Peter
First off,if your 4x5 prints are falling apart at 24x30 then there's something seriously
wrong with your process to get to the point of printing.
It's really AT about 24x30 that quality large format images start distancing themselves from
prints using a 1Ds Mkll,for example. Up to that point,in my opinion, the Canon files generally
hold their own very well.
As for your main question,I have been in a somewhat similar 'holding' pattern for a couple of
years trying to determine what is the 'proper' time for me to move my workflow to a
digital back.
I currently shoot 1Ds Mkll and 5D as well as incorporating a fairly significant volume of
4x5 and 6x9.
My principal source of income is as a stock photographer but I am growing,with some success,
a print sale business.
For stock,I have been of the opinion that there has been no advantage to me to invest the
not insignificant dollars into a MFDB system,regardless of the quality advantages I see, for a
number of reasons that I won't go into here as it will stray too far off-topic.
As my print business grows,and knowing the markets appetite for large prints,I am now
putting a back purchase at the top of my list.
My 4x5 images (which I scan on my Imacon 848) are no less impressive than they were a day,a month,or a year ago but the reality is that I can no longer,as a small two person business,
produce the volume and dedicate the neccessary time to scan and clean the 4x5's to
sufficiently populate my stock and fine art interests.
Over the past six months,I have logged enough time with each of Leaf,Phase,and
Hasselblads 'largest' backs to know that all will easily fullfill my technical need to eliminate
4x 5 from my workflow and foreseeable print needs.
Prints from each to 30x 40 are flawless and,though i haven't yet done so,I see no reason
to expect they will falter at larger sizes.
I have seen no moire,or other such imaging artifacts, in landscape work as was mentioned
earlier in the thread with Hasselblad files from their H3D-39 camera.Occasionally,moire will be
an issue with manmade content such as window blinds or ventilation grills on buildings,etc
but I have yet to see it in more randomly patterned natural subjects such as sand,rock,etc.
In short,if you've been satisfied with your Canon files (you don't say which camera)
then you will be very satisfied with the files from Hasselblad cameras or backs (and all
equivalent backs for that matter)
MT