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Severe Clear Skies and Noise


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I'm not looking for a complete tech workflow answer here. Obviously that would be too much to deal with in the forum. I'm just wondering if I'm thinking in the right direction.

 

>> I was shooting the new Freedom Tower yesterday, and yesterday there was an ultra-clear blue sky, called "Severe Clear" by flyers. I judged that I had a one-stop underexposure, and when I tried open up some to lighten the sky I got noise (ISO200 on the Sony NEX-6). 

 

I'm wondering if the way to try to rid myself of this noise is by using "Layers" in CS5? Is that where I should be, in layers? I have not used layers in a long time, so I'll have to review the workflow in a few YouTube videos.<<

 

 

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If you shot raw, then the best way I think is to use the noise control (particularly the color noise control) in Lightroom under the Detail panel (LR4) and make sure you are not applying any sharpening. Alternatively in PS you could select the sky and apply a slight gaussian blur or similar to the sky area only - no need to use layers for this but you could make a copy of the background layer if you want to make sure it is non-destructive.

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Ed

 

I am considering, still, buying the NEX 6 for stock work but noise in the sky at 200 ISO does not sound so good. This after shooting clear blue skies with Canon 5D II at 400 ISO and no, or very little, noise.

 

Is the noise from NEX 6, in this situation, particularly bad in your opinion?

 

Allan

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As I pointed out, Allen, this was an unusual situation. Opening up under-exposed shadows normally will cause noise, regardless of the ISO. I've taken hundreds of images with both the NEX-6 and NEX-7. So far I've never had a NEX image fail QC. Even at ISO800 or 1,600 almost all noise was correctable in LR, as MDM suggested. Yesterday's sky was most unusual. You will never see a sky like that is the British Isles. 

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As I pointed out, Allen, this was an unusual situation. Opening up under-exposed shadows normally will cause noise, regardless of the ISO. I've taken hundreds of images with both the NEX-6 and NEX-7. So far I've never had a NEX image fail QC. Even at ISO800 or 1,600 almost all noise was correctable in LR, as MDM suggested. Yesterday's sky was most unusual. You will never see a sky like that is the British Isles. 

 

Thanks Ed.

 

Allan

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I've been using the NEX 6 for some months now ISO200, 400, 800 and 1600 and haven't come across any noise issues so far. On the very rare occasion that noise does appear with any of my cameras I find its easily dealt with in LR's detail panel.

 

As Ed says, we are unlikely to see such a sky in the UK, so I cant really imagine what he is seeing in his picture.

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I was shooting in Mexico earlier this year. There were some intensely blue skies, and I noticed a bit of sky noise in several images taken with the NEX-3 (ISO 200). A touch of regular noise reduction in PP cleared it up easily and the images passed QC. 

 

Also, it was very hot where I was (the Yucatan), and I was wondering if the high air temperatures might have somehow affected the camera's sensor.

 

I haven't used "layers" since I last baked a cake. ^_^

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DEF81J  This is one One World Trade Center image that went up on Alamy this morning. Have you even encountered a sky like this? 

 

 We do get some ultra blue skies like that in Vancouver, and some ultra grey ones as well, unfortunately.

 

Nice composition. I wonder if the glare from all the glass might have affected the camera's sensor in some mysterious way. Vancouver is now a city of glass, and the glare can get pretty intense on some days. Personally, I'm still a fan of natural stone architecture, of which you've still got plenty in NYC. It's much easier on the eyes.

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Remember the sensor is least sensitive to blue and most to red, and that the filters and raw balance bias in a big way towards noise in blue sky tones - on every camera made. Generally you can get rid of them using colour NR plus luminance NR in a balance which does not remove any detail. Many monitors exaggerate the appearance of blue sky noise because they do not have the correct bit depth and therefore create banding - which also shows up as noise.

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I lived there for about 8 years, Mark. Pull the other one; it's got bells on it.  :)

 

John, what is most interesting about the Wall Street area is that it has some of the earliest buildings in America and some of the newest. I'm going to go down there again right now . . . with the NEX-7. I can't put my finger on it, but I suspect myself of making a small mistake in my workflow. Unfortunately, I don't know what it might have been.  :rolleyes:

 

This is the last severe clear day; rain tomorrow, I think.

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I lived there for about 8 years, Mark. Pull the other one; it's got bells on it.  :)

 

John, what is most interesting about the Wall Street area is that it has some of the earliest buildings in America and some of the newest. I'm going to go down there again right now . . . with the NEX-7. I can't put my finger on it, but I suspect myself of making a small mistake in my workflow. Unfortunately, I don't know what it might have been.  :rolleyes:

 

This is the last severe clear day; rain tomorrow, I think.

