Spots

[Rosco]

One for the more tech savvy types. WE have a Sony A350, which from new, had a spot upper RHS of all images. We took it back to be fixed under warranty and it disappeared. Figured it may have been a speck of dust on the image sensor gizmo. Anyway it's back in the same possie. Camera to go back for them to have another crack at it, but curious what you think is the cause? Highly unlikely to get dust again in exactly the same spot. Do you think the camera body may have a significant fault, which will give us grief down the track when the warranty has expired?

[werdan]

You might like to post an example pic so we can see whether it's dust or a hot pixel. It sounds like dust on the sensor though.

Unlike film cameras, the photographic sensing area doesn't get replaced between shots. If a bit of dust works its way into the body when you are changing lenses, it can easily settle on the sensor and it won't move until it's cleaned off.

Check your user guide. I'm pretty sure all the new Sony DSLRs have a self clean mode where the sensor is vibrated so the dust falls away.

Also invest in a puffer bulb for 'blasting' dust away from inside the camera. They are probably the cheapest bit of camera gear that you can buy and well worth the money. The manual should also tell you how to set the camera to lock open the mirror and shutter so you can blow the dust of the sensor manually. If that doesn't work then it's probably best to go back to having it professionally cleaned.

[dullbird]

have you had the lens checked also?

[Rosco]

[img=http://img18.imageshack.us/img18/396/newyof.th.jpg] (http://img18.imageshack.us/my.php?image=newyof.jpg)

Yep ... camera has autoclean feature and I also have a blower bulb.

Note the spot upper RHS corner .... zacary same as previous.
What's the go with a "hot pixel"??

[Rosco]

have you had the lens checked also?

Change lens ... spot stays. :mad:

[Chucaro]

Looks like a faulty sensor :(
Post an image of the spot area @ 100% resolution
Cheers

[Rosco]

http://img297.imageshack.us/img297/4850/new1s.th.jpg (http://img297.imageshack.us/my.php?image=new1s.jpg)


That OK ???

[werdan]

That looks like dust to me. I got quite a few shots like that from the last airshow. Pointing the lens up to the sky makes the dust fall on the sensor.

Try cleaning the sensor with the blower bulb while holding the lens mount facing down.

[Rosco]

Possibly, but this one was taken last year and the spot is in exactly the same place ...:question: Seems unlikely to have 2 spots of dust in the same place.


http://img23.imageshack.us/img23/5521/oldxcy.th.jpg (http://img23.imageshack.us/my.php?image=oldxcy.jpg)

[werdan]

Possibly, but this one was taken last year and the spot is in exactly the same place ...:question: Seems unlikely to have 2 spots of dust in the same place.

Yeah. It does. :(

[Chucaro]

A hot pixel should glow and a death pixel is black. In many cases when there is a hot pixel a line is visble on the image.
The spot in the image looks like dust.
Read THIS article that explain better that what I can do with my english :)

[dmdigital]

It certainly looks like a dust bunny.

Do you:

Change lenses very much? - When changing lenses point the camera straight down helps with dust ingress
Use a telephoto lens that moves in and out a resonable amount? - Rapid use of a telephoto can have a bellows effect and actually draw dust in. Especially with kit lenses.
Store the camera without the lens on? - This means you should have the camera body cap on, but it also means you are taking the lens of unnecessarily.
Have any spots on any of your lenses? - Not because of the spot being on the lens, but rather it could indicate a fungal problem which is also in the camera body.


Can you raise the mirror with the lens off? If so, do so with the camera pointing at the ground and use the blower fairly aggressively (make sure its clean first). Then see what happens. Most dust bunnies are reasonably easy to remove but some can be persistent.

As it's come back in the same location I suspect it may be fungal growth on the sensor though.

[Rosco]

It certainly looks like a dust bunny.

Do you:

Change lenses very much? - When changing lenses point the camera straight down helps with dust ingress Not all that often and always try to point camera down.
Use a telephoto lens that moves in and out a resonable amount? - Rapid use of a telephoto can have a bellows effect and actually draw dust in. Especially with kit lenses. No, just the 2 that came with the camera ... 28/50 and 70/200
Store the camera without the lens on? - This means you should have the camera body cap on, but it also means you are taking the lens of unnecessarily. Always with lens attached.
Have any spots on any of your lenses? - Not because of the spot being on the lens, but rather it could indicate a fungal problem which is also in the camera body. Same spot, same place with both lenses.


Can you raise the mirror with the lens off? If so, do so with the camera pointing at the ground and use the blower fairly aggressively (make sure its clean first). Then see what happens. Most dust bunnies are reasonably easy to remove but some can be persistent. Have tried that on occasions. The camera is back at the workshop for fixing.

As it's come back in the same location I suspect it may be fungal growth on the sensor though. It was there from new ... fixable? Or should I push for a replacement body. Only purchased last July/August.

See above.

[Rosco]

A hot pixel should glow and a death pixel is black. In many cases when there is a hot pixel a line is visble on the image.
The spot in the image looks like dust.
Read THIS (http://en.wikipedia.org/wiki/Defective_pixel) article that explain better that what I can do with my english :)

Interesting read. Could it be a stuck pixel ??

[dmdigital]

That really does sound like a sensor fault then.

[Rosco]

That really does sound like a sensor fault then.


Turns out is was a faulty CCD .... whatever that is ... :rolleyes:

[dmdigital]

Turns out is was a faulty CCD .... whatever that is ... :rolleyes:
That's the "sensor". Hope it is all fixed now.

[Rosco]

HowStuffWorks "What are CCD or CMOS image sensors in a digital camera?" (http://electronics.howstuffworks.com/question362.htm)

mind you...I haven't read it ;)

Thanks for the link. I read it and was impressed ... with how little I knew.