Focus Stacking Flowers

[Davidgypsy]

I have been playing around with Focus Stacking, a process I have rarely used. After some trial and error this afternoon at the Hobart Botanical Gardens I wish I had used the technique years ago.

Gear was a Pentax K3, Pentax FA50 f2.8 Macro and a heavy tripod. Software was LR CC and Photoshop CC. The focus stacking processing is a Photoshop Automate Photomerge task.

Focus Stacking really shines with macro but I will be experimenting with other focal lengths and subject distances. The technique would also produce better results with a FF digital camera rather than the C Class sensor devices, ie K3. I am waiting to see what the Pentax FF will be like at the end of the year (so is my bank manager).

CC on these shots would be much appreciated.

Thanks, David

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4


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6

[chauncey]

PS's automated processes, whether they be the photostacking or photomerging, requires clearly
defined edges to grab onto, otherwise you end up with smudging on the petals as you have on
your #2,3,4,5 petal close-ups. It is repairable by manually inserting parts of your original images
into the final product.

Heeding your background to avoid pulling the eye away from subject. In the field, some folks use
paper cards to block the bright splotches that offend the eye.

Photostacking does work in other genres, but does require a game plan...dead calm milieu and
where to start and stop the stack process.

BTW, for our viewing pleasure, please skip a space between images when posting.

[gregj1763]

A fellow Tasmanian . Welcome to CiC David.
Focus stacking can give you great result and is something worth while practicing.
#1 is my pick of the images though I would try cropping tighter to lose a bit of the top left of frame and maybe work on the white flowers in the background to darker them a little more.
Nice work mate.

[DanK]

David,

Welcome to CiC. Glad to have another person doing (stacked) flowers on this forum.

By and large, nice stacks. I agree with Chauncey--you have some classic stacking artifacts in a few of the shots. It's most obvious in #4. This doesn't require a lack of sharply defined edges, as Chauncey suggests. Rather, it happens when an edge is quite far (front to back) from the surface behind it. Because of parallax, there is no image in the stack that avoids some overlap.

This is to some degree correctable, as Chauncey wrote, but not always. Sometimes you can fix it by painting from one of the images in the stack, but if the problem is severe enough, it's not always possible to fix it completely. There are also stacking algorithms that are less prone to that. I use Zerene for all of my stacking. One of its methods, DMap, is similar to PS. I prefer it for colors and textures, but it retains less detail and is much more prone to halos of this sort. The other, PMax, is the reverse. In cases like this, I often stack with both and then paint from the PMax composite to the DMap to get rid of or lessen halos. Zerene has a retouching tool that makes this painting very easy.

The technique would also produce better results with a FF digital camera rather than the C Class sensor devices, ie K3

This will have no effect on the quality of the stacking, and it won't have much of an effect in other ways unless you are printing very large or work with poor lighting. If you look at my site, you will see dozens of stacked flower images, most done with an old Canon 50D (APS-C) and some done with a FF 5DIII. I can't tell the difference at screen resolution or when printed small (A4).

I will be experimenting with other focal lengths

Focal length doesn't matter a great deal for flowers. It changes the working distance modestly, but since flowers stay put, this matters much less than in insect macro. However, longer focal lengths have more background blur (which is distinct from DOF--see http://toothwalker.org/optics/dof.html), which is some benefit for photos like your first, which have a nonuniform background. Focal length is irrelevant to stacking per se.

Dan

[Cantab]

David, welcome to CiC. I enjoyed all the photos, especially #1, but will leave any technical comments to those with a lot more expertise than I have.

[Wandjina]

Thanks David, I have learned something new about Photoshop. .. and hey, those are great photos. Well done

[Davidgypsy]

Well, a steep learning curve ahead. Thank you for the comments and advice. My FF reference was concerning DOF. I have a vintage 50mm f1.2 lens which has a razor thin DOF wide open on tubes or a bellows. Hence the interest in stacking. I can see lots of studio time needed to get better results.

David

[IzzieK]

Welcome to CiC from me too, David...we have one member here from Tassie too and his name is Greg Jones from Launceston. Moving on...you got some nice shots here. My favourites are #1, #3 and #6...they are most attractive...

[DanK]

Well, a steep learning curve ahead. Thank you for the comments and advice. My FF reference was concerning DOF. I have a vintage 50mm f1.2 lens which has a razor thin DOF wide open on tubes or a bellows. Hence the interest in stacking. I can see lots of studio time needed to get better results.

David

David,

A few other suggestions:

For the same framing, a full frame camera will have less DOF, not more. This is explained well here.

Also for the same framing, focal length has very little effect on depth of field. Check out the depth of field tutorial on this site.

As for whether you would get a different DOF with a different lens of the same focal length: in general, the answer is no, but in the case of macro work, it's not clear. You need to know things like the pupil magnification of the lens. Canon, at least, doesn't provide that. However, as a broad generalization, the problem you are having with DOF is a function of distance from the lens, not the particulars of the equipment. Razor-thin DOF is just part of macro work, and you can't get around it with equipment. There are only three solutions:

1. Stop down. This helps a little, but often not enough. I rarely shoot macro wide open. This means controlling light, either providing more or using a suitably long exposure. This is why most bug macro is done with flash. I use long exposures for flowers indoors.
2. Stack images, as you have started to do.
3. Step back for more depth of field and then crop for magnification. This is often recommended, but I never do it because it decreases the detail in the image.

Dan

[Davidgypsy]

For the same framing, a full frame camera will have less DOF, not more. Yes Dan I was aware of that but I was thinking of doing lots of slices at minimum DOF to see what happens. Controlling the shoot is obviously paramount so that means studio type work. I will try your suggestions with a range of lens/distances etc and see what happens. I haven't tried stacking at high macro with an auto bellows yet. It's all good fun and now and then you get that image.

Regards,David

[DanK]

Yes, I do most of my flowers in a studio in order to avoid wind and to control lighting and background.

AFAIK, there is in most cases no advantage to decreasing DOF and increasing the number of slices to compensate, but please let me know if I am missing something. As of now, I generally pick a moderate aperture where the lens will be sharpest and set the number of slices accordingly.

I look forward to seeing what you produce. I do most of my indoor flower work in the winter, so I may not be posting more stacked flowers for a while.