Questions about HDR

Pixel Popper · September 12, 2007

Hello. I'm very, very new to post processing and, gladly, I am picking up a lot of great information through these forums. I have just recently heard about HDR, but don't know the first thing about how to accomplish that. If my understanding is correct to this point, it is about somehow stacking virtually identical shots with different exposure values to come out with an evenly exposed image as the end product, correct?

After getting that vague understanding (I'm sure there is much more to the process) I found myself standing in front of a subject knowing, even before I made the first shot, that there were going to be exposure issues. So I made seven shots of the same image with different exposures, which I will post here.

This issue may be covered extensively somewhere else on this site, and if so, a kind nudge in the direction of the proper thread would be appreciated, bearing in mind that I am the kind of person (read Newbie) who would need step by step instructions.

Further more, I am wondering if specific software is needed to get the results I am after. My version of Photoshop is fairly old (Photoshop 7.0) and to date, I have only used it for very basic cropping, color corrections, contrast, sharpening, etc.

Do I need to purchase different software before I can even begin this process?

With all that said, let me show you the images i want to converge for an even looking exposure.

Of course, this isn't all 7 images, but some were so close in value that it doesn't really matter. But with these, I think it can be seen what I need to accomplish, to get the statue and the text above evenly exposed in the same image.

What suggestions might you have to help me accomplish this goal?

Thank you very much in advance for any assistance you might offer with this shot!

cabbey · September 12, 2007

Pixel Popper wrote:

Hello. I'm very, very new to post processing and, gladly, I am picking up a lot of great information through these forums. I have just recently heard about HDR, but don't know the first thing about how to accomplish that. If my understanding is correct to this point, it is about somehow stacking virtually identical shots with different exposure values to come out with an evenly exposed image as the end product, correct?

That matches my understanding, but I'll admit to not being an expert at HDR by a long shot... I've only done it 4 or 5 times now... and they're not all that great.

After getting that vague understanding (I'm sure there is much more to the process) I found myself standing in front of a subject knowing, even before I made the first shot, that there were going to be exposure issues. So I made seven shots of the same image with different exposures, which I will post here.

This issue may be covered extensively somewhere else on this site, and if so, a kind nudge in the direction of the proper thread would be appreciated, bearing in mind that I am the kind of person (read Newbie) who would need step by step instructions.

Have you read http://stuckincustoms.com/2006/06/06/548/ ? He does some eye popping images with custom software that's intended for HDR work... but in reality... as near as I can tell it just boils down to transparent layers in photoshop and some skill with the eraser.

Further more, I am wondering if specific software is needed to get the results I am after. My version of Photoshop is fairly old (Photoshop 7.0) and to date, I have only used it for very basic cropping, color corrections, contrast, sharpening, etc.

if you think that's old and crusty, then what I'm using should be dust by now. Photoshop Elements 2.0. Officially you can't even upgrade this beast anymore. (Though I've found an offer from adobe to upgrade it through November... still trying to decide if it's worth it... it was free with my camera after all.)

Of course, this isn't all 7 images, but some were so close in value that it doesn't really matter. But with these, I think it can be seen what I need to accomplish, to get the statue and the text above evenly exposed in the same image.

What suggestions might you have to help me accomplish this goal?

Thank you very much in advance for any assistance you might offer with this shot!

I took images 196 and 192, loaded them both into PS, copied 196 to clipboard, created a new layer in 192 and pasted it in. At this point I closed 196. Now I picked them in that order because I like to have the background image be the one I'm going to keep the most of, and the statue from 196 seemed smaller than the background from 192. At this point I hid the background layer and made sure I was editing the layer with the statue. A quick magic color selection selected almost all of the black background behind the statue, cut and it was gone. That left a bit of junk around outside edges that went away quickly with the eraser. It also left a thin black border on the statue, basically one pixel wide that was part statue and part background. A small, soft edged eraser slid along the edge got rid of that and softened the edge around him. That was about it... turn the background back visible and export to web. Total time spent: 2 minutes. Mind you, it shows that it was less than 2 minutes. My point wasn't to do a bang up great job, but to show that it doesn't require fancy software.

cabbey · September 12, 2007

and to supplement the previous reply, a small 'in progress' view:

pyrtek · September 12, 2007

That's certainly one way of doing it, but I find all the painting and masking very
tedious, so here's a different method, which works wonders when you have
several images to work with (it doesn't work very well with just 2 - 3 images).

1) Open all your images in Photoshop and stack them so that you have them
all in separate layers. The lightest one should be at the bottom, the darkest
at the top. I'm assuming that at this point you have the lightest image at the
bottom and named "Background" and all the darker images are named "Layer
1" through "Layer N".

2) Make Layer 1 active by clicking on it. Hit Ctrl-Alt-Shift ~ (that's a tilde), which
will select all the highlights in the image, then click on the Create layer mask
icon at the bottom of the layers palette (it's the gray square with a white
circle in the middle).

3) Repeat step 2 for all the remaining layers.

