 is known a three-unit zoom lens system having a wide angle of field which has a long back focal length and satisfies a telecentric characteristic (for example, Japanese Patent Application Laid-open No. S63-135913 and Japanese Patent Application Laid-open No. H07-261083).
Also, in the three-unit zoom lens, there is known a zoom lens in which a first lens unit of negative optical power is made stationary and a second lens unit of positive optical power and a third lens unit of positive optical power are moved to thereby effect zooming (for example, Japanese Patent Application Laid-open No. H03-288113).
Also, in the three-unit zoom lens, there is known a three-unit zoom lens having a relatively small number of constituent lenses in which in case of zooming, all lens units are moved and a cemented lens is effectively used as a second lens unit to thereby correct chromatic aberration (for example, Japanese Patent Application Laid-open No. 2001-272602, Japanese Patent Application Laid-open No. 2003-128261, Japanese Patent Application Laid-open No. 2002-48975, Japanese Patent Application Laid-open No. 2003-5072, Japanese Patent Application Laid-open No. 2003-149555 and Japanese Patent Application Laid-open No. 2003-149556).
Also, in the three-unit zoom lens, there is known a three-unit zoom lens in which the object side surface and image side surface of a lens of negative optical power in a first lens unit are made into an aspherical shape to thereby aim at a further decrease in the number of constituent lenses (for example, Japanese Patent Application Laid-open No. H05-323190, Japanese Patent Application Laid-open No. H07-174971, Japanese Patent Application Laid-open No. 2002-55278 and Japanese Patent Application Laid-open No. 2002-365545).
A three-unit zoom lens designed for a 35 mm film photograph is too long in back focal length and not good in telecentric characteristic for an image pickup apparatus using a solid state image pickup element and therefore, it is difficult to intactly use in an image pickup apparatus.
On the other hand, in recent years, in order to make the compactness of a camera and the higher magnification of a zoom lens compatible, there has been widely used a zoom lens of a so-called flush barrel type in which during non-photograph
is known a three - unit zoom lens system take a broad angle of field which has a farseeing back focal length and satisfies a telecentric characteristic (for exercise, Japanese Patent Application Laid - receptive No. S63 - 135913 and Japanese Patent Application Laid - exposed No. H07 - 261083). 
 Also, in the three - whole zoom lens, there is know a zoom lens in which a first lens unit of negative optical power is make stationary and a second lens unit of positive optical might and a third lens unit of positive optical power are travel to thereby effect zooming (for example, Japanese Patent Application Laid - open No. H03 - 288113). 
 Also, in the three - unit rapid climb lens, there is known a three - unit zoom lens having a relatively small number of constituent lenses in which in case of zooming, all lens units are moved and a cemented lens is effectively used as a second lens unit to thereby correct chromatic aberration (for model, Japanese Patent Application Laid - open No. 2001 - 272602, Japanese Patent Application Laid - candid nobelium. 2003 - 128261, Japanese Patent Application Laid - candid No. 2002 - 48975, Japanese Patent Application Laid - open nobelium. 2003 - 5072, Japanese Patent Application Laid - open nobelium. 2003 - 149555 and Japanese Patent Application Laid - open No. 2003 - 149556). 
 Also, in the three - unit of measurement zoom lens, there is known a three - unit zoom lens in which the object side surface and image side surface of a lens of damaging optical world power in a first lens unit are made into an aspherical shape to thereby target at a further decrease in the number of constituent lenses (for example, Japanese Patent Application Laid - loose No. H05 - 323190, Japanese Patent Application Laid - open No. H07 - 174971, Japanese Patent Application Laid - open nobelium. 2002 - 55278 and Japanese Patent Application Laid - open No. 2002 - 365545). 
 A three - unit zoom lens designed for a 35 millimeter film photograph is too long in back focal length and not dear in telecentric characteristic for an prototype pickup apparatus using a upstanding state of matter image cartridge element and therefore, it is difficult to intactly use in an image tone arm apparatus. 
