Hi, alex,
Good questions--I know some of this information can be quite difficult to find.
a)do I need less (or different)sharpening with these files (currently using photokit sharpener)
Yes, ideally, the sharpening parameters will vary with capture size.
PhotoKit sharpener does a good job of taking the size of the capture into account when you pick which resolution of Capture Sharpening you wish to perform. I don't know what resolution the highest resolution algorithms are optimized for, but I suspect Jeff Schewe could probably tell you.
Some of the best information I've read on this topic is Bruce Fraser's excellent Real World Image Sharpening. Highly recommended.
I have been told that I need to downsize to 480ppi for smaller prints; however,I have printed from >1000ppi and dont see any problems
Your printer driver will discard what it deems to be "excessive" printer data. What "excessive" is will vary by printer driver (usually anywhere from 360 to 720ppi). The 480 advice you have received is hedging between these two figures.
So why downsize when prints come out just fine (as you have discovered) at >1000ppi? Because you control how the excess information is discarded. Do you want to use bicubic sharper to downsample? Will your particular subject matter respond better to a simple bicubic? Do you have access to more advanced algorithms (which yield fewer artifacts) such as Spline or Sinc?
Admittedly, most of us would not be able to tell the difference under most circumstances, but it is good to know what is happening to your data and where. Expect the average printer driver to use either bilinear or possibly bicubic for interpolation.
c)do you consider that the hasselblad raw converter is better than going dng and then lightroom?
I cannot comment on the Hasselblad raw converter specifically, because I shoot Phase. But in general, it is rare for 3rd party converters to exceed the manufacturer's raw converter quality. That is not to say the manufacturer's raw conversion quality cannot be rivalled by a 3rd party converter, though--Adobe has been making very substantial strides with ACR, for example, and are rivalling 'native' raw converters on many platforms. As these tools mature, the differences in quality are diminishing. It is a pleasure to be able to recommend going with the offering that meets your creative needs.
The DNG issue is complex, because much depends on whether the proprietary raw data is being demosaic'ed *before* being packaged into DNG or not. I won't delve too deeply, but I will say that from and image quality standpoint, in general, it is preferable for the demosaicing *not* to occur as a part of the DNG packaging. Unfortunately, I do not know if Hasselblad's software is performing demosaicing or not when it performs a DNG conversion.
If you can't tell the difference between the two approaches after visual inspection (with raw converter sharpening disabled, look for differences in high-frequency areas such as long hair or other fine repeating detail, shadow noise, highlight fringing, smoothness of color, detail without looking unnatural, etc.) then it's probably safe to go with whichever is the more efficient, intuitive workflow that meets your needs as an artist and as a business person.
Hope that helps a bit, at least. Thanks for posting! I also teach digital imaging, and I will look at addressing these questions in my intermediate course material. I'm sure there are many others who have these same questions.
Best regards,
-Brad
