Dead/hot pixels

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Sweety

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Neil
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Sorry if this is in the wrong section. I noticed the other night that my Canon 750D is suffering from what looks to be around 11 dead or hot pixels showing as either blue, red or white dots & wonder if this is normal for a 6 month old DSLR with maybe a thousand actions under it's belt. I have googled the subject & have tried the manual clean to map these out a couple of time but it only removed 3 leaving me with 11 & the dots are there on any long exposure is 1-30 sec & no matter what the ISO.
TBH i'm a little disheartened by this as my cheap Sony bridge camera has never suffered from anything like this so was wondering if I should take the Canon back for repair/replacement
 
That's odd. I was only thinking of posting the very same question myself. I will see what replies you get. All I will say is that your not alone.


Gaz
 
Are the dead/hot pixels visible at normal resolution and/or on prints? If not, I'd just live with them and not pixel peep! BUT, if they're intrusive in normal use, you might be able to reject the camera as unfit for purpose (but please note the "might".)
 
Your camera should have a setting to enable or disable long exposure noise reduction. It's purpose is to get rid of these hot pixels that only show up on long (> approx 1 sec) exposures. Check that you have this enabled. If you have this disabled what you are seeing is quite normal for almost any camera when this feature is disabled.
 
The pixels are showing up clearly on my laptop mainly in the bottom 3rd of the image as the area was very dark. I don't have the long exposure noise reduction switched on as everything i've read about doing star trails etc says to switch it off & tbh never had this issue before with it off, they seem to have just developed over night. A friend has the same camera & doesn't suffer from this even though the shutter count is a great deal higher than mine, maybe it'll be worth trying a warranty claim then
 
I have just taken 2 test shots with the lens cap on one without the NR off as I have been doing & then one with the NR switched on & there is no difference between the shots as they both show the pixel dots in the same place so going to see what can be done under warranty tomorrow
 
The reality is that any camera will have some stuck/dead/hot pixels. No sensor is 100% perfect. Normally these are mapped out at manufacture. Over time though more may develop. Sending the camera in for a warranty service will more than likely just result in them remapping the sensor rather than do anything radical like replacement unless it is clearly a dud.

There was a rumour that earlier canons used to do a remap during a manual sensor clean with a body cap on. No idea if it was true though.

For info, my day job involves Infra Red sensors of a (comparatively) low resolution. Seeing the output from some of these with the Non Uniformity Correction switched off looks horrible. With it on though they look perfect.

If you have warranty, Canon will sort it one way or another.
 
I'm with the above, if only 6 months old you have nothing to loose by chasing the warranty.
I have a 6d.Not sure how long I have had it, at least 4 years though.Had a few dead pixels for a while,only visible at night with long exposures. It now as lots of dead pixels. Not counted them but it is a tad shocking when I first open a 30 second exposure.
I have not done re map thing or used the long exposure noise reduction. Obviously I will live with it as I love the camera and don't change stuff until it's goosed. I just worry about it getting worse.


Good luck.

Gaz
 
When you did the test with the noise reduction on you did use a long enough exposure? On my 350D and 550D it only kicks in above 30 sec. I use the 350D for astro photography and unless I use dark frames (not the same as the in camera noise reduction which tbh I found pretty useless) in the image integration I'll be cloning the hot pixels out of the final image for quite some time...........
What you're seeing may be quite normal. You're not very clear on what type of shot you were taking or whether it's something you've done before.
 
Jannyfox said:
When you did the test with the noise reduction on you did use a long enough exposure? On my 350D and 550D it only kicks in above 30 sec. I use the 350D for astro photography and unless I use dark frames (not the same as the in camera noise reduction which tbh I found pretty useless) in the image integration I'll be cloning the hot pixels out of the final image for quite some time...........
What you're seeing may be quite normal. You're not very clear on what type of shot you were taking or whether it's something you've done before.
Click to expand...

I was doing between 15 & 30 second exposures at night which I have done several times with this camera & never had this issue before until Saturday night. I did the manual sensor clean to try & map these pixels out & it did remove some of them but it can't seem to remove the 11 i'm stuck with. It's going back to the shop on Wednesday so will report back to the out come of that when I know what's what
 
Good job it wasn't a grey import!
 
My 1d3 had best part of 100 stuck pixels and was unusable so that went back under my CPS membership. As it was a Canon refurb they wouldn't change the sensor just remapped it. Couldn't see any when it came back even with a 60 second lens cap on exposure.

My 5d2 developed a line down the display so sent that back under CPS for a warranty repair. I mentioned a large number of stuck pixels and whilst it was apart they replaced the sensor too.

Get it sent back and mention your into astrophotography and that in its present state its unusable :D
 
It got returned to the shop it came from & they have sent it off to Canon so now have a 2-4 week wait
 
Update
After 3 weeks I have got my 750d back & all of the dead & hot pixels are no longer showing up & the technical info was Canon have done a sensor clean & re-calibrated the camera so I take it that they have just mapped out these pixels which has all been done under warranty. Now here's the funny bit the camera was sent off for repair by John lewis to canon UK I think who in turned sent it off to Canon in Germany to sort it out which has shocked me somewhat, luckily for me it was sent back from Germany directly to John Lewis in Newcastle otherwise it might have been after Xmas before I got it back
 
Another update, after taking around 80 shots I got hit again with even more hot & dead pixels this time some of them were in large clusters so to say I was a little unhappy is an understatement so contacted John Lewis about it & the guy who I spoke to said it wasn't on & would I like a refund or a replacement, so tomorrow I will be picking up a new Canon 750D including a new kit lens etc.
I have to say the service from John Lewis has been great & my 2 years warranty will restart from tomorrow, just hoping this one is ok & I don't have to make another warranty claim
 
Well I seem to have no luck at all as my replacement Canon 750D is also faulty in that the grids for your thirds etc will not display in the viewfinder at all so it'll be going back for another replacement but this will be the last time because if I get another faulty one I will be giving up on Canon for good & will have to change brand
 
Sweety said:
I know how to select it & it makes no difference if you select grid 1 or 2 neither will show in the viewfinder like my first one did but with this one all you get is the focus points & camera settings so I think it must be a software issue or something along those lines
Click to expand...

Is a firmware update possible?
 
Sweety said:
I know how to select it & it makes no difference if you select grid 1 or 2 neither will show in the viewfinder like my first one did but with this one all you get is the focus points & camera settings so I think it must be a software issue or something along those lines
Click to expand...
Are you sure the grids should display in the viewfinder? My 650D and 80D have these on the rear screen with live view, but they do not show up in the viewfinder.
 
After a factory reset & scouring through all of the menus again found that the viewfinder was unticked in the menu where the copyright info is so ticked it & switched grid option 1 on & it is now showing up in the viewfinder. This must have been switched on at the factory on my first one but not on this one causing me the confusion & even the guy at the Canon tech department I spoke to never mentioned the the switch on bit in the other menu & said I had a software issue lol.
Ok I feel a bit of a prat but in my slight defence my fibromyalgia has been bad lately & suffered a great deal of fibro fog where you just can't think for love nor money
 
Don' let it worry you, my 5d2 came back and wouldn't focus. They had set back button focus to on. It took me ages to figure it out even nearly sending it back. I also left a card in it which came back with a video of Canon Elstree car park.
 
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