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Thread: Focus stacking/HDR/bracketing

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    Focus stacking/HDR/bracketing

    Hello, I am going to be doing some trips soon and I wanted to try out a bunch of new things, mainly things like focus stacking and/or F-stop stacking, bracketing, so on.

    Is there a particular technique to use for certain situations? For instance, after reading this tutorial:

    http://www.cambridgeincolour.com/tut...amic-range.htm

    I was thinking about doing some sunset/wave photos. Is this a good time to use bracketing since the movement will be too much for the other techniques?

    Am I correct in thinking that the time to use bracketing (should I manually do this or select on my camera?) is used best when the colors and brightness are the issue, and use focus/F-stop stacking for photos in which you want to increase DoF?

    On that same note, is it safe to say that focus stacking/aperture should be avoided when movement is in the photo? Obviously something like a sunset could be captured both ways since the movement isn't quick, but if there are things in the shot that move quickly focus/F-stop won't work.

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    Re: Focus stacking/HDR/bracketing

    When there's waves or other moving objects within the image, most merging programs can go astray, creating holes in the image, mostly they are black holes. Water thus can be tricky for making HDR images. Stacking might work, but often tilt is a better solution to the depth of field problem, in those instances where stopping down is not sufficient. All multi-exposure and merging techniques are best executed on perfectly still subjects.

    When you bracket for brightness issues, fewer images often is better than many, so if you carefully measure the dynamic range you need and make two shots, which have to be done manually in most cameras, you might get files that are easier to manage than if you have umpteen very closely spaced exposures. Bracketing for dynamic range should always be done by altering exposure time, never by f-stop or ISO setting. If your camera has bracketing, setting +2, 0 and -2, often gives sufficient dynamic range, and the middle one can be skipped in processing.

    Focus bracketing mostly is done with many exposures, spaced so that each of them overlap the other a bit for DOF. With a smaller aperture, it can be done with fewer exposures than with a large aperture, but a large aperture can give bokeh that may be wanted for more distant objects than the one we want in focus. So different techniques are used, depending on what you want to achieve by stacking. If your goal is to have depth of field over a limited range of distance, and throw the rest out of focus substantially, you use a large aperture. If you want to have everything sharp, you need many exposures, closer spaced the closer you get to the camera. When doing it very close-up, the lens shall not be moved for focusing, but the camera body, if you are using bellows. Most bellows units can be inverted, so that the moving standard takes the mount for the camera and the fixed one takes the lens.

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    Re: Focus stacking/HDR/bracketing

    On the Nikon D5000, I have the bracketing on AE, then it gives me options AE0.3, .7, 1, 1.3,1.7 and 2.

    So you recommend the 2 setting?

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    Re: Focus stacking/HDR/bracketing

    Where movement would cause problems with HDR shots I often use a different approach.

    Meter for the brightest area and manually set the camera based on that. Any over exposure means lost details.

    Shoot Raw.

    Do a couple of Raw conversions with different exposures etc; one to suit the highlights and another for midtones/shadows.

    Combine the two conversions as layers and masks. Edit the mask to show the best from each conversion.

    Not real HDR but usually a lot better than having to work with just one shot and only one exposure setting.

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    Re: Focus stacking/HDR/bracketing

    Thanks, here is my first attempt in CS at stacking images. This is using focus stacking. As you can see, I am still getting certain blurry points, is that because I let CS do it auto or because I didn't use enough focus points? If I look at the set of three photos I can see they are blurry where Im still getting blurs in the final stacked image so that tells me it's probably due to my use of only three focus points?

    As I shot, I just got the closest rock, then went for the middle ground, then infinity.

    Any suggestions? Obviously the picture isn't anything special, just my backyard, I am just looking for things so I can get some time in PP and help since this is my first time doing anything like this. Thanks!
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    Re: Focus stacking/HDR/bracketing

    Here is another set. Same thing I think.. maybe because there is so many things to focus in on in this picture I should have used maybe 5 photos or something?
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    Re: Focus stacking/HDR/bracketing

    maybe because there is so many things to focus in on in this picture I should have used maybe 5 photos or something?
    It's hard to say without examining the full-sized images in detail, but the bottom line is that for focus stacking to work well, every detail that you want to be in focus in the composite must be in focus in at least one image in the stack. How many images that takes depends on the aperture you use, the distance to the subject, and the depth of the subject. I use focus stacking only for macro work, where DOF is very small, but in that work I usually end up with between 5 and 12 images, although sometimes as few as 3 or as many as the low 20s. It is always safer to err on the side of too many. If you have out-of-focus areas in the composite, that generally means that you have no base image with that area in focus. you can map the out of focus areas to the originals to see.

