NOT Hot Dead pixels, but something I found on accident

[steveboatman]

Okay.

So you know how there is this whole possibly myth/possibly fact/something we can send to MythBusters some day, about setting your camera on manual-clean mode for X-amount of time, to map out bad pixels?

Well, that doesn't work, at least for me.

But something I noticed today, since I have my larger monitor (and hence, Camera RAW is full-screen now as well) - the hot pixels ARE THERE when I FIRST LOAD THE RAW FILE IN ADOBE CAMERA RAW, but after about two seconds, the "!" in the top right corner goes away, and so do all the hot pixels.

Can somebody explain this please?

I can count 6 hot pixels in a regular JPG shot RAW/Large JPG mode. 2 red ones, and 4 blue ones. Happens in every picture, and for night shots, it really is quite annoying to be honest.

But I noticed if I process in RAW, they are not there.

So, upon loading another RAW full screen, I saw the hot pixels show up, but there was that exclamation point in the top right corner of ACR. When that disappears, so do all the hot pixels!

Is this a feature of the camera, Adobe Camera RAW, or a Canon firmware thing? What is this?

I will TRY and get a screenshot if I can, but it happens so quick I will most likely have to try a few times.
--
Steve B.
Grants Pass, OR

 

[RicksAstro]

ACR does this by default...it did it with my Nikon D300 as well as the Canons.

--
Rick Krejci
http://www.ricksastro.com

 

[steveboatman]

Okay good, because that means I'm not just seeing things!

I was successful in getting screen shots to prove my (our?) points.

Somebody with knowledge, please advise! Is there a way to do this for JPG's as well (in Photoshop CS4). I would love to know this secret, would GREATLY help me out in doing batches!!!!

BEFORE



AFTER



--
Steve B.
Grants Pass, OR

 

[Matt_3D]

You can process jpegs with ACR too, not sure if it will remove the hot pixels though. Right click on the image in Adobe Bridge and select 'Open in Camera Raw...'
--
--
-Matt

The old - http://matthew-herdel.fotopic.net/
And the new - http://www.flickr.com/photos/matthewh26/

 

[CanonPhotog]

as well as some other RAW programs, have automatic hot pixel elimination built into them. It's been around for a long, long time. Nifty feature actually, I just wish DPP did the same.

--
B

 

[Lenny uk]

Its pretty clever, it didnt work on my first raw image but after that its working on my small one in the corner... I wonder if dpp and lightroom have something similar tucked away .............
--
http://www.tvlicensing.biz/

 

[steveboatman]

Ahh, see this is what was intriguing me.

I had the same issue - it never used to do this, but now it does.

I wonder if it "learns" of these hot pixels and identifies hot spots that spread through all shots taken with the same camera number, or something in the EXIF. Maybe it has something that identifies that camera, and it learns of the hot pixels for future use... and removes them without asking.

I kind of like it. Thankfully I use ACR.

-----

And yes, I have tried loading a JPG into ACR - and it didn't work. A shame, really. But at least I can simply batch everything in RAW, set the picture style, maybe a bump in sharpness, select all my RAWs and just batch them to JPG's. It worked on a run of 10, in removing the hot pixels.

This just made my life a whole lot simpler.
--
Steve B.
Grants Pass, OR

 

[Glenn_Sydney]

Okay.

So you know how there is this whole possibly myth/possibly
fact/something we can send to MythBusters some day, about setting
your camera on manual-clean mode for X-amount of time, to map out bad
pixels?

Well, that doesn't work, at least for me.

But something I noticed today, since I have my larger monitor (and
hence, Camera RAW is full-screen now as well) - the hot pixels ARE
THERE when I FIRST LOAD THE RAW FILE IN ADOBE CAMERA RAW, but after
about two seconds, the "!" in the top right corner goes away, and so
do all the hot pixels.

Can somebody explain this please?
I can count 6 hot pixels in a regular JPG shot RAW/Large JPG mode. 2
red ones, and 4 blue ones. Happens in every picture, and for night
shots, it really is quite annoying to be honest.

But I noticed if I process in RAW, they are not there.
So, upon loading another RAW full screen, I saw the hot pixels show
up, but there was that exclamation point in the top right corner of
ACR. When that disappears, so do all the hot pixels!

Is this a feature of the camera, Adobe Camera RAW, or a Canon
firmware thing? What is this?

I will TRY and get a screenshot if I can, but it happens so quick I
will most likely have to try a few times.
--
Steve B.
Grants Pass, OR

--

I wonder if this is somehow related to the Dust Mapping feature within the newer cameras XS, XSi. You can find it in the Menu Functions. There is a function to map. Apparently this attaches some info to the RAW file which can be used by a RAW convertor to negate dust specks etc. DPP should be able to do it but i would be surprised if DPP can.......but hey, you never know !!!!. Just wonder if this has something to do with it ? Maybe others knowledgable in this can shed some light !!