LensRentals has loaned me a Hasselblad XCD 55mm f/2.5 V lens for testing. It arrived today, and I’ll be testing it over the next three or four weeks. One issue the new V lenses have had — at least the 38 and 90 both had it — is odd bokeh at very high mechanical shutter speeds. That’s because the putative mechanical shutter on the XCD lenses is not really fully mechanical. The exposure is initiated electronically, with a very fast rolling chip reset while the mechanical shutter is open, and the closing of the mechanical shutter ends the exposure. It’s sort of like EFCS, although the details are different, and, like EFCS, the bokeh at high shutter speeds is affected. The bokeh effects of EFCS are usually subtle, but this effect is not. It is much worse on the 90V with its 1/4000 second mechanical shutter than on the 38V, which has a 1/2000 second mechanical shutter. The 55V has a mechanical shutter capable of only 1/2000 second, so I would expect the bokeh effects to be similar to the 38V. However, expectations in camera testing often are jarringly wrong when the testing starts, so I felt I had to test.
I made exposures of a LED flashlight about 25 feet away with the camera set to ISO 64, the lens wide open and focused to 0.45 meters.
The above is at 1/2000 second. Let’s blow that up and look at some longer shutter speeds as well.
About the same as the 38V.
By 1/500 the strange bokeh is completely gone. There are some onion ring effects. We’ll look at them more closely when I test with the electronic shutter.
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