click to expand...

I think that most of dust can be removed by a gentle air blast ( Canon's recommendation - worked for me ) or the brush method recommended by Pettori, and the methanol ( aka Eclipse fluid ) should be the method of last resort, ore where you know particulates will actuall adhere to the glass cover of the sensor. I held the camera upside down when I used the air blast method.

Kate Street said:

Also, any ideas on how that could have gotten inside a sealed
camera? I'm stumped!

Click to expand...

No sure, I's suspect it's fallen from some corner somewhere, most of the fibres in mine appear to be from the black flexible foam.

As always, patience, care, and not panicing will overcome obstacles. Just give yourself time to explore, so you can stop at any time and review new information, an hour should be plenty. Good luck.

Bruce Hamilton

Just the kind of reasurance and advice I needed. I've copy and pasted your reply and saved it in My Docs for this time and every time hereafter.

Thanks again!
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Kate