[janda]

邊支成像及質數比較好 ??

[tommyfu]

在菲林机,騰龍28-75mm 2.8 評價都幾好,

[流浪客]

我都想呢個問題好耐喇！

因為我剛剛想轉新D-SLR，而o的原?鏡又太貴，所以我都想o係上述兩支鏡中選一支，但兩支鏡都各有長處，真係希望各位網友可以俾多一o的意見！

[genewch]

Both lenses stretch when zooming, and this lengthening is quite obvious. There might be a risk of dust entering to the lens barrel.

Sigma 24-70mm f2.8 also stretches whem focussing. It's quite a foolish design. So beware of it.

I haven't used these 2 lenses, so it's unfair for me to give comments. In my opinion I prefer Tamron 28-75mm.

[dixonkwok]

I used to have Sigma 24-70 F2.8. It is good for film SLR and very competitve price. But it comes with teh following shortcomings:

1. 82mm filter thread. Filters become very expensive.
2. Heavy like all other lens and hence you won't hang around with it.
3. Extensive vignetting when using polariser.
4. Flash blocking with in-camera flash.

Photo quality is nice and colour is good. Construction is very sturdy and feels good.

Hence, it is good for the price. For Tamron, I have no idea about it.

[frankie152]

i've bought Tamron today at Wing Shing
I read many reviews before buying it

http://www.photozone.de/2Equipment/easytxt.htm#F100

its quailty is excellent, just slightly beyond 28-70 L Canon F2.8
at $2850, (23 Nov 04) it's best...
and it use 67 mm filter only, so it's cheaper

I've tried Sigma in other shops, the problem is
1. the motor noise is very loud when zooming...
2. very heavy, i think you will get tired easily with it.
Tamron is lighter, at least, normal weight.
3. 82mm filter is very $$ , I agree with Dixon Kwok.
4. the string for zooming is very narrow on the lens,
that you can only use 2 fingers to stretch for zooming,
while the tamron zoom grip is very thick for easy grip

Only limitation for Tamron is the zoom is quite tight,
it's not as smooth as canon zoom lens. but not a problem
as you do it for portraits but not sports.

I wish i can give more opinion after using it for more time.