Hot pixels at 30D

localchap · 27th of May 2006 (Sat)

Hello all, I've never found similar thread so decided to start off a new one here.
There's been a lot of talks about dead/hot pixels at camera sensor. I've tested mine brand new 30D and...(for God sake I regreted I've done it 'cos it made me really upset)
SO, I put kit lens 18-55 on, ISO 100, RAW file, manual mode, shutter speed, 1sec-nothing, 1/30, 1/60, 1/150 and up to 1/600 with the same ISO level, nothing. But when I went for longer 10 and 13 seconds speed, I've found (while watching at PC at 1:1scale) a white little tinny dot and another blue one which appeared at one shout and gone at second shot. Its not seen at any of pictures taken since I've bought it
I'd like to hear some experienced opinion, how crucial it is, is there need to apply to Canon service for sensor remmaping (its s bit complicated for me I've bought it in States now back home to Europe). Besides, like I heard remapping could make sensor working worse so you never know.
Also, I heard that every sensor had at least one dead/hot pixels, is that true.
All opinions and sharing thoughts at the point are really welcome!

Ronald S. Jr. · 27th of May 2006 (Sat)

As I understood it (I don't do long exposures much), hot pixels in very long exposures are fairly common.

localchap · 27th of May 2006 (Sat)

I don't do long exposures myself just decided to have it tested an at 10 then 13 sec those dots appeared.

Jon · 27th of May 2006 (Sat)

One or two hot/dead pixels out of 8.2 million at exposures of over a couple of seconds aren't worth worrying about. It's when you have several hundred at 1/500 that you need to think about worrying.

JBF · 27th of May 2006 (Sat)

Canon's tech support told me that at long exposures and high ISO speeds acceptable hot pixels would be less than .01 percent. If that is the case then on an 8 megapixel camera if you had 8,000 hot pixels it would be in the acceptable range. However I tested mine and at 30 sec and ISO 1600, I had 144 hot pixels, so I am not too upset. And even at that type of shot I can't see the hot pixels unless I zoom in at 100% or higher. Don't sweat the small stuff.

SteveO · 27th of May 2006 (Sat)

I heard a rumor that with the 30D, if you do a "sensor clean ", the camera automatically maps out hot pixels. Any truth to this?

Steve

Jon · 27th of May 2006 (Sat)

Nope. That rumour first surfaced with the 5D. It seems to have a strong link to people forgetting they've turned automatic noise reduction on.

Keiffer · 27th of May 2006 (Sat)

Quote:

Originally Posted by localchap

I don't do long exposures myself just decided to have it tested an at 10 then 13 sec those dots appeared.

So if you don't normally do 10-13 sec exposures you'll never notice this again

Isn't that a happy thought.
That's the bad thing about looking for trouble or problems, you normally find them.

calicokat · 27th of May 2006 (Sat)

I wouldn't worry about it

Tdragone · 28th of May 2006 (Sun)

This 30 minute exposure has more than 30 pixels of various colors in it:

but none of them show up after Post Processing (Noise reduction) or when printing the original below 8.5X11 (Where 2 are viewable with NO post processing)

Hope it helps calm the nerves

Richard7481 · 28th of May 2006 (Sun)

They can be removed in PP, so why worry.

calicokat · 28th of May 2006 (Sun)

Quote:

Originally Posted by Tdragone

This 30 minute exposure has more than 30 pixels of various colors in it:

but none of them show up after Post Processing (Noise reduction) or when printing the original below 8.5X11 (Where 2 are viewable with NO post processing)

Hope it helps calm the nerves

thats a great photo

roli_bark · 28th of May 2006 (Sun)

Quote:

Originally Posted by JBF

.... However I tested mine and at 30 sec and ISO 1600, I had 144 hot pixels, so I am not too upset. ....

Are you serious ? How could you count exactly 144 hot pixels ? Or, for that matter, how can Hot Pixels be counted at all ?

Am I missing something ?

adas · 28th of May 2006 (Sun)

Roli, he's using a Dead Pixel Test program, wich will count it for him.
Another way is to look at the numbers given by the histogram in Photoshop.

prep · 28th of May 2006 (Sun)

High dark current pixels can be partly corrected by subtracting the data number that accumulateds between the clear out read and the read down of the array. This will be longer than the shutter open time, and possibly the exposure time if it is a gated array.

I woud expect Canon to have done it right.

BTW, you may want to stack several shorter exposures, you get better S/N that way.

27th of May 2006 (Sat)	#1
localchap Member Join Date: May 2006 Location: Ireland Posts: 84	Hot pixels at 30D Hello all, I've never found similar thread so decided to start off a new one here. There's been a lot of talks about dead/hot pixels at camera sensor. I've tested mine brand new 30D and...(for God sake I regreted I've done it 'cos it made me really upset) SO, I put kit lens 18-55 on, ISO 100, RAW file, manual mode, shutter speed, 1sec-nothing, 1/30, 1/60, 1/150 and up to 1/600 with the same ISO level, nothing. But when I went for longer 10 and 13 seconds speed, I've found (while watching at PC at 1:1scale) a white little tinny dot and another blue one which appeared at one shout and gone at second shot. Its not seen at any of pictures taken since I've bought it I'd like to hear some experienced opinion, how crucial it is, is there need to apply to Canon service for sensor remmaping (its s bit complicated for me I've bought it in States now back home to Europe). Besides, like I heard remapping could make sensor working worse so you never know. Also, I heard that every sensor had at least one dead/hot pixels, is that true. All opinions and sharing thoughts at the point are really welcome!

