First Image Attempt using HDR in photoshop UPDATED IMAGE


petekd

Link Posted 15/04/2007 - 18:58
Hi All

I am sure most of you have heard of HDR (High Dynamic Range) in PS. Below is my first attempt using this method by merging 3 identical image that were taken underexposed to capture the nice sunset, a mid range exposure to capture mid tones and over exposed shot to capture the detail of the the foreground image.

I then used HDR merge and the setting to automatically aline the images and finally played with the curve settings of the dark and light points of the histogram. I finished off with a little sharpening and ended up with the image below.

Please bare in mind it may look different on different monitors ie: to light or to dark but on mine it looks fine as my monitor has been caliberated using eye one display gadget so it should be fairly accurate

Let me know your thoughts on the image and the outcome using HDR method

Cheers Pete



Wedding & Portrait photographer

Arthur Dent

Link Posted 15/04/2007 - 20:14
Excellent image. I don't know if it counts, but I've done similar things by rendering a RAW image for highlights and then for shadows. I combine them into one image.

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113136AA.html

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113140AA.html
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petekd

Link Posted 15/04/2007 - 20:25
Great images Arthur I love the second one especially.

Cheers Pete
Wedding & Portrait photographer

ChrisA

Link Posted 15/04/2007 - 20:27
Interesting. Are the foreground flowers any sharper in the one you exposed for the foreground?

I'm wondering if superimposing three shots like this loses definition due to any slight movements of the flowers from one shot to the next due to air currents.

golfdiesel

Link Posted 15/04/2007 - 20:49
Arthur Dent wrote:
Excellent image. I don't know if it counts, but I've done similar things by rendering a RAW image for highlights and then for shadows. I combine them into one image.

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113136AA.html

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113140AA.html

Did you take one RAW image and you rendered two different images out of it which you then combined? May I ask how?

I played with HDR merge and there is something strange with it.
When I take a bracketed image (-2,0,+2) then it works.
Do I take the 0 image and create a -2 and +2 from the RAW image then HDR merge stops and complains about the lack of dynamic range.
Camera:K20D|Ist*DS|Spotmatic II|MZ-10
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Takumar Lenses: SMC 55 1.8
Sigma Lenses: EX DG 50-500 'Bigma'|EX 50mm Macro
Flashes: Metz 58 AF-1|Samsung SEF-36PZF|Pentax AF-220T

petekd

Link Posted 15/04/2007 - 20:50
Hi Chris

Yes I noticed the flowers didnt quite show focus or sharpness. This maybe to do with PS merging the 3 images and trying to automatically aline them together. I will check all three. It may have been slight breeze or if I remember I did focus on the tree with the camera. Also could it be the apeture as this was set to 7.1

Quick update all three image appear a bit out of focus on the flowers so it must be slight movement.

The shots were taken on a tripod using the 12 sec timer so I did not touch the camera at all. The tripod is a very unsteady a real cheap one. I am getting a new one soon. I think it even moves when the mirror opens on the camera Seriously the K10 is a bit noisy and clonky with the shutter and I was wondering if this could cause very slight movement when it opens and closes. Perhaps someone might care to tell us.

Pete
Wedding & Portrait photographer

petekd

Link Posted 15/04/2007 - 20:55
golfdiesel wrote:
Arthur Dent wrote:
Excellent image. I don't know if it counts, but I've done similar things by rendering a RAW image for highlights and then for shadows. I combine them into one image.

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113136AA.html

http://www.gartenphotography.com/images/attractions/Pages/LDG_20070411-113140AA.html

Did you take one RAW image and you rendered two different images out of it which you then combined? May I ask how?

I played with HDR merge and there is something strange with it.
When I take a bracketed image (-2,0,+2) then it works.
Do I take the 0 image and create a -2 and +2 from the RAW image then HDR merge stops and complains about the lack of dynamic range.

I actually took 3 seperate jpegs+Raw image with the camera itself but used the jpegs for this experiment. I could have used the RAW files but for quickness used the jpegs.

I never thought of your idea it sounds good. One image copied twice more and then under expose it with the first copy and over exposure the second copy and merge all three. Interesting idea I will try that.

Cheers Pete
Wedding & Portrait photographer

ChrisA

Link Posted 15/04/2007 - 21:06
petekd wrote:
Quick update all three image appear a bit out of focus on the flowers so it must be slight movement.

If ALL the images show out of focus flowers, it's unlikely to be movement of the subject unless your shutter speeds were very slow, and you didn't say what these were.

