Nowadays, we are spoilt by technology and there is a tendency to think in terms of a camera controlling the output of flash guns via its DTTL exposure system. Even better, it can do this without the use of cables via a WiFi set up. However, the arrival of digital cameras has made the use of older manual flash guns easy, even though you are denied the camera’s DTTL system.

Once upon a time, a flash gun was simply triggered by a camera hotshoe or, off-camera, via its flash synchronisation (synch) socket. Other ‘slave’ flash guns for fill-in or back lighting could be triggered via  simple photoelectric triggers that fit the flash hotshoe and reacts to the main flash pulse with a very slight delay.

To get correct exposure demanded a flash meter – an exposure meter that can respond in a very short time (milliseconds). Readings were transferred from meter to camera and flash gun positions adjusted accordingly. Many professionals in studios used a polaroid film back to get a rapid assessment: with close-up work experiments had to be done with flash gun position noted and frames taken over a range of apertures to find the optimum. Nowadays you can use your camera’s LCD screen to make a visual assessment of exposure.

Eyespots of the wings of the Spanish moonmoth (Graesiella isabella) photographed using a Nikon SB 29 macroflash as a manual gun - designed for a TTL system it did not function with DTTL flash meterin

Eyespots of the wings of the Spanish moonmoth (Graesiella isabella) photographed using a Nikon SB 29 macroflash as a manual gun – designed for a TTL system it did not function with DTTL flash metering so the exposure was tweaked via the camera’s LCD

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Shortly after I put my experiences with the Pansonic GH4 4K post focus mode on the Learn Macro site I had a very helpful email from Catherine at Helicon Focus. The more recent versions of Helicon Focus cope directly with MP4 video snippets which you can send directly from Lightroom thanks to a plug in. Last year I had a hard drive in my iMac fail and re-installed most of what I had lost but omitted to upgrade the version of Helicon Focus… I can also speed things up by ‘trimming’ clips in QuickTime™

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The depth of detail in this image of an Oleander hawk caterpillar (Daphnis nerii) is something I cannot achieve in any other way… it employs macro lenses used at optimal apertures, diffraction minimised by not closing down to small apertures and a soft background blur associated with a wide aperture.

The program cleverly extracts the individual frames and they appear in the right hand panel in Helicon Focus. There will often be far more of them than you need – at both the beginning and end there might be extraneous frames:

  1. where recording begins before the first frame of the stacking sequence
  2. at the end where it extends focus to the background.

It is also better to remove these because you tend to get artefacts in the image which take time to clean up in Photoshop and I also like the soft Bokeh achieved by working at f/4 – 5.6 in the original frames and do not need the sharp background images.

NB I find this happens to a much greater extent when using a cable release  than when using ‘touch focus’ from the LCD of the Panasonic GH4 or via the App for my iPad Air. In the latter case the camera focuses first on the closest detail and then the sequence begins: with the cable release there is a tendency to start recording whilst focus is being found. Read More