4) Believe it or not, you're almost done. And without a single brush stroke!
At this point, the image will contain all the details of all the exposures you
took. The problem with it at this stage is that it will be very flat and not
very attractive. This is easily remedied with a curves adjustment layer. So
create one and increase the contrast with a standard S-curve.

The image below is the result. I made the background much darker than it is
in the lightest of the images, but only because I thought it looked better this
way. If you do all of the masking steps you'll get an image with a much lighter
background, so if you want a lighter background, you'll just use a different
curve in step 4.

And that's about it. You can now merge all the layers and do any other
tweaking you want (like a perspective crop, which this image is begging for).

Here's what I got in literally under 60 seconds without even touching the mouse:

Pixel Popper · September 12, 2007

Thank you both for your responses. I really appreciate the help. I know this isn't the best image, having problems with perspective and needing some straightening, but now that I have some insights, I can readily apply that technique to other shots I might capture in the future. Again, many thanks!

However, when I say newbie, I mean NEWBIE!!! If it's not too much trouble, would you mind going into further detail about the following?:

*QUOTE*
1) Open all your images in Photoshop and stack them so that you have them all in separate layers.

-- What is the process for "stacking"?

*QUOTE*
4) Believe it or not, you're almost done. And without a single brush stroke! At this point, the image will contain all the details of all the exposures you took. The problem with it at this stage is that it will be very flat and not very attractive. This is easily remedied with a curves adjustment layer. So create one and increase the contrast with a standard S-curve.

-- Along with the first question, how exactly do you go about creating a "curves adjustment layer" and then make a "standard S-curve?

I know that to you experienced users, these must sound like very elementary school type questions. Well, I do feel like a Kindergartener compared to the rest of you out there, but I greatly appreciate the assistance. At the very least, once I get it down, I won't have to ask again!

Thanks!

pyrtek · September 12, 2007

Pixel Popper wrote:

-- What is the process for "stacking"?

1) Open the first image (in this case, the lightest one) in the normal way for
your system. So either through the File -> Open menu, or by dragging an
image over to Photoshop.

2) Open the next image in the same way. It will become the active document.
Select it with Ctrl - A, copy it with Ctrl - C, close it with Ctrl - W. Now it's in the
clipboard and the first image you opened is active. Now just do Ctrl - V (paste)
and the new image will be added as a layer to the first image. Repeat for all
the other images.

Pixel Popper wrote:

-- Along with the first question, how exactly do you go
about creating a "curves adjustment layer" and then make a "standard S-
curve?

1) Click the Create new adjustment layer icon, which is at the bottom of the
layers palette. It's the black & white circle that looks like a Yin & Yang symbol.

2) The curves dialog box will open. Here's a little something about curves.
There's an S-curve among the examples (example 9).

Holler if you still have questions.

zweiblumen · September 12, 2007

Egads, pyrtek just posted all of this same info in different form during my commute into work

. Well here you go anyway.

Pixel Popper wrote:

-- What is the process for "stacking"?

The last comment by Devbobo is exactly what you are looking for here.

Pixel Popper wrote:

-- Along with the first question, how exactly do you go about creating a "curves adjustment layer" and then make a "standard S-curve?

You can find a great tutorial on S-curves right here

FWIW, I found the stacking tip by doing a search, and the S-curves under the tutorials link.

pyrtek · September 12, 2007

zweiblumen wrote:

The last comment by Devbobo is exactly what you are looking for here.

Not exactly. What I meant by "stacking" is simply opening all the necessary
images one on top of the other. That's all. What those threads mean by
"stacking" is a little bit more involved.

zacker · September 12, 2007

You asked about HDR... so here is an example using HDR & tone mapping software by Photomatix. I used your 5 posted exposures.

the Photomatix version

and the same image but taken into Photoshop after HDR and adjusting levels and hue / saturation and sharpening a touch.

google photomatix for HDR software or if you have adobe photoshop cs2 or cs3 use the merge to HDR tool..

zweiblumen · September 12, 2007

pyrtek wrote:

Not exactly. What I meant by "stacking" is simply opening all the necessary
images one on top of the other. That's all. What those threads mean by
"stacking" is a little bit more involved.

Opps. Sorry about that. Thanks for the correction.

pyrtek · September 12, 2007

zacker wrote:

google photomatix for HDR software or if you have adobe photoshop cs2 or cs3 use the merge to HDR tool..

Some people like what Photomatix does to images, others hate it. I'm one of
the latter, but you're right, of course, in mentioning it in this thread.
Completely slipped my mind.

vdotmatrix · September 12, 2007

Dude:
go to flickr and search on the HDR tags and see some of my work, and others.

Next: google HDR (high dynamic range) photography.

stuckincustoms.com has a great tutorial. but you'll find a dozen tutorials which teach you all you want. don't worry they are short and sweet.

Next, you'll need a tripod. a camera that shoots RAW, and software like photoshop CS2 or CS3 which can merge to HDR. But there is an excellent program that I recommend called PHOTOMATIX for creating HDR. there is a free trial version, that keeps a water mark. ( you can get a discount through stuck in customs). It also comes with an optional tonemapping pluggin that is very helpful.

