tamron 28-300 problem? pls advice

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i have a tamron 28-300.. rather old lens... using with my A200... lately i realise there is something but dunno whether izzit a problem..

1) whenever the camera is not in focus, i cannot turn the barrel for zoom... is this normal? but once i anyhow focus lock on some item i can turn the zoom barrel...

2) i find turning the zoom barrel esp when crossing over from 50mm to 100mm.. it doesnt seems veri smooth.. like there is a kinda restriction... is this normal cos is like extending 3 barrel...

3) where can i find the lens hood for this lens... cos its 72mm filter... rather big...


i hope someone can help me... thks...

 

[Octarine]

3) where can i find the lens hood for this lens... cos its 72mm filter... rather big...

Hoya offers round rubber lens hoods, to be screwed on the filter thread. MS Color has them, around 20 bucks, IIRC.

 

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so any advice/help? juz wanna see whether others probably have something similar... cos what i experience might not be a prob at all...