Full-framer logic

Two kinds of weight to consider. The kind you have in your bag, and the kind you have in your hand.

If you pick the camera up and take a shot or a few every few seconds or minutes or you are using a monopod or tripod you can hang all the weight you need on the camera. But if you have to hold it to your face for 15 - 30 minutes at a time, you might find it easier to carry a bag that is made heavier by more lenses and put something lighter on the camera.

I shot a museum last month on the other side of the country. I took a PL-7 because I didn't take a big lens. In my bag I had the camera with a Panny 12-32, Panny 35-100, Bower fisheye, OLY 45, OLY 75, OLY 17 f/2.8. That was a nice small kit to take on the plane.

Indoors I only used the Panny 12-32 f/3.5 - 5.6 and the fisheye. Outdoors I used the 35-100 f/4-f5.6. Didn't use the OLY 45 or the 75. Can't remember if I used the 17.

Dim light inside, but no moving parts so with IBIS, slowed the shutter down and the camera stayed on ISO 200 even though the lenses are not fast.

A friend brought his Canon 7D and two lenses. He wanted to bring three, but he didn't have room in his bag for his fisheye so I gave him those images.

His bag with camera and two lenses weighed more than my bag with 6 lenses. His camera and one lens might have weighed as much as my camera and six lenses  minus the 75 maybe. We examined the images on the same monitor didn't see a difference in IQ. He ended up looking at me and asking why he didn't have my kit.

The EM1.2 + 12-100 f/4 cost as much at MSRP as everything in my bag if I take out the 75 f/1.8. I bought it all used. It's only a little faster at the long end than the 35-100. Otherwise no advantage but weather sealing. It weighs almost as much as my 5 lenses - take the 75 out I never needed. That's why I haven't bought the PRO 12-100.

The 12-32 and 35-100 Panny's are so small changing them is easy. I don't have to put a lens or the camera down. I changed them one handed hanging on a chain with the other hand on the side of a mountain in December. Easier and faster with no lens change, but I missed nothing.

At a road race track I can shoot the OLY 45 and OLY 75 where the range works, with the camera on my face for 35 minutes at a time - all day. Because they aren't heavy. When I have to use a 40-150, I can't. I'm not strong enough to hold it more than 15 minutes before my arm shakes and starts to hurt.

If you have to carry more than one OLY PRO lens, you lose the size/weight advantage, but if you can mix up slower glass, when you aren't shooting moving subjects and you have good light, you can carry multiple lenses and still travel light. Very light, have more options/lenses/range. The OLY 40-150 kit lens, and the 14-150 are pretty good solutions too, The 75-300 weighs 10 oz. and surprisingly good for the price when they are fast enough for the light and the subject matter.

It is not true that multiple M43 lenses weigh more than a single lens solution - not always.