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Comment by LeifCarrotson | Hacker News Reader

The focus stacking technique was news to me. I've been doing some macro photography of PCB components with an extension tube, but the depth of field is just so shallow that it's hard to see what you're doing. You can't read the text on top of an IC and see sharp solder joints on the bottom at the same time.

But if you put it on a threaded rod, move the camera, and take the in-focus parts from a bunch of pictures, you can see the front and back of the fly at the same time. How cool!

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That's pretty cool. Maybe this would actually be a good use for the failed Lytro cameras. Changing focus after the shot is taken was always a parlor trick with little use in regular photography, but for microscopy it could be game changing. Has anyone tried microscopy with a Lytro Illum? Seems like you can still buy them used.

A lab I used to work at had a light field microscope system. Sorry, though, its existence is pretty much all I know about it since I never personally got to use it.

If you're photographing stills (like PCB components) then you might as well use a smaller aperture and increase the exposure time to get an image that is globally in focus.

This only works up to a point before diffraction sets in and the picture quality starts to very noticeably suffer, and comes nowhere close to the depth of field acquired with focus stacking. In fact, with stacking, the lens should be stopped down to the best f-stop anyway (f/8-11).

Good (Vis/NIR) microscope optics go up to f/0.56 (NA 0.9) without oil immersion. Granted, such an objective will cost you 3.5k$ [0], but they don't go to these lengths without expecting near-diffraction-limited performance.

[0]: https://www.thorlabs.com/thorproduct.cfm?partnumber=RMS60X-P...

with very wide apertures and magnification the depth of field may still be too narrow, and longer imaging time (if not focus stacking) would just make the image brighter not more in focus. Taking multiple shots with different depth of field and stacking them would work.

and then stack those images. :)

Jeff Geerling just uploaded a tutorial video on focus stacking if you want to check it out!

https://youtu.be/pinYVZxBF2Q

On my hacked Sony camera, you can program the camera to change focus and take a picture each time in rapid succession, no need for anything more than a tripod :)

There's a device called the Helicon FB Tube [1] which comes in Canon and Nikon variants, and purports to do this with any camera and lens pair it supports.

I've thought about trying one out - it's not that expensive compared to most camera things, but I'd want it for shooting handheld, and I'm not sure how well it'd play with either the recycle rate on my flashes or the movement rate of the insects I shoot this way. Probably not well with either, but for still stuff I guess it's probably still cheaper than a driven macro rail...

[1] https://www.heliconsoft.com/heliconsoft-products/helicon-fb-...

For Canon, wouldn't it be possible to also do it in software with Magic Lantern?

Apparently! I don't have any Canon gear and I'm not sure I'd reflash it if I did, although if their software is as unergonomic as I've found their hardware to be, I might - that said, while I can't try it out for myself, a bit of searching does turn up any number of howtos on the subject.

Yes, even the old CHDK did that job nicely on my old IXUS 100 IS. A script for this (and adaptive exposure stacking, very useful for unlit roman interiors when you're looking out a window with bright sunlight) came with the download back then.

And at least for CHDK, there wasn't actually any flashing. It just used the firmware flashing mode as a bootloader.

The newer Nikon cameras have it built in as well.

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