BLUE SKYS - Digital Noise in Digital SLRs

[kpy]

DIGITAL NOISE IN BLUE SKYS

Not sure of the correct digital term for this type of noise and noise speckles through blue skys - is it called "moire"???

I'm new here, and not sure best spot for this question in these forums, in a lot of ways its a general question, but the issue arose for me with some daytime sports shots with a Canon 40D.

Haven't done a lot of middle of the day type landscape or sky shots with digital SLRs, but the effect really caught me by surprise, especially with actual prints or enlargements. Got me thinking about using the Eos Vs or 3 for some of this stuff instead.

For these types shots (its motorsport with a few different types of sports within it) a lot usually involve a lot of blue sky if u can get it (though sometimes its also at night which is will not have this particular issue), and then sometimes shots are at sunset also. Other versions of the sport are a bit more grounded, but they all get aerial so to speak.

Have since read this can be a problem for the digital SLRs generally - we get lovely bright blue skys here, and if u add a polariser its an even deeper blue.

Guess there’s a number of ways to approach it, including camera swap/replacement - though also have lots of pix which would otherswise be fabo without this very pesky pesky problemo

And so guess I have 2 question types:–

A. HOW TO FIX / MINIMIZE PROBLEM - IN CAMERA / IN SOFTWARE??

guess there are different ways to minimize/correct problem in raw or other file types in software or perhaps in the camera also?

have considered a few different options on this, and tried reading up on it e.g. ---

- replacing the blue sky (sounds like a lot of work)
- fiddling with saturation settings in software settings in raw settings etc (?)
- making the sky lighter in software (?)
- noise reduction and sharpening in software (no idea on that really)
- sharpness and noise settings in camera was another suggestion - but maybe not really if I need the sharpness of the subject
- etc ???

- my photoshop skills are self taught and primitive - been meaning to ask in some forums ….. if this digital blue sky problem has been around for a while, maybe there’s some software experts out there who know the best way/s to minimise or fix it?

B. UPGRADING DIGITAL CAMERAS TO A BETTER CANON/NIKON

- in terms of upgrading cameras above the level of the 40D/50D - any ideas/feedback on whether other digital SLR canon/nikons may still have this same kind of problem? And if not which might be okay/much better?

- to be honest any blue sky grain is gonna be a pain for my purpose, and is really tempting me to go back to Eos Vs or 3 with at least some of this.

- are the latest higher level canon and nikon digital slrs really up for sky landscape photography now? and with sky shots, and blue sky shots? or is it still best to go with film for now for anything remotely landscapey or blue sky ?? Maybe the Canon DMkIII or DsMkIII could both handle it?

- guess full frame digital may do a better job with this, but I really need the 6.5 / 7 ++ fps for the sports option, for this motorsport stuff and other sports/action photography as well. (the 40D raw buffer and processing time is also not handling the demands of some of this sport either really.)

Wondering perhaps if this new Canon 7D may help to eradicate this problem of digital grain/artifects in blue sky ?????? Or best to wait for a new Canon D or Ds Mk 4 ? Im guessing/hoping that with all the ISO improvements now its less of a problem???

Would be great to shoot at 800 ISO or 400 ISO etc without this blue sky noise effect.

The 5DII is tempting but far too few focus points overall, and especially frames per second for the sports stuff.

Nikon stuff is very very tempting now too.

Regards
KPY

[JFSanders]

The answer depends on your level of commitment. Pros buy or rent whatever gear is needed to produce the product that sells. They calculate the cost of doing business and charge appropriately. Amateurs buy the best they can afford and then compensate as much as possible with camera skills. If you have the money then go all out. If you don't then knowledge will be your only chance!

As to digital noise in the sky. It would help if you posted an example of what you are seeing with the exif data attached so we can see what settings and types of noise.

Welcome to DPS. It is nice to have another motorhead on the forum.

