Anyone know a good source of info (internet or otherwise) on how to blend multiple exposures that have been focused at different lengths, to maintain sharp focus throughout?
Posted by Larry Puckett on July 27, 2009 at 10:48 AM
Stan--see this discussion in the Digital Imaging forum:
Tony Kuyper's ''Digital Scheimpflug' tutorial (available via a small donation) is a great start. There are some sample chapters at that link.
If you want to automate the process, then you can try a 30 day free trial of HeliconFocus.
If you have PSCS4, then you could follow this tutorial titled 'Extending DOF with CS4'.
I must give a recommendation for HeliconFocus, in my (albeit limited) experience it does a really fantastic job.
Posted by Paul Wegemann on July 27, 2009 at 12:34 PM
Tony K's article is great, Stan. If you want to dive in and play with some software, Helicon Focus is great, but the price reflects that. A really good free software is CombineZP. CS4 has this feature built-in, but it's not ready for prime time IMO.
I'd give Helicon Focus a spin (I've been using the "Lite" version of the program for a couple of years now). You've got a 30-day period to see if it does what you want it to do.
My typical workflow is to align the photos, and then use Tufuse (free) or hand blend.
Since photos focused at different distances have slightly different fields of view, aligning them makes blending much simpler. I usually try Photoshop’s Auto-align, but if it doesn’t work well I use PTAssembler (this program gives complete control of the aligning process, but there is a learning curve).
If there wasn’t a lot of movement in the areas to be blended, Tufuse can work wonders. The free version is a command line program, but simple to run from a batch file.
If there was movement (flowers blowing in the wind for example), I usually fall back on blending by hand. I have much better luck with a narrowly feathered (I usually use a three pixel feather) selection that I use to create a mask than I do with a gradient or broadly brushed mask.
When blending by hand I have the best luck by loading the two photos to be blended into seperate layers, and then I set the top layer to Difference Mode. Areas in the two photos that are identical turn black, and then I just trace a selection using the lasso tool that follows the black. This way, you can move around and through subjects that moved following a seamless line. Once the selection is created, just change the mode of the top layer back to Normal and create a mask for the top layer using the selection.
As always YMMV, but it's a lot of fun to get that massive DOF .
Thanks John--it the aligning process that ive had issue with. Ive tried the 'difference' blend method but as you said, because of the different fov for each layer, it gets tricky. Im wondering if maybe im doing something wrong during the actual shooting stage.
Posted by Jeff Pritchard on September 19, 2009 at 2:10 AM
Different lenses vary quite a bit in how much the FOV changes as focus changes. Also each zoom will have a different amount of shift at different points in its zoom range.
Also, I have found that when I'm out shooting I always try to convince myself I can do more with this technique than is really practical. You still need to use your aperture setting and other "old school" techniques to control depth of field and not rely too heavily on the blending of multiple shots. f2.8 with one shot racked all the way out and one racked all the way in just won't cut it no matter how good your computer software or technique is. :)
My best results with this have been to get one shot that is in focus from "a stones throw to infinity", and then a second shot with the same aperture setting focused a little closer that I can use to fill in some sharp texture in the foreground. The opposite approach is more intuitive to me, but hasn't worked as well for me so far.
My attempts with Helicon have all looked very fake to me. (though at the time I wasn't taking my own advice from above)
jp
Posted by Steve France on September 29, 2009 at 9:25 AM
wow Stan.. I give you credit for even trying...
Is a T/S lens out the question, or buy an adaptor? There are a few on the market.
Sounds like a lot of time in front of the pc to me.... which is why im hoping to go 4x5 next year :)
Discussion
10 replieshttp://www.naturephotographers.net/imagecritique/bbs.cgi?a=vm&mr=45061&CGISESSID=e296e5157427f23327cb9d8e05126e40&u=17111
If you want to automate the process, then you can try a 30 day free trial of HeliconFocus.
If you have PSCS4, then you could follow this tutorial titled 'Extending DOF with CS4'.
Since photos focused at different distances have slightly different fields of view, aligning them makes blending much simpler. I usually try Photoshop’s Auto-align, but if it doesn’t work well I use PTAssembler (this program gives complete control of the aligning process, but there is a learning curve).
If there wasn’t a lot of movement in the areas to be blended, Tufuse can work wonders. The free version is a command line program, but simple to run from a batch file.
If there was movement (flowers blowing in the wind for example), I usually fall back on blending by hand. I have much better luck with a narrowly feathered (I usually use a three pixel feather) selection that I use to create a mask than I do with a gradient or broadly brushed mask.
When blending by hand I have the best luck by loading the two photos to be blended into seperate layers, and then I set the top layer to Difference Mode. Areas in the two photos that are identical turn black, and then I just trace a selection using the lasso tool that follows the black. This way, you can move around and through subjects that moved following a seamless line. Once the selection is created, just change the mode of the top layer back to Normal and create a mask for the top layer using the selection.
As always YMMV, but it's a lot of fun to get that massive DOF
Also, I have found that when I'm out shooting I always try to convince myself I can do more with this technique than is really practical. You still need to use your aperture setting and other "old school" techniques to control depth of field and not rely too heavily on the blending of multiple shots. f2.8 with one shot racked all the way out and one racked all the way in just won't cut it no matter how good your computer software or technique is. :)
My best results with this have been to get one shot that is in focus from "a stones throw to infinity", and then a second shot with the same aperture setting focused a little closer that I can use to fill in some sharp texture in the foreground. The opposite approach is more intuitive to me, but hasn't worked as well for me so far.
My attempts with Helicon have all looked very fake to me. (though at the time I wasn't taking my own advice from above)
jp
Is a T/S lens out the question, or buy an adaptor? There are a few on the market.
Sounds like a lot of time in front of the pc to me.... which is why im hoping to go 4x5 next year :)