Focus Stacking in the field has become a practical reality for me thanks to what Panasonic calls 4K post focus, avaiilable in the GH4 and several other models…..

The very first time I saw the remarkable images that a scanning electron microscope could generate I was completely hooked. The Sunday Times colour supplement, a journal of quality in those pre-Murdoch days published a series of images by the remarkable Lennart Nilsson. Every detail was revealed in sharp focus by taking layers within the target and building up an image created via reflected electron beams from these. I dreamed of one day being able to do something similar with natural light and with living material, not the dead specimens coated with a thin layer of gold deposited in a vacuum chamber…now I can.

Grasshopper 5 (B, 3, 5)(LR) copy

Head of an Egyptian grasshopper (Anacridium aegyptiacum): this is a section of the 4K frame (original 1153 x 1730 pixels) that reveals the level of detail the stacking process picks up. Note the softness of the background..this is determined by the aperture used in creating the stack. Here Exposure per frame was f /5,6 at 1/500th sec.

The Revolution: 4K post focus in the Panasonic GH4 (and various other Panasonic cameras that boast a 4K video capability)

For the past few weeks I have been like a kid in the proverbial candy store using a feature of the Panasonic GH4 called 4K Post Focus. The result has been some superb stacked image results.What this camera does differently is to use its high resolution video capability (something for which many pros have bought it) rather than a burst involving the shutter. The 4K video mode employed allows super detailed video for the 4K refers to the approximate value of the long edge of each frame captured.

a. The frame rate is 30 fps and the exposure of individual frames is set beforehand. I use f/4-f/5.6 as the marked lens aperture for this tends to cover the proverbial ‘sweet spot’ where the lens has its optimal performance.

b. You also get the Bokeh associated with the wide aperture and this gives soft backgrounds that accentuate the detail of the final stacked image

c. I then adjust the ISO between 200 and 400 (say) to get a shutter speed that will freeze movement. The stacking software can cope with tiny movements between frames when it aligns images but the more you can cut down movement of subject and camera the better. To this end I always use a tripod and a flexible arm when possible to steady plant stems during the scanning of the subject and focus shift by the camera. Read More

Maybe you have been attracted by the thought of the far lighter bodies of micro 4/3 cameras or the amazing array of functions (superb video and precision focusing aids for example) they boast  but been deterred by the 2x crop factor from changing formats – or even adding a body via an adapter and using manual focus on your lenses. Metabones have produced a intriguing optical device – the Speedbooster XL 0.64 that lowers the crop factor substantially  (to 1.28) and also produces an increase in the speed of the lens you are using by 1 and 1/3 stops… interesting, then read on.

Mt Terminillo, Lazio, Italy, July 2016

Eugenia’s pansy (Viola eugeniae) occurs in huge numbers on high mountains in the Apennines. Here the Laowa 15mm f/4 behaves as a 19.2mm f/2.5 equivalent used with a Metabones Speedbooster and gives an obvious wider ‘feel’ that when used with a simple adapter when it behaves as a 22.5mm equivalent wide angle on APS-C format.  

Before I began using a Sony NEX 7 about three years ago, I had realised that there were certain advantages to using mirrorless cameras for my experiments with wide-angle macro imaging, macro and microscopy: I am still finding new ones.  Everything stemmed from the fact that, thanks to the absence of a mirror (a feature of all DSLR cameras), the distance between the lens flange on the front of the camera body and the sensor can be made much less, making lens corrections easier to deal with because of a diminished air space.  Thus, when you use so-called legacy lenses you have to use adapters that not only convert to the lens mount but also build in some distance (effectively an extension tube with different mounts at either end) because lenses meant for full frame (and other)  DSLR cameras have their rear element further away from the sensor to accommodate the presence of the mirror. This allows some interesting experimentation and great flexibility in the use of legacy lenses. Read More