Digital Photography Forums

Full Version: Messing Around With HDR
You're currently viewing a stripped down version of our content. View the full version with proper formatting.
Pages: 1 2
A few of the people on the site - most notably Irma and Guerito, but more recently Adam have been posting HDR shots that are realy very impressive. I finally decided to see what they are up to, and downloaded the Photomatix Pro trial package from their website.

I have to say I'm impressed. I have been converting using different exposures of the same RAW photos and the results are pretty cool. Using this different exposure technique from the same RAW frame isn't as good working from multiple braketed photos, but it is much simpler than bracketing as you need only one shot to do it. That way, I can also browse through my library and look for shots that can be saved by this technique. The flaw is that you cannot recreate badly blown highlights and you get a lot of noise in very dark areas when you overexpose the RAW. This would never happen if you had multiple shots each exposing part of the picture correctly. But what the hey...it's good enough for a test, and for shots where the difference between the highlights and the shadows is not too great, it works fine.

Here are a couple of shots from my New York junket that were idle in my junk photo file because they were basically unusable without spending a LONG LONG time in PhotoShop on each one to fix the exposure. For each one, I saved 2 exposures from the same RAW file, one exposed for the highlights and one for the shadows - which is about as basic as it gets in HDR processing.

I am definately going to buy this software. BTW: the trial download is fully functional and does not expire - but the final shots are watermarked all over the place with the PhotoMatix logo. This is a great way to demo software and I wish more companies would adapt this anti-piracy technique. At least then, you can actually test the software before purchasing.

[Image: Times%20Square.jpg]

[Image: Central%20Park.jpg]
They look great Rob. for what it's worth you could also emove those watermarks as I'm sure you know.
After fooling around with this all day, I think I am geting the hang of tone mapping... the last one is now somewhat improved...I now get the "spooky" look I was trying for...

[Image: 91_Central%20Park.jpg]
Toad Wrote:After fooling around with this all day, I think I am geting the hang of tone mapping... the last one is now somewhat improved...I now get the "spooky" look I was trying for...

]
Yep, that's certainly spooky. Fun stuff. Big Grin

I only have one remaining copy from any of my recent HDR experiments. This is one where I shot a series specifically for HDR and my aim was to get exposures for both the sky and the dark areas (mainly the tree) so I could balance them and get what I actually saw with my eyes - more sky detail along with dark area detail too.

I took a reading for the sky, took another for the tree then shot about 5 frames iirc. I'd used a tripod and cable release and started with the sky exposure then worked down to the tree trunk exposure at 1.5 intervals. The mistake I made was that I underestimated the movement of the clouds so that shows in the final image - I should've bracketed and the movement would've been less obvious.

Not anywhere near the sort of stuff we see from Guerito and Irma - not very exciting, just a nearby village green, but here it is anyway.

[Image: yew-st640.jpg]

Polly
The last shot of yours turned out beautifully. I'm not sure I see it as "Spooky" but it's now a perfect exposure.
That works really well Toad..sort of still "real" but with added presence; some folks' efforts I've seen almost look as if they've been superimposed on a background, a bit tacky. Your forays above have given me many musings around mono landies with this technique, yet thus far I've been stymied by Photoshop's insistence that I bracket ridiculously so have just lost interest. The skyline above has more than resurrected my interest.
btw Polly: is yours also done with photomatix? If so, I do like the subtler treatments you both have achieved with it..and actually that resulting "timed exposure" feel from yours Pol has set me thinking of all sorts of possibilities...say when doing an HDR of a lake and sky scene, for example...hmmm... I will investigate.
Yeah Zig - I was thinking the same thing as far as B&W landscapes with this technique - the skyline above converted to B&W (with Channel Mixer) looks something like this...

[Image: 51_Central%20Park%20B&W.jpg]
Heeeey, that looks very cool. I like it.Smile
Zig Wrote:btw Polly: is yours also done with photomatix? If so, I do like the subtler treatments you both have achieved with it..and actually that resulting "timed exposure" feel from yours Pol has set me thinking of all sorts of possibilities...say when doing an HDR of a lake and sky scene, for example...hmmm... I will investigate.
The images were merged to HDR in CS2 then tweaked with the Photomatix Tone-Mapper plugin (in CS2). I've only tried doing a specific series twice - the content of other series was even more boring. I need to get out more. Big Grin

A lake and sky scene would probably be an ideal candidate. I've noticed how the surface of water seems to have responded very well to HDR in some of Guerito and Irma's images. It seemed to have a very nice sheen and sparkle to it.

I've dug out the original files and am attaching a screenshot of how it all looks with the CS2 'merge to HDR' function. The hdri is then opened in photoshop and you take it from there with the tone-mapper and any other PS tools you wish until you get the final image you want.

