Custom functions: a jargon-free guide to unlocking the power of your DSLR

Custom functions: a jargon-free guide to unlocking the power of your DSLR

What are custom functions? In this no-nonsense guide we cut out the jargon and explain your DSLR’s array of options to tweak settings, as well as which of these are safe and sensible to alter.

Custom functions: a jargon-free guide to unlocking the power of your DSLR

What’s so special about custom functions?

Custom functions are DSLR options and settings that you access through on-screen menus. They enable you to customise the operation of the camera – to fine-tune it to the way that you prefer to take your pictures, or to suit a particular type of photographic subject.

I don’t remember having these on my old 35mm film SLR…

This amount of flexibility simply wasn’t possible on film cameras. Technological development means that even a modestly priced DSLR can be customised by the photographer.

What’s more, the fact that the image is recorded digitally means that there’s a whole range of on-board processing options that weren’t available to the film-using generation.

How many custom functions do cameras provide?

The number of customisation options you have will depend on your model of DSLR. The more you pay for your camera body, and the more professional its target market, the more functions it will have.

An entry-level DSLR might provide 12 custom options, with 32 possible settings. Meanwhile a professional-level camera can provide over five times more permutations, with 62 custom functions and a whopping 177 settings.

What makes custom functions different from other settings?

Not much. The Custom menus simply provide a place in which to put all those overrides that don’t have a more logical place to go.

They might simply be better known as ‘miscellaneous’ on the menu functions. In fact, features that are custom functions with one brand may be filed under a more mainstream menu path on another.

Turning off the beeping noise on a Nikon, for instance, is as a custom function, but on a Canon the same function is found within one of the higher menu paths.

Do I really need to set up any of these custom settings?

Possibly not. The camera comes with each of the custom functions in a default position that the manufacturer chose to suit the majority of users.

What’s more, in some shooting modes (those designed for point-and-shoot operation) the custom overrides won’t be accessible anyway.

However, some of these settings are definitely worth getting to know. Some custom options are best suited to experienced photographers and to those shooting specialist subjects, but there are plenty of others that are more generally useful.

Such as?

Some of the most useful custom functions enable you to change the function of a particular button on the camera. In order to simplify design, manufacturers limit the number of knobs and dials on their DSLRs – and the buttons you do get may offer a function you never use.

The depth-of-field preview button is helpful to some, but an irrelevant waste of space to others. The ability to reassign this button to offer quick access to a different feature can make a camera much easier to use.

Similarly, most shutter releases not only fire the shutter, but also engage the autofocus and lock the exposure. For some types of photography, it may be useful that this trigger doesn’t lock focus and exposure simultaneously – a custom function is likely to offer this.

Custom functions: a jargon-free guide to unlocking the power of your DSLR

What processing options do custom functions offer?

They can provide preferences that define how and when the camera reduces noise in your picture. They can also enable you to control whether the camera adjusts the contrast of an image for you automatically (this feature is called Auto Lighting Optimiser on Canons and Active D-Lighting on Nikons).

How do you decide which functions to use?

Ideally, you should try them out for yourself and see which setups and effects you prefer based on the results you get. Some custom functions help you make a new camera work more like the one you had before, or help you adjust the controls to suit a particular type of subject.

Should you adjust custom functions once to your liking and then leave them – or adjust them on a shot-by-shot basis?

A bit of both. The option you choose for some will do for every shot you take – others are best used only for particular shooting situations (say, for night photography, or when using studio flash). Some cameras enable you to set up custom modes or workspaces so you can switch a whole set of presets at once.

What are the most complex custom functions?

The Canon EOS-1D Mark IV has 16 custom functions set aside for autofocus alone. However, this isn’t really surprising. This camera is used by professional sports photographers who need to be able to adjust responsiveness and target areas depending on which sport they are shooting. If you’re struggling to make sense of which to use, it’s worth looking on forums and talking to photographers that shoot similar subjects to discover exactly which custom functions they find useful.


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