Merging Two Exposures From Digital Cam

Shotster · #1 10-04-2003, 01:55 AM

I'm having a heck of a time trying to get a "believalbe" looking composite of two photos of the same scene taken with a digital camera. The scene is of a mountain shrouded by awesome cumulus clouds. Due to the lame dynamic range of my digi cam, I took two exposures - one for the clouds and one for the mountain. Otherwise, the cloud highlights are blown or the mountain under exposed. However, I can't for the life of me "merge" the two images into one. There are wispy clouds which overlaps the bright sky and dark mountain. What's the best approach to take? I've tried creating a selection to isolate the clouds using a blend mask, saturation mask, etc., but I can't seem to target them precisely, and I can't blend them together into one photo without an obvious seam. Anyone have any suggestions?

Stephen M · #2 10-04-2003, 06:23 AM

Hi Shotster, there a few things one can do.

Can you zip up both images and post them here, or upload both images?

The 'obvious' common method is to mask by luminance, presuming that each has either a light or dark area of interest that is being blended.

http://members.ozemail.com.au/~binar...litymasks.html

Has more on some common masking methods such as luminance masks.

What I prefer to try is the layer option blending sliders, the grey range and the upper layer and lower layer slider interaction will give you a lot of flexibility (opt/alt click the sliders to split them to feather the effect).

http://members.ozemail.com.au/~binar...V_links.html#B

Has links on layer option blending sliders.

Often a combination of blend if sliders and layer masks based off channel content or luminance content are used - not to mention selective painting or toning on the mask etc.

There are also some plugs and apps for merging and averaging or combining various exposures, but they may not be needed in a case like this.

P.S. Being a full version user and knowing next to nothing about what Photoshop Elements can do, I am not sure how helpful this info will be. <g>

Hope this helps,

Stephen Marsh.

Richard_Lynch · #3 10-04-2003, 09:02 AM

As Stephen suggests, it would be easiest seeing the images.

There are new tools included with Hidden Power Actions III (highlight and shadow masks) that can help with this. You SHOULD be able to accomplish the same (or better) using blend masking. Again, without more specifics on the images or how you were trying to do this (and the results) it is hard to point to a solution.

Richard

Shotster · #4 10-04-2003, 11:42 AM

Thanks alot for the tips, Stephen and Richard. I've attached a zip archive of two images. This is not the exact photo I was referring to, but it's exactly the same problem. I want the clouds on exposure 1 to be "blended into" exposure 2.

I just can't seem to accomplish this seamlessly with HPE tools using Photoshop Elements - probably due to my lack of proficiency with the tools. I'm not sure what would be the best approach to take.

If I can accomplish this, I'd be in business, as I encounter this type of situation often.

Thanks for any help or insight you can provide!

Regards,
---
Steve

CJ Swartz · #5 10-04-2003, 01:08 PM

Take a look at the tutorial link here -CreativePro.com

This is using Luminance masking, as Stephen mentioned above.
Additional tweaking would be left to your taste.

Shotster · #6 10-04-2003, 05:03 PM

Thank you very much, CJ, for taking the time and effort to work up that sample. I'll check out the link you provide. It looks like it addresses exactly my problem.

Thanks again!

---
Steve

Stephen M · #7 10-04-2003, 06:48 PM

Shotster, here is a quick go using the methods I originally posted (luminance masks, blend if etc) - below is also a correction of only the blown out sky, if you did not have two exposures, using the new Shadow/Highlight command of Photoshop CS (PS8). Similar results could be obtained by isolating the sky and blending in multiply mode.

I have also uploaded an action for the full version (this is not my action):

http://www.retouchpro.com/forums/sho...0864#post60864

Stephen Marsh.

Shotster · #8 10-04-2003, 08:13 PM

Thanks, Stephen. The blended exposure looks much better - more detail in the highlights. Thanks for the samples. I did acheive some success using Photoshop Elements and the Hidden Elements tools.The info posted here and on the Creative Pro site was very helpful. I used Curves to create a blend mask using a luminosity layer. I think this is equivalent to the luminosity mask you describe. One of the problems is that I didn't feather the mask enough before, and that created too harsh a boundary around the blended regions. If I do this a few times with different images, I think I'll have a good work flow down.

Thanks for the help,
---
Steve