27th of May 2006 (Sat)	#2
Ronald S. Jr. Prodigal "Brick" Layer Join Date: Aug 2005 Location: Sayre, Pennsylvania Posts: 16,010	Re: Hot pixels at 30D As I understood it (I don't do long exposures much), hot pixels in very long exposures are fairly common. __________________ Mac users swear by their computers. PC users swear at theirs.

27th of May 2006 (Sat)	#3
localchap Member Join Date: May 2006 Location: Ireland Posts: 84	Re: Hot pixels at 30D I don't do long exposures myself just decided to have it tested an at 10 then 13 sec those dots appeared.

27th of May 2006 (Sat)	#4
Jon Moderator Slayer of Trolls Join Date: Jun 2004 Location: Kensington, MD USA Posts: 42,957	Re: Hot pixels at 30D One or two hot/dead pixels out of 8.2 million at exposures of over a couple of seconds aren't worth worrying about. It's when you have several hundred at 1/500 that you need to think about worrying. __________________ Jon ---------- EOS, PowerShot and Domke - it doesn't get any better than this! T90 and stuff \| F-1n, New F-1, FTb and more stuff out on loan Image Posting Rules and Image Posting FAQ Maryland and Virginia activities Report SPAM, Don't Answer It! (link) Marketplace Changes * IMPORTANT! *

27th of May 2006 (Sat)	#5
JBF Member Join Date: Dec 2005 Location: Lexington, KY Posts: 986	Re: Hot pixels at 30D Canon's tech support told me that at long exposures and high ISO speeds acceptable hot pixels would be less than .01 percent. If that is the case then on an 8 megapixel camera if you had 8,000 hot pixels it would be in the acceptable range. However I tested mine and at 30 sec and ISO 1600, I had 144 hot pixels, so I am not too upset. And even at that type of shot I can't see the hot pixels unless I zoom in at 100% or higher. Don't sweat the small stuff. __________________ JBF 1D Mark III, 5D Mark II, 7D, 24-105L, 35L 1.4, 50 f/1.4, 85 f/1.8, 200L f/2.8, 17-40L f/4.0, 70-200L IS f/2.8, 300 f/2.8IS, 580ex Flash, 430ex Flash, 1.4X Converter. Bunch of other crap! I want the 85L and the 200L f/2.0

27th of May 2006 (Sat)	#6
SteveO Junior Member Join Date: Jan 2003 Posts: 16	Re: Hot pixels at 30D I heard a rumor that with the 30D, if you do a "sensor clean ", the camera automatically maps out hot pixels. Any truth to this? Steve

27th of May 2006 (Sat)	#7
Jon Moderator Slayer of Trolls Join Date: Jun 2004 Location: Kensington, MD USA Posts: 42,957	Re: Hot pixels at 30D Nope. That rumour first surfaced with the 5D. It seems to have a strong link to people forgetting they've turned automatic noise reduction on. __________________ Jon ---------- EOS, PowerShot and Domke - it doesn't get any better than this! T90 and stuff \| F-1n, New F-1, FTb and more stuff out on loan Image Posting Rules and Image Posting FAQ Maryland and Virginia activities Report SPAM, Don't Answer It! (link) Marketplace Changes * IMPORTANT! *

27th of May 2006 (Sat)	#9
calicokat calicokat is BANNED Join Date: Oct 2005 Location: Southern California Posts: 14,722	Re: Hot pixels at 30D I wouldn't worry about it __________________ "You are going to fall off a cliff trying to get a better shot someday"- My hopeful and loving wife My Website My Gear Calicokat 1990-2007 RIP My Loving Kitty

28th of May 2006 (Sun)	#10
Tdragone Senior Member Join Date: Sep 2004 Location: San Diego, California Posts: 1,679 IMAGE EDITING OK	Re: Hot pixels at 30D This 30 minute exposure has more than 30 pixels of various colors in it: but none of them show up after Post Processing (Noise reduction) or when printing the original below 8.5X11 (Where 2 are viewable with NO post processing) Hope it helps calm the nerves __________________ -Tom Dragonetti 1Dmkiii, 50D, 30D, G9 10-22, 16-35 2.8L, 50mm 1.4, 70-200 2.8L IS, 100-400L IS Canon 1.4X ii and 420 EX and 580 EX flashes

28th of May 2006 (Sun)	#11
Richard7481 Member Join Date: May 2006 Location: Kawasaki, Japan Posts: 79 IMAGE EDITING OK	Re: Hot pixels at 30D They can be removed in PP, so why worry.

28th of May 2006 (Sun)	#14
adas Senior Member Join Date: Aug 2004 Posts: 1,415	Re: Hot pixels at 30D Roli, he's using a Dead Pixel Test program, wich will count it for him. Another way is to look at the numbers given by the histogram in Photoshop.

28th of May 2006 (Sun)	#15
prep Member Join Date: May 2006 Location: Perth WA Posts: 245 IMAGE EDITING OK	Re: Hot pixels at 30D High dark current pixels can be partly corrected by subtracting the data number that accumulateds between the clear out read and the read down of the array. This will be longer than the shutter open time, and possibly the exposure time if it is a gated array. I woud expect Canon to have done it right. BTW, you may want to stack several shorter exposures, you get better S/N that way.

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