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Beginners questions

Post by guest » 04.11.2008 00:25

Hi!

I am trying out Helicon Focus and have some questions: (I am referring to the Mac version. And I hope to use your app for landscape, not microscopy).

1-Prefs, Resample method:
Please could you state what System Default is, and what none-low-high mean in technical terms, as you do in the Windows version, as I can see on the screenshot in the Help. (Nearest neighbour -bicubic-...)


2-Options > Auto-adjustments:
I don't understand these. Are these input values? In other words: Do they mean: 2 images may differ max. x% in e.g. vertical alignment, otherwise they will be discarded from the process? How am I to know which max value I should choose? (I use a tripod.)

3-Options > Auto-adjustments > Brightness:
What does it mean that brightness is "normalized"? Adjusted to a value which averages the brightness of the images in a stack? How is the average defined?

3a- What will happen, if I deselect this option, and the images in the stack show uneven brightness, i.e. the light has shifted between shots?

4-In your description of the difference between the lite and the pro version, you promise more advanced features in the future for the latter. May I suggest 2, and ask if/when there is a chance to exspect them?

The first is anti-ghosting, of which I am almost dependent. It will limit the usability of the program severely, if I can only shoot if there is absolutely no wind, so that no leaf of grass moves at all.

And DNG output would be a good thing. (I am happy to see that the program can take un-demosaiced DNGs as input!)

Kind regards - Hening Bettermann.

Dan Kozub
Posts: 355
Joined: 24.03.2004 18:14

Post by Dan Kozub » 04.11.2008 13:52

Hello Henning


>Please could you state what System Default is, and what none-low-high mean in technical terms, as you do in the Windows version, as I can see on the screenshot in the Help. (Nearest neighbour -bicubic-...)

Yes, this is resample algorithm. Neighbour-bilinear-bicubic as far as I know.


>2-Options > Auto-adjustments:
I don't understand these. Are these input values? In other words: Do they mean: 2 images may differ max. x% in e.g. vertical alignment, otherwise they will be discarded from the process? How am I to know which max value I should choose? (I use a tripod.)

The values mean how much the program shifts the image trying to align it. 2% means that maximal shift is 2% of the width. Normally 2-3% is ok for tripod and microscope. If you shoot from hands, you may need to set higher values.

>3-Options > Auto-adjustments > Brightness:
What does it mean that brightness is "normalized"? Adjusted to a value which averages the brightness of the images in a stack? How is the average defined?

Program tries to change the brighness so that the difference between two images is minimal. Use manual exposure to avoid brighness changes.

>3a- What will happen, if I deselect this option, and the images in the stack show uneven brightness, i.e. the light has shifted between shots?

You will get "layered" images with well defined areas on the result, especially if method B is used.

>4-In your description of the difference between the lite and the pro version, you promise more advanced features in the future for the latter. May I suggest 2, and ask if/when there is a chance to exspect them?

Yes, we are testing new beta version now.

>The first is anti-ghosting, of which I am almost dependent. It will limit the usability of the program severely, if I can only shoot if there is absolutely no wind, so that no leaf of grass moves at all.

Retouching brush from the Pro version solves this problem very easily.

>And DNG output would be a good thing. (I am happy to see that the program can take un-demosaiced DNGs as input!)

The program processes RGB image. There is no way to save DNG once it is already demosaiced. I would suggest you to use 16 bit TIFF with Adobe RGB or ProPhoto RGB color profile to preserve all the quality.

guest

Post by guest » 04.11.2008 17:12

Hi Dan!

Thank you for your very fast reply. I have already decided to go for Helicon Focus rather than PhotoAcute, which I find does not deliver as far as focus stacking goes.

As always, new answers rise new questions... ;-)

> Neighbour-bilinear-bicubic as far as I know.

Well if YOU don't know, who does?? - However, this is not so important, since it only concerns the preview.

One further detail concerning auto-adjustments: Apart from shaking hands, there is another possible source of misalignment: As you shift focus, the size of the image changes (unless you use front focussing on a view camera). (This might be the reason for the problem of the user who could not align close-ups of a test chart; I fail to retrieve the post right now):

Depending on the nearness to the subject, the difference may be considerable and may exceed 2-3%. I assume, that rising the value will decrease the sharpness which Helicon can deliver?

So if I want to maintain max quality, how can I "help" Helicon:

What is the critical value for Helicon: the total difference between near and far layer, or the max distance between 2 adjacent layers? In other words: can I overcome a maybe gross total size difference between image layers by increasing the number of layers? Is there an optimum for the number, or for the distance between them?

This leads to the next question, concerning the even-ness of the distance between layers. There could in principal be 2 methods of determining the position of the layers in the subject: visual and "metric".

