Ihave an Omega 4x5 Variable Condensor enlarger that I bought used and it came wi th an "Elgeet 135mm f/4.5 Colorstigmat" lens. The lens worked OK but I decided I needed a better lens so I bought a 135mm f/5.6 Schneider Componon-S (on ebay) a nd have encountered the following problem with the Schneider. There is a 1 stop variation in the amount of light in the center of the print and the corners (8x1 0 print size) when the lens is set at mid aperatures (F8 or F11). This drops to about 1/2 stop variation when stopped all the way down (F45). I went back and ch ecked the "Elgeet" and found only about a 1/4 stop variation at mid aperture set tings. I noticed that the "Elgeet" has a 12 bladed diaphram which produces an al most round hole and the Schneider has a 5 bladed diaphram. Any suggestions on wh at I might do to resolve this problem. The light fall-off is very apparent in th e prints produced with the Schneider.
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