has anyone experiece with the 5,6/90 lense. at the moment i use a 8/90 SA fpr 4x5", where i have the experience that the centerfilter is essential......what about the 5,6/90. i just bought one second hand and i forgot that my centerfilter wont work for this lense....and a new one with 85mm is real expensive....so i would prefere to buy a 5,6/90XL where i can use the center for the 72mm too,....but the 85mm just work for this lense....and the 120mm in which i am not interested. also i would like to know if someone has experience to say which lense is the best in the aspect of shape for 4x5". SA8/90 , SA5,6/90 or SA5,6/90XL.....thanks....

-- rainer viertlböck (viertl@t-online.de), August 25, 2001

Answers

Rainer,

I have had experience with all of the lenses you mention and my answer is simple - if you can afford, or find an affordable centre-filter, then have it there ready to use when needed.

Certainly the 'longer' wide-angles might not necessitate the use of a CF when used on axis - but the delight of a 90XL or 120 is their relatively large image circle and it is when you exploit this that the centre-filters become a necessity.

The light fall-off is a function of the perpendicular distance from the lens axis to the image plane relative to the distance to the corners (cos 4).

Some compositions may not require the CF - they may, in fact, benefit from the emphasis derived from the vignette. But other subjects are rendered hideously when shaded across their surface.

There have recently been other threads discussing the merits, or otherwise, of Centre-Filters, and they certainly have their detractors who place no value upon them. Others want to make enlarger masks or Photoshop masks to counter the fall-off. A lot of fiddling about to attempt to correct something so easliy done at the time of exposure by simply screwing on a filter.

Hope this is of some value ... Walter

-- Walter Glover (walterg@netaus.net.au), August 25, 2001.

I have an F 5.6 90 mm Super Angulon and have never thought that I needed a center filter. However, you don't say what kind of photography you do. I do only black and white work. If you work mostly with color and landscape/a lot of skies, the situation might be different.

-- Brian Ellis (bellis60@earthlink.net), August 26, 2001.