Focus stacking methods

[russell_hodder]

<p>Hi all, Although not new to photography there are many techniques I haven't used but am now coming to grips with. As an avid gardener I like taking macro shots but alas they do suffer from overall depth of field---hello focus stacking. Are there different ways to photo stack, I get the feeling that you can keep the camera fixed and try turning the focus ring only, or I thought you could keep the same focus distance and just turn the lens around to take pics in focus at all different parts of a flower for example, then into say Helicon focus to process. Can someone advise me if there are different ways to focus stack. Is it ok to turn my lens and focus on different parts of a flower whilst keeping the focus distance set ?<br>

Any help would be greatly appreciated, Regards Russell</p>

[MichaelChang]

<p>Hi Russell, I'd suggest looking into a macro rail slider attachment for your tripod to facilitate micro-focus changes. <br>

[<a href="https://www.google.ca/search?um=1&hl=en&q=camera+macro+rail+slider&bav=on.2,or.r_cp.r_qf.&bvm=bv.47244034,d.dmg&biw=1440&bih=813&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=2cWmUbzMOfSo4AO6yYGoAQ">Link</a>]</p>

<p>Of course the resultant images will then be imported into any number of focus stacking software. </p>

<blockquote>

<p><em>"or I thought you could keep the same focus distance and just turn the lens around to take pics in focus at all different parts of a flower for example"</em></p>

</blockquote>

<p>If I understood your remark correctly, the fixed-distance, angular changing sequences of photos are for 360 views typically used in commercial product presentations. </p>

[JosvanEekelen]

<p>+1 for the macro rail. Manfrotto offers one that is perhaps not the best but it is affordable and stable (when you lock it after each adjustment). Stay away from the 3-way cheap ones since these are not stable. In general a macro rail gives me better results than turning the focus ring.</p>

<p>As for software: in my experience there is no "best" software, it depends on the input files and the subject which one does the better job; it is a bit a way of trial and error. My favorites to try are Photoshop (CS4), Enfuse, Helicon focus ($) and CombineZ. The latter is a surprise since it is not so well known and seems to be upgraded only once in a while but it did the job remarkably well.</p>

[sgust]

<p>You can even pull off taking images for stacking without a tripod. What I've done before is to manually focus on the closest part of my subject and then, with the camera in rapid fire mode, take a series of images while slowly leaning in. With my Sony α55 I can take 10 shots/sec. for about 15 shots which is enough to do some modest stacking. I've only done it a handful of times, always manually aligning the images in GIMP and then selectively revealing the in focus sections, but the results have been decent.<br>

On a side note, are there any free stacking programs out there? Are they any good?</p>

[anne_kerr]

<p>I don't know if this'll be of much help, but I found this article a few weeks ago and have been practicing this way:</p>

<p>http://www.photo.net/learn/macro/focus/stacking/harold-davis/</p>

 

[MichaelChang]

<p>Siegfried, CombineZP is freeware. I've tried an early version a few years ago and it does the job. <br>

<a href="http://www.hadleyweb.pwp.blueyonder.co.uk/CZP/files.htm">http://www.hadleyweb.pwp.blueyonder.co.uk/CZP/files.htm</a></p>

<p>While on the subject of technique, the camera mounted macro rail is adequate for larger objects, but an X-Y linear stage to move the object will be a better choice if higher precision is required for tiny objects like the head of a housefly. These things can be quite expensive but can often be found on eBay at bargain prices.<br>

<a href="https://www.google.ca/search?q=X-Y+linear+stage&oq=X-Y+linear+stage">https://www.google.ca/search?q=X-Y+linear+stage&oq=X-Y+linear+stage</a></p>

[sgust]

<p>Michael,<br>

thanks, I'll check that link out later.<br>

On the subject of "X-Y Linear stages", I had no idea that people were using them for focus stacking, but it makes sense. <a href="http://www.grizzly.com/products/Compound-Slide-Table/G5757">A cheaper, although heavier alternative</a> would be to use tables made for milling. You can get cheap ones for less than the ones made for photographic purposes. </p>

[MichaelChang]

<p>Siegfried, I guess it depends on the level of precision one requires for tiny increments. </p>

<p>The X-Y linear stages are very high precision in resolution increments of 1um, but a microscope X-Y stage will also work well (and much cheaper) if high precision is not required and one can tolerate sloppier mechanics:<br>

<a href="http://www.ebay.com/bhp/microscope-x-y-stage">http://www.ebay.com/bhp/microscope-x-y-stage</a></p>

[sgust]

<p>Yeah, I suppose your right. My macro photos rarely go past 1:1 and at the very most I may get 3x magnification. So even then my DOF isn't so thin to need to move in micrometer increments. The milling tables can move reliably in about 0.1 to 0.05mm increments which would be plenty for my needs. Maybe one of these days I'll put my Bridgeport to use for stacking. Gotta see how the CombineZP programm works first. Stacking manually is too time intensive.</p>

[paddler4]

<p>Russell,</p>

<p>you don't need a rail for 1:1 macros. At 3:1 perhaps; I don't do more than about 2:1. I do a great deal of macro, and most of my flower shots are stacked. I don't even own a rail. It works perfectly fine to focus first on the closest point and then move the focus out a tiny bit at a time by turning the focus ring, as you suggest. That is exactly what I do. Starting at the front is a way of guaranteeing that your framing is sufficiently wide.</p>

<p>If you would like to see images done this way, check out <a href="http://dkoretz.smugmug.com/Flowers/Flowers-and-mushrooms/5909118_4XFdxt">this gallery</a> and <a href="http://dkoretz.smugmug.com/Flowers/Wilted-flowers/18646411_HfRNcp#!i=710719226&k=sdLFbrq">this one</a>. Most of those images are stacked, with anywhere from 3 to 25 shots per image.</p>

<p>For software: there are lots of reasonable options. I and the majority of macro shooters I follow use Zerene. It has two entirely different stacking methods that can produce quite different results. (For flowers, I find that DMap is usually better for preserving textures and colors.) It has an invaluable retouching tool that allows you to correct for the haloing that can be produced by parallax (in particular, when an edge and the surface it hits on the plane parallel to the sensor are far apart front to back). It's also reasonably fast. </p>

<p>The retouching tool can also be used for a form of masking. For example, take this image:</p>

<p><img src="http://dkoretz.smugmug.com/Flowers/Flowers-and-mushrooms/i-rZ72hsQ/0/XL/2013-04-12-20.59.52%20ZS%20retouched-XL.jpg" alt="" width="972" height="768" /><br>

<br />This is a stack of roughly 20 images. The problem with this was that to get the back anthers in focus, I had to take a shot that had the petals in crisp focus, which I didn't want. So, I stacked the images, and then I used the retouching tool to paint the area of the petals from the front image, in which they were nicely blurred, onto the stacked composite.</p>

<p>Dan</p>

[sgust]

<p>Dan, that's stunning! Definitely makes me want to try my hand at it. Thanks for posting.</p>

[paddler4]

<p>Siegfried,</p>

<p>Thanks. It's a lot of fun, once you get the hang of it.</p>

<p>Dan</p>