 

I haven't been in that area for a long time. My grandfather, who was a stone mason, emigrated from Britain to NYC during the early 1900's. He worked on buildings in Manhattan, including the Empire State Building according to my father.

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Remember the sensor is least sensitive to blue and most to red, and that the filters and raw balance bias in a big way towards noise in blue sky tones - on every camera made. Generally you can get rid of them using colour NR plus luminance NR in a balance which does not remove any detail. Many monitors exaggerate the appearance of blue sky noise because they do not have the correct bit depth and therefore create banding - which also shows up as noise.

 

I can echo what David has wrote here. I've read that using too low an ISO for the sky can produce noise in it. I understand the mechanics of why however I'd be rubbish at explaining it. 

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I guess I owe all you UK members, and perhaps the Crown, an apology for dissing your weather. Forgive me, please!  :o

 

Reexamining the last few days at the Freedom Tower, I must point out a few details I failed to mention: (1. On the first day I had a friend with me who was talking into my ear. (2. I'm coming down with a virus. (3. The NEX-6 sensor needs attention, a wet clean kit. Some of that "noise" was "dust." (4. I suspect that I made a few mistakes while trying to follow my normal workflow.

 

I mentioned that I had under exposed (about a stop) and then opened up that dark blue sky. And because I was shooting at ISO200, I may not have used the LR5 noise tools at all. Not sure about this, but I think so. Thanks for your help. Onward and upward!

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I shoot mostly in Florida and we have brilliant sunlight year round and those bright blue skies are quite common in the winter months.  I've find images will often have some noise in those intense blue skies but Photoshop/Lightroom or other noise reduction software handle it readily.  Like others suggested you can selectively blur the blue sky portions of the image.

 

I just purchased and have been shooting with the NEX 6 with 16-50mm kit lens for two weeks and although it's APS-C sensor has a bit more noise at high ISO's than my 5DM2, it's not a serious problem and most images are bright and sharp, even when shooting with ISO 400 and 800.  I'm quite happy with the NEX 6 as a everyday compact alternative to my 5DM2.

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Ed

 

I am considering, still, buying the NEX 6 for stock work but noise in the sky at 200 ISO does not sound so good. This after shooting clear blue skies with Canon 5D II at 400 ISO and no, or very little, noise.

 

Is the noise from NEX 6, in this situation, particularly bad in your opinion?

 

Allan

 

 

Allan,

 

Dont worry. I shoot for longer time with the NEX 6 now and i dont ever had failed QC. Also the ISO performance is amazing. It is far better than i ever had with my Canon 50d. ISO 1600 no problem for this camera.

 

Mirco

 

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Ed

 

I am considering, still, buying the NEX 6 for stock work but noise in the sky at 200 ISO does not sound so good. This after shooting clear blue skies with Canon 5D II at 400 ISO and no, or very little, noise.

 

Is the noise from NEX 6, in this situation, particularly bad in your opinion?

 

Allan

 

 

Allan,

 

Dont worry. I shoot for longer time with the NEX 6 now and i dont ever had failed QC. Also the ISO performance is amazing. It is far better than i ever had with my Canon 50d. ISO 1600 no problem for this camera.

 

Mirco

 

 

Thanks Mirco

 

Allan

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I guess I owe all you UK members, and perhaps the Crown, an apology for dissing your weather. Forgive me, please!  :o

Ed, no apology necessary. The UK weather is consistently c**p!

Although we have had a pretty good summer this year. As far as the Crown goes, the Queen is probably in agreement with me..............but she probably doesn't use the same language to describe it.

 

The Duke of Edinburgh probably does though!  ;)

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  • 3 weeks later...

I'm having this issue right now with photos taken in Seattle with my NEX-7 last weekend. I've never seen it this bad, the blue skies are a mess really. I'm experimenting with different combinations of colour and luminance NR but I keep seeing darker blotches in the skies.

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I recently processed some NEX6 shots taken within and then outside a church. Forgot to change the ISO and took the outside shots at ISO800 with a clear blue sky. There is some noise in the sky, but nothing that couldn't be handled in LR. Using a vintage fixed focal length lens, the detail in the 800ISO shots is amazing.

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I'm not a lens nerd by any means, but I wonder how much the optical quality and other characteristics (e.g. focal length, coating, etc.) of lenses have to do with the appearance of noise. It seems to me that sky noise --  which is of course produced by the sensor -- can look worse with some lenses.

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