Weird focus on RB67 90mm 3.8 (Non-C)

[MichaelMcC]

I picked up an RB67 90mm 3.8 on eBay and had it serviced. All good except when focusing it seems to have just the slightest amount of focus when focusing up. Results are really odd. The absolute centre of the lens is sharp but everything outside this small centre area swirls away almost like a tilt shift or helios. Including areas on the same plane. Anyone come accross anything similar to this before?

Cheers from Dublin!

 

[Donald Qualls]

Sounds like you should contact your servicer; that "center only" sharpness is suggestive that one lens element or group was installed backward, causing field curvature.

 

[MichaelMcC]

Sounds like you should contact your servicer; that "center only" sharpness is suggestive that one lens element or group was installed backward, causing field curvature.

Thanks so much Donald! Really appreciate you taking the time! I'll mention to the servicer and see if it's worth opening again. To be fair it was in very bad shape before they got it to look it.