Is a little wiggle normal on a 28-PC lens?

[dritz]

Just received a used 28 PC (perspective control) lens. There is a little wiggle space at the adjustment juncture, that is, the ability to rotate the lens just a little. The plane of rotation/wiggle is parallel to the film plane... but still.

Is a little bit of this normal?

Thanks.

Dean
Seattle, Washington

[masjah]

Dean

Mine is quite an early example (but has had a service at Solms recently). It has a very small amount of backlash parallel to the "normal" movement of the shift, but in practice this is of no importance in use, since gravity takes up the movement! Mine doesn't rotate though. I wouldn't worry too much provided that you are sure the slight play maintains the lens correctly parallel to the film plane.

The thing to be aware of is that, if you are using the maximum 11mm shift (as distinct from stopping at the 9.5mm detent position) you can go slightly out of the image circle in some extreme parts of the frame, and performance inevitably then falls off - so use the extreme with discretion - e.g. when the bit in question is just sky (or something of no significance in terms of detail). Actually you can see a fall-off at extremes even within the image circle if you look at Leica's published MTF graphs. Given what this lens is being asked to do though, it is an absolutely formidable design achievement. "Shifted" performance definitely requires the lens to be stopped down to f/8 or f/11 for very best results, so I usually use mine with a tripod. Best to focus before shifting is possible, and be aware of what they say about metering before making a maximum downward shift. Finally, don't forget to stop-down before metering and shooting - my most common mistake!!! Enjoy it - it's a revelation into the world of perspective!