Why the locked thread? Only wanted to follow up.

[jrista]

The "X" is perfectly normal, that's just how the demosaicing software interprets it when a green pixel goes. In DPP when first loading a picture they start out as green dots and then turn into the little x's.

In LR, they start out as green, red, or blue pixels with a white halo...then they disappear. I think LR has automatic code that deals with obvious hot pixels. Which is why I wanted Gas am to send his RAW images through ACR or LR, to see what happened. DPP uses a much more primitive demosaicing algorithm than ACR/LR, I don't really think it does much of anything advanced at all. I highly suspect any iPad apps would be the same.

I would bet that the hot pixel problem largely deals with itself if he would just run the RAWs through LR.

 

[eos650]

I have the exact same issue (an X), in a couple spots on one of my 5D3's. It's always there. Sometimes, due to color, it's harder to see, but if I look for it, I can always find it. With dark backgrounds it jumps out, so I often hit these spots with the healing tool in Lightroom. I also have some similar white pixels on my 7D, but I don't remember if they form an X. Neither my 60D or 2nd 5D3 have these types of dead/stuck/whatever pixels.

I normally shoot sports. I shoot around 1000th of a second or faster and often shoot ISO 3200 or ISO 6400. It's not a long exposure issue, at least not in my case.

 

[Don Haines]

So I gave it a try on my camera....
ISO320, 30 seconds, in a dark room....

With long exposure noise reduction turned off I got 9 red dots, 2 blue dots, and one white "x".
With long exposure noise reduction turned there were no spots.

It did not matter if I looked at the JPG, the RAW file in lightroom, or the RAW file in DPP, the results were the same... same dots, same color, same location....

and yes, the "x" is a single very white pixel in the centre, with 4 grey pixels diagonally around it to make the "x"

At 1/100 second, there are no spots

 

[ahab1372]

Long exposure noise reduction is not recommended for ISO 1600 or higher, if I remember correctly from my T3i/600D manual. Not sure if that has changed. Maybe the algorithms are overwhelmed?

 

[Loswr]

Tried a set of 30 s exposures with the lens cap in place (40/2.8 pancake) on my 1D X, ISO 100 and ISO 3200, with and without LENR. Viewing RAW images in DPP, at ISO 100 without LENR, I was surprised to see a whole bunch of off-white spots on the image. Then I figured I should wipe off my display and try again…

That left me with a single hot pixel in the red channel at ISO 100. At ISO 3200 without LENR, there were quite a few (>30) hot pixels, in all three color channels. After the high quality image rendered in DPP, the green hot pixels were displayed as the little 'x' whereas the red and blue hot pixels retained their original color (but the demosaicing interpolation effect was visible). LENR removed all the hot pixels from the ISO 100 and ISO 3200 images. (Side note: I tried the Auto setting for LENR, and at both ISO 100 and 3200 with the 30 s exposure, the camera decided there was no need to apply LENR, and the images had the same hot pixels as with LENR set to off.)

When opening any of the non-LENR images in DxO Optics Pro, at both ISO 100 and ISO 3200 all of the hot pixels were eliminated. Opening the ISO 100 image with ACR (in CS6, I don't have LR) didn't show the hot red pixel, and in the ISO 3200 image with ACR, most of the hot pixels were removed but ACR left a couple of the red ones in the image.

EDIT: Aperture seems to leave blue hot pixels in the RAW image, but removes the red and green ('x') hot pixels.

 

[Quasimodo]

So if I am understanding this correctly: hot, dead... pixels does not matter so much in practical life, as long as there are no negative effects of LR or CS remove them. I have never seen any such thing on my pictures, which makes me believe that I probably have some, but that the software has taken care of it for me.

The next thing must be for me to learn how to make an action in LR and PS6 to remove dirty spots from the sensor without leaving any trace It is a tedious job to attack one and one of them....

 

[Loswr]

The next thing must be for me to learn how to make an action in LR and PS6 to remove dirty spots from the sensor without leaving any trace It is a tedious job to attack one and one of them....

You could try an action a little earlier in your workflow…

http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor

 

[ahab1372]

so the x is a DPP-only phenomenon (or feature)?

 

[Mt Spokane Photography]

Here is a 45 sec RAW exposure from my 5D MK III taken at ISO 100 and developed in Lightroom with no exposure correction, no NR. I did see one little X, but then I wiped it off my monitor.

Since I also saved it as a jpeg image to the second card, its below the raw image:

Then, I increased the exposure in Lightroom by 5 stops. Sure enough, there are some white dots in the jpeg version and some tiny red hot pixels in the raw version. They are hard to see though.

Some photo editors / viewers will boost the exposure automatically, and sure enough there will be white dots. That's completely normal. Also notice how using jpeg locks the blacks.

This is why we can only help someone when we know not only the exposure settings, but if it was RAW or jpeg, and what software was used to view it. A screen grab is of no help and is the type of thing that can be used to mislead inexperienced photographers, but those on this site recognize the issue. I could have told you that the jpeg image 5 stops over exposed was what I'm seeing, and would have received all sorts of advice on how to fix it.

RAW

JPEG

Raw Boosted 5 stops

JPEG Boosted 5 stops

 

[Don Haines]

so the x is a DPP-only phenomenon (or feature)?

No. I could see it a jpg, in the RAW file viewed in lightroom, and in the RAW file viewed in DPP.

 

[Quasimodo]

The next thing must be for me to learn how to make an action in LR and PS6 to remove dirty spots from the sensor without leaving any trace It is a tedious job to attack one and one of them....

