dots on Canon 7D sensor?

[darrenm]

Noticed there are two dark dots when i look through my viewfinder on my Canon 7D over the weekend and asume they must be on the sensor has they appear through all my lenses, they dont not appear to affect static bird shots but are appearing on BIF shots and also found the camera was having difficulty in focus at times. The only way i can think that they have got onto the sensor is when i have changed lenses outdoors but i try to be very, very carefull. Also the camera is now giving me soft and slightly blurry results when i use the 1.4xconverter.

I have tried blowing the sensor but reluctant to try and manually clean it after reading that they can be easily damaged and now wondering if i will have to send it back to Canon to be cleaned and how much it will cost and the turn around time?

With the spring migrants now arriving in numbers this couldnt have come at a worse time and will now have to hope and prey i can get some decent shots with my Canon 60D.

[John D]

Darren,

The spots you see when you look through the viewfinder is dust on the 'mirror' or internal surface of the viewfinder, not the sensor. Any dust on the sensor will be seen on an enlarged view of the image when viewed on your monitor.
To check for dust on the sensor set to around f16 and take a shot of a nice blue sky or white paper and view on your monitor, enlarging each section as you view, dust will be seen a small greyish patches/spots.
Dust on the sensor normally needs a bit more than a blower to remove it.

John D

Zenfolio | John's Wild World

[Geoff F]

You may find some of these topics from a photo forum site to be useful

Cambridge in Colour Forums

Depending on exactly how you blew onto your sensor, you may have already done one of the worst possible actions, so a full cleaning with a decent pro cleaning kit would be simple.

Only use a brush/bulb blower on your sensor or a proper cleaning kit.

But as John said, spots on the viewfinder are something different. I just get used to them.

[Tricia]

Geoff, do you mean to use the brush/blower inside the camera? I was advised to do this when my first camera had dust in it and I ended up with fibres from the brush inside the camera. Although the camera was fine after a visit to Nikon for a clean.

I was interested to see your reply because I have always thought that I must have misunderstood the advice which was to use the blower to remove the dust and then use the brush to sweep out the dust.

[Geoff F]

Yes that is correct, Tricia. Use a 'good quality' brush and bulb blower. Not high speed air or blowing from your mouth.

I use the Digital Duster kit which comes with a mini vacuum cleaner instead of a brush blower, plus some wet swab wipes for persistent problems.

I have even 'hovered' a household vacuum cleaner suction pipe above the camera to remove dust, but not with an airtight seal around the camera. Even then this is an 'at your own risk' idea!

[freiston]

When I had this problem, firstly, I used the blower (minus brush) whilst holding the camera pointing downwards - hoping that any loose dust would fall out. I can't really say if this achieved anything or not but a couple of spots remained. That was the method in the Canon manual for my 350D. The manual does give the advice to use either the AC adaptor kit or have plenty of charge in the battery - if the battery gets too low, the mirror will return from locked-up.

I then used a pen-type tool called 'SpeckGRABBER' by Kinetronics (got it free with a copy of Photography Monthly) to remove a couple of stubborn specks. I couldn't see the specks that well with the naked eye so I had to estimate the position from test-shots (using mirror-image flipped upside-down to estimate) but perseverance with the grabber and a few test shots to check progress, did the job.

Edit: - Doh! I just re-read the thread and saw that this is likely to be a mirror-dust issue and not sensor-dust. Oh well, I'll leave my reply in anyway.

[darrenm]

looking at it again last night realised it must be spots on the mirror rather than the sensor but will take the camera back to the shop later today seeing has it's only a few months old for them to give it a look over as i am loathed to touch anything inside it now.

Also cant understand why it all of a sudden it started to give soft and out of focus shots with the 1.4xconverter and with my 400mm5.6 lens on its own now and up until a few days back it worked fine.

Spoke to another 7D owner yesterday who is one of the lucky ones who has never had any problems with his 7D but i have had two now which started off very sharp but all of a sudden went soft and now wishing i had gone for Nikon of the same price range instead of Canon.

I dont have any problems with my 60D and wonder if it's down to high demand for the 7D and quality control slips at times or bad batches occur. Both of my 7D's were bought from the same shop and one went back within a month and the new one is just over two months old.

[eeyore]

Originally Posted by darrenm

Also cant understand why it all of a sudden it started to give soft and out of focus shots with the 1.4xconverter and with my 400mm5.6 lens on its own now and up until a few days back it worked fine.

.

If the camera is under warranty i'd definitely have it looked at - but if its only a problem with the 400m f5.6 that could be down to corrosion/oxidation on the focussing contacts of the lens (the little gold covered bits at the rear)

you can clean these (gently) with a pencil rubber.

WRT your spots if they are on the mirror not the sensor I strongly suggest not blowing air to remove them - it probably will work but might well blow assoted grot off the mirror (where its only a minor issue) onto the sensor (where its a Pita)

[Tricia]

Thanks I have found this thread very helpful. Shall definitely be getting a cleaning kit for my camera bag.

[DorsetDunk]

get it cleaned professionally all too easy to scratch the sensor if you are inexperienced £50 and two weeks loss of the camera is small price compared to the cameras price tag