Essentially you set your camera to shoot at least 3 bracketed RAW shots of a subject in interesting light on a tripod. the more you can successfully bracket the better. Secret: you can also get an HDR from 1 RAW shot with PHOTOMATIX, don't tell anyone, but you get much more dramatic results with 3-5 bracketed shots. then you mrege the brackets esentially going from 5 f-stop range to nearly 12 f-stops of lattitude. WHOA!!!!!!!

I don't want to be responsible for readers becoming insomniacs after being turned on to HDR. But once you discover and get a working knowledge of this technique you will become a monster behind the lens and screen.

Have fun!!!!!!!

-v

Pixel Popper wrote:

Hello. I'm very, very new to post processing and, gladly, I am picking up a lot of great information through these forums. I have just recently heard about HDR, but don't know the first thing about how to accomplish that. If my understanding is correct to this point, it is about somehow stacking virtually identical shots with different exposure values to come out with an evenly exposed image as the end product, correct?

After getting that vague understanding (I'm sure there is much more to the process) I found myself standing in front of a subject knowing, even before I made the first shot, that there were going to be exposure issues. So I made seven shots of the same image with different exposures, which I will post here.

This issue may be covered extensively somewhere else on this site, and if so, a kind nudge in the direction of the proper thread would be appreciated, bearing in mind that I am the kind of person (read Newbie) who would need step by step instructions.

Further more, I am wondering if specific software is needed to get the results I am after. My version of Photoshop is fairly old (Photoshop 7.0) and to date, I have only used it for very basic cropping, color corrections, contrast, sharpening, etc.

Do I need to purchase different software before I can even begin this process?

With all that said, let me show you the images i want to converge for an even looking exposure.

Of course, this isn't all 7 images, but some were so close in value that it doesn't really matter. But with these, I think it can be seen what I need to accomplish, to get the statue and the text above evenly exposed in the same image.

What suggestions might you have to help me accomplish this goal?

Thank you very much in advance for any assistance you might offer with this shot!

zacker · September 12, 2007

pyrtek wrote:

Some people like what Photomatix does to images, others hate it. I'm one of
the latter, but you're right, of course, in mentioning it in this thread.
Completely slipped my mind.

you are correct, and the debate will rage on and on if allowed..lol
its mostly the user and not the program though... just like with "over Photoshopping" some go too far, I love the more "surreal" look i can get with HDR but then again, HDR doesnt seem to be enough for me to get my thrills...lol I GOTTA drag the file into PS and have at it there also..lol but, we all cant love everything, thats why Art is suggestive. I really dont like Black and whites.. they just dont do it for me..I love colors though, muted, highly saturated... i love it all!

TIP for OP: With HDR, if your going for a more realistic scene, take more exposures to capture more info.

foxfire09 · September 12, 2007

Pixel Popper wrote:

If my understanding is correct to this point, it is about somehow stacking virtually identical shots with different exposure values to come out with an evenly exposed image as the end product, correct?

What suggestions might you have to help me accomplish this goal?

Not really sure if this has already been resolved but I just started working with HDR a couple of months ago and this is a link to a tuturial that a friend sent me and I found it to be extremely helpful!!

http://www.naturescapes.net/072006/rh0706_1.htm

Hope this helps you out!

Pixel Popper · September 12, 2007

WOW! Thanks so much everyone. I had no idea I would get so much great information so quickly. I really appreciate the support here in these forums. I think it would be difficult to justify the cost of going to a photography school with so many great folks here willing to share their insights, skills, and knowledge. I have a tremendous amount to learn, but you all have just given me a giant step forward. Hooray for Dgrin!!!

BinaryFx · September 14, 2007

This thread has featured two different approaches to dealing with low dynamic range in capture. Blending bracketed exposures via layers/masks in Photoshop and merging exposures in HDR software. The two are very different approaches to the same problem. For example, the HDR group at Flickr does not accept blending and only true HDR software is accepted. http://www.flickr.com/groups/hdr/

For many, their output is not HDR, if using HDR software they are faced with the task of mapping the huge tonal range into a pleasing range for monitor display or printed output. Those blending exposures in 8/16bpc in non HDR editors have the advantage of being able to see and work with all the tones without having to do tone mapping (bad examples of tone mapping often have strange halos).

Manual Photoshop methods of layering and blending have been mentioned earlier in the thread. Another way to do this is with software designed to combine the bracketed exposures into a single image with a balanced exposure. One such product is the Blend Exposures plug-in from [SIZE=-1]www.reindeergraphics.com

Some good links to HDR include:

http://www.cybergrain.com/tech/hdr/index.html
http://www.cambridgeincolour.com/tutorials/high-dynamic-range.htm
http://www.anyhere.com/gward/hdrenc/hdr_encodings.html
http://www.cs.huji.ac.il/%7Edanix/hdr/results.html
http://www.cs.huji.ac.il/%7Edanix/hdr/panorama.html
[/SIZE]

Regards,

Stephen Marsh.
http://members.ozemail.com.au/~binaryfx/

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