The technology news site The Verge revealed that a video that was meant to show off the Lumia 920's ability to produce sharper photos and videos was in fact filmed with an SLR camera.
A reflection in a window seen in one part of the video seemed to show a cameraman holding what looked like a digital single-lens reflex camera.
Nokia issued an apology on its company blog Thursday, which said in part:
"In an effort to demonstrate the benefits of optical image stabilization (which eliminates blurry images and improves pictures shot in low light conditions), we produced a video that simulates what we will be able to deliver with OIS.
"Of course, hindsight is 20/20, but we should have posted a disclaimer stating this was a representation of OIS only. This was not shot with a Lumia 920. At least, not yet. We apologize for the confusion we created."
Analysts not impressed with new phone
The blunder just added to the overall disappointment with the product launch, which saw Nokia's shares fall more than 13 per cent on Wednesday in Helsinki and drop as much as four per cent on the market's open Thursday.
In New York trading, Nokia shares fell 16 per cent to close at $2.38 US on Wednesday, trading at the same level as in the mid-1990s. They were up slightly Thursday, trading at $2.44 at midday.
Most analysts were unimpressed with the Lumia 920, which is Nokia's attempt to catch up to rivals and make a mark in the competitive smartphone market.
"People were looking for something that would dazzle," RBC analyst Mark Sue told the Reuters news agency.
"Most investors will view it as evolutionary, not revolutionary. Nokia has made some good progress, but investors were looking for quantum leaps. We didn't get that."