[Image: mergess.jpg]

Pol
Lovely, Toad! Yes, I can see that work on skies can be given a great boost, as the mono results would be more faithful to real darkroom D+B...and I just know you'll be getting your teeth into some more!
Thank you Polly, thoroughly helpful as usual; nice to to have it as plug-in.
Miserly I know, but I did get hold of the basic free version: tantalisingly frustrating. Spectacularly crap too, in my present hands, leaving some worrying banding in the sky that I had to hose off with bucketloads of diffusion. I might have to save me pennies for the real one.
[Image: combo.jpg]
Wooa, now thats spooky! Awesome Zig.
Why, thank you my man!
I really don't like the haloing that it often creates around objects of different brightness.
Pretty cool work... I can see how your shot would have been easily blown out under conventional means, Mr T, but it looks great now.

Hm... they should build it into cameras as a special function, methinks... something like a cross between bracketing and multiple exposure...
StudioJ Wrote:I really don't like the haloing that it often creates around objects of different brightness.
I know what you mean - I don't really care for that either. I am working on methods of reducing it... I notice a lot of the publicity examples on Photomatix's own site exhibit that as well.
StudioJ's point has intrigued me: I don't know if it's just my eyes but this odd halation effect does seem more evident in the stuff on the site... I haven't come across it any of the HDR images I've seen here on the forums. Furthermore, it seems as though it is there on the pre-merged images and most evident on the pano example.
Now, that series of shots does seem as if the original pics were taken with a grey grad of some sort, with the main light source being behind the tree(sorry, am referring to something that some of you haven't seen): thus, the halo effect. This has subsequently come through all the shots into the resulting final image.
Toad, Polly or anyone else: is this effect rife(ie, software-based) as StudioJ has maybe indicated? Or is it merely the logical consequence of what happens in the original shots?
Sorry to drag out this thread, yet after Irma and G's initial forays and Toad and Polly's work with this, I confess I'm catching the HDR bug(and even the spending of 40 quid sterling needs much justifying in the povertystricken halls of Castle Zig of late!)
Zig Wrote:StudioJ's point has intrigued me: I don't know if it's just my eyes but this odd halation effect does seem more evident in the stuff on the site... I haven't come across it any of the HDR images I've seen here on the forums. Furthermore, it seems as though it is there on the pre-merged images and most evident on the pano example.
Now, that series of shots does seem as if the original pics were taken with a grey grad of some sort, with the main light source being behind the tree(sorry, am referring to something that some of you haven't seen): thus, the halo effect. This has subsequently come through all the shots into the resulting final image.
Toad, Polly or anyone else: is this effect rife(ie, software-based) as StudioJ has maybe indicated? Or is it merely the logical consequence of what happens in the original shots?
Sorry to drag out this thread, yet after Irma and G's initial forays and Toad and Polly's work with this, I confess I'm catching the HDR bug(and even the spending of 40 quid sterling needs much justifying in the povertystricken halls of Castle Zig of late!)
I've also noticed the tone mapping can produce some weird and unwelcome halo effects. You need to look closely as you map otherwise you can end up with the lighting all cock-eyed - sun apparently shining into the shadow as well as sunlight coming from another source to produce shadow ... ie apparently 2 sources of sunlight. Big Grin the other thing you need to watch is the colours in the sky. Any burned out areas can end up looking a sort of flat and unrealistic grey - once again I've found that to be better managed by using a separate layer for the tone mapping.

I mainly use the tone-mapper on a second layer so that I can tweak to 'lift' the lighting where I want it and 'dim' it slightly in other places. I find changing the smoothing and microcontrast as well as the luminosity and strength usually gives me something closer to what I want - then I copy/paste the tone-mapped second layer over the original and select the blend mode I want (usually normal or multiply) and reduce the transparency of that layer to anything between about 7-20% ..... depending on the image and what pleases my eye.

As for those images on the site - they always look rather extreme to my mind, though they do give some idea of what's possible.

David Nightingale (chromasia.com) and his friend John Washington have quite a lot of very artistic HDR images ont their blogs. I wish I could get the same sort of results but I sin't sussed how they're doing it yet so I just pootle along at my own pace.


Pol
Lovely, Pol; hmm. Am continuing this on another thread(getting lazy with scrolling!)
Sorry, Pol, I lied(it might look rude of me if I hijacked!).

[Image: w1and2combo-web.jpg]

OK, this is with Photomatix basic(free) version. It combines 2 versions of the same image; the range between the 2 images is 2 stops, yet of course each image has its own dynamic range anyway. The scene itself has a considerable dynamic range: shot at midday in strong sunshine, glary white limestone, deep and angular shadows...an exposure nightmare of (I'd guess) 4 stops or so(?}
This is a noisy image, evident upon close inspection and in the detail in the crop lower down, shot at 800ASA.
I again found that darn "haloing" but also found this can be mitigated to some degree by keeping contrast low at the conversion stage.
Firstly, I have to say I'm pleased with what the software can give me in terms of extracting more detail..though I don't trust it to give me a final, finished image. What it does provide is more "choice", more information and detail, so as to provide one with a better chance!
I've found in this mono conversion that I have to do less dodging and burning to get what I want: this is fine for me as CS2 doesn't really do either in terms of what one expects from a darkroom. In short, Photomatix at the very least, provides me with opportunity to avoid getting into the "contrast spiral" when using D+B on a mono image.

