Panasonic Lumix S-series Telephoto Lenses.

 The one thing that isn't good about 135 Format is the telephoto lens selection and Panasonic only has one that ends at 300mm, a 70-300 f/4.5-5.6 and it's about US$1100. It took Panasonic a while on micro Four-Thirds to get any good telephoto lenses and that format is much better for reach because of the sensor size.

I've been looking for a 135mm f/2.0 lens, like what Rokinon/Samyang had, even if it's manual.  There is a Sigma 135mm f/1.8 but it appears to be going away.  For US$1400, it's not bad, but it has the hypersonic motors that were being introduced in the dSLR days for faster auto focus.  In my experience, they are not great for photographing video with AF and stepping motors work much better with mirrorless cameras and hybrid AF.  It's possible that we'll see the version change from HSM to HLA in the near future, as some of their lenses have already made the transition.

As an aside, my first 135 Format film camera came with a 55mm f/2.2 Fujinon kit lens and I later bought a Vivitar 135mm f/2.8 lens for something like US$45.00 when a 50mm f/1.4 would have been US$350 and a 50mm f/1.2 would have been US$500.  Back then, Vivitar was a good brand and had the first push-pull zoom mechanism.  Working in the camera department of a department store a bit later, I had the opportunity to test the equipment, so that I could give an accurate opinion.  Sadly, we didn't have any Medium Format equipment.

Have you noticed all of the long telephoto zoom lenses?  I haven't, either.  Sigma has the 60-600mm f/4.5-6.3, which is the latest rendition of what we used to call Bigma.  For US$2000, it's a deal, but it's over 5 pounds at 88 ounces or 2.49 kg.  You'll need to hire a photo assistant and have a tripod ready.  Panasonic has a 70-300 f/4.5-5.6 and it's about US$1100.  These are weather-sealed lenses.  If you're photographing sports, you're going to be ready.

 In the meantime, I opted for something used, a Canon 180mm f/3.5 macro lens substitute from Tamron for US$243.00 + a Viltrox (Pro) adapter for US$163.50.  They actually had a Canon L-series lens but it was missing parts and I didn't want to pay extra and not have all of the parts.  Besides, the L-series lenses were sometimes good, sometimes not.  I used to see a sizeable number of refurbished L-series lenses.

180mm isn't terribly long, but the 70-200mm f/2.8 isn't much longer, and I'm not sure I'm wanting to pay for that 70-300mm f/4.5-5.6, even though the Dual I.S. will make it steadier.  Neither the Canon or Tamron lenses seemed to have image stabilization.  The IBIS in the S5 Mk II probably won't be completely effective at 180mm, which is partly why I already have a Smallrig CT-20 tripod/monopod.

Update 2024.12.23: I mentioned something about the lack of a Panasonic 85mm f/1.4 on L-Rumors and someone mentioned that the Sigma lens was amazing.  As great as that is, where is Panasonic's lens?

Next month, they have an announcement at CES, which is not exactly the place for professional equipment, but maybe, just maybe, they're announcing replacements for the S1, S1H, and S1R, plus some lenses.