Firmware update for 5D3 Problem? Black halos around stars in RAW

[nubu]

For those starting this "black orb" discussion please post a raw pic showing this somewhere. Then we can have a look at it. Posting oversharpened (e.g. default settings of unsharp masking in dpp is horrible!) jpgs does not help. I am still convinced that this is a postprocessing artfact of an highly overexposed pixel....

 

[epsiloneri]

I agree with nubu. Looks like a postprocessing artefact (sharpening filter, NR).

 

[Bosman]

You don't need this full version, this isn't from processing. What you see with your eye is what is there, you won't find new data that will change the fact of the black haloed circles you see. Also to be clear this is unprocessed.

 

[epsiloneri]

Anyone out there having the same problems while doing night sky?

Yes, I happened to take a night shot with stars using a 5D3 yesterday, and I see this precise phenomenom for saturated stars when the default sharpening is used (just tested). When I turn sharpening off, the black halos disappear. I just tried it but am to lazy to produce screenshots for you... just try it yourself. Using unsharp mask as a "sharpening" filter is particularly good at producing black halos.

 

[Bosman]

Ok, for you who can't believe. I cannot post a 7.3 mg file here and if i shrink it to do so won't there be another reason why this is a processing issue? Sorry, i am annoyed by the comments. When i say it hasn't been processed and what is going on with images then it is still suggested i am lying and that it in fact has been sharpened, it bugs me a little. Sorry, maybe i am in a bad mood about it now.

 

[epsiloneri]

Re: 5D3 Problem black halos around stars in RAW files...hmm

I can't say but what about the fact that your points of light are ovals?

Since your question hasn't been addressed yet... the 'ovals' are due to motion blur.

 

[epsiloneri]

When i say it hasn't been processed and what is going on with images then it is still suggested i am lying and that it in fact has been sharpened, it bugs me a little.

I was commenting on Pedro's image. In your case it looks like hot pixels with demosaicing artefacts. Are the bright spots in your picture visible at the same pixel positions in other pictures taken at the same time with similar settings? There's always processing going on in producing images, it doesn't need to be the post-processing that introduces problems.

 

[wockawocka]

Looks like blown highlights to me. The light on the shiny point of her lip and the sequin of her veil catching it in exactly the wrong position.

Well sure it got blown in those tiny spots but being outlined in black is an artifact, un-natural to what an eye would see.

Could you send me the RAW file if I sent you my details?

 

[Bosman]

Looks like blown highlights to me. The light on the shiny point of her lip and the sequin of her veil catching it in exactly the wrong position.

Well sure it got blown in those tiny spots but being outlined in black is an artifact, un-natural to what an eye would see.

Could you send me the RAW file if I sent you my details?

I could, just pm me. It is jpeg.

 

[Bosman]

When i say it hasn't been processed and what is going on with images then it is still suggested i am lying and that it in fact has been sharpened, it bugs me a little.

I was commenting on Pedro's image. In your case it looks like hot pixels with demosaicing artefacts. Are the bright spots in your picture visible at the same pixel positions in other pictures taken at the same time with similar settings? There's always processing going on in producing images, it doesn't need to be the post-processing that introduces problems.

I am sorry, I apologize for being wrong about that. I didn't have any extra processes in camera, all that was off at the time. I have since allowed standard noise reduction in camera since it does so well. But yea I figure a firmware fix would be in order, but i don't know.

 

[wockawocka]

Looks like blown highlights to me. The light on the shiny point of her lip and the sequin of her veil catching it in exactly the wrong position.

Well sure it got blown in those tiny spots but being outlined in black is an artifact, un-natural to what an eye would see.

Could you send me the RAW file if I sent you my details?

I could, just pm me. It is jpeg.

Ah, will need the RAW file. Jpeg compression does all kinds of crap to the file, not to mention any adjustments Canon decides to apply (even with everything switched off in camera)....which I'm sure they do.

 

[pedro]

Anyone out there having the same problems while doing night sky?

Yes, I happened to take a night shot with stars using a 5D3 yesterday, and I see this precise phenomenom for saturated stars when the default sharpening is used (just tested). When I turn sharpening off, the black halos disappear. I just tried it but am to lazy to produce screenshots for you... just try it yourself. Using unsharp mask as a "sharpening" filter is particularly good at producing black halos.

