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I'm interested in focus-stacking as a way to achieve sharp, close-up images of bugs with relatively cheap equipment. My equipment:

  • Canon 550D w/ 18-55mm kit lens or nifty fifty
  • Cheap extension tubes with metal contacts to allow AF
  • Planning to make a simple lightbox to use with desk lamp
  • Magic Lantern to automate image capture between two focus points
  • Lightroom 6
  • Zerene Stacker

So my question: Is it better to adjust the captured images in LR before stacking, or is it better to adjust the final image after stacking?

Zerene works with TIFFs, so what I've been doing is capturing a set of (say) 10 RAW images, converting to TIFF in LR, stacking with Zerene, then editing the stacked TIFF in LR.

If it doesn't matter either way then I might do a comparison but as I'm short of time I thought I would ask to see if theres already a recommended or 'best practise' way of doing it. I've read some articles online but they either don't specify enough details of their workflow, or they don't provide an explanation as to why they edit before/after stacking. Thanks in advance!

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I've done it... I'd suggest leaving the originals alone as far as cropping (especially cropping) and exposure, assuming they're all similarly exposed. A good stacking program will match exposures so the final 'stack' is seamless.

A focusing rail which moves the camera/lens assembly is useful for fine work- the lens focal length and other parameters may change if you focus the 'normal' way. With a rail you can leave the lens focused on a near or far point and shift the focus point without disturbing the lens again.

That said, again, a good stacking program will correct any distortion or variations in image size before assembling the final image.

  • So you're saying to edit the final stacked image rather than the images to be stacked right? ML is able to automate image capture by moving through the focal plane with AF and capturing each slice for you without any user input - no need to turn knobs or anything. You just set it and let it take the images. Then you get a perfectly-spaced set of images without the need for a focus rail. – Ichneumonid Dec 5 '16 at 0:23
  • Can't edit comment after 5m minutes...I understand what you mean now about the parameters changing, I don't think it will be much of an issue from my test runs so far. Results seem better than when I was using a rail. – Ichneumonid Dec 5 '16 at 0:30
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I always edit sharpen BEFORE stacking. I've actually tested this and find that the stacking engine propagates edges in the Z axis more reliably if focus has been heightened somewhat. You can always de-sharpen after stacking, as part of the rest of your LR editing.

I also don't use a focus rail, despite having a few. If your lens has a barrel adjustment for focusing, use that. On the other hand, if yours is a fixed focus microscope lens attached to bellows then use the bellows adjustment. Tests have shown, and my own testing has borne this out: racking in or out causes weird stepped "Zoom-Like" artifacts around the subject, largely because by racking, you're changing the size of your image.

I don't know how well the Zerene stacker handles large TIFFs, but PS5 doesn't like them nearly as well as JPEGs, for some reason.

I use the PhotoShop CS 5.1 stacking feature as well as Bridge...it makes pre-editing/sharpening all images in a stack pretty seamless.

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