On February 15, a UHH contributor asked about tethering D3100s to iPad tablets. I commented that it is possible and said I would try to add some value in a later comment, so here you go. While my hands-on experience is with tethering my Nikon D3100 to a computer, for transmitting RAW files, my remarks here likely apply to many cameras from many manufacturers. Likewise, these remarks may apply to many mobile devices, that is, tablets and smart phones. The D3100 is something of a worst case as the electronics are old and Nikon's firmware-level support for earlier tethering approaches has been less than I might have wished, if not zero. I believe Nikon has actively enabled the Eye-Fi approach discussed here. This is a little long, but hopefully useful and with explanation of terms.

As for tethering an iPad to a D3100, the topic of the February 15 question, I just now got working a product, Eye-Fi (http://eye-fi.com), on an Apple MacBook Pro laptop, which has larger storage and larger displays than mobile devices like iPads. The Eye-Fi vendor's site says that iPads are supported, among other mobile devices and a large number of cameras.

Now, my next Apple OS-X task is to export the laptop display to one or two large external, screens, to see lots of apps and images at once, for example, to edit in Adobe Camera Raw, etc., etc. For these three reasons -- storage, image size-screen quality, and multi-tasking -- I have started with a computer and have not tried my iPad and iPhone with Eye-Fi.

I inadvertently turned off the camera during a transmission to my computer and then turned it on again. The hoped-for transmission finished completely, consistently, and correctly. I'd never have expected this; somebody needs to get a promotion at Eye-Fi.

How does Eye-Fi work with a D3100 conversing with a computer? First, with Eye-Fi, I can pick up my transferred D3100's NEF files wirelessly in Adobe Bridge, in my Mac folder hierarchy ...Pictures > Eye-Fi > <transmission or creation date>, as I requested in the Eye-Fi setup. Adobe Bridge is an Adobe adjunctive app to Adobe Photoshop and other Adobe applications, reminiscent of the Adobe Lightroom Library.

Second, there is a YouTube video with a D800(E?) transmitting a NEF (Nikon Electronic Format, that is, RAW) file to a computer. This clip documents a moderately satisfactory speed, given that these files are larger than their D3100 counterparts. While I have not yet tried to speed up my own Eye-Fi transfers, I am finding Eye-Fi pretty slow for my D3100 NEF files. I am not satisfied on this point, but after all, my NEF files are 10MB.

Third, A likely workaround to halve transmission time, could be to transmit only JPEG Basic versions of my images using Eye-Fi while saving (1) a NEF file and (2) a smaller JPEG Basic file with each D3100 shutter click, as the D3100 can do. Of these two file types, I would transmit only the smaller to meet my main goals: to check focus, color, and composition – in case I need to re-shoot before tearing down my setup and moving on to the shot. At my leisure, I would edit the larger NEF keepers, later in my workflow. This way, the advantages of editing information-complete NEFs in Adobe's Camera Raw -- a Photoshop plug-in -- are open to me because the detail-rich NEFs (and the information-reduced JPEGs) will be on the SD card when I am ready for post processing a batch of shots. Stated differently, this compromise of transmitting JPEGs would presumably allow for much faster-paced, timelier reviews of what has just been shot, since the inferior-but functional JPEG files can transmit faster, being smaller.

Once again, I have only just started – two days ago -- with Eye-Fi's wireless tethering. I may learn enough about speed in due course to justify another comment later, if there is interest. I am confident the vendor, Eye-Fi, could detail the D3100’s choke points and suggest improvements, as normally software vendors can access their own log files, hopefully with event time stamps.