Help with Focus Merging

[Mring]

Dear Ladies and Gentlemen,

I was playing around with the Focus Merging algorithm. I tried several lenses with different apertures on my XT-3 System. However, I observed a blur/haze along the edges which is not visible on the single images.

Do you have any suggestions on this topic? Sample image below. Kind regards, Michael

 

[John Rostron]

@Mring, Is this image as displayed at 100%? I cannot see any obvious blurring. Where is the blur you see? Is it on the edge of the red rod? On the edge of the white pieces? On the white-on-white edges? How many images did you stack? What aperture did you use?

We would need this information to make any assessment, as well as an image at 100%.

You need not post the entire image at 100%, just the bits of interest.

John

[Old Bruce]

20 minutes ago, John Rostron said:

I cannot see any obvious blurring. Where is the blur you see?

Obvious to me, if you look at the red rod at the top of it there is a 'halo'. I think the background is what I call cork board and there is a transition from sharp to fuzzy (plus the reddish smear).

1 hour ago, Mring said:

Do you have any suggestions on this topic?

Have you looked at the Affinity Video tutorial on this 

It took a few viewings to make sense for me about this particular problem.

Oh, Welcome to the forums.

[John Rostron]

56 minutes ago, Old Bruce said:

Obvious to me, if you look at the red rod at the top of it there is a 'halo'. I think the background is what I call cork board and there is a transition from sharp to fuzzy (plus the reddish smear).

Yes, I can see that now. My eyes are no longer fit for such critical assessment.

John

[Mring]

Thank you very much for the swift reply and the warm welcome to the forum 🙂 I will post this image at 100 percent as soon I am back at my PC.

So here is what I tried today: I wanted to get a feeling of the characteristics of various lenses of mine. So i just grabbed the LEGO from my nephew and made images at various apertures - 80 images for each aperture and with the Focus-Bracketing function of my FUJI camera. I then tried the Focus Merging function with Affinity and came up with this result above. I tried this function both with the *.raf files and *.tif files (exported from Capture One, with and without lens corrections). To sum this up, since the single images are sharp around the respective edges, I do not think, that the lenses, the recording settings or these initial steps led to this 'halo' effect.

I also took a look at the tutorial where a related effect is described. I may give the Clone Brush Tool a try - but to be honest, the effort to correct this effect along these edges is just too high for me. The most important thing for me right now is to understand, under which circumstances this 'halo' effect occurs in order to avoid these. I have not figured this out yet. I am also not quite sure, if I am observing the same effect as in the tutorial. 'My' blurring seems to be very homogeneous along all edges (white and red) and for all directions. All other edges within the original image are perfectly sharp.

 

 

 

 

 

[h_d]

If you've already applied focus bracketing in camera, then I don't think the Affinity Focus Merge is going to help much. Changing the aperture is simply going to give you different depths of field across the images (which might explain the blurs).

And to be honest I'm not sure that Focus Merge is the best tool for exploring lens characteristics.

Affinity Focus Merge expects a group of images from the same viewpoint, with the same exposure and aperture settings, but with different focus. It's good for combining macro images which generally have a very shallow depth of field. It finds the sharpest areas of each individual image and combines them to give an image with the 'best of all worlds' in terms of overall sharpness, and from my limited testing of it works very well indeed. 

Try setting up your camera on a tripod, switch to manual focusing with a fairly shallow depth of field (ie quite a large aperture, but probably not fully open), then take a series of pictures gradually changing focus from the front to the back of the object. Then run these pictures through Focus Merge without changing them in camera or in any other software, and you'll get an idea of what Focus Merge can do. 

Hope this helps!