Lavender buds

footman

footman

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Laurence
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footman said:
There is a halo now that I have looked closely, we're camping at the moment, I'll check on the settings when we get back.
What’s an overlap halo?
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It isn't a generally used term, it's just one I made up. Suppose you have two surfaces that overlap and you want both in focus. It's fine getting the nearer one in focus, but as the plane of focus moves back towards the further one the front one will go out of focus, and as it does it gets bigger. By the time the more distant one is in focus the larger, out of focus edge of the nearer one will be obscuring part of the further one that you want in focus. You can't correct this by painting in from one of the individual images that has that area in focus, because there isn't one that has that area in focus. I demonstrated this from 21:55 in this You Tube video.

Sometimes you can reduce the effect by using a different stacking method, or using different stacking parameters. Sometimes you can do "reconstructive surgery" on the image with cloning. Sometimes I find I can't cure the problem to my satisfaction, or perhaps I could but I'm not prepared to spend as much time on it as it would need.

If the overlapping surfaces are close enough to one another this won't be a problem.

I strongly suspect this is more of a problem with flowers etc than with insects etc, because botanical scenes, at least the ones I photograph, do quite often have overlapping elements that I want in focus but are at significantly different distances. But this is a surmise - I haven't done enough invertebrate stacks to be sure it doesn't happen so often for insects, spiders etc.
 
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Thanks for the reply Nick, we've spoken about this phenomenon before I believe and I mentioned that I understood the concept as you explained it.
Consequently thanks to your explanation I've been able to eliminate haloing around the edges of petals, leaves etc by using a small enough aperture to bridge the focus gap between the edges of the subject and the background but in this case the halo occurred within the subject and I'm pretty sure I used an aperture of about F8 or F11 so I'm baffled.
Like you I don't think I'll spend too much time on this :)
 
Tidy Macro that Laurence - I'm away on Anglesey next week for 7 days - be taking my Macro lens along :)

Les
 
footman said:
Thanks for the reply Nick, we've spoken about this phenomenon before I believe and I mentioned that I understood the concept as you explained it.
Consequently thanks to your explanation I've been able to eliminate haloing around the edges of petals, leaves etc by using a small enough aperture to bridge the focus gap between the edges of the subject and the background
Click to expand...

I'm puzzled by this. You shouldn't get overlap halos around a petal that is against an out of focus background. I find that those can usually be removed by altering one of the stacking parameters (in Helicon Focus, by increasing the Radius parameter).

The only aberration I can see around the edges of the flower is the one indicated below, which I believe is a fragmentary overlap halo induced by the thread.


NOT MY IMAGE - footman - Lavender buds - with GA annotation by gardenersassistant, on Flickr

footman said:
but in this case the halo occurred within the subject and I'm pretty sure I used an aperture of about F8 or F11 so I'm baffled.
Click to expand...

With a big enough distance between the overlapping (in-focus) elements (and possibly also depending on the magnification), using a smaller aperture may not be enough to reduce the halo to insignificance.

footman said:
Like you I don't think I'll spend too much time on this :)
Click to expand...

Generally a good idea, but in the interest of trying to understand what is going on here in case there is a solution you could use for similar issues in the future, what are you using for the stacking? If it is Helicon Focus (that is the only one I'm familiar enough with to make suggestions about), what method and parameters did you use?
 
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Lez325 said:
Tidy Macro that Laurence - I'm away on Anglesey next week for 7 days - be taking my Macro lens along :)

Les
Click to expand...
We're in East Sussex in our motorhome on a camp site for a few days, did some macro work yesterday and took the full monty with me. Tripod, focus rail, field monitor and various other bits of kit, I was knackered by the time I got back!
Going out today much lighter :)
Enjoy Anglesey.
GardenersHelper said:
I'm puzzled by this. You shouldn't get overlap halos around a petal that is against an out of focus background. I find that those can usually be removed by altering one of the stacking parameters (in Helicon Focus, by increasing the Radius parameter).



With a big enough distance between the overlapping (in-focus) elements (and possibly also depending on the magnification), using a smaller aperture may not be enough to reduce the halo to insignificance.



Generally a good idea, but in the interest of trying to understand what is going on here in case there is a solution you could use for similar issues in the future, what are you using for the stacking? If it is Helicon Focus (that is the only one I'm familiar enough with to make suggestions about), what method and parameters did you use?
Click to expand...
I use Zerene for stacking, I don't think it has those options. I'll check when I get back home and also my settings for the lavender bud photo.
 
footman said:
We're in East Sussex in our motorhome on a camp site for a few days, did some macro work yesterday and took the full monty with me. Tripod, focus rail, field monitor and various other bits of kit, I was knackered by the time I got back!
Going out today much lighter :)
Enjoy Anglesey.
Click to expand...

I will certainly try Laurence - I too will be taking 2x Mirrorless bodies several lenses & my tripod with Gimbal head- weathers looking fair too :)

Les
 
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