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 p.6 #9 · Fuji XF 90mm f/2 Rolling Impressions | |
Steve Spencer wrote:
I agree that if we could compare like for like then we would have equivalence. Like for like, however, would mean same pixel density, same underlying electronics, same CFA (colour filter array), and a lens with the FOV (field of view) and DOF (Depth of Field) properties. Very few FF (Full Frame 35mm) sensors have the same pixel density, some have the same underlying electronics, and none have the same CFA. So we can't compare Fuji right now to any FF cameras, IMO, without recognizing that they have different CFAs. One place you might want to start is compare Fuji to the Sony A7, they at least have a similar pixel density and similar underlying electronic (note the A7r II doesn't have the same underlying electronics so it would again be hard to talk about equivalence), but the Sony A7 doesn't have any 135mm lenses yet in native mount, and importantly has a different CFA. The x-trans CFA if you listen to theSuede around here, does provide a real advantage at high ISO (and a real loss in resolution at low ISO), so even if Sony makes an excellent 135 f/2.8 lens (which I would not be surprised by at all) the Fuji with the 90 f/2 would probably do better at high ISO with the cost of some resolution at low ISO.
Perhaps you could compare it to the Nikon D800 (or maybe even the D810 which might have tweaked the underlying electronics) but you would still have the CFA difference. Comparing it to the DF makes little sense to me as they have very different pixel densities, and comparing it to Canon makes little sense because not only do you have the CFA difference, and underlying electronics differences, but also no sensors will similar pixel density.
So yes if you are trying to talk about equivalency you need to compare like to like, but please realize that like for like isn't always possible and part of the strengths and weaknesses of different sensor sizes is that they each provide some things (at least for now in what is available) that other formats do not. Micro 4/3rds for example provides several quality zooms with a FF equivalent max DOF of f/5.6. Nobody has ever made a zoom anything even close to equivalent to those zooms for FF. Similarly, they make a tiny wide angle zoom with a full frame equivalent max DOF of f/8 to f/11. I don't think FF equivalents of these m4/3rds lenses are ever going to be built. In the same way I don't think that Canon and Nikon will ever make a FF equivalent to the Fuji 90 f/2, although I think it is likely that Sony and maybe Pentax will build something close.
In general what Fuji has done is build a set of high quality lenses that often have an equivalent FF max DOF that is about a stop slower than most of the high quality lenses for FF (here specifically I mean the Fuji 14 f/2.8, 16 f/1.4, 23 f/1.4, 35 f/1.4, 56 f/1.2, and 90 f/2 and for zooms the 10-24 f/4, 16-55 f/2.8, and 50-140 f/2.8). Sometimes the equivalent lenses are there for FF, sometimes they are not (for the 90 f/2 they are not), but Fuji has this type of lens consistently across its platform. This has allowed Fuji to have a smaller set of high quality lenses with considerable capabilities. In addition, they put a CFA on their sensor that helps high ISO performance and therefore whittles away at the FF advantage to turn up ISO and stop down the lens (it comes at the cost, however as described above of sacrificing some resolution at low ISO). So Fuji has had a very consistent approach and one that makes sense to a lot of enthusiasts. Build high quality lenses that are small, accept some of the weaknesses of the smaller sensor, but try to compensate for them with your CFA. I think this platform makes a lot of sense if you want a smaller size kit, but still want quality and you care more about being able to extend shooting into high ISO, than having maximum resolution especially at low ISO. You can do that with Fuji at a price that will be noticeably less than going with FF.
In contrast if you want greater resolution and DR (dynamic range) at low ISO (although MF--medium format--will be a bigger advantage) and maximum high ISO capability, then FF will get you there but it will do so with a cost in price and size in most cases. On the other end, if you want an even smaller kit, m4/3rds can get you a size that even Fuji cannot match.
Different horses for different courses. We don't need a format war whenever we talk about a new lens. Sure if there is an equivalent lens and fairly equivalent sensors we can compare. In this case, however, there isn't, so let's just appreciate both the lens and the system for what it is....Show more →
There's no format war here, just a discussion (aside from one clown with the attacks).
I'll leave it here since I categorically disagree with most (but not all) of what you wrote above.
However, I do agree that Fuji has built up a very nice set of prime lenses that perform very very well. That's why I read Jordan's posts like this, because I'm always tempted to wade back into the Fuji world somewhat.
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