[Image: w1and2-web-detail.jpg]

Here's a 100% crop of some detail.
Notice the hints of that haloing: this increased when I chanced using a higher contrast pair of initial images...and I've no doubt that it would quickly worsen upon any but the most careful use of D+B. It is not "fringeing": it does not exist on either of the inputted images; rather, it seems to remind me of the same "blend"-type algorithm on some panorama-making or depth-of-field enhancing(eg, Heliconfocus?) tools. I'm not sufficiently knowledgeable about such matters, but am inclined to think that the "answer" to any problems with this haloing lies in a) keeping contrast low at the inputting stage; b) ideally having the option to save as layers.
I may be well off-track here and am keen to be educated by the experience of you who are really getting to grips with the tone-mapping side of things. Of course, the free version of this software IS free and hasn't been tweaked for a year or so, so it may perform more raggedly than its "Pro" stablemate....but at present I'm drawing shy of spending my cash on something that quite honesly won't have the "legs" to make it to hard copy at decent sizes(well, with my 350D at any rate)
I'd also be interested if anyone knows the limitations of it in terms of file size...I'm guessing 2 gigs. (The reason I'm musing about this, is because of its implications for doing a tone-mapped combo of the same pano/mosaic at different exposures btw...maybe the guys at tawbaware have additional experience here too?)
The haloing occurs mainly on very high contrast edges and it affects the blue channel the most (at least in my images). I find you can reduce the haloing a great deal by playing with a combination of the white clip, luminosity, and strength settings (on the full package anyway - not sure about the freeware) and with the blue channel in curves (PhotoShop). So far, I can't manage to eliminate it on all shots - and when it is extreme - I don't use that technique. At PhotoMatix, they must *like* the effect, because they show it front and center on such shots as the tree one Zig is describing.

This software doesn't work well on "noisy" cameras like my A2 - it greatly enhances the noise as well as the detail - but works great on the D200. It also is not that great when your photo has large patches of sky and that sky is featureless - i.e. no clouds - just a blue expanse. This may be due to the blue channel issue I was talking about (but who knows? I'm no bloody scientist)

My newest workflow involves tone mapping using only a single RAW image - I read an explanation of how blending exposures of the same RAW image adds nothing when tone mapping - and that is probably true. The exposure blending software gives a much more natural look than the tone mapping, but the tone mapping is also pretty cool. The first 2 shots in this thread are exposure blending (you need at least 2 exposures of the same RAW image for this) and the rework of Central Park is done with tone mapping. You can see the difference in the techniques. As far as I can tell, exposure blending doesn't exhibit the same issues with haloing.

Like all Photo techniques, this is just a tool - not an auto generator of great photos. I always take the blended/mapped image into PhotoShop and do my own thing with it afterwards anyway. What this software does is really not that much different than what I have done many times by brute force in PhotoShop using masks, levels and curves. It is a huge time saver however, and time is (if not actually money) still worth something to me.
Nice, Toad.
Oddly(though I'm sure quite logically to those in the know as to why), it's with the blue channel and with the contrast you mention that I've always had to be very careful when doing monos: seems to be very unforgiving with noise and artefacts anyway, and things can get very blocky.
Thanks too for pointing out the exemplars of the difference between the blended and TM pics, as I couldn't readily visualise the difference. "Brute force" indeed; neat.
More peripherally, was it Jules who mused recently about the possibility of having something like this quite literally "in camera", as 'twere? I realise too there are folks out there who for a ridiculous fee, can disengage the limiter on the sensor, thus making accessible the more infra-red end of things. This is a propos nothing, I suppose, yet I'm beginning to feel that digital snapping is or can be an extremely different animal than we presently view it..indeed, that there is more under the hood that can be done rather than just satisfying the "more MP=better" drive.
I'm wandering here; at times like this I have to remember that the reason I got this camera was somehow to do with spending time outdoors and using it.
Thanks for all your thoughts and help with this.
I've had a play too see what I can come up with from recent shots. I'll try some people shots next to see how odd I can really get it! This is from the weekend, I've tried to control the haloing which is also apparent with the action I have been using before the current batch of HDR packages were around.

This is a Photomatix shot...

[Image: three.jpg]
I meant to fix the barrel distortion but forgot about it, forgive the curvyness of this last shot!
Actually mate, the curviness adds drama...(though it's just aiming the lens down a bit isn't it, rather than inherent barrelling within the lens?)
OK...is this "tonemapping" then? I do like the shot, though not sure I'm all that impressed with this effect...sort of makes everything look a bit "2D"; guessing that less is more here: mind you, I guess one could use it as a layer...?
(Oops, sorry 'bout all the questions: 2 of them are rhetorical really!)
Firstly I need to learn how to actually use the features so I can make a decent image, I don't like the effect it has had however from the original capture this image has a huge range now, I don't like it but I can see the purpose of it at least.

It really does have a bulge in the middle but its not that noticeable except on the horizon line where it bulges outwards in the centre and low in the sides.
Pages: 1 2