The reason I asked was because if you take three shots, even only seconds apart, the subject really has to be extremely still to lose no sharpness at all when you combine the images.

If they were all individually sharp, but the end result not, the loss of sharpness would probably have been due to movement between the shots.

If they are all out of focus, it's either camera shake, or simply that you didn't focus properly, or shutter speeds so slow that movement during each shot is significant. But this is different from movement between shots.

Quote:

The shots were taken on a tripod using the 12 sec timer so I did not touch the camera at all. The tripod is a very unsteady a real cheap one. I am getting a new one soon. I think it even moves when the mirror opens on the camera Seriously the K10 is a bit noisy and clonky with the shutter and I was wondering if this could cause very slight movement when it opens and closes. Perhaps someone might care to tell us.

Well of course it can cause slight movement.

The issue is whether it's enough to cause the amount of blur you've got there. And given that the tree seems quite a bit sharper than the flowers, I'm guessing that it isn't. But it's only a guess.

Rather than guess, why don't you do a proper experiment using your tripod, and the 2s and 12s delay settings on the camera, set to the same shutter speeds you used for the flowers. The 2s one locks the mirror up before the shutter opens so in theory there should be less chance of vibration.

Come on, this time, do a properly thought-through, carefully conducted experiment, and get a result that actually means something.

ChrisA

Link Posted 15/04/2007 - 22:32
petekd wrote:
Let me know your thoughts on the image and the outcome using HDR method

Ok, I've had a few more thoughts on this, but let me say this before I articulate them.

I think, in general, people are far, far too free with superlatives. Words such as "excellent" should be rare, since excellence is rare. Undiluted honesty is going to make me improve far more quickly than sugar-coated flattery, so that's what I want to hear.

So, in that spirit, I'll say this in response to Pete's request for feedback.

As a first exploratory exercise in a PhotoShop technique (one, I might say, that I haven't tried myself), I think it has great value, and may lead to great future skill. It's an interesting technique, and has lots of potential. So I salute him for having a go, and for his willingness to put his work up for scrutiny, not to mention his good humour when he gets a good slagging.

Talking of slagging, as a photograph to be assessed in its own right, I think it's pretty unremarkable, and has a few things about it that I really don't like. It's quite an achievement to get a shot of the sun as good as that, facing directly towards it, so long before sunset. But it still looks garish to me, with the white circle, the yellow ring round it, and the orange surround with its harsh border.

The blurred flowers ruin what would otherwise be a lovely foreground, and exposing for them should yield the rich colour that I'm sure they had. The silhouette of the tree is quite nice, and frames the sun, but how much more majestic would it have looked if the whole of the tree had been in the frame.

So as a photo, my reaction is quite negative, I'm afraid. For having an initial first stab at an interesting technique, one that might be useful in the future, top marks.

Having seen quite a few of Pete's shots now, my overriding sense is one of very unremarkable initial capture, followed by a lot of messing around on the computer that doesn't really recover the situation.

I strive to get the initial capture right. Usually I fail. But I think it's there, rather than in the subsequent sodding about that I think Pete should really put his efforts.

Just my tuppence worth.

Arthur Dent

Link Posted 15/04/2007 - 22:49
golfdiesel wrote:


Did you take one RAW image and you rendered two different images out of it which you then combined? May I ask how?


Each image was only one exposure. I rendered the images in ACR so I could get one interpretation for the shadows and one for the bright sunlight. Then I put one on top of the other and used masking to create the final image.

That's why I said I'm not sure if it counts. HDR supposedly requires a tripod and several exposures. What I used is a single DNG file and basic Photoshop tools.
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Prieni

Link Posted 16/04/2007 - 08:16
Pete,
good first try, but as Chris pointed out there are some weaknesses. One thing that hasn't been mentioned is the halos around the tree trunk. There are lighter areas directly next to the tree that don't make sense.

I also had a go at the technique a while back, here are original (i.e. straight in CameraRaw (that was before I used SilkyPix)) and "HDR" version.

*ist D, Sigma 105/2.8 DG EX Macro, 20 s, A 22.
Original:



HDR from a few different RAW conversions:



In SilkyPix with the highlight correction one could get away with fewer RAW conversions (or with one only).

