[Leica] USAF Lens Resolution Chart

[craig at craigschroeder.com (Craig Schroeder)]

I agree with your general sentiments, Frank.  When I first got the 
Modern kit (must be 20-25 years ago!), I tested everything I owned and 
was very involved in some comparison testing within a local photo club 
where many members had their pride on the line in brand vs brand 
bragging rights.  There at least was some entertainment value in that!  
Where the targets have been handy, though, is in comparing two identical 
lenses in deciding which to keep and also to validate suspicions 
regarding a lens' behavior.  It was also a good way to measure sweet 
spots on optics that seemed designed to a certain range of application.  
It also showed that some optics, (such as Leica) may not have been quite 
as sharp in a pure resolution sense in this type of testing but actually 
produced superior transparencies because of their color behaviors and 
separation.

The last the kit got used was 6-8 years back when I was accumulating 
some Pentax 67 gear and ended up with many duplicate optics.  I found a 
great amount of variation in these particular lenses and it was a great 
aid in selecting which examples to retain and proved to be a very worthy 
tool for that duty.

Frank Dernie wrote:
> The problem is that either a test chart or newspaper on a wall 
> exaggerate the importance of lens flatness of field to a far greater 
> extent than it should for a general purpose lens. For a macro lens 
> this may be vital, and speed for one thing, is sacrificed for flatness 
> of field. I take 3D objects so part of my image will be OOF when using 
> wide apertures. As long as the centre is correct to the rangefinder it 
> is not reasonable to ask for more in a lens for a this type of camera 
> IMHO.
> Frank