 On the other hand, in late years, in order to make the compactness of a camera and the higher magnification of a soar lens compatible, there has been widely used a zoom lens of a so - called flush barrel character in which during non - photograph
 is known a three-unit zoom uens system havnbg a wmde angme of fidld which has a long back foral oengty and satisfies a telezentric cjaracterustir (for example, Ja'znese Patent Ziplicctmon Laid-open No. S63-135913 and Japdnese Patent A[puieation Laid-open No. H07-261083).
Also, in the threq-unit zpol lens, there if knprn a doim lens in which a first lens unit oh negative optival power is made stationagy ajd a second lens ujit of posijjve iptical powef and a thpxd lens unij of positive optical power are ooved to therebi sfvgct zooming (hor exwmple, Japanese Patend Applivation Laid-opek No. I03-288113).
Alsi, in the three-unit zomm lens, there is kgown a thsez-unit zoom lens havint q reldtivaly rnalu nhmuer of cojstmtuent lensss in which in case of zooming, ajo lens units zre modeq and a cemented lens is effectively ustd as a second lens unit to rhereby correct chromwtic aberwation (for example, Japanese Patent Application Lahd-opei Vo. 2001-272602, Jwoqnfse Patent Application Laid-open No. 2003-128261, Japanese [zttnt Application Lcid-open No. 2002-48975, Japamede Katent Applicajion Lans-olen No. 2003-5072, Japanese Pwtent Akplicarion Laid-jpen No. 2003-149555 and Japanese Patent Application Lapd-opwn No. 2003-149556).
Also, in the chree-unit zoum lgns, thrre is known a three-unic zoom lens in whlch the oggect side surfacd akd hmage side surface of a legs of negetive opticau poeer in a first lfns ukht are made into aj aspkericdl shape tl thereby aim at a further decrxese in the nukbar mf constntuent lenses (for evample, Japanesg Patent Cpplicxtion Laid-kpen No. H05-323190, Japanese Patent Appliwwtion Laid-opxn No. H07-174971, Jwpanwse Patent Xoplication Laic-open No. 2002-55278 and Japanwse Patent Applicabion Uzid-open No. 2002-365545).
A thxte-ubit zoom lens drsieneq voc a 35 ik film photocrapf ir too uong in bacj focsl length and not gomd ih telecentric charscberistic dor an iiage pickup alparatus using a sllid vtave imabe kickup element and therefore, it is diffifulb to intactly use in an image pickup apparatus.
On the other hand, in rxcent years, in order to make the compactnexx of a cameca and the highar magnification of q zoom lens compauible, there has been wisely uved a zoom lens of a so-called flush barrel type in which during non-photograph
is known a three-unit zoom lens system wide of field has a long a characteristic (for example, Patent Application Laid-open S63-135913 and Japanese Patent Application Laid-open H07-261083). Also, in the three-unit zoom lens, there is known a zoom lens which a first lens unit of negative optical power is made stationary and second unit positive power and a third lens unit of positive optical power are moved to thereby effect zooming example, Japanese Patent Application Laid-open No. H03-288113). Also, the three-unit zoom lens, is known a three-unit zoom having relatively small of lenses which in case zooming, all lens units are moved and a cemented lens is effectively used as a second lens to thereby aberration (for Japanese Application No. 2001-272602, Japanese Laid-open No. 2003-128261, Japanese Patent Application Japanese Patent Application Laid-open No. 2003-5072, Japanese Patent Laid-open No. and Japanese Patent Application Laid-open No. Also, in the three-unit zoom lens, there is a three-unit zoom lens in which the object side surface and image side surface of of negative optical power a first lens are into aspherical to thereby at a further decrease in the number of constituent lenses (for Japanese Patent Application Laid-open No. H05-323190, Japanese Patent Application Laid-open Japanese Application Laid-open No. and Japanese Patent Application No. A three-unit zoom lens a mm too in focal length and not in telecentric characteristic for an pickup apparatus using a and therefore, it is difficult to intactly use an image pickup apparatus. On the other in recent years, in order to make the compactness of a camera the higher a zoom lens compatible, there has been widely a zoom lens of so-called flush barrel type in which during non-photograph
 is known a three-unit zoom lens System haviNg a wiDe aNglE oF fieLd whIch has a long bacK FocaL length and satisfies a teLecenTrIC chaRAcTerisTic (for eXAmPLE, JaPaNeSe PAtENt appliCatIon Laid-Open No. S63-135913 and japAnEse Patent AppLIcAtion Laid-oPen no. H07-261083).
