For most photographers the only upside to dropping a lens is when you can look at it on the ground and say "thankfully it's a rental" and send it back to the rental house with a note of apology. When one of their rental 70-200mm f/2.8 G Master OSS lenses was dropped and damaged, the team at Lens Rentals decided to make lemonade by tearing down the lens to get a better look at some of the technology inside. The 70-200mm had already puzzled them in early tests so Roger Cicala and Aaron Closz put the lens on the bench set about voiding the warranty.
"The Sony FE 70-200mm f/2.8 GM is just a bit different. It has three aspheric elements, one of which is an extreme aspheric, and six extra-low dispersion elements. Ultra-low dispersion elements are pretty standard in telezooms, but aspheric elements not so much. It also has a unique autofocus system with linear motors moving a rear focusing element and a ring ultrasonic motor moving the larger front focusing group. So we were pretty interested in getting a better understanding of how this lens works.
"As part of that Holy Quest, we wanted to take a look inside the FE 70-200 f/2.8, because, well, that’s what we do. They’ve been in such short supply, though, we just haven’t been able to take one apart. But a customer was kind enough to drop one of ours, jamming the focusing system. We decided the opportunity to do a repair/teardown was too good to pass up.
"It’s not the first time we’ve made a bad decision, and it probably won’t be the last. It ended up being the longest and most complex (6 hours) teardown we’ve ever done. If you’re interested, read along and come feast your eyes on one of the oddest lenses we’ve ever looked into. But it’s going to be a fairly long read."
Yes, the post is long, detailed and complicated, but the 70-200mm G Master is a unique lens. Cicala notes that Sony is pushing out new technology and innovation where other manufacturers are coming out with evolutionary refinements. "And finally, we learned there’s some really elegant and complex engineering in the Sony FE 70-200 f/2.8 GM OSS lens...I’ll repeat what I say all the time: Sony is trying a lot of new things; that’s how you advance. I completely admire the risk taking and efforts to try new things when most manufacturers are just fine-tuning what already is."