Halo prevention and Post-editing

Shooting in macro mode, techniques, tips & tricks

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John C. House
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Halo prevention and Post-editing

Unread post by John C. House » 23.05.2010 00:17

Screen shot 2010-05-22 at 6.01.01 PM.jpg
Screen shot 2010-05-22 at 6.01.01 PM.jpg (158.4 KiB) Viewed 10235 times
I continue to have problems with halos, and I have not been able to figure out either how to prevent or to fix the problem. I have spent a good deal of time in Photoshop trying to clean images up, but I'm confident there is a better way. I have tried somewhat methodically to find the best combination of radius and smoothing, and 7/2 seems to work best, but there is still significant blurriness. After reading other threads, I have lowered depth map feathering to 1, but that did not seem to make it any better. Here is a bit of an orchid image (stack of 9) at 100%. What am I doing wrong?

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Stas Yatsenko
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Re: Halo prevention and Post-editing

Unread post by Stas Yatsenko » 24.05.2010 13:07

You are welcome to upload your stack to our server (as described at http://www.heliconsoft.com/ftp.html) so we can analyze it.

There are two types of artifacts. First type is cause by the program which was not able to find the best area for the resulting image. We recommend to fix it with retouching brushes of Helicon Focus (Pro and X64 version). You can fix artifact by a couple of rough stokes, cloning areas from the prealigned source image. In photoshop you do not have this infomaion and have to make a lot of meticulous work.

The second type is caused by optical problem. The forground object which is out of focus, masks the background details around it. The only way to avoid this is to increase DOF.

John C. House
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Re: Halo prevention and Post-editing

Unread post by John C. House » 27.05.2010 06:36

Thanks, Stas. I can certainly increase dof; I'm not sure what the aperture was on these (I'd have to fine the originals), but what is generally a good setting? Would f14 or f 16 be okay?

As far as the editing, is there a tutorial on how to use the retouching brushes in Helicon Focus Pro? I've looked at Lynda and did not find one. I'd like to have a video or a detailed description to go by if that is available.

Thanks,

-John

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Stas Yatsenko
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Re: Halo prevention and Post-editing

Unread post by Stas Yatsenko » 27.05.2010 13:11

John,

There is no online video tutorial yet, but we will prepare it soon. The use of brushes is quite straitforward anyway.

I cannot tell you for sure which aperture is the best. F5.6-F8 is condered to be the optimal, giving the best resolution. How it degrades toward F16? I think it depends on the lens and size of the sensor. I may find some calculation online. I would suggest you to make a couple of shots to see the difference between F8 and F16.

John C. House
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Re: Halo prevention and Post-editing

Unread post by John C. House » 31.05.2010 17:01

Thanks, Stas. Where would I find a detailed description of how to use the brushes?


John C. House
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Re: Halo prevention and Post-editing

Unread post by John C. House » 07.06.2010 04:07

I guess I am a bit daft here. I have some trouble knowing which image(s) to use as a source image. I suppose I have not played with this enough, but still have not been very happy with my level of understanding or the results. I, for one, look forward to a video or more detailed description of the process.

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Stas Yatsenko
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Re: Halo prevention and Post-editing

Unread post by Stas Yatsenko » 07.06.2010 14:32

Please note that you can press F1 in the program to get detailed help for Helicon Focus.

agiyo
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Re: Halo prevention and Post-editing

Unread post by agiyo » 18.06.2011 20:00

Most of the halos are caused by the blurring in the original images where that part of the object is extremely out of focus---the opposite end of the stack from where that part is sharp. Stopping down to smaller f/ stops will help some, but diffraction, caused by the image light rays bending around the edges of the aperture, will begin to degrade image quality. That's why f/64 works well enough for three dimensional images on a large format camera, but in smaller formats, requiring enlargement, it does not.
Generally, a lens is sharpest 2 f/stops down from wide-open, but I normally shoot at f/16 in a compromise between sharpness and depth of field. At f/16, in images with more depth relative to the magnification, there are plenty of halos.I use HF retouching and Photoshop to deal with them, along with many other "tricks" I'm figuring out as I go along, but inevitably some will remain because they are part of the original images---the lens never got a clear image of that area of the subject.
Consider it part of the aesthetic. The pictures can be quite beautiful as we all see.

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Stas Yatsenko
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Re: Halo prevention and Post-editing

Unread post by Stas Yatsenko » 20.06.2011 15:28

Yes, some artifacts cannot be automatically corrected because there is no information to properly render some parts of the image. The best thing we can do in such situation is to make retouching more efficient. I hope you like the recent changes in Windows version (Live preview of brush effects and fast source image selection).

gregbenz
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Re: Halo prevention and Post-editing

Unread post by gregbenz » 17.07.2011 19:27

I'm not sure what fast brush options are in the Mac version (which at v4.x sounds like it is releasing behind Windows), but it would help greatly if the retouching could be faster on a Mac. I have fast Mac Pro that often hesitates quite a bit when I change between source images, which makes it difficult to use the retouching tools. I would also love to have a keyboard shortcut to move forward or backward in my image stack so that I could keep adjusting to quickly pick the right source.

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Stas Yatsenko
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Re: Halo prevention and Post-editing

Unread post by Stas Yatsenko » 18.07.2011 10:05

We are preparing new version which will be faster in processing and retouching.

gregbenz
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Re: Halo prevention and Post-editing

Unread post by gregbenz » 19.07.2011 06:46

Looking forward to it. I really appreciate how responsive you guys are, nice to know you're open to making an already great product better!

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