HDR in Photoshop CS2

FreeAnd..

Hey,

I just recently tried to do a few HDR's in CS2 but kept getting an error like - not enough dynamic range to create a useable shot. I didnt look too much into it but i was wondering if anyone else came across the same before.

To create the HDR i took a raw image and saved it at a few different exposures and then File->Automate->Merge to HDR to join the images but this step does not complete successfully.

Any suggestions would be appreciated.

Thanks,

FreeAnd..

rymus

Moving to Digital Darkroom...

projectmayhem

never done it myself tbh but check this out

Zillah

Everything I've read explicity states that you cannot use different extractions from one RAW file, you have to take several different exposures.

FreeAnd..

Thanks Zillah, i havent read that myself (not that i have read all that much on HDR) but it seems a bit of a limitation. I was sure someone on this forum had detailed using just the one raw image at different exposures but i could be wrong. What is the difference between bracketing a shot manually when shooting the photo or braketing it later using cs2 camera raw? Is it not essentially the same thing except manipulating the raw removes the need for a tripod?

Zillah

I don't know all that much about RAW, but as far as I do know a RAW image is just the sensor data without formatting. You're still inherently limited in the depth of tone in one exposure. If you make it too bright then you lose bright details and if you make it too dark then you lose dark details. You have to use several different exposures or else you'll still only have the tonal range of one exposure.

The fact that it says you have insufficient tonal range to make an image when using the RAW would imply that I'm right that using one RAW image will lack sufficient tonal range

FreeAnd..

But using Raw can you not set the exposure (not just the brightness) as it would have been set on the camera? Basically what i am saying is if you shot a photo and bracket -2 ev to + 2ev so you end up with 3 images, one underexposed, one correctly exposed and one over exposed. This is what needs to be done to create the HDR, right?

If this is the case then cannot the exact same results be got by shooting one image at correct exposure then in camera raw setting the exposure of this image to -2ev and then to + 2ev and saving both of the resulting images. In this case you too will end up with 3 images of different exposures except you used the desktop software to control exposure rather than the camera. Using raw you have the full sensor data so exposure can be modified correctly as opposed to working on a jpg in photoshop. Does this make sense?

Zillah

FreeAnd.. wrote:

But using Raw can you not set the exposure (not just the brightness) as it would have been set on the camera? Basically what i am saying is if you shot a photo and bracket -2 ev to + 2ev so you end up with 3 images, one underexposed, one correctly exposed and one over exposed. This is what needs to be done to create the HDR, right?

Nope. A RAW file is still just one limited exposure, the scene is gone and you cannot capture any more details simply by playing around with settings. I'm not sure what exactly "exposure" in photoshop and RAW does but it fundamentally cannot increase the tonal range. The settings on your camera dictate how much tonal detail is captured at the moment, and while a RAW will provide more than a jpg, it is still just one exposure. Once that RAW file is made it has all the tonal detail it is ever going to have and no amount of photoshopping will make it capture parts of the scene it didn't get in the first place.

Three images extracted from one RAW file still only have the tonal range of one RAW file.

A HDR image has the tonal range of three or more different files.

FreeAnd..

That goes aganist everything I thought about raw files, if you bracket a shot on the camera you are basically capturing the same information but at different exposures so you will end up with the same image at three different exposures this will give you exactly the same results as doing it later in RAW as the exact same data is available to the image sensor for each image when bracketing on the camera.

A quick search definitely proves its possible, here is how: (i think my problem was that i did not save in .tiff or .psd but rather jpeg)

The first thing is to use your RAW conversion software to create a number of bracketed exposures. To do this, correct the white balance if necessary but do not adjust the exposure. Now set the exposure value to -3 and save the resulting image as #1 to TIFF. Then move the exposure value to -1.5 and save as #2 to TIFF. Continue adjusting exposure until you have 5 images saved #1 at -3EV, #2 at -1.5EV, #3 at 0EV, #4 at 1.5EV and #5 at 3EV. I like to use steps of 1.5 EV but you can use any interval you like, producing more or fewer bracketed exposures.

