A list of good/bad MFT lens for new owner?

Started Oct 1, 2012 | Discussions thread
shihhan
Regular MemberPosts: 307
Like?
Re: 45-150 or 45-200
In reply to josbiker, Mar 2, 2013

josbiker wrote:

Thanks you are so helpfull and i am learning every time you answered my questions.

"OIS takes time to adjust, and in many cases when you're trying to pan, will try to *correct* movement giving you blurred shots.an you give me an idea "

Can you give me an idea what the difference could be? If it is possible in a not subjective way but concreet?

To get this, you need to understand how OIS works.

Basically, OIS lens have a set of 'floating' lens elements, which is designed to move in the opposite direction to any lens motion (typically hand shake). In this way, the OIS effectively 'cancels out' external movement (in the lens).

The exact mechanism of OIS is not revealed, but basically OIS compensation depends on:

- frequency of movement: how fast the movement is
  - magnitude of movement: how much movement is
  - direction of movement

Frequency:
MegaOIS typically compensates for high frequency movement (hand shake).
PowerOIS is said to also compensate for low frequency movement (shutter shake).

Magnitude:
MegaOIS is typically advertised as being able to compensate for 3 stops.
PowerOIS is said to compensate for 4 stops.

Direction:
Normal mode compensates in 2-axis (up/down, left/right)
Panning mode compensates in 1-axis only (left/right)

Now the problem with action shots / panning and OIS is that basically the OIS is dumb and can't tell the difference between purposeful movement and shake, as it will try to counter *any* movement you're doing.

So say if you're trying to follow a fast moving sports car by moving the camera, the OIS will attempt to compensate your movement... causing EVF/liveview lag, blurry pictures etc. It also becomes much less effective as your OIS system is 'overloaded' by your movement that it effectively can't compensate for shake.

The use of panning mode is suppose to help this, but it isn't fool proof.
And for sports / high speed action, there is no substitute for a large aperture lens. (as you cannot steal aperture stops using OIS this way...)*
OIS can *never* steal real aperture stops. (as in doesn't turn your f4 lens into an f2.8...)
As you can think of it as only able to steal shutter speed / ISO stops. (allows you to use a lower shutter speed / lower iso).

Reply   Reply with quote   Complain
Post (hide subjects)Posted by
Keyboard shortcuts:
FForum PPrevious NNext WNext unread UUpvote SSubscribe RReply QQuote BBookmark post MMy threads
Color scheme? Blue / Yellow