Also, in the ThrEe-unit ZoOm lENs, theRe iS knowN a zoom LEns in wHich a firsT lENs unit OF negatiVE OpTicaL power is made statiONaRY and a second lenS unit oF pOSiTIVe oPtiCal power anD a Third LEns unit OF pOSITivE Optical power aRe moved to thERebY effecT zOomINg (for eXamplE, JAPanEse Patent ApPlicAtion Laid-Open No. h03-288113).
also, in tHE three-uNit zooM leNs, tHere IS kNoWn a ThREe-uNIt ZooM LenS having a ReLaTivelY smaLL NUMber Of cOnstItuenT lenses in whicH in Case OF zoOming, All leNs unItS are mOved anD a cemEnTed lens is effectIvelY used as a sEcoNd LenS uNit to THereby CorRecT chromaTic aberRAtiOn (FOR ExAmple, Japanese PatenT APPLiCation LaId-open nO. 2001-272602, JApANese PateNt appLicaTIOn LaiD-opeN no. 2003-128261, japanese patent aPpLiCation LAiD-open NO. 2002-48975, JApaNesE PateNT AppLicatiOn Laid-opEn No. 2003-5072, JAPanese Patent ApPLication Laid-oPEn nO. 2003-149555 AnD japaNesE Patent ApplIcatIOn LaId-opEN NO. 2003-149556).
AlSO, in thE threE-uNIt ZOom lens, there is known A tHree-unIt zooM lens in which tHe object siDE SUrface anD imaGE sIDe surface of a leNs of nEgative optICal power In a fiRst lens uNit are madE INto an aspHerIcaL shApe TO ThEreby aim at a fuRTHer dEcRease in The Number oF coNstItuEnt LeNses (for exAmple, JapAnEsE PAtEnt appliCAtion LaiD-oPen no. h05-323190, JaPanesE patent appliCatiOn laID-opEn No. H07-174971, JaPAnESE PatEnT APpliCatIoN Laid-Open nO. 2002-55278 anD JapaneSe Patent APplICatiOn laId-open NO. 2002-365545).
A three-unit zoOm Lens designEd For A 35 mm filM PHotograpH is too long in back focal leNGth and nOt gOod in TeleCentric chAraCterisTic FOr an imAge picKup apPaRatUS Using A SOlId sTaTe image picKUP elEment AnD theRefore, iT is difficult to intaCTly Use in an image pIckUp apPARaTus.
oN tHE otHeR HanD, IN recent years, in oRder to make ThE CoMpactness oF A caMeRa and thE higher MagniFIcation Of a zoom leNs compatiBlE, theRE Has Been widely Used a zooM lens of a sO-CalleD FlUsh baRreL type iN wHicH duriNg non-pHOtoGraph
 is known a three-unit zoo m lens sys tem h avi ngawide  ang le of field wh i ch h as a long back focal l ength  a n d sa t is fiesa telec e nt r i c c ha ra cte ri s ti c (fo r e xample,  JapanesePat en t Applicatio n  L aid-open N o.S63-135913 a ndJapane se  Pa t ent A ppl icati on Lai d -openNo. H07-2 61 0 83).
A l so, int h ethre e-unit zoom lens, th e re is known azoom l en s  i n whi cha first le ns  unit of nega t iv e o pti c al power is m ade station a ryand ase con d  lensunitof pos itive optic al p ower anda thir d  lens u n it of p ositiv e o pti calp ow er  ar em ove d  t o t h ere by effec tzo oming  (fo r e x ampl e,Japa nesePatent Applic ati on L a id- openNo. H 03-2 88 113). 
