Apple's iPhone 4S helped Amazon's Kindle Fire sales, if a new study is to be believed.

The release last October of the newest iPhone made the iPad a tougher sell for Apple, according to a new study from IHS iSuppli Market Intelligence. That left an opening for Amazon, which took advantage of the wary buyers by releasing a tablet at a much lower price point.

As Apple-heads all made sure to get the iPhone 4S at $199 a pop, many of them were left feeling a little uneasy about shelling out another $499 for iPad tablet.

So the Kindle Fire was a perfect second-choice option at only $199, which many consumers could feel better about parting with, the study postulates. The Feb. 16 report adds that Apple's share of the tablet market decreased in Q4, and that the iPhone 4S may have been behind some of that depressed market, which Amazon deftly took advantage.

Rhoda Alexander, tablet analyst for IHS iSuppli, described the phenomenon in her own words:

The rollout of the iPhone 4S in October generated intense competition for Apple purchasers' disposable income, doing more to limit iPad shipment growth than competition from the Kindle Fire and other media tablets.

But she added that Amazon took a business gamble by pricing the Fire at only $199, and that the company will need to sell large amounts of content in order to turn a sizeable profit. 

The report estimated that Apple shipped 15.4 million iPads last quarter, up 40 percent over the number shipped in 2011's third quarter, but that the companies share of the worldwide tablet market fell from 64 percent to 57 percent in the same stretch.

Amazon was responsible for selling many of the tablets that made up the difference (the company shipped an estimated 3.9 million Kindle Fire tablets in Q4, earning the company 14.3 percent market share.) Q4 sales are seen as the most important of all for retailers, as it includes Black Friday, Thanksgiving and most importantly, Christmas. The Barnes & Noble Nook was also released in Q4 of 2011, and it sold 1.9 million units, making up 7 percent of the tablet market, according to IHS iSuppli.

Samsung was the previous king of tablets, but its station fell in the fourth quarter of 2011, when it sold only 2.1 million Galaxy Tab tablets. The company sold 6 million tablets total in 2011, IHS iSuppli reported.