I would be very surprised if the iq180 and its resolving potential is at the heart of your problem.
I would be more inclined to think it comes down to a combination of mirror/shutter bounce.
I used to have a complete Contax 645 system from 35 to 350 apo and used to have extreme
difficulty getting a sharp image,free of movement, with the 210 and 350 when shooting with shutter
speeds from about 1/125 to 1/2 second- tripod,mirror lockup,etc.
Their electronic release would not mitigate the issue and only when I used the electronic release
to trigger the self timer was I able to get reliable results in combination with mirror lockup.
You can verify if you are getting any internal vibration by testing your mirror lockup/release
sequence by testing in a situation where your shutter speeds exceed 1 second.
This allows the system to stabilize a little and the micro vibration is camouflaged in the
I went to Photokina, this year, as i wanted to upgrade to a 180 to, but because i use mostly technical wide angles, I had some questions about the colorshifts/aberations.
After asking around I saw 7 people at the stand, finally talking to a "engerneer" who of the most part was a salesman i think.
He said: the 160 an P65 are perfect, bla bla bal,
but i kept on insisting on info on the 180 ,
Untill he said: Look when the H20 came out people said it wasn't good for the same reason, but our engineers worked on it very hard and resolved it.
I said, so there is a real problem ? Frimware ? .. will it be resolved ?..
Wel like the H20 the engineers are working, and they will find a solution
- So honestely, i think, it's the backs fault, as that isn't the only situation one can get the problem with. The problems mostely appear to be with other camera's than the phase/mamiya system..
I would stay with the P65+, and w8 until the engineers solve the problem in the firmware;..