You could try an action a little earlier in your workflow…

http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor

lol! You don*t think that I have not tried that route... I have, both blowing, dry swab and wet swab on my 1Ds III and 5D II, but I am pretty sure I made it worse than it was. I am scared to apply to much pressure that might destroy the sensor.

 

[Mt Spokane Photography]

The next thing must be for me to learn how to make an action in LR and PS6 to remove dirty spots from the sensor without leaving any trace It is a tedious job to attack one and one of them....

You could try an action a little earlier in your workflow…

http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor

lol! You don*t think that I have not tried that route... I have, both blowing, dry swab and wet swab on my 1Ds III and 5D II, but I am pretty sure I made it worse than it was. I am scared to apply to much pressure that might destroy the sensor.

It can be tough to remove some dirt from sensors. I've had to use five or more swabs on a particularly dirty one. Its easy to make it worse if you stop with just one or two swabs and the sensor is still dirty. Keep using clean swabs until the job is finished.
Also be aware that some swabs do introduce fibers and other nasty stuff. they are not all equal. I've had pre-moistened swabs do this while dry swabs of the same brand that I moistened with eclipse were fine.

 

[Quasimodo]

The next thing must be for me to learn how to make an action in LR and PS6 to remove dirty spots from the sensor without leaving any trace It is a tedious job to attack one and one of them....

You could try an action a little earlier in your workflow…

http://www.lensrentals.com/blog/2010/04/how-to-clean-a-camera-sensor

lol! You don*t think that I have not tried that route... I have, both blowing, dry swab and wet swab on my 1Ds III and 5D II, but I am pretty sure I made it worse than it was. I am scared to apply to much pressure that might destroy the sensor.

It can be tough to remove some dirt from sensors. I've had to use five or more swabs on a particularly dirty one. Its easy to make it worse if you stop with just one or two swabs and the sensor is still dirty. Keep using clean swabs until the job is finished.
Also be aware that some swabs do introduce fibers and other nasty stuff. they are not all equal. I've had pre-moistened swabs do this while dry swabs of the same brand that I moistened with eclipse were fine.

I might have given up to easily... Which brand do you use?

 

[Orangutan]

I am scared to apply to much pressure that might destroy the sensor.

If I remember correctly, the actual silicon sensor is underneath at least one layer of glass. Don't scour the surface, but the glass should be tough enough that you can apply a bit of pressure.

It can be tough to remove some dirt from sensors. I've had to use five or more swabs on a particularly dirty one. Its easy to make it worse if you stop with just one or two swabs and the sensor is still dirty. Keep using clean swabs until the job is finished.

I agree. Sometimes the first couple of swabs just loosen the grime; then it takes another one or two to mop it up.

 

[Northstar]

Have to say that there is some good info in this post...thanks for starting it gas am. I learned something.

Thanks to others who took the time to explore this issue....mt spokane and neuro.

 

[jhaces]

I had similar problems a long while ago (white Xs appearing in random places in my photos) but they would appear either in DPP or in LR. They went away from my RAWs after I updated both ACR and DPP. Didn't do any hot-pixel/sensor dust mapping nor cleaning. Is your software up to date?

 

[Mt Spokane Photography]

I might have given up to easily... Which brand do you use?

I use Sensor Swabs (Brand) and moisten them with eclipse fluid. I've had a lot of junk get on my sensors from the pec pads I bought, and from the pre-moistened Sensor Swabs.
Good sensor swabs are not cheap, and when it takes 5 of them plus the expensive eclipse fluid, I cringe. $32 for a dozen ff sized dry ones plus you need the eclipse fluid.

Most of the time, a rocket blower does the job, but I've had some gunk that was difficult to remove on my 5D MK II and my 1D MK III.

Amazon has them.

 

[Rienzphotoz]

Have to say that there is some good info in this post...thanks for starting it gas am. I learned something.

Thanks to others who took the time to explore this issue....mt spokane and neuro.

+1

 

[Rienzphotoz]

I use Sensor Swabs (Brand) and moisten them with eclipse fluid. I've had a lot of junk get on my sensors from the pec pads I bought, and from the pre-moistened Sensor Swabs.
Good sensor swabs are not cheap, and when it takes 5 of them plus the expensive eclipse fluid, I cringe. $32 for a dozen ff sized dry ones plus you need the eclipse fluid.

Most of the time, a rocket blower does the job, but I've had some gunk that was difficult to remove on my 5D MK II and my 1D MK III.

Amazon has them.

It is comforting to note that it does take that many swabs ... I always get scared when I had to use more than 2 swabs, thinking that I might damage the sensor, coz the bloody dust doesn't always go away with a couple of swabs ... so its good to know that I can take 5 swabs or more to get the dust off sometimes. As I shoot in very dusty environments most of the time, I have to clean my sensor frequently, so the info on this thread is very useful.
Thanks to all the useful contributions to this thread. Maybe the mods/admin should put all this good info in a separate thread with a more appropriate title.

 

[Quasimodo]

I might have given up to easily... Which brand do you use?

I use Sensor Swabs (Brand) and moisten them with eclipse fluid. I've had a lot of junk get on my sensors from the pec pads I bought, and from the pre-moistened Sensor Swabs.
Good sensor swabs are not cheap, and when it takes 5 of them plus the expensive eclipse fluid, I cringe. $32 for a dozen ff sized dry ones plus you need the eclipse fluid.

Most of the time, a rocket blower does the job, but I've had some gunk that was difficult to remove on my 5D MK II and my 1D MK III.

Amazon has them.

I am wondering if those are the ones I have. I have to check when I get home from the office