Ricoh GW-3 wide angle converter on DP1m

[NigelC]

I've just bought a Gw-3 to try out on my DP1M - it was a bit opportunistic - London Camera Exchange had them for £95. I did wonder - with the Ricoh GR you have to use an adaptor which in effect is a spacer, whereas with the Sigma it screws directly into the filter thread. Is there any optical reason to experiment with filter spacers to increase that distance - I've found a 6mm spacer at SRB but they could be stacked of course. I'll try it as is, probably well stopped down but if results are not good, do you think adding spacers is a route worth going down? (PS, what I know about optical theory would have agrophobia on a pinhead)

I'm not expecting miracles as it's less than 10% of the cost of the DP0 Quattro, but arguably 10x more portable.

 

[NigelC]

Well no-one else interested so I'll start a conversation with myself. On the basis of a few handheld test shots in the fields round our village, actually better than Iad expected. Rather than being hopeless in the corners/edges, seems to be fairly even degradation of sharpness across frame. This is just onscreen at up to 100%; no idea how it will look in A4, A3 size printed.

What I don't understand is the optical theory behind these converters; why does it focus at all, given its screwed directly into the lens filter thread whereas on the camera its designed for, the Ricoh GR, it has a big spacer.

 

[foveon]

..What I don't understand is the optical theory behind these converters; why does it focus at all, given its screwed directly into the lens filter thread whereas on the camera its designed for, the Ricoh GR, it has a big spacer.

Me too, so I couldnt answer, but I am interested.^^