Old 24-08-2009, 06:19 PM
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hotspur (Chris)
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Join Date: Apr 2009
Location: south east QLD,Australia
Posts: 2,852
comparative testing,at astrofest

Recently i got a canon 70 to 300mm IS USM lens,it cost me approx $800

its only a few weeks old,Unfortunatly i felt the images were not as sharpe as my old kit lens,i was dissapointed,however,i thought it must be me,so i did every setting adjustment i could to see if a sharper pic would result.it didnt,i mentioned this to retailer,but ni didnt complain,i kept
thinking it was me

After,many pics i sterted to suspect lens,but you cant just ring up shop and whinge.i had to be sure,

At Qld Astrofest,i had a friend who has exact copy of the very lens,now

we coud do a proper comparative test,tripod,cable release,same settings

etc,and most importantly 4 or 5 other people with experience to give their thougts.

Suprisingly it didnt take long to show the short fall in my lens,however

i wanted to be really sure,so we swaped lens to different camera bodies

changed settings etc,etc,etc

I conacted retailer,and sent two photos via e=mail,the chap was able

to put halves of each pic on screen,and i havent had too much of a problem yet,i have sent it back,Surely,i hopr they will test it,send it to

canon for recalibration,or replacement

I cant believe my bad luck(yes i am having a whinge now,not avent)

i have done everything possible to look at this objectivly

I wish i could post highjer res pics on this site of tests,i can post a hawk

photo in terestrial items

regards Chris
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Old 24-08-2009, 06:33 PM
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Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 6,431
Yes.. even Canon is not Canon any more..
And the only relevant test to realistically asses the lens quality is a photo of a star field. Because stars are spots of light .. and unless they are spots on image from centre to corners (or bigger disks, however round), the lens is not good enough.
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