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Rooster_kool 10-14-2008 08:14 PM

Len Suggestion.
Wat is different and advantage between Sigma 18-200mm f/3.5-6.3 AF DC II ($170) and Sigma AF 18-200mm f/3.5-6.3 DC OS (Optical Stabilizer) Zoom Lens ($416). It's kinda the same but different. Y it different ? I have plan to buy it.

AdrianW 10-15-2008 02:17 PM

Re: Len Suggestion.
The OS version has an optical image stabilizer built-in. At it's simplest that means that if you're handholding, the number of sharp shots you get will be higher if the subject isn't moving.

The two lenses have different internal designs, the result is that the OS version should give somewhat sharper results most of the time.

Finally, if you're a Nikon user, the OS version has HSM, which means it should focus more quickly and quietly on a Nikon body. Check that your camera supports the various focussing/metering modes of whichever lens you choose.

Advantages of the non-OS version: It's cheaper, uses smaller filters, and it weighs less.

Personally, of the two, if finances permit I'd choose the OS version particularly if you're a Nikon user whose camera supports HSM fully.

It's less clear cut if you're a Pentax user with in-body stabilization though, I'd probably choose the cheaper one for the Pentax, as the OS is redundant.

Obviously if you always shoot from a tripod, OS is less of an advantage; so I might go for the cheaper lens there as well.

Luko 10-20-2008 11:35 AM

Re: Len Suggestion.
Hi Adrian,
As you are sometimes interested in setting up field tests upon various technical subjects, have you ever drilled into the "IS/VR at high shutter speed" issue.

It seems there is a growing buzz with it : Is IS/OS/VR functionnality REALLY decreasing sharpness when shooting at normal or high shutter speed.... and btw, what is the limit in terms of shutter speed above which IS improves sharpness?


AdrianW 11-04-2008 11:16 PM

Re: Len Suggestion.
That's a very interesting question Luko.

If I get some time, I'll look into that and get back to you via the messaging system!

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