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calvin

macrumors newbie
Original poster
Apr 7, 2005
17
0
Hi,

I have noticed that all my recent shots have a dark spot in the picture, in exactly the same place. I've attached an image to this post as an example. It appears whichever of my lenses I use, so I know that it is not a lens problem. The camera is a Sony Alpha-100.

From people's experience, is this just a dust particle? I am concerned that it is too large for this (photo was originally 10MP, scaled down for this post), as I think these generally cause small spots. Should I be concerned? There are no other spots that I can see.

Thanks for any input!
Calvin
 

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GoCubsGo

macrumors Nehalem
Feb 19, 2005
35,742
155
It is dust. No need for alarm. The reason it looks larger is the magnification of the lens. My advise is to buy a Giotto Rocket Blower. This is an alternative solution to cleaning your sensor on the go without the use of liquid. There is a highly capable cleaning system that many photographers will certainly support. It is easy to use but would require you to be home or at a stationary place to use it. I highly recommend that for the dust that simply won't move, however in 3+ years I have not ever cleaned my sensor with such system. I have cleaned someone else's system. I use the Rocket Blower and it works very well.

It's inexpensive and will go right into your bag.

Here's the link to the other system that is a bit more involved but nonetheless nothing to be afraid of. CCD / CMOS Cleaning
 

calvin

macrumors newbie
Original poster
Apr 7, 2005
17
0
Wow, quick response, thanks! I'll give the rocket blower a go first... I'm not in the US, however I think Jessops in the UK sell a similar product.
 

Westside guy

macrumors 603
Oct 15, 2003
6,400
4,266
The soggy side of the Pacific NW
Whatever you do, don't use compressed air. Not only is the force of the air too great; but worse, you'll get at least a little of the propellant onto your CCD/sensor.

I have a Rocket Blaster as well. I haven't needed to blow off the sensor yet, fortunately. One thing that Derrick Story recommends (and I think it's a great idea) is this: when you're about to change lenses, use your Rocket Blaster to first blow any dust off around the mounted lens and from the lens you're about to use. This lessens the chance of dust falling off the lenses and into the camera. It only takes a few seconds.
 

Plymouthbreezer

macrumors 601
Feb 27, 2005
4,337
253
Massachusetts
Woah, creepy. I seriously came here to post a thread about dust on my sensor.

Big black spot... Kinda freaked out.

Guess I'll go down and get one of these.
 

GoCubsGo

macrumors Nehalem
Feb 19, 2005
35,742
155
They have them at Jessops because I bought mine there while in the UK in November. I got one a year ago and left it behind when I went on my trip. Much to my dismay I had dust (windy there at times and the moisture didn't help) so I bought another. Technically it cost me double but paying double for that rocket blower is worth it's weight in gold compared to the amount of time I'd spend cloning out those damn dust bunnies.
 

Plymouthbreezer

macrumors 601
Feb 27, 2005
4,337
253
Massachusetts
Ritz was nice and blew it for me. It was a quickie too, only took a minute to come out...

...Apologies for the innuendo. But taken literally, that's what happened. Now I am dust free. :)
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
I highly recommend that for the dust that simply won't move, however in 3+ years I have not ever cleaned my sensor with such system.

Wow, 3 years is a long time- have you taken any small aperture photos of the sky recently? Say f/16 or so?

Whatever you do, don't use compressed air. Not only is the force of the air too great; but worse, you'll get at least a little of the propellant onto your CCD/sensor.

It should actually be the anti-aliasing filter that catches the crud and gets cleaned, not the sensor itself unless you go through the filter!
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
Okay, okay, I was being sloppy...

It's what most people say (I'm guilty myself-) but though I've heard of people having to have their sensors replaced after doing something dumb, generally it should just be the AA filter (still not a cheap swap out, but not as harsh as paying for a new sensor too!)

I just wanted to try to increase the accuracy- although folks will understand when you say "Cleaning my sensor" and might not when you say "Cleaning my AA filter."
 

Coheebuzz

macrumors 6502a
Oct 10, 2005
511
148
Nicosia, Cyprus
My 400D has a filthy viewfinder - hairs, dust and everything. There goes the dust-cleaning system!

There are so many that it's distracting me from taking a shot. They appear sharp in the viewfinder although in the photos i only see a couple.

Am sure they are not on the lens since i can see them with both of my lenses. My viewfinder glass is also pretty clean.

It must be either on the sensor or the mirror, but i've tried air with a blower many times and i can't even get a speck to move. Also on close inspection i can't really see any dust on either.

Anyone has any ideas where that dust might be?

Thanks.
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
My 400D has a filthy viewfinder - hairs, dust and everything. There goes the dust-cleaning system!

There are so many that it's distracting me from taking a shot. They appear sharp in the viewfinder although in the photos i only see a couple.

Am sure they are not on the lens since i can see them with both of my lenses. My viewfinder glass is also pretty clean.

It must be either on the sensor or the mirror, but i've tried air with a blower many times and i can't even get a speck to move. Also on close inspection i can't really see any dust on either.

Anyone has any ideas where that dust might be?

Thanks.

If you can see it through the viewfinder before you take the picture, it's the mirror or the prism. If you can see it in the picture, it's the AA filter over the sensor. A soft lens brush should be ok on the mirror.
 

Coheebuzz

macrumors 6502a
Oct 10, 2005
511
148
Nicosia, Cyprus
If you can see it through the viewfinder before you take the picture, it's the mirror or the prism. If you can see it in the picture, it's the AA filter over the sensor. A soft lens brush should be ok on the mirror.

Thanks compuwar. I used a loupe to look closer and i can see the dust on the thing on top of the mirror, you know, the 'ridged' one with the AF points on it. Is that the prism, and if so can i use a soft microfiber cloth to carefully wipe the dust off?
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
Thanks compuwar. I used a loupe to look closer and i can see the dust on the thing on top of the mirror, you know, the 'ridged' one with the AF points on it. Is that the prism, and if so can i use a soft microfiber cloth to carefully wipe the dust off?

Ah, the focusing screen? Forgot about that! I'd start with a soft lens brush, cloths pick up lots of stuff and it's easy to be too heavy-handed.
 
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