Kirk McElhearn, in his DPReview article Opinion: Do we really need all those buttons and dials? :

Today’s cameras are computers with lenses, and like computers, they have a plethora of features, far more than any film camera. As with any computer, we need to be able to adjust these many settings. There are menus that allow us to enable, disable, and tweak the many features available, and buttons and dials give us quick access.

But with many modern cameras now offering a dozen or more control points – some customizable with no obvious markings – there’s a risk of overwhelming certain users. More importantly, the sheer complicatedness of digital cameras can get in the way of taking photos.

[…]

There will always be complicated cameras available for those who want the utmost control. But having a plethora of control points doesn’t necessarily make a camera any better – for some, it makes it worse.

I have too many cameras. Still more film cameras than digital cameras, but recently, thanks to a mixture of very good deals found on eBay, and the generosity of some photographer acquaintances and friends, I’ve also been adding quite a few digital cameras to my collection.

Shooting digital is certainly more practical, more instantaneous, and more affordable today, but one of the things I’ve always preferred about film photography is just how well-designed many film cameras are, whether we’re talking of simpler point-and-shoot cameras, rangefinders, or professional SLRs.

Many film cameras have buttons, dials, and controls that are so well-placed you can easily adjust everything manually and take your shot without even moving your eye away from the viewfinder.

The problem of too many digital cameras is not the sheer amount of buttons and dials — it’s their user interface in general. It’s their menus and settings. It’s the balance between physical controls and virtual controls. It’s the way user interaction is designed.

With all the photography literature and expertise accumulated so far, it should be easier to design a camera’s user interface, instead I often keep seeing unnecessary complexity.

Buttons and dials should be used for all basic functions, everything a photographer needs to quickly adjust in an intuitive way. Setting ISO speeds, changing the white balance, adjusting exposure compensation, focus lock, shooting modes, etc. — all these are functions the user should be able to change without having to look for them in a sprawling menu hierarchy.

Yet I’ve used a lot of digital cameras where the manufacturer chose menus over physical controls to offer a more minimalistic camera design, or perhaps to save costs. The results are cameras that look simpler to use, but ultimately they are not. Users tend to get more confused by several pages of menu options and settings (often even cryptically abbreviated due to space constraints), rather than the amount of buttons and dials.

An annoying design choice with some digital cameras is that you have both a button/dial and a menu option to access the same function or adjust the same parameter. This just increases confusion and clutters the on-screen interface.

An increasing number of digital cameras today feature a touchscreen and their main interface relies a lot on touch input. While I do think that some touch controls can be handy, especially while filming yourself with cameras with fully articulating screens, this is another instance where I greatly prefer having buttons and dials.

There’s a sort of obsession with touch interfaces today, and manufacturers seem to want to put them everywhere in their products; but they’re not a panacea. They may look cool and futuristic, but from a sheer usability standpoint they’re simply terrible. Cameras and cars are the first examples coming to mind. Cameras and cars have one rather important thing in common: in both cases you want the operator to be able to perform the highest number of tasks without averting their gaze, from the viewfinder and from the road ahead respectively.

It’s kind of semantically ironic how touch controls, despite the name, are the ones lacking feedback. So, every time you want to change something, move a virtual switch, activate or deactivate a feature, you need to be looking at the screen first. And the problem with many cameras with touchscreens is that these controls are generally tiny and not really easy to select. Or they’re crammed together and you may end up changing some other parameter by mistake. And in the best case scenario they slow you down noticeably. What do you think it’s more convenient for changing ISO or WB settings, having to tap repeatedly a small target in the corner of a 3‑inch touchscreen, or turning a dial with your left hand while you see updated information in the viewfinder and you still have your right index finger on the shutter button, ready to take the shot?

So yes, I think we need all those buttons and dials — provided they’re laid out thoughtfully, and provided their arrangement is part of a greater interface design that includes the menu layout and navigation, a balance between direct physical controls and what you set up by navigating menus and submenus, and deciding a hierarchy of priority. Buttons and dials should always prioritise frequently-used and frequently-changed controls, and the access to the provided functions should always be as direct as possible. You want to push a button or move a dial, and the associated parameter to change on the fly. You don’t want to push a button or move a dial and have a mini-menu appear, and have to navigate that menu with the arrow pad and press OK to confirm.

When the arrangement of buttons and dials is well designed and their functions clearly marked (or very easily memorised), then you end up with a better overall interface, which is much preferable over cameras that are heavily menu-based and whose few buttons have to necessarily serve multiple purposes. Here you have an interface that slows you down and is harder to memorise.