Interview with Hasselblad Lead Optical Designer Per Nordlund

[TechTalk]

Below is a link to a nearly hour long interview with Per Nordlund. He has been with Hasselblad a little over 30 years and is the lead optical designer. This is the first time I've ever seen him interviewed.

The first 30 minutes covers the history of "V" and "H" lens designs. Of note in the "V" lens history portion are a couple of special designs from Zeiss: the 60mm f/5.6 Biogon which was made for the moon landing and the CFE 250mm f/5.6 Superachromat Sonnar.

The 60mm Biogon is unique in that it protrudes deep inside the body, so it's made for a body which has had the mirror removed. Also, the distortion is incredibly low! It's a little hard to see in the presentation, but the distortion chart for this lens isn't graphed in the usual 1% increments. It's distortion graph is in increments of +/- .002% and it stays within that range! Here's a data sheet from NASA...  https://www.hq.nasa.gov/alsj/Biogon5.6_60mm_ZEISS.pdf

The 250mm Superachromat is another remarkable lens. It's also a bit difficult to see how remarkable it is from the chart in the presentation. The chart shows a normal amount of wavelength deviation from the focus plane in blue, but the amount for the Superachromat is a gray line that barely has any deviation from the focus plane in the chart. What makes this lens even more unique is that it is beyond "apochromatic" in bringing infrared and other wavelengths into focus at the same image plane.  https://www.zeiss.com/content/dam/consumer-products/downloads/historical-products/photography/hasselblad-cfi-cfe/en/datasheet-zeiss-sonnar-superachromat-56250-cfe-en.pdf

The second half of the video discusses some of the design challenges that an optical engineer encounters. He uses the XCD 30mm lens as an example and shows various iterations of the lens design as it progressed over several months of development.

It's a little dry, as these remote conference videos tend to be, but I found it worth watching. Hope you find something of interest...  https://www.youtube.com/watch?v=zKG-bUc3qDY

[Ken Schuster]

Here are comments on the Sonnar 250mm Superachromat and 350mm Tele-Superachromat by another Zeiss lens guru, Dr. Kornelius J. Fleischer, posted on photo.net 20 years ago. (You have to be logged-in to this forum to see and download the attached PDF.)

[JV]

The interview was interesting, unfortunately he is not exactly an exuberant personality, language might have been a barrier as well, still respect, Hasselblad lenses are often underappreciated IMO.

[kers]

Thanks for the links- very interesting to hear about lensdesign from an expert.

[TechTalk]

Thanks for the links- very interesting to hear about lensdesign from an expert.

Yes. I found the design process the most interesting part of the video. It isn't someone just entering specifications into a computer that then hands you a design. The collaboration of multiple optical engineers and mechanical engineers and manufacturing process engineers in different countries working with a team leader such as Per, I thought was interesting. Then the iterative nature, first with computer models and then functional prototypes, I enjoyed hearing about as well.