It is not accurate to compare the capacity in Amp-hours because the Nikon EN-EL15C battery has twice the voltage (two Li-ion cells in series) of a single-cell smartphone battery.

As well I'd like to add the thought that the smart phone could be running all kinds of battery draining things in the background. So actual battery life depends not only mAh but how efficiently the device uses its capacity.

And the camera batteries are replaceable. Quickly. In the field. There are also "battery grips" that have extra battery slots in them and automatically switch between the batteries. The camera never has to sit on a charger, only a spare battery does.

Alternatively: I'd point out that the camera app tends to be a highly battery-draining activity on a phone. Most phone users do not leave the camera app up 24/7.

(And as a digital camera user - at least I can hot swap batteries. I miss my old cell phones that allowed for this.)

Napkin math: 7V/2280mAh = 16Wh or equivalent to 3.7V/4300mAh (USB power banks are always measured and marked in 3.7V and mAh as unit to produce largest comparable numbers)

I've always thought it was odd powerbanks didn't advertise in mWh. That's a bigger number and comparable regardless of voltage.

If you want napkin math then just multiply 2280 by two. It'll be faster and more accurate than converting to watt hours.

Keep in mind that my Nikon really only consumes power when it's _doing_ something. I can leave my camera "on" for months at a time and come back to a fully charged battery.

The screen is off except when I'm previewing a photo. The viewfinder is physical. The metering is only on for 10-20 seconds after I wake the camera by touching the shutter release and is only displaying on a low power monochromatic LCD. Autofocus only happens while I'm holding the shutter release until it finds focus then locks.

Meanwhile the iPhone battery is powering what is, effectively, an entire laptop with a 5+" screen and cellular, wifi and bluetooth radios.

Articles I can find are quoting an iPhone taking a few hundred shots on a charge. Nikon's testing puts my camera able to take a few _thousand_ per charge. There's literally an order of magnitude difference from my Nikon's 1400mAh battery to a iPhone's 2500-4500mAh battery. Two to three times the capacity for 1/10 the pictures.

That comparison doesn’t work for newer mirrorless cameras. I have a DSLR and mirrorless strapped to my body at each wedding and I go through more than twice the amount of batteries in the mirrorless.

They also take a second or so to wake from standby which is super annoying for my job, so I have it set to 5 minutes. That essentially means it never goes in to standby on a wedding day.