It happens to every company sooner or later: Wall Street sets a mark for quarterly earnings, and the company misses that goal. Sometimes an earnings stumble is a signal to sell, but digging in the dirt is also a good way to find turnaround candidates while they're getting beaten down. This report is a little bit late this week thanks to the Labor Day holiday, but better late than never. So today, we'll look at a digital camera somewhat out of focus, a few stranded cargo ships, and a diamond ring that won't shine.

OmniVision underrated?
Our first disappointment this week is OmniVision Technologies (NASDAQ:OVTI), a maker of digital camera sensor chips. The company reported quarterly sales of $137 million and pro forma earnings of $0.39 per diluted share -- lagging estimates on both counts. The analyst community had hoped for $152 million in gross revenues and earnings at $0.44 per share. That's 42.7% sales growth year-over-year, but only 10.4% growth on the bottom line.

OmniVision is a heavily shorted stock, to the tune of more than a quarter of all shares outstanding. It doesn't look like an overvaluation situation, since the P/E ratio of just 9.6 is well below the industry average among camera chip makers, which stands at roughly 27 times trailing earnings. One might be tempted to think of this one as a bargain.

As for business opportunities, OmniVision mostly caters to cameraphones and consumer-level digital cameras, and I don't see those markets cooling down anytime soon. It's true that OmniVision is competing in a crowded market, with rivals ranging from tiny Pixelplus to giants like Samsung and Matsushita (NYSE:MC). However, a promising new product scheduled for debut this month could make a real difference in this highly commoditized industry.

Dubbed OmniFocus, the chip results from a $30 million acquisition finalized in the spring of 2005. It promises to replace the mechanical autofocus functions of today's cameras with digital image processing techniques performed by the sensor chipset. Fewer moving parts should lead to cost savings and more reliable end products, and the technology is unique to this company. If OmniVision does indeed deliver on its promises, it should end up with all the customers it can handle.

OmniVision isn't even on the list of tech companies under investigation for stock option problems. I have to say that I'm mystified by the low valuation here. It might be fair to drop the price a bit with a missed earnings target, but not when the shares were so inexpensive to begin with. OmniVision goes on my watch list for further investigation.

Dry-dock this one, captain
How about our next underachiever, DryShips (NASDAQ:DRYS)? The cargo ship operator was expected to deliver earnings per share of $0.56 and revenues around $54.5 million. The sales result was right on the money, but earnings fell short by $0.03 per share. If that sounds OK to you, consider that revenues were down 31% from the year-ago period, and net income plummeted by 72%.

Fellow Fool Stephen Ellis did a fine job pulling together the dirt on DryShips, and I strongly suggest you read his article if the company interests you at all. Suffice it to say that I think we're talking about a shaky operation, run by a substandard management team.

If our Motley Fool Hidden Gems newsletter has taught me anything, it would be never to invest in a company with questionable management, and DryShips CEO George Economou certainly qualifies for that epithet. If you really must invest in shipping operations, try a company that can actually grow its business, such as Excel Maritime Carriers (NYSE:EXM), or Diana Shipping (NYSE:DSX) with its 11% dividend yield. Whichever way you go, you're still in Greece. All roads lead to, um, Athens?

Shine on, you crazy diamond
That brings us to the final low-grade report this week, and it's a household name. International jewelry hawker Tiffany (NYSE:TIF) reported a $0.29 per-share profit where Wall Street wanted $0.32, though its $572 million of sales was slightly above the average estimate.

That's lower earnings than last year's $0.35 per share, in spite of 9% higher revenues. Management pointed to "above-average expense growth," and assured investors that these results are not typical of Tiffany's history. The company aims to grow through expansion, with plans to open between three and five new stores in the United States this year. It's a significant boost atop only 55 stores here today. Considering the anemic same-store growth rates in Tiffany's largest and most established markets -- 5% in the United States and -3% in Japan -- that looks like the way to grow right now.

Management thinks that the stock is undervalued these days, and the board recently approved a $700 million expansion of the stock buyback program. All told, the company could repurchase about 18% of all outstanding shares at today's prices, though the mandate to do so runs all the way to 2009. Don't expect any binge buying, in other words.

In terms of business strategy, Tiffany is emphasizing more expensive items now, partly in response to high gas prices. What? Go high-end in the face of a consumer spending crunch? Well, this isn't exactly Wal-Mart's (NYSE:WMT) jewelry department, folks. We're looking at an affluent customer base to begin with, one that doesn't get affected much by cheaper or more expensive gas. In that light, the move does make some kind of sense. The next few quarters should show us whether or not those rich customers agree.

Now it's time for "so long"
Some of these underperformers are victims of larger circumstances, while others might have only themselves to blame. It's up to you to decide which down-on-their-luck companies should be able to pull themselves up by the bootstraps, and which really are stuck in the mud. Come back next Monday, and we'll take a look at another batch of mishaps and disappointments. It'll be fun and educational. Promise.

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Fool contributor Anders Bylund holds no position in any of the companies discussed this week, and he promises not to wear white until Memorial Day. The Fool has a disclosure policy, and you can see his current holdings for yourself.