Obtaining interface documentation without restrictions

[James Davis]

I've recently bought myself a Nikon D70 digital camera which supports 
the PTP (ISO 15740) protocol for transferring images from the camera and 
controlling the hardware. Although basic functionality (transferring 
images for  example) is available through tools such as libptp,gphoto2 
and gtkam, the more advanced features are as yet, not supported in Free 
software.

Essentially PTP allows the user to read, and set a number of properties 
on the camera. The properties are referenced by numerical values ( a 
subset of which are common to all devices) and not by a descriptive label.

According to Nikon's customer support the documentation for this 
properties is available gratis in the SDK for the D70 and not available 
separately. The application form for the SDK requires the signing of an 
NDA which would prevent me from contributing any patches back to 
gphoto2/gtkam. The SDK contains, besides the documentation, binary 
libraries which I presume is essentially a PTP client customized for 
this camera. I'm not particularly concerned by a NDA covering the 
binaries as I have no absolutely no interest in looking at them or using 
them but I'd really like use the PTP interface fully in Free software.

I could reverse engineer the PTP properties and it wouldn't be too 
difficult but I'd rather not have to. Has anyone on the list got any 
recommendations or experience with approaching hardware manufacturers 
with requests of this type?

Regards,

James