p.1 #1 · dynamic range how to deal with posturisation
Hi I have been shooting a few snow scenes with my 7D and Tokina 11-16 lens
I have noticed a bit of blotchness in the sky whats called I think posturisation
not had it before I think its caused by a lack of dynamic range at high ISO but was surprised to see it at low ISO and good light
Its only slight and I have to look hard to see it
Is it my monitor or can others see it?
this is the shot and also a big crop of the sky to show it
this shot was at 60th at F16 and ISO 200 processed in lightroom , did not push the exposure at all in converting the raw
Is it just a fact of life with the 7D or can I minmise it?
p.1 #2 · dynamic range how to deal with posturisation
Looks mainly like noise to me although there may be a small amount of clumping/posterizing due to the dark blue tones falling into the sparse region of the raw file's linear gamma.
The good news is that it is pretty easy to eliminate this with some targeted noise reduction.
p.1 #3 · dynamic range how to deal with posturisation
Considering 7D is bit noisy I think ISO 100 might be better choice?
What you are seeing isnt posterization but whats left after noise removal. Solutions are probably both in shooting and post-processing.
In this case I would probably process photo as two, one for everything except sky (means regular sharpening, NR etc.) and one for sky (no sharpening and strong NR) and then blend them together.
Since you are using Lightroom you can simply apply various effects selectively in it, so you dont even need blending of photos or PhotoShop.
Considering I saw pretty good landscapes from 7D I guess it must be possible somehow.
p.1 #4 · dynamic range how to deal with posturisation
Ahh I see thanks for that
Glad its noise as I can deal with that
Will redo them with noise removal for the sky
I,ve not noticed this before but I dont do that much landscapes mainly macro , I guess blue sky is more prone to noise than the green backgrounds that I normally have
p.1 #6 · dynamic range how to deal with posturisation
LCPete wrote:
Ahh I see thanks for that
Glad its noise as I can deal with that
Will redo them with noise removal for the sky
I,ve not noticed this before but I dont do that much landscapes mainly macro , I guess blue sky is more prone to noise than the green backgrounds that I normally have
Yes, blue sky is problem for many cams. Its because red and blue channels are always weaker than green. In case of 7D red is weakest (sorta normal for Canon) and blue needs to be boosted about 150% to match green under daylight (at least thats what DxOmark says). Its different under different lights. As light in this scene was probably quite cold, it might caused slightly worse performance (winter blue sky scenery is usually harder than summer one on camera).
Add to that fact that its simply bit noisy camera and it can now and then produce this.
p.1 #7 · dynamic range how to deal with posturisation
Mescalamba wrote:
Yes, blue sky is problem for many cams. Its because red and blue channels are always weaker than green. In case of 7D red is weakest (sorta normal for Canon) and blue needs to be boosted about 150% to match green under daylight (at least thats what DxOmark says). Its different under different lights. As light in this scene was probably quite cold, it might caused slightly worse performance (winter blue sky scenery is usually harder than summer one on camera).
Add to that fact that its simply bit noisy camera and it can now and then produce this.
Thanks for explaining that
That does make sense I did have to warm up the white balance on the raw as it did come out a bit blue (cold)
p.1 #9 · dynamic range how to deal with posturisation
Beni wrote:
Are you making sure to output in 16 bit? That used to make a big difference for skies back when I was shooting the 1Ds.
Am shooting in raw and converting the raw in lightroom then sharpening in PhotoShop
Only going to 8 bit when I change it to jpeg
p.1 #10 · dynamic range how to deal with posturisation
Does LR only output in 16 bit? Sorry I use ACR which gives the choice.
Apr 09, 2013 at 05:14 AM
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p.1 #11 · dynamic range how to deal with posturisation
the 7 is known to be noisy. blue channel has the most noise generally on every camera. under exp shows this as well and can be seen and evaluated in the second exp with more light.
so always ETTR where possible.
