Save 50% On Affinity Photo Today!

Noise in HDR images


Phil_D 13 81 Scotland
16 Feb 2007 8:02PM
I am still playing around with different methods of working HDR images, but a recurring problem seems to be levels of noise in areas of shade - see the keel on this boat.

I am using a Nikon D80 shooting RAW. I use Photomatix Pro, and have tried processing both raw, and TIFFs produced via Capture NX. Raw vs. TIFF doesn't seem to make much difference?

Does anyone else experience this, and what workrounds have people come up with.

Thanks in advance.

Phil.

Join ePHOTOzine for free and remove these adverts.

culturedcanvas 14 4.7k 59 United Kingdom
16 Feb 2007 8:05PM
Your initial exposures are probably out, or there isn't enough range in the exposures you are taking to cover the whole dynamic range of the image. Make you you get the mid exposure spot on ... and that you retain information in the most underexposed shot you do and also in the most overexposed shot.

The other thing to remember is that you need to make sure your exposures are evenly spaced as the software relies on this.

Dan
culturedcanvas 14 4.7k 59 United Kingdom
16 Feb 2007 8:10PM
How many exposures were in that shot out of interest?
Phil_D 13 81 Scotland
16 Feb 2007 8:20PM
Three . . .

dit - let me be a little more helpful (!) three images, each 2 stops apart, with the middle image reading as 'correct' according to the camera's 3-D metering.
culturedcanvas 14 4.7k 59 United Kingdom
16 Feb 2007 8:22PM
There's your problem

Smile

5-7 should see you right.
Phil_D 13 81 Scotland
16 Feb 2007 8:24PM
Thanks Dan, I'll try & give that a try.

Phil.
keithh 16 25.7k 33 Wallis And Futuna
16 Feb 2007 8:28PM
Most daylight HDR is done using about three exposures at two stop differences. There is a huge discussion going on at the moment amongst PM users but the big players are going with three. Without seeing the histograms for your three exposures it's impossible to say anything for sure here other than the noise in this case appears because your lowest exposure wasn't low enough. The software then calculates the weight across the pixels and attempts to build in a shadow area and comes up with the noise. Your lower exposure needed to be one/two stops under what it was.
culturedcanvas 14 4.7k 59 United Kingdom
16 Feb 2007 8:30PM
Different for night shots tho Keith or shots where there are large areas of bright light and dark shadow in the scene. Obviously using the histogram is the easiest way to check.

Dan

EDIT - you may get away with three exposures on a camera that has a high dynamic range to start with however Im not totally convinced by this .. and am surprised that you would go along with that too??

Reasoning behind it?
Boyd 16 11.2k 11 Wales
16 Feb 2007 8:33PM
I thought you were talking about Timberjack's image? That boat doesn't look like night-time to me.
ZenTog 18 7.9k 1 England
16 Feb 2007 8:33PM
i am still undecided about HDR landscapes, every one I see looks a lot different to the average landscape, but most seem to have an unrealness to them the light doesnt look right, it reminds me of the old colour three D pictures from the 70s . It may be heresy to suggest this, but I am looking from outside the world of landscape photography inwards
culturedcanvas 14 4.7k 59 United Kingdom
16 Feb 2007 8:34PM
True - day or night is actually irrelevant ... its the total dynamic range in the shot that really matters. Mathematically at least .....

Its just that night shots tend to have more dynamic range that you might initially imagine.

Dan

EDIT - Paul ... it's perfectly possible to produce HDR images with a totally realistic effect. My recent posts are created slightly unreal for a reason - however straight (or seemingly straight shots) can be achieved quite easily.
keithh 16 25.7k 33 Wallis And Futuna
16 Feb 2007 8:35PM
Boyd 16 11.2k 11 Wales
16 Feb 2007 8:36PM
I agree with you partly Paul. There are a lot of HDR images that look unreal but there are a few that do convey a sense of realism.
A lot of it I suspect is down to expertise with the software and camera craft.
ZenTog 18 7.9k 1 England
16 Feb 2007 8:38PM
keith and Dan which images in your portfolio were the first to use HDR
I remember the pier shot keith with the totally weird lighting did this use HDR

even somebody like patrick smiths landscapes wit hHDR are pickable as hdr from the thumbnails
Boyd 16 11.2k 11 Wales
16 Feb 2007 8:39PM
The thing is Paul, how many didn't you spot?
;o)

Sign In

You must be a member to leave a comment.

ePHOTOzine, the web's friendliest photography community.

Join For Free

Upload photos, chat with photographers, win prizes and much more.