[kpy]

lol, thanks muchly for the welcome

yes, im looking forward to doing a whole bunch more of the motorsport stuff, and am gonna need the camera upgrade

... and that much I do know ! lolll

but this problem with the blue sky was a new one on me - and it was potent most of all when printing (even smalls)

?no one has ever heard of this blue sky noise / moire problem for digital cameras problem?

yes, im waiting to see what Canon do with their next couple of cameras over coming months, and yes, but renting is $400 / weekend (which I may do, but if I do I dont want the same problem?? in a Canon DMkIII), or else some film which will also cost, still for the night time gigs coming up I'll probably rent (my little camera is still getting over the dust also haha ....)

regards

[kpy]

Since found this an interesting thread discussion -

- like where they talk about this problem, and how its magnified for colours like blue/blue skies - even with a Canon 5D II


iStockphoto.com thread -- " 5D Mark II and the blue skies ":-


http://www.istockphoto.com/forum_messages.php?threadid=105571


Basic shot info:-


Canon 40D

ISO 800 + similar effects with ISO 400 also, but bit better

Shutter 1/1000th

F 9 - 11

Polariser

Day temperature/s
- medium to warmish
- & camera had been in used in sun, as is mostly the case here, and in the car during driving but in Lowe backpack (as was being used for much of day/s or a number of hours) - from what I read on this & other sites,
possible temperature influence also I guess

[LoveDSLR]

Originally Posted by kpy

DIGITAL NOISE IN BLUE SKYS

Not sure of the correct digital term for this type of noise and noise speckles through blue skys - is it called "moire"???

According to DPanswer: Defects, "Noise in digital images is most visible in uniform surfaces (such as blue skies) as monochromatic grain (luminance noise) and/or as colored speckles (color noise)."

Image Noise: Examples and Characteristics

Originally Posted by kpy

- noise reduction and sharpening in software (no idea on that really)

noise ninja?

Originally Posted by kpy

- guess full frame digital may do a better job with this, but I really need the 6.5 / 7 ++ fps for the sports option, for this motorsport stuff and other sports/action photography as well. (the 40D raw buffer and processing time is also not handling the demands of some of this sport either really.)
..
Would be great to shoot at 800 ISO or 400 ISO etc without this blue sky noise effect.

Nikon D3 is FF, low noise high ISO (up to 6400) and 9 fps.

Originally Posted by kpy

Wondering perhaps if this new Canon 7D may help to eradicate this problem of digital grain/artifects in blue sky ??????

7D is not FF and noise will decrease with increasing sensor pixel size.

Originally Posted by kpy

Or best to wait for a new Canon D or Ds Mk 4 ? Im guessing/hoping that with all the ISO improvements now its less of a problem???

I doubt 1D4 is FF and 1Ds4 has fast fps.

[kencaleno]

Your problem is luminance noise. In photoshop,select sky area with lasso tool and apply smart blur at default setting. Ken

[OsmosisStudios]

Originally Posted by kpy

Basic shot info:-


Canon 40D

ISO 800 + similar effects with ISO 400 also, but bit better

Shutter 1/1000th

F 9 - 11

Any particular reason you chose f/9-11? Opening up just one stop to F/8 would get you back into the iso 400 range, and cutting your shutterspeed in half (if your subject can handle it, which is usually at that speed) gets you back into the ISO200 range.

What are you shooting that requires such high shutterspeeds?

Not only that, but I have no problems shooting 400iso in daylight as long as the image is properly exposed. Even 800 can give some AMAZING results. And thats on a D80!

[Doug Pardee]

The problem of red noise in blue skies is fundamental to Bayer sensors (which effectively means anything other than Sigma DSLRs). Each individual sensor site is particularly sensitive to one primary color, and the camera uses a "demosaicing" process to detemine the color for each output pixel.

In a blue sky, the sensor sites dedicated to Red aren't picking up much of anything and are mainly just producing noise. With most camera sensors, the Red sites need to be amplified quite a bit to achieve proper white balance in daylight conditions. The result is red noise in the blue sky.

What to do about it? Here are some options.

