moxfactor

如果好用我會選tamron.  呢支鏡係天涯王, 連N/C記既DX鏡都比下去.

如果睇二手價值, 咁當然係C記會高啲, 但係如果睇二手價值來玩相機, 咁你只係一個玩家.  兩者價錢差唔到一千.  我用緊非PZD舊版, 有時為求方便會用上full frame機上.  12MP轉落8MP, 不過啲相出來非常sharp.  PZD版因為比舊版輕, 可能會容易啲手震, 不過呢樣唔係問題.  另外, 買時一定要試鏡.  PZD版聽講有部份鏡有VC問題, 開VC後影乜都唔清.  check清楚先買~  有少部份鏡, 如Sigma 50 f1.4, Sigma 150mm f2.8 macro, Tamron 18-270, 為求相片quality, 一定唔會買比下去的N/C記同級鏡.  真係影相既人係唔應該對副廠有偏見.  好鏡就係好鏡.

moxfactor

check out the MTF charts @ photozone.de
ddr 發表於 2011-6-19 10:14 AM

sure!  lets try all the worst circumstances

Tamron 18-270(test with 60D) - Canon 18-200 EF-S(test with 60D) - Nikon 18-200 DX(test with D7000)

barrel distortion at 18mm: (smaller number better)
T -3.88% - C -4.48% - N -4.13%
Canon loses

vignetting at 18mm: (smaller number better)
T 1,02 - C 1,48 - N 1,19
Canon loses

MTF (borders) at 18mm: (bigger number better)
T 1757 - C 1703 - N 1932
Canon loses

MTF (borders) at 200mm: (bigger number better)
T 1503 - C 1597 - N 2025
Tamron loses but can go further to 270mm...

Chromatic Aberrations (smaller number better)
at 18mm f3.5:
T 1.6 - C 1.28 - N 1.48

at 200mm f5-5.6
T 2.82 - C 2.45 - N 2.11
Tamron loses in across the board with CA~

which is not a big deal when it's pretty even across the board.

their verdict:  "All-in-all the lens may be a tad better than Canon's 18-200mm f/3.5-5.6 IS..."

overall, Tamron is a winner, although not by much, but very comparable to similar offerings from Nikon and Canon, and it has the added advantage of 201-270mm range that neither Nikon nor Canon can match.

moxfactor

天涯鏡有邊支唔係"普普"?

moxfactor

not sure, i bought my non-PZD version in Cam2.  picked 3 before settle on a good one.  always check lens thoroughly before buying.  esp. 3rd party lens have lots of QC problems.