Macro Focus Stacking

Started Apr 8, 2013 | Discussions thread
_sem_
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Re: Macro Focus Stacking - Zerene Stacker results
In reply to newtoy, Apr 26, 2013

newtoy wrote:

_sem_ wrote:

So, are there any images with sharp bits in the affected areas? It is interesting that elsewhere the edge is well-defined... so it might be a software issue.

There are sharp edges, but your camera never record them.

Well, I meant whether the camera recorded them (but they are gone in the processed image) or they were really never recorded. I mean, some parts of the yellow-orange edge look quite well-defined, despite no less distance in depth. The software seems to have issues with sharp bits at different depths around the same xy position. Pls check the "transparent foreground" discussion in the photomacrography link I've pasted above.

When you focus on the green object, you also record blur edges of the red object. But as you focus on the red object. Your camera no longer see the red edges. When you stack the pictures. The the red edges will be blur. There is nothing you can do unless you move both your camera and the focus ring to make sure the perspective of your camera remain the same on all pictures. That would be nearly impossible! Or use a very long lens to minimise the effect.

You mean a very long lens to reduce relative foreground blur (this is what I meant with a different focal length)? Stopping down the aperture would also reduce it, by reducing the blur radius.

Making the perspective the same on all pictures is not always impossible, it is called an object-space telecentric lens. AFAIK it is achievable with certain macro stacking approaches. But I guess the foreground-blur issue remains. Macro lenses also tend to "breathe" when moving focus; the nominal FL is valid at infinity but gets shorter at close focus, I recall up to 50%, and the nodal points move too. Both with extending and non-extending lenses, to different degrees. These characteristics are largely undocumented but I guess relevant for stacking purposes.

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