Interesting comparison. I'm not familiar with the auto-resize zoom option. That said, the first picture looks slightly sharper to me but it may be my imagination or may be due to the loss of some resolution due to cropping (i.e., digital zoom) in the other pictures. At the sizes posted, it doesn't seem like a huge difference, though, which was a little surprising. Ultimately, I just wish Ricoh would release a 40mm GRD
There were also some rumors at some point about a GRD zoom but I haven't heard anything else so they may just be rumors.
Thanks for your comments & interest. We are all normally a bit 'sniffy' about digital zoom but perhaps we should think again? My understanding is that when you normally use a digital zoom the camera saves the image at whatever image size setting that you have - so if it is 10M it will still save a 10M image despite having zoomed and this can cause pixelation (a bit like enlarging). With auto resize the IV saves the image without enlarging...so at x1.2 you get a 8M image and at x1.4 you get a 5M image - if someone can provide a better explanation I should be so grateful! On the IV if you have the zoom set to normal you see x1.2 or x1.4 on the display as you zoom but with auto resize (only in 4:3) you see 8M or 5M etc instead. Ricoh claim that this (auto resize) helps maintain IQ and I think they are right.
I love the GT-1 lens on the GRD despite the famous flare problems which means you may need to crop the image (the GRD doesn't allow 1:1 capture which nearly always eliminates the flare) but it is a big and heavy piece of glass. I think the IV using auto resize and x1.4 (actually 5M) comes quite close...where I expect it is very close in IQ is at x1.2 (ie 8M and roughly 35mm equivalent) and I've just returned with 2 shots posted below taken at this setting (with auto resize) as it seems to have stopped raining (for now). I suppose the real proof would be to post crops or to take prints.
I've re-thought my settings as a result and now have the zoom button set to digital zoom and the exposure compensation set on FN1 (FN2 switches between AF & Snap and with the IV I leave the snap on auto as this seems to work really well).
I expect to be asked to leave the forum as result of using digital zoom!