Friday, February 5, 2021

MUSIC: Use Case 6 - Handheld optimum exposure bracketing

In this post I'll discuss MUSIC's use case 6: the handheld (HH) exposure bracketing option.

Unlike 'normal' exposure bracketing, where we are likely to be on a tripod and adjusting exposure time, in HH exposure bracketing we need to account for the fact we are, obviously, hand holding.

I wrote use case 6 for those times I can not use a tripod or stabilise my camera, and I'm forced to handhold, albeit, maybe, using a string tripod to 'eliminate' at least one degree of freedom of potential motion blur. UC6 is well suited for wide angle captures.

I've also tweaked MUSIC’s UC6 (download the latest version on the right) and included a shutter-triggered option, ie in addition to the other two triggering modes: via the script run feature or via the LV quick access feature.

Before looking at the new UC6 functionality a quick reminder about HH bracketing, that assumes your base exposure is an ETTR set one, based on the lowest ISO value you can use, which covers the highlights. UC6 then takes two other images:

  • The second image is taken at your base ISO and with the slowest shutter you set in MUSIC: this gives you the maximum photon capture;
  • The third image, for the shadows, is then taken at the second image's shutter, ie your slowest, but at an ISO value that you set in the script as the start of your camera's ISO invariance zone. There is no point increasing the ISO beyond the start of this ISO value, which, for example, I define as ISO 1600, or even 3200, on my 5D3, and 800 on my M. One of these two links should help you find your ISO value:

The UC6 menu now looks like this:

Here we see two new menu items: HH Shutter and Shutter triggered?

The HH Shutter allows you to specify your minimum hand holding shutter speed: 1/30s shown above. With the Shutter triggered option set to no, UC6 can be used in LV mode, run from the script or by turning on quick access and doing a long press of your selected triggering key, eg the SET button on my 5D3 or a 1-finger long press on mu EOSM.

With Shutter triggered set to yes, the UC6 menu switches to looking like this - note there is no bookend option if using UC6 in shutter triggered mode:

Having set UC6 triggering to the shutter, all I need to do now is leave the ML menu and use the camera’s shutter, either in LV or looking through the VF: in each case, UC6 bracketing will take place, giving me the 'perfect' handheld bracket set, ie from a low ISO ETTR base exposure.

My personal capture technique being to allocate auto ETTR to the double half shutter press on my 5D3, thus allowing me to compose and set the base exposure, before doing a full shutter press, all the time looking through the VF and using the camera against my face to help stabilise the camera.

Post processing is as normal, eg:

  • Ingest into Lightroom
  • Set and sync the WB across the bracket set
  • Look at the ISO 1600 capture and consider extending the bracket set with a virtual copy and 2-3 Ev uplift of the ISOless captured image
  • Process in LR's HDR Merge
  • Finish post processing on your floating point TIFF, ie you will have +/- 10Ev range to play with, either in LR or in Photoshop, but, of course, there may not be data everywhere ;-)

Bottom line: Use Case 6 gives you a optimum bracketing feature when hand holding. It also allows you to trigger this from the MUSIC script, the LV, via MUSIC's quick access feature, or via the normal shutter.

As usual I welcome any comments on this post or any of my posts.

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