1. Nothing. People get all worked up about noise that isn't visible in the prints. You'll always see noise if you're pixel-peeping at 100%.
2. Use a lower ISO. ISO 800 is going to be noisy on anything less than a "full frame" camera. Take off your polarizer and use ISO 200.
3. Be careful not to overexpose. If you overexpose the sky it will overload the blue channel, giving the green and red channels more power there, and the red channel is mostly noise in a blue sky. If you properly expose, the sky will be nice and blue without needing the polarizer.
4. Use a good noise-reduction tool, select the blue sky, and reduce the noise in the sky. Go easy on this. You'll never remove all of the noise. You just want to remove enough noise to get good prints (or whatever your output medium is).

[kpy]

thanks very much for all the advice peeps

Prints - yep, and the test prints (to me at least) were crap (i.e. the sky part)
- shocking in terms of speckles in the blue sky - totally surprising
- never eva seen anything like it actually - even a bunch of 6 x 4's
- except where the sky was lighter there was some noticeable improvement (but still not great for bigger prints), so yep agree leaving off the polariser sounds a goer

but there seems no problem with the main subjects in the photos (e.g. riders and bikes)
- they turned out really good, and pretty sharp and clear (even though they tooo were blue or partly blue)
- so much so really want to fix it, and try prevent it happening again, & would maybe give serious consideration to total sky replacement in the best pix of these pix if knew how, or something ? gotta be something ?

400 ISO is a little better, and yes far preferable, tho not heaps in terms of this blue sky problem here
- had not really used the ISO 800 much on the 40D (in daylight)
- so pretty disappointing
- & also pretty reluctant to bother much with ISO 400 for skys/daytime landscapes on 40D now.

Why prefer ISO above 200 for fast action sport / motorsport / unpredictable sports (where possible) ??

yep, for usual very good reasons

- because it is an action packed motorsport
- because they are moving across the lens, & not towards it
- lots of continual panning is involved
- because there is 1, or more different things/peeps contantly moving high through the sky in unpredictable paths doing unpredictable movements like turns, twists & somersaults (& literally all of those at once)
- subject will often also be a fair distance away - eg. 50ft high or even much more, plus some ground distance away
(sometimes shots will also be at night or sunset, but which perhaps has a somewhat different set of factors to consider)

This is fun to shoot and watch and the shots are fine - except for the crappy digital artifects in the sky.

Possible Heat Factor - from reading, it seems possible heat may have also been a factor to heighten the speckles on this particular day/usage - maybe this may help to explain the extremity of the effect???

Fuji pro 800 or 400 film on an EOS3 or VS

- seems Fuji film would have done an exceptional job with the sky by comparision to the 40D, and even to the new 5DII by the sounds of it???

How do u reckon a EOS DMk III or Ds Mk III might go with the sky? Similar problems? or much better? How are they with the higher ISOs?

[kpy]

Originally Posted by OsmosisStudios

Any particular reason you chose f/9-11? Opening up just one stop to F/8 would get you back into the iso 400 range, and cutting your shutterspeed in half (if your subject can handle it, which is usually at that speed) gets you back into the ISO200 range.

What are you shooting that requires such high shutterspeeds?

Not only that, but I have no problems shooting 400iso in daylight as long as the image is properly exposed. Even 800 can give some AMAZING results. And thats on a D80!

Yeah, guess ur correct there.

Admit it was also an experiment initially, not having seen this division of the sport live before.

It involves motorsport and people and things flying 50 ft plus in the air doing tricks, and in various light conditions - in this case mid-afternoon.

Perhaps one of the more challenging sports in sports photography, but the results turned out real good, except for the crap digital sky!

Havent tried ISO 200 yet, but doubt it will cut it overall for this action packed motorsport
sometimes its all a compromise I guess
we'll have to try a bunch of test shots next practice time as well and see what happens
Safe action shots are few and far between with this fast wild action sport

A Nikon D80 hey ..... true? ... damn.... lucky u ...... some of these Nikon's are sounding good nowadays.
Been very partial to Canon for ages, and their focusing and colour, sounds like some Nikons may have skooted ahead!