I MA gE C APTuR E MATCHINg CAMERA TECHNOLOgY TO WORKFLOW NEEDS Despitetensionbetweentheracetohigherresolution (megapixels)andtheoverallimagequality(IQ),digital cameratechnologyhasbeenadvancingatasteadyrate. New cameras in every category are generally better than preceding models. Yet higher megapixel counts havesometimesprecededtheabilitytoachievehigher image quality. Manufacturers, however, have been extremelycleverinovercomingissuesthatoccurwith packingmorephotositesintothesame-sizesensor.As a general rule, bigger sensors and bigger photosites on a sensor can achieve higher image quality.This is onlyageneralrulesincemanyotherfactorsenterinto theequation. Sensor Type (CCD, CMOS, Foveon CMOS, Trilinear Array, Multishot) Although CCD (charge-coupled device) preceded CMOS (complementary metal oxide semiconductor) chips to market, most smaller sensor cameras (up to full-frame 35 mm) use CMOS chips. The larger sensors found in medium-/large-format cameras are currently all CCD technology. At this point, both technologies can achieve the highest image quality. TheFoveonCMOSsensorhasgreatpotential;unfor- tunately, that potential has not been fully realized since it is not available in high-end cameras. The trilinear array (digital scan back) cameras and the multishot cameras (the red, green, and blue channels arecapturedinthreeseparateexposures)aregenerally reserved for special uses such as museum photogra- phy. Some intrepid photographers, such as Stephen Johnson, continue to prove that every rule can be broken by using digital scan backs to create photo- graphs of exceptional quality, even of dynamic land- scape subjects. 108 Sensor Dimensions Digital sensors come in a wider variety of sizes than we were used to with film formats. They range from the tiny (5.76 × 4.29 mm) to the large (53.9 × 40.4 mm). A few even larger sensors are being made, such as Fairchild Imaging's 81-Mpixel CCD595 3 × 3 inch sensor,buttheyaregenerallyfloatingaroundinspace taking detailed pictures of the Earth. Larger sensors canholdmorephotosites(ormorephotositesthatare larger).Bothareanadvantagefromthestandpointof resolutionandimagequality.Anotherimportantfactor forphotographerstoconsideriswhetherthesensoris "fullframe"orwhetheritwillcropthelens'sangleof view.Equallyimportantistheaspectratio.Somepho- tographers are used to and prefer the 35 mm 1.5:1 ratio, while many others are wedded to the 1.33:1 ratio of the medium format. The 1.33:1 ratio fits normalpublicationpagesizesbetterandisoftenpre- ferredforthatreason.Theso-calledcropfactorwasan impedimentformanyphotographersintheearlydays ofdigitalcapture.Somehavegrowntolikeitsadvan- tages, whereas others were relieved when full-frame sensors allowed full use of wide-angle lenses. Since digitalsensorsarenottiedtoanyparticularfilmformat, needingonlytobecompatiblewithlenscoverage,we wonder why there hasn't been more innovation in aspectratios.Whywouldn'twehavea1.33:1oreven a1.25:1DSLRsensorthatusesthefull36-mmwidth, thatis,36×28 mmor36×29 mm? Pixel Pitch (relative size of the photosites/pixels) Increasingthenumberofmegapixelsresultsinhigher resolution,butalsoinsmallerphotosites(pixels).Pho- tosite size is referred to as the pixel pitch. Smaller photosites gather less light, so they have less signal strength. Less signal strength, all other things being