GoPro (GPRO) isn't the only company making action cameras. Although its name has largely become synonymous with any waterproof, mountable, digital camera, the company is not without peers.

GoPro's management argues that it can become a media company, and thus stave off many of the long-term effects of margin-killing competition. Still, investors should be aware of what GoPro's emerging rivals -- including HTC (NASDAQOTH: HTCXF), Garmin (GRMN 0.96%), and Sony (SONY -1.34%) -- are offering.

HTC's non-active, action camera
HTC's RE digital camera is a GoPro alternative for those without particularly active lifestyles. Like GoPro's Hero cameras, HTC's RE is a digital camera and camcorder that connects wirelessly to a smartphone. It offers users the ability to quickly shoot images or capture video without having to pull out their smartphone.

The RE isn't as rugged as a GoPro -- HTC freely admits whitewater rafters should stay away -- but it could compete with GoPro for a particular subset of users. At $200, it's priced on par with GoPro's mid-tier Hero3, but it's capable of capturing higher quality images and video.

HTC's RE is a new device (it debuted only last month), and admittedly, it's hard to say for sure that a market for it truly even exists. Still, HTC's RE (and its likely successors) is something GoPro shareholders should watch closely.

Garmin isn't giving up
Unlike HTC's RE, Garmin's action cameras are quite comparable to GoPro's. Its current flagship, the Garmin Virb Elite, is -- in terms of functionality -- almost identical to GoPro's Hero3+ Silver, able to capture 1080p video and take digital photos while offering intense ruggedness and waterproofing.

But despite offering a similar product, Garmin hasn't seen nearly as much success as GoPro. On the company's most recent earnings call, Garmin CEO Clifton Pemble admitted that its action cameras had not caught on as well as the company had anticipated.

Still, Garmin remains undeterred. The company is only on its second-generation action camera, and, according to management, will continue to invest in the space. It may seem somewhat outside of Garmin's core business, but its expertise with GPS, and small, consumer electronics could help Garmin emerge as a top GoPro competitor in the quarters ahead.

Sony takes on GoPro
Historically, Sony has competed in nearly every consumer electronics market -- from mp3 players, to TVs, to video game consoles and everything in between. Sony's recent financial struggles, however, have taken a toll on its product line. The Japanese electronics giant, for example, no longer makes PCs. But despite its diminished role in the electronics space, Sony has branched out into action cameras, and its AS100V may be GoPro's most significant competition.

Sony's camera is -- spec-wise -- on par with GoPro's Hero 3+ Black, but is distinguished by the inclusion of GPS and NFC technology. Image quality is comparable, but reviewers have praised the audio quality of Sony's camera, noting that it bests GoPro's by a fairly wide margin.

GoPro has since one-upped Sony: Its top of the line Hero4+ Black offers superior specs, but is several hundred dollars more expensive. The AS100V, though, was released in the first half of 2014, and a successor should be arriving shortly to close the gap. Sony's cameras haven't attracted as much attention as GoPro's, but given the strong reception and Sony's experience in both digital cameras and consumer electronics, they should not be overlooked.