Why I am Dragging my Feet with the Voigtlander 50mm f/2 APO-Lanthar: Possible Issue with Sony A7R IV Lens Mount Flange/Sensor Planarity
UPDATE Feb 20: Sony Professional Services is going to take a look at my Sony A7R IV, so I am sending it in today and it should be back in a few days.
Update Feb 28: the A7R IV is delayed for "parts on order".
Update March 1: Sony replaced the entire sensor module.
That the Voigtlander 50mm f/2 APO-Lanthar is one of the sharpest lenses I have ever tested is clear. But that’s different than sharpness across the field, which is incredibly important on a 60MP sensor when shooting at distance, even at f/5.6 or so. Or on a planar (flat) target.
So... I am feeling really frustrated with both samples of the 50/2 APO because I am seeing lens swing (left/right lens skew) on the demanding mosaic target. I have gone back and re-shot in triplicate and reproduced the same problem as a prior shoot.
What I am trying to sort out is how much of this is the lens (I have two samples), and how much is the camera. The Sony A7R IV that I am shooting is brand-new, and unlike the excellent A7R IV I had last fall, at least some suspicion falls on the Sony A7R IV Lens Mount Flange/Sensor Planarity. This sort of thing drives me crazy. It can be very hard to sort out with only one camera body because both lens and camera can compensate or add up their errors.
I am debating how much more to show of the Voigtlander 50mm f/2 APO-Lanthar until I can assure myself of whether it is the lens or camera or both—it looks to be both camera and lens, since the two lens samples show varying degrees of swing.