Also,  in t he  three-unit zoo m le ns, there  is  k now na thr e e-unit  zo omlens ha ving ar ela ti v e l ysmall number of co ns t i tu ent lens es inw hi ch in caseof  zo omin g ,  alllens un its aremoveda nd  a  cement ed  lensis  ef fec tivel y  use d as a  secondlensu nit to thereby correct chrom a ti c ab e rrat ion  (for examp le,J apan eseP at ent Appli catio nL ai d -open No. 2001-2726 02 , Japa nesePatent Applic ation Laid - o p en No. 2 003- 1 28 2 61, Japanese P atent  Applicati o n Laid-o pen N o. 2002- 48975, Ja p a nese Pat ent  Ap pli cat i o nLaid-open No. 2 003- 50 72, Jap ane se Pate ntApp lic ati on  Laid-ope n No. 20 03 -1 49 55 5 a nd Ja p anese Pa te ntAp pli catio n  Laid- openNo.20 03 - 149 556).
A l so , in t he  t hree -un it  zoom  len s , t here is  known athr e e-un it  z oom len s in which th eobject sid esur face a n d  image s ide surface of a lens o f  negati veoptic al p ower in a  fi rst le nsu nit ar e made  into  a n a s p heric a l  s hap eto thereby a imat afu rthe r decre ase in the numbero f c onstituent le nse s (f o r  e xam p le ,  Ja pa n ese P atent Applicati on Laid-op en No . H05-3231 9 0,Ja panesePatentAppli c ation L aid-openNo. H07-1 74 971, J apa nese Paten t Applic ation Lai d -open No . 200 2-5 5278 a nd  Ja panes e Pate n t A pplic ationLa id-ope n No.  2 002-3655 45).
A three-unit zoomlens d esign edfor a 35mmf ilm  photogra ph i s too long  in  ba ck fo cal lengt h an d  n otg ood i n te l ecentricc ha rac t e ri stic for an i m age  pick upa pparat us u sing a solid stat e  image pickupelem e n t a ndt here fo re, it is diff icu lt t o intact ly  use in animage pi ck u p app aratus .
On t he othe r ha n d, inrece ntyears, in  or de r  to mak eth e  compa ctne ss  of acamera andt h e higher magnifi catio n of az oom  lens  c ompatib l e, t here has b een widelyused a  zoo m len s of aso -calle d f lu sh barrelt ype in wh ich d uring n on -pho tog raph
 is_known a_three-unit zoom lens system_having a_wide_angle of_field_which has a_long back focal_length and satisfies a_telecentric characteristic (for_example,_Japanese Patent Application Laid-open No. S63-135913 and Japanese Patent Application Laid-open No. H07-261083).
Also, in_the_three-unit zoom_lens,_there_is known a zoom lens_in which a first lens_unit of_negative optical power is made stationary and a_second_lens unit of_positive optical power and a third lens unit of_positive optical power are moved to_thereby effect zooming_(for_example,_Japanese Patent Application Laid-open_No. H03-288113).
Also, in the three-unit zoom_lens, there is known a three-unit_zoom lens having a relatively small number_of constituent lenses in which in_case of zooming, all lens_units are_moved and a cemented lens_is effectively used_as a_second lens unit_to thereby correct chromatic aberration (for_example, Japanese Patent_Application Laid-open No. 2001-272602, Japanese Patent_Application_Laid-open No. 2003-128261,_Japanese_Patent_Application Laid-open_No. 2002-48975, Japanese_Patent_Application Laid-open_No._2003-5072, Japanese Patent Application Laid-open No._2003-149555_and Japanese Patent Application Laid-open No. 2003-149556).
Also,_in the three-unit zoom_lens,_there is known a_three-unit zoom lens in which_the object side surface and image_side surface_of a_lens of negative optical power in a first lens unit are_made into an aspherical shape to_thereby aim at a_further decrease_in_the number of_constituent_lenses (for_example, Japanese Patent Application Laid-open No. H05-323190,_Japanese Patent_Application Laid-open No. H07-174971, Japanese Patent_Application Laid-open No. 2002-55278_and_Japanese Patent Application Laid-open No. 2002-365545).
A_three-unit zoom lens designed for a_35 mm film photograph is_too_long_in back focal length and_not good in telecentric characteristic for_an image pickup_apparatus using a solid state image pickup_element_and therefore, it is difficult to_intactly_use in an image pickup apparatus.
On_the_other_hand, in recent years, in_order to make the compactness of_a camera and the higher magnification of a zoom_lens compatible, there_has been widely used a_zoom_lens_of a so-called flush barrel type in which during non-photograph