I posted this on APUG verbatim because I doubt too many people would be able to help with this. Sorry for the redundancy.
I am finally trying to enlarge some 8x10 negatives. I converted my enlarger with the Beseler kit and went through the recommended alignment procedure for the 45MXT. First, I aligned left to right which required a slight shim of the upper assembly which includes the negative carrier and light source. Then I aligned front to back. Then I attached the lens and repeated the procedure for the lens plane. I used a Versalab laser which had previously aligned my 4x5 enlarger with no problem.
The result is that the very center of the projected image is sharp but the rest of the image is not. It looks like field curvature. I checked this with both the glass and glassless negative carriers without difference. Also, I could never get the edges sharp, even when tilting the easel or attempting to focus on the edges. The negative is tack sharp edge to edge with a loupe and is a photo of a wall which was flat to begin with.
I tried to focus on the easel and on just the baseboard with the same result so it is not an easel problem.
I have never used this lens before. It is a Beseler 240mm HD lens that I bought used but appears to be in excellent condition. The problem happens from wide open at f9 all the way to f64 so stopping down does not help.
Any ideas? Thanks.