Well, yours is a very valid point. After reading the tips provided by fellow posters, I went back and put the RAW sharpness settings and unsharp masking to zero before converting the file to TIFF and: halos are gone. So there is a simple cure to all that. Then in post in CS2 I just did some unsharp masking and that was it. Very satisfied about the result halo wise. But I also will take care next time and won't do 45 shots within 15 minutes!
Here's the new sample. I took these RAWs in mRAW.
http://www.flickr.com/photos/guatitamasluz/7963652382/#

 

[Mt Spokane Photography]

I went thru my 5D MK III images looking for a situation like yours, but could not find one. Here is a image of the sun reflecting off a gazing globe. Its a 100% crop, but no black ring. It is not badly blown out, but, if there were a issue, I'd expect to see it here.

This is a straight conversion from raw to jpg in LR 4, all the settings are nominal, no sharpening or NR.

 

[epsiloneri]

But I also will take care next time and won't do 45 shots within 15 minutes!

I have taken long-exposure (30s) shots continously for hours (star trails!) without noticing any significant increase in noise, so I'm not sure this is a real problem. It should be very easy to find out though: do you notice a significant noise increase in your last image (when the sensor is "heated up") compared to your first image (with the sensor still at ambient) of that 15 min interval?

 

[epsiloneri]

Here is a image of the sun reflecting off a gazing globe. Its a 100% crop, but no black ring.

The effect is more pronounced the greater the contrast (steep brightness gradient) and smaller the blown image, i.e. stars and hot pixels are ideal to produce dark halos. The sun in your image is more extended and bright also outside the saturated region, so sharpening shouldn't produce as easily visible halos.

This is a straight conversion from raw to jpg in LR 4, all the settings are nominal, no sharpening or NR.

Isn't sharpening applied when using nominal settings? (I'm not too familiar with LR4, but other software apply it by default) If you push sharpening using unsharp mask I'm sure you can produce a dark halo around the bright dot in the right hemisphere. Just to illustrate the effect. (looking closer at your image there actually seems to be a dark edge to the white spots [not the sun] - implying some sharpening may have actually taken place?)

 

[epsiloneri]

I went back and put the RAW sharpness settings and unsharp masking to zero before converting the file to TIFF and: halos are gone.

You can also reduce the halos in unsharp mask by playing with the unsharp radius, e.g. making it much bigger removes background on a larger, smoother scale. You can increase the brilliance of the stars quite a bit by doing this (by reducing the sky haze), but have to take care to not introduce artefacts on large scales, e.g. foreground objects like the mountains in your case (or the dark lanes in the milky way). You can get around this by using masks etc, but I'm starting to get off topic.

 

[wockawocka]

Yeah lightroom has default sharpening at +25

 

[Mt Spokane Photography]

Here is a image of the sun reflecting off a gazing globe. Its a 100% crop, but no black ring.

The effect is more pronounced the greater the contrast (steep brightness gradient) and smaller the blown image, i.e. stars and hot pixels are ideal to produce dark halos. The sun in your image is more extended and bright also outside the saturated region, so sharpening shouldn't produce as easily visible halos.

This is a straight conversion from raw to jpg in LR 4, all the settings are nominal, no sharpening or NR.

Isn't sharpening applied when using nominal settings? (I'm not too familiar with LR4, but other software apply it by default) If you push sharpening using unsharp mask I'm sure you can produce a dark halo around the bright dot in the right hemisphere. Just to illustrate the effect. (looking closer at your image there actually seems to be a dark edge to the white spots [not the sun] - implying some sharpening may have actually taken place?)

I set all the sliders for sharpening, NR, etc to zero. Other settings like brightness, highlights, etc were at the zero position.
LR does not actually have a default sharpness, you can set it and save it for different ISO levels of your cameras as well as setup it to process images with pre determined colors, etc. However, you can turn all the settings bacxk to zero. Lightroom does not actually change the image, it just saves settings for each image in a database, and they can be zeroed or changed at any time. Then, when you render a image to jpeg or other format, the settings are burned in for that exported image, but the original is unchanged.
The white spots are deposits left by birds going to our feeded, and indeed might have some black or various colors in them, so I'd not try to judge them from the photo.
As noted, I did not have a blown out image from my 5D MK III, it does a very good job of setting the exposure, and we did not have many sunny days when I was testing it.

 

[Bosman]

Canon has asked me to send them this file i screen shot. I just sent it so maybe later today or tomorrow i'll hear back from them.

 

[THX723]

Curiously enough, I did come across this black halo/ring phenomenal about a month ago. It was a night shot of the city and all around the bright city lights where these mysterious black rings. It was shot in RAW. No post processing. I will post the photo after I get home tonight.

I was a bit concerned initially (5D2 black dots?), but after a hasty Google search turned up nothing, I thought pleading ignorance would be the better part of valor. The fact is this was the first run-in after thousands of pictures taken (since 1st batch release); I brushed it off and never thought of it since.