Test & Validate Exif Data

Okay. A case of beer up for grabs for the first person to get this one (you have to come to Johannesburg to get it though!)

I have to write an application that extracts EXIF data from photographs uploaded to the server and stores it in a database.  So I try the following:

<cfimage action="read" source="#file.serverfile#" name="image" />
<cfset exif = ImageGetEXIFMetaData(image)>
<cfdump var="#exif#">
<cfquery name="yadda" datasource="#dsn">
insert into pics (focal_length) values (#focallength#) where yadda yadda fishpaste.
</cfquery>

Problem solved, right? Wrong!  The dump file gives me a bunch of variables like "Exposure Time" and "Max Aperture Value".  (note the spaces).    I need to isolate that "exposure time" and "Max Aperture Value" variables.

<cfset focallength = ImageGetExifTag(image,"Focal Length") />
<cfoutput>#focallength#</cfoutput>

Whoo hoo!

But now, what if some malicious idiot uploads a file WITHOUT exif data? OOPS!  This is where I get stuck - how do I test for the variable?  How do I test if that variable exists?  Easy enough to do without spaces.  How do I do it WITH that space between "focal" and "length"?  I've "isdefined" my way from hell to breakfast, without any luck!

PS: its late, I'm tired, and had three beers already!

Spank you in advance. Now go out and conquer!