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Comment by int0x2e | Hacker News Reader

The "big on purpose" crowd is used to long focal length lenses being super big and heavy, and therefore need a heavy body as a counterweight. I know some would consider this blasphemy, but the micro-four-thirds (m43) platform with its 2x crop factor means that a pro level 600mm equivalent f4 telephoto with exceptional clarity can weigh under 1.5kg (instead of the 3 to 4kg of similar offerings for full-frame). When you factor in the weight of the total package (camera body, lens, accessories), the differences are very substantial. Sure - you won't be able to print your photos on wall-sized posters, but you will get great livability/usability, good performance at an attractive price.

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> 2x crop factor means that a pro level 600mm equivalent f4 telephoto with exceptional clarity can weigh under 1.5kg (instead of the 3 to 4kg of similar offerings for full-frame)

You mean a pro-level 600/f8 equivalent. You can get something similar for full-frame, like the Canon 600/f11 or 800/f11 which are like a kilogram.

The new Nikon 800mm f/6.3 fits in this niche perfectly.

There's a new 400mm f/4.5 on the way too.

If I was starting from scratch I'd totally be taking this route.

That sounds good in theory, but it really doesn't work out in practice. If you want a like-for-like comparison, you end up with similar weights.

The Olympus OM-D E-M1X comes in at 850g for the body alone, which puts it squarely between the Canon R3 (~1kg) and the Sony a1 (~750g). Once you adjust for the equivalent light-gathering ability of the whole kit , the Panasonic Leica 200mm f/2.8 is 1245g, versus the Canon 400mm f/5.6's 1250g.

This may be my ignorance showing, but wouldn't the DOF be equivalent and the panasonic is getting more light to the sensor? The pixels may end up larger on the canon thus leading to less noise or something, but I thought in terms of light hitting the sensor Fstops were equal, but for DOF you adjusted for crop factor.

Instead of trying to figure out what's happening by changing the sensor size, a fun hack is to instead think about it in terms of a teleconverter. The micro 4/3 format gives you roughly half the area of a full-frame sensor so let's think in terms of a x2 teleconverter.

Let's assume you have a 200mm f/2 lens, and you put that x2 teleconverter on. The way you get the equivalent of 400mm out of that is that you're taking all the light that comes out of the back of the original lens, then spreading it out into a bigger circle. Same total amount of light, stretched thinner, so the sensor is gathering less light overall. That's why that 2x converter that turns your 200mm into 400mm also takes away 2 stops of light and reduces your effective aperture from f/2 to f/4.

Now, the trick is that with the smaller sensor instead of the teleconverter, you have the exact same situation: You're taking that same amount of light projected by the optics, and cutting a smaller slice in the middle. You're just doing the slicing differently.

Would you really do sports with an m43, tho?

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