With the visual method, I will try to focus on the most important parts of the image, or on significant distances, so the max sharpness would be on these distances.

But I could also use a different approach: I could determine the max and min distance, and then try to place a number of slices evenly between them, using marks on the focussing ring rather than looking through the viewfinder.

Which method would be best with Helicon? In other words: How important is the even-ness of the distribution between layers?

Concerning the anti-ghosting:
> Retouching brush from the Pro version solves this problem very easily.

Yes, or the Clone Healing tool in Photoshop. However, this is all manual. And since so to speak all of my images need focus stacking, this may become a lot of work. It would be really fine if this could be automated. PhotoAcute promises this, but does not deliver. I have read that some pano software does it, but have no experience myself.

>The program processes RGB image. There is no way to save DNG once it is already demosaiced.

Well, Photoshop/Adobe Camera Raw has an option of saving as "linear" DNG, which is a de-mosaiced DNG, as I understand it. But I have to admit, that the advantage of *such* a DNG is not quite clear to me.

Thanks again, and great success for your program!

Hening.

Hening
Posts: 7
Joined: 06.11.2008 02:07
Location: Oslo, Norway

DNGs from DxO

Post by Hening » 13.11.2008 02:36

Hi Danylov!

1- I am disappointed that you have not answered my post of 04. november. This is not good style.

2- Concerning the anti-ghosting:
You may retouch a single leave of grass manually, but if it is the foliage of a whole tree, or moving water, you're out of luck. l think you should focus on this feature!

3- Helicon Focus does not load DNGs, that are output by DxO. The list of images appears, but no image is shown, and clicking the Run button results in a sound, which obviously is intended to be a Failure sound. What could be the reason, and could it be cured?

Kind regards - Hening.

Hening
Posts: 7
Joined: 06.11.2008 02:07
Location: Oslo, Norway

Post by Hening » 14.11.2008 05:17

I have now found that HF does not handle linearized DNGs in general. Could this be changed? - Kind regards - Hening.

Dan Kozub
Posts: 355
Joined: 24.03.2004 18:14

Post by Dan Kozub » 20.11.2008 14:51

> One further detail concerning auto-adjustments: Apart from shaking hands, there is another possible source of misalignment: As you shift focus, the size of the image changes (unless you use front focussing on a view camera). (This might be the reason for the problem of the user who could not align close-ups of a test chart; I fail to retrieve the post right now):

The program compensate the changes in object size (see Magnification on Autoadjustment tab in Preferences)

>What is the critical value for Helicon: the total difference between near and far layer, or the max distance between 2 adjacent layers? In other words: can I overcome a maybe gross total size difference between image layers by increasing the number of layers? Is there an optimum for the number, or for the distance between them?

Yes, too many layers may result in worse image. Reason: several focused areas are mixed for the result. Even with perfect alignment this makes the image soft.

Focused areas should cover the whole object and overlay by 20% to help alignment.

>Which method would be best with Helicon? In other words: How important is the even-ness of the distribution between layers?

It is not important for method A (average), but important for method B (depth map) because the latter one assumes that layers are equally spaced. It is important for method B to keep the same order (1,2,3 but not 1,3,2).

>Yes, or the Clone Healing tool in Photoshop. However, this is all manual. And since so to speak all of my images need focus stacking, this may become a lot of work. It would be really fine if this could be automated. PhotoAcute promises this, but does not deliver. I have read that some pano software does it, but have no experience myself.

No, Clone brush from Photoshop is not the same. Try our brush and you will see the difference. It uses diffent method so you do not need to be precise. Only a few rough strokes over the edges solve the problem.

>Well, Photoshop/Adobe Camera Raw has an option of saving as "linear" DNG, which is a de-mosaiced DNG, as I understand it. But I have to admit, that the advantage of *such* a DNG is not quite clear to me.

I believe 16 bit TIFF with appropriate color space is the ideal store format.

>1- I am disappointed that you have not answered my post of 04. november. This is not good style.

Sorry, this forum is for users not for support :) Please contact our support to get help ASAP.

>3- Helicon Focus does not load DNGs, that are output by DxO. The list of images appears, but no image is shown, and clicking the Run button results in a sound, which obviously is intended to be a Failure sound. What could be the reason, and could it be cured?

Please send us a sample image to http://heliconsoft.com/ftp.html

>I have now found that HF does not handle linearized DNGs in general. Could this be changed? - Kind regards - Hening.

Yes, latest Helicon Focus uses several RAW/DNG converters. It is possible to choose converter for RAW files but not for DNG so far. Will be added to to-do list.

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