Live bug partial focus stacks

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LordV
Posts: 1571
Joined: Thu Nov 22, 2007 10:28 am
Location: UK

Live bug partial focus stacks

Post by LordV »

I like to capture fairly fine detail in bugs but was rather disappointed when I first started using the MPE-65 on the softness of the shots (think I was using F11 for all mags). This lead to doing some diffraction tests where I obviously found the need to open up the aperture to get the detail I wanted at mags higher than 1:1. So what I tend to do is take partial focus stacks that would give the same DOF I would have got say at F11. In practice this really means getting all the bits of the subject that I want to get some sharp detail in focus in the sequence. With flies this often just most of the head, the eye and part of the thorax. The main challenge in putting them together is to make it look as if it is a single shot.
To do this I try to take a fairly fast sequence of shots checking the focus point for each shot- I can normally manage about 1 shot a second when doing this.
Often the biggest problem with this is very sharp unnatural looking DOF boundaries. I have toyed with the idea of taking a couple of small aperture shots and then stacking wide aperture shots on the top but in practice i find it very difficult to change apertures during a handheld shot sequence. I often resort to what I call differential hand stacking where I am purposely not stacking the whole picture but just the parts I'm interested in. This can get round sharp DOF boundaries on the background/foreground but obviously you have to be very careful.

At it's simplest- I might just be doing 2 shots- one with the head and part of the thorax in good focus and one with the eye in good focus but obviously this depends on the magnification being used.

The slightly tricky part is stacking them . If I have had a solid surface to rest on and the bug has not moved then the normal stacking progs such as zerene work pretty well, however if there is either some FOV movement or bug movement the I tend to resort to hand stacking the shots in Photoshop using mainly the repair brush to transfer in focus parts from one picture to another. Sometimes you have to rotate the donor picture and rarely you have to re-size it before doing this.

Couple of examples below where the first photo is a single shot and the second shot a hand stacked version made from several shots. In both these shots I was holding the leaf the bug was on and resting the camera lens on that hand (you can see some oof finger in #1)

Brian V.

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www.flickr.com/photos/lordv
canon20D,350D,40D,5Dmk2, sigma 105mm EX, Tamron 90mm, canon MPE-65

PaulFurman
Posts: 595
Joined: Sat Oct 24, 2009 3:14 pm
Location: SF, CA, USA
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Re: Live bug partial focus stacks

Post by PaulFurman »

Thanks for sharing your methods. I did several of these yesterday and boy it was a lot of work. Maybe I should be less ambitious about the number of hand held frames to attempt stacking. I started with 10 to 30 images and did a lot of weeding to find the good ones and identify where mismatches caused problems due to changing position, often ending up with about 4 useful images. Some came out with bands of in focus and out although that doesn't bother me as much as I'd have thought, maybe I'm not being objective after all that work <g>.

What I do is hybrid manual in PS roughly then let zerlene take a stab and finish up by stepping through each frame to clean up in zerlene. For one, the boders were mismatched badly, I basically was doing a panorama so I enlarged the canvas to fit them all and wound up with a 16MP square crop from 12MP frames. What made it work was stitching up a seamless OOF background where I actually cloned out the subject to fill in with adjacent blur. This eliminates halos & rotation problems where I might have placed it a bit wrong in PS and minimizes edge problems for partial frames. So the background is the bottom layer and I turn each successive layer on above that, erase out any linear edges or useless partial detail to reveal the soft background. In some cases, blurring out the distracting details so that zerlene has less to worry about & matches what I want matched only. This is the pano one described with 4 frames in the end after struggling to get 10 frames to match: http://www.flickr.com/photos/edgehill/4 ... 765458318/

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