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    Re: Focus stacking/HDR/bracketing

    Thanks Dan, that makes sense. I am going to go out again today and mess around with more shots, see if I can't figure it out

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    Re: Focus stacking/HDR/bracketing

    Quote Originally Posted by Inkanyezi View Post
    When there's waves or other moving objects within the image, most merging programs can go astray, creating holes in the image, mostly they are black holes. Water thus can be tricky for making HDR images. Stacking might work, but often tilt is a better solution to the depth of field problem, in those instances where stopping down is not sufficient. All multi-exposure and merging techniques are best executed on perfectly still subjects. .
    This stacking business is new to me too but as far as various applications using more than one exposure my feeling is that it is better to work manually in a good editing programme than use a specific programme designed for the job which cannot think like a human.
    Here I wanted to show Sharon Lee the loco with the countryside of the Taieri Gorge but the clouds were racing across the sky.
    I first shot my panaramic images before she arrived and finally when she did I was lucky that the clouds cleared to match the lighting of the basic pano.
    Focus stacking/HDR/bracketing
    This "Fetch" is probably a little different to what you will get in CO but comes from several hand held images which had to be first registered and then selected out the bits I wanted to tell the story.
    Focus stacking/HDR/bracketing

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    Re: Focus stacking/HDR/bracketing

    Interesting shots. It looks like you used a lot more manual work, specially in that last photo.

    I still try to get what I want in the shot in one, but am interested at the possibilities of stacking and merging, basically the entire post processing world.

    I am still at a loss about bracket stacking though, the contrast/brightness hurdle seems like its to tall to jump over for me. I think I've read the tutorial here about three times. I guess the best way is to do rather than read and re-read and see what happens.

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    Re: Focus stacking/HDR/bracketing

    So here is another try... (it was super slow at the music store) I think I am understanding the process much more now, but have one question. As you can see the fluorescent lights look a bit odd after stacking, blending and flattening, it almost looks like it tried to use a little of all 5 photos. In the final image you can tell the lighting looks like it has 'ghostly' wisps of smoke coming off it and the further focus point the lights are much clearer.

    Any tips or tricks when it comes to odd lighting and the draw backs of focus stacking? Ill attach the final and the most extreme focus points.
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    Re: Focus stacking/HDR/bracketing

    s you can see the fluorescent lights look a bit odd after stacking, blending and flattening, it almost looks like it tried to use a little of all 5 photos.
    That is exactly what focus stacking does. It picks from each image pixels that are in focus and combines them in to a single image.

    If you focus at different points--which you have to do for focus stacking--the images will differ in size. Compare them yourself to see. Combining them could cause problems with perspective if you have straight lines in the image.

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    Re: Focus stacking/HDR/bracketing

    Right, I understand the concept, its more or less how to fix that small area where the merging went wrong, as in I know that it takes the sharpest parts of all the photos, but if you look at the lights it seems like CS wanted to use all 5 images on that area and in return I get the ghost looking lights, rather then the 5th image where they are much sharper.

    The only way I would know is to import the photo with the sharpest lights and then erase, or select the lights from the sharper photo and import it and paste.

    Just looking for feedback on if this is the way to correct that issue or if you CS guru's know better.

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    Re: Focus stacking/HDR/bracketing

    Right, I understand the concept, its more or less how to fix that small area where the merging went wrong, as in I know that it takes the sharpest parts of all the photos, but if you look at the lights it seems like CS wanted to use all 5 images on that area and in return I get the ghost looking lights, rather then the 5th image where they are much sharper.
    Sorry, I misunderstood your question. That's one of several reasons I stack with Zerene. It lets you pick any image in the stack and paint from that to the composite. So, for each area, you would find which image has that edge in focus and paint from it.

    It looks to me as though the lights are blown out. I wonder if that contributed to the problem.

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    Re: Focus stacking/HDR/bracketing

    Thanks Dan, thats true, I believe they are actually blown out. I'll look up Zerene, I'm still battling with Adobe to give me my second download of CS so I might have to budget accordingly.

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    Re: Focus stacking/HDR/bracketing

    Helicon Focus is another. When shooting HDR exposures on waves use the continuous release mode. Also when shooting waves, set your tripod, use the same exposure and fire away as the waves pound in. Later combine several images into a composite using Layer Masks. You can combine a wave breaking over rock #1 with a wave breaking over rock # 2 into one photo with waves now breaking over both rocks. You might even have 8 or 9 different photos of breaking waves and combine into one.

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