Fuji GSW690III w/65mm Lens, Need a Center filter?

[bherman]

I have a Fuji GSW690III camera with a 65mm F/5.6 EBC Lens. I've heard from some users that it is recommended that you get a Center Filter to address light fall-off on this wideangle lens.

Has anyone run into this or is this necessary?

Thanks

Brad

 

[FrankS]

I wish that someone who knows would answer this question. I'm interested in the answer too.

 

[Dante_Stella]

What?!

What?!

No.

I never observed falloff from mine that would merit such an expensive fix. In fact, I don't recall ever seeing falloff at all.

But think of it this way: outdoors, you're probably never shooting wide open, and indoors, you'd never notice.

 

[han1953]

Light fall off with wide-angles

Light fall off with wide-angles

"Officially" a real wide-angle lens should have light fall-off according to the cos4 rule, e.g. with a 90 degree angle you would have a two stop fall-off.

Most wide-angles use a trick against this (like the Zeiss Biogon in the Hass SWC), by introducing some residual coma. This brings back fall-off to less than a stop.

If you want to know exactly how it works, google for "Slussarev principle".

BTW: retrofocus wide-angles do not have this problem, or in a far lesser degree, because the rays do not hit the film at such extreme angles.

 

[x-ray]

Never needed on on mine even at f5.6. Very fine camera and lens.

 

[jan normandale]

here's one taken with a Fuji 690. There might be a small amount of vignetting but I'd attribute it to the fact that the subject itself was the only illuminated building in the area. Like Xray I've never felt the need for that centre filter either

http://farm1.static.flickr.com/73/226810915_442a8c4929_o.jpg