Covey

FreeAnd.. wrote:

Hey,

I just recently tried to do a few HDR's in CS2 but kept getting an error like - not enough dynamic range to create a useable shot. I didnt look too much into it but i was wondering if anyone else came across the same before.

To create the HDR i took a raw image and saved it at a few different exposures and then File->Automate->Merge to HDR to join the images but this step does not complete successfully.

Any suggestions would be appreciated.

Thanks,

FreeAnd..

The reason for this is CS2 reads the exif data, which all look the same and thinks there is no difference in dynamic range from picture to picture. If you delete the exif data on your .tiff files it should work.

T.

FreeAnd..

Nice one, thanks Covey. I must give that a try i have a couple of images that i want to convert to HDR so ill stick up the results in due course..

Covey

And if you want to get great results from HDR, Photomatix is great software. Used be free but not sure if it still is. Beats CS hands down.

T.

FreeAnd..

will do, thanks again

elven

If you want to do more natural looking HDR, don't use a gimmick, blend the exposures yourself. There's a couple of tutorials on the luminous landscape site, and a video one on radiant vista too.

Raw is just the imformation straight from the sensor without having the in-camera white balance, contrast, sharpening etc, and compression applied.

It's not always the case that the range of tones is beyond the latitude of the sensor - you can have a raw file with detail in both shadows and highlights, but when you process it to look right for one, the other loses detail. Blending different instances of the same raw file gives you the chance to do different 'exposures' per se, in that you can process it once so there's more detail in highlight areas, then process it again for the midtones, and once more for the shadows, then blend the results to use the right 'exposure' in the right places on the final image. Because it's also not compressed like a jpg, there's more information in the file to be pulled out and manipulated as you want. Quite often I've had a shot with a bright sky and have been able to bring out a surprising amount of contrast simply by putting the raw file through the processing again, and tweaking the exposure/shadows/contrast, then blending the sky of that copy into the other image with the brighter sky but the rest of it looked ok.

Obviously if you do have a large tonal range that is beyond the latitude of the sensor, that's when you have to actually do more than one exposure in camera. Then you'll have 3 files, whether raw or not.

Valentia

Zillah, have a look at this video. It explains how RAW can provide multiple exposures.

http://www.radiantvista.com/media/video_tutorials/wmv/radiantVista_tu_combTwoExp.wmv

PaulieC

tried using a digital blending technique as described on The luminous landscape, but the end result is still a rather fake looking pic
<a href="http://www.flickr.com/photos/cambogueno/284623257/" title="Photo Sharing"><img src="http://static.flickr.com/104/284623257_28953edf74_o.jpg" width="1280" height="853" alt="CRW_6670-01 copy" /></a>

I don't suppose you can do anything with this apart from some very manual work in PS? I was more successful using pics with a lesser dynamic range

5uspect

From what I've heard about RAW files (Nikon RAW files at least) is that they are 12bit images so you've 4096 levels of grey per channel instead of the usual 256 for 8bit. So when playing with the exposure settings in the RAW dialogue box you're just selecting a 8 bit range of the 12 bits available. So if you want to make a 32bit HDR from a RAW file you essentially take multiple 8 bit chunks from the RAW file and upscale the final product to pseudo 32 bit. Surely if this is the case then there should be a plugin for doing just this.

So I'd imagine you can get HDR from a single RAW file but taking a good number of exposure bracketed shots is going to give better results.

digitalage

For HDR files I use the software package photomatix http://www.hdrsoft.com/, its very easy to use and the tone mapping software is very good. I have done comparison with photoshop CS2 and I liked the results from photomatix better and much quicker to use.

sionnach

You have to take seperate bracketed shots to get a good looking HDR, adjusting the exposure value on one raw file isn't the same at all.