Is my thinking about equivalence right?

Started 2 months ago | Questions thread
jwilliams Veteran Member • Posts: 6,177
Re: No, not really ...

Muster Mark wrote:

I don't think I was cherry picking. I was just looking at two mounts. The canon looks like an excellent lens.

I wasn't implying you were cherry picking. Sorry if it came off that way. Just pointing out that a comparison of just one lens from each format is too narrow to come to a general opinion. Some people will pick those lenses that favor some point they are trying to make. That's all.

The Sony GM 50mm 1.2 lens performs very well when stopped down (and is pretty good wide open), but now we are back to being much heavier and costlier than the olympus. I am NOT saying it's a rip off, but I also don't think the lens needs defending as no one seems to doubt it.

Until one has shot with one of these FF 50 1.2s I really don't think they can appreciate these type of lenses. I've never been a huge ultra shallow DOF fan but I've got the Canon 50 1.2 and the capabilities of this lens are fantastic. Once you've shot one its hard to go back to something like an ordinary 50 1.8 much less something like a m43 25 of any aperture. I'm packing for a trip right now and despite being rather large and heavy that lens is going along because of its very unique capabilities.

Fair enough. I hope you have a great trip!


The Zeiss 55mm 1.8 has lovely bokeh, but bad Long. CA and needs to be stopped down to 2.8 to be sharp.

Sigma ART lenses start to really shine honestly. Generally very well corrected optically, much less vingetting on FF than other lenses when wide open, and even slightly cheaper priced to the olympus. They are significantly bigger though (the 50mm 1.4 is 815g, versus 410g for the oly).

So what do we make of all this? My take away is that there is no free lunch.

My favorite saying, but I'm not sure you've got it in the right context.

If you want a certain level of optical performance you're going to pay for it regardless of the size of the sensor sitting behind the lens. Take a bunch of m43 lenses and find their APSC and FF equivalents and you'll discover there is very little size/weight difference between the equivalent lenses from the different formats.

Sure. I think the point I was trying to make that you didn't pick up on is that they don't really make premium, small (dim) lenses for FF systems. To match the IQ aspects of a premium m43 lens you need to also be looking at premium lenses. The stuff that is equivalent in terms of max aperture also seems to have other flaws. That's really all I was saying. Truly equivalent lenses (and by that I mean not just aperture size but all the other aspects of the lens too) don't really exist. And it seems to me that you generally get what you pay for on any system. Of course individually one might not value the optical aspects that one maker chooses to compromise to save money etc. so person to person there are better value options or worse options.

I'd argue against the part I highlighted. The f2.5 Sony lenses are exactly the type of FF lenses that combine high IQ and reasonable size while still giving you an equivalent aperture (or better) of the fastest, largest, and most expensive lenses in m43. Sigma's new f2 lens line is similar. Tamron also has f2.8 primes for FF mirrorless. FF mirrorless does not have to mean only large heavy lenses and as time passes we'll get more modest sized lens options.

I'm not sure what you seem to think is missing in lenses like those I mentioned?

Just one example I looked up, lets look at 35mm (or similar) equiv lenses. The Sigma 35 f2 is 11.5 ounces and is definitely a premium build high performing lens. The Oly 17 1.2 (FF 34 2.4) is 13.7 ounces. The Sigma is also significantly less expensive ($639 vs $1299). Similarly Sony's 40 2.5 ($598, apparently they don't make a 35 in that line) is 6.1 ounces. I've read nothing but glowing reviews for both of those lenses. The Oly is also very good but its bigger, no faster and way more expensive.

This is the value proposition that m43 users face now that FF mirrorless is becoming widespread.

Also realize that FF mirrorless is relatively new for Canon, Nikon and even Panasonic. Initially they are concentrating more on higher performing lenses but they do have a few smaller lenses in production. Time will round out the lens lineups. It's early days in FF mirrorless except for Sony and not surprisingly that's where most of the smaller FF lenses are available (for now).

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