That's another 2 p
Prieni

thomastherhymer

Link Posted 16/04/2007 - 09:17
that last one looks like another really bright exposure was needed to get the last bit of shadow detal out of the trees and buildings - they are pretty grainy still.

its a big improvement in the water and sky though.

was this 3 exposures though? seems to me it only covers the highlights and midtones effectively. EDIT I just saw this is not full HDR but from different raw conversions, which explains the grain in the shadows, there wasnt a brighter exposure to go to... sorry!

Also , it seems to me that modern digital cameras should be able to cope with very high dynamic range anyway, isnt that what 22 bit AD is about?

so why do they only give us 12 bits in a raw file?

I can see the day coming when every shot is always subdivided into several time slices straight off the camera, which are then automatically (or manually) recombined both for maximum dynamic range and for maximum exposure time before the subject (or camera) moves.

we shouldnt need to take 3 separate shots, the camera should be able to time divide the continuous output from the CCD...

I must try this HDR technique!

what free or cheap software allows HDR?

MattMatic

Link Posted 16/04/2007 - 09:37
Just my penny's worth...

* For true HDR you must take multiple exposures - you can't take a single RAW and process three times. However, that technique has its place - but it won't work for HDR because there simply isn't enough dynamic range even in a single RAW file

* The HDR process is split into two phases:
1) The composition of multiple images
2) The "tone mapping" from HDR back into regular 8 or 16 bit.


Step (1) is poorly handled by Adobe, IMHO. If there's any movement it really goofs up. Maybe CS3 is better than CS2, but either way it's not brilliant. Photomatix and Artizen are better. (In fact, Artizen will composite the multiple images where you can save as an HDR file and allow CS2 to tone map)

Step (2) is also poorly handled in CS2. Artizen has the most flexibility. And additionally, the tone mapping is something of an art. For example, in Pete's image, there's a horrible halo around the trunk of the tree, plus a nasty posterization (stepped colour) around the sun, and the foreground flowers have far too little contrast and look very "eurgh". These issues can be addressed with different "tone mapping operators". Only Artizen allows the choice of mapping.

Best route to HDR:
* Take 5 or 7 RAW shots
* Process them in your RAW converter of choice, but DO NOT adjust the exposure in any of them - adjust curves/white balance/contrast the same in all.
* Save as 16-bit TIFFs
* Composite in Artizen
* Either: Tone map in Artizen, or save as HDR and tone map in CS2

BTW, you will need a ton of RAM to do this, and a lot of patience


There's plenty of info in the ePhotozine forums on HDR if you care for a long, long, long read

EDIT: Thomas - if there was a full 22-bit RAW mode that may cut down the number of exposures for HDR, but the full HDR dynamic range is unbelievably massive. So massive you cannot possibly represent it properly on any display, print or otherwise (hence the tone mapping). Also, the software is Artizen HDR. Definitely worth checking out - although admittedly clunky in areas, but it does have the maths to do the job properly

Matt
http://www.mattmatic.co.uk
(For gallery, tips and links)

Prieni

Link Posted 16/04/2007 - 09:54
Matt,

this is well put and also the reason why I put "HDR" in quotation marks in my post. HDR doesn't work without tone mapping as the dynamic range would be too huge to be shown on any output device.

Thanks for the tip on Artizen, sounds interesting...

Cheers,
Prieni

thomastherhymer

Link Posted 16/04/2007 - 10:05
Matt, I wasnt disregarding the need for tone mapping at all, just commenting that it could potentially be done from a single 22bit per channel file, rather than combining several separate exposures. Of course there may be limitations in the analog response of the sensor that makes 3 exposures with different apertures/shutter speeds more useful.

3 or even 5 exposures at 12bit is still much less than the theoretical range of 22 bit, but the question really is can the camera actually capture all that 22 bits of detail or is 22 bit overkill for the analog amount of brightness gradation coming through the lens at a given exposure? (sorry if i'm not clear I know what I mean but don't know the photographic specific terms)

how many bits would we need to get down to measuring individual photons per pixel? (if a CCD could be designed that sensitive) how many photons are needed to create a measurable difference in a CCD output? what is the prognosis for technology improvement in CCD sensitivity?

do you see what I'm getting at?

I will check out artizen, thanks!

MattMatic wrote:
Just my penny's worth...
EDIT: Thomas - if there was a full 22-bit RAW mode that may cut down the number of exposures for HDR, but the full HDR dynamic range is unbelievably massive. So massive you cannot possibly represent it properly on any display, print or otherwise (hence the tone mapping). Also, the software is Artizen HDR. Definitely worth checking out - although admittedly clunky in areas, but it does have the maths to do the job properly
Matt

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