Caltar 90mm and this creature called center filtergreenspun.com : LUSENET : Large format photography : One Thread
I am new to 4x5, I am looking at a caltar 90mm 1:6.8 ll-n. I will be shooting some architectural work and will make full use of the movements. So, is there anyone who has a feel for my potential need of a cf? Also maybe you have a reccomendation for some rich literature covering all these alien issues I've bought into. Thanks
-- Josh DunhamWood (email@example.com), March 11, 2000
A 90mm is not that wide of a lens for 4X5. I do not believe a center filter is needed. Test the lens and if you feel one is needed then buy the filter. Jeff
-- Jeff (firstname.lastname@example.org), March 11, 2000.
I am not sure the f/6.8 version of this lens needs a center weighted filter (cwf) as the image circle isn't as large as the i.c. for the f/4.5 version. I use use a Heliopan C.W.F. with my 90mm f/4.5 Caltar Iunder 2 cirmumstances: 1.) Using extremes of rise/fall or shift or both and 2.) Using it on the 6x17cm ( 2.25 x 6.75 inch) V-pan camera. i use the Heliopan (the o.45ND version) rather than the Calumet or Rodenstock filter as the quality is just as high and the cost is significantly lower.
-- Ellis Vener (email@example.com), March 11, 2000.
This lens has light falloff typical of wide angles. The coverage is about 2/3 stop down at the top of the frame (2 in. from center), about 1 stop down at the side (2.5 in. from center) and about 1 1/3 stop down in the corners. The center filter is designed to reduce the light on the optical axis to give even illumination across the entire frame. This is important in some applications (architectural, for one). Again, this is typical of wide angles, not just the Caltar. The wider, the worse it is. Try a few shots and see if its a problem for you, and then decide. If you get serious with architectural photography, you are going to get very intimate with wide angle lenses!
-- Ron Shaw (firstname.lastname@example.org), March 13, 2000.