Welcome back to the long delayed latest part in the series of choosing lenses for the Fuji X-System. Previously I was discussing some generalities about big zooms vs. little zooms vs. primes. Consider this an extension of that with a bit of specific comparisons as well as a bunch of pixel peeping and of course some philosophy.
Disclaimers & Such
Hmmm, flat targets. We'll leave that to the labs. I'm sure there are a few people out there that copy flat artwork and things like that but for the rest of us (meaning me) I make pictures of three-dimensional stuff that exists in an environment of other stuff having varying distances to the camera. Having said that, I do pixel peeping tests of things with multiple layers and planes of focus. I also use things that have broad detail as well as tiny detail.
Today I'm using a multi-colored shimmery bunch of fabric strands that happens to have 80 million different planes of focus. On top of that I'm shooting from an oblique angle (mostly to show OOF rendering and focus transition). One of the reasons I do this is the insane difficulty of exact, I mean exact-exact focus repeatability lens to lens when comparing and even a bit shot to shot (shot at very close distances). I rather have a way to evaluate micro differences in focus by taking a look at the sharpest things at various planes.
I typically shoot really close so for this set of comparisons I'm about two feet away. Trying to evaluate exact plane of focus with wide angles at this distances is difficult, even with 100% in camera magnification and manual focus. I made six to ten exposures in each case and picked "the best", in most cases there was more consistency than there was lack of given my setup.
- Tripod mounted camera
- Zero ambient light contribution
- No motion blur given something north of 1/1000s flash duration
- A broad (60 inch) soft light source from the side for a bit of contrast
- No fiddling around in LR with sharpening tricks, de-haze, clarity, nothing
- In camera custom WB for the strobes/modifier and use of LR's Astia camera profile
The 18mm XF F2 R
Wanna see why this lens gets a bad rap? As opposed to say the 18-55mm kit lens that is universally praised? Let's take a look. (Download the screenshots to see what I see, except for the JPEG compression of course)
This is the absolute corner performance of the 18mm f/2 and 18-55mm f/2.8-4. As far out as you can reasonably get with a focus point on any current Fuji X camera. What do I see?
- Yep the 18-55 performs better at all levels of detail but be careful here when evaluating, the focus planes are not identical. The threads are pretty small and the fibers making up the thread are microscopic, much finer than typical fibers (some sort of shiny microfiber).
- The biggest difference is actually in contrast in the corners which is definitely important visually.
- The rendering is very different between the two lenses, neither of them bad but if push comes to shove I like the 18mm f/2 rendering a wee bit better.
This is probably why the 18-55mm has such a good reputation. The prime should slaughter it right?? Especially with the zoom wide-open and the 18mm stopped down one stop. Well it's not the whole story lets take a look at the center.
Hmmm, I don't know about you but I consider the center to be a very different story. The 18/2 slaughters the 18-55. What about at f/4?
A little closer but be careful, I still think the 18/f2 walks away with the win. The 18-55mm can trick you because it's not quite as wide at 18mm as the prime so everything is a hair bigger. When in doubt evaluate the finest fibers in focus planes that are the most perfect for each.
What about rendering and focus transitions? You can see the transitions across a very narrow field in the above shots. Below is a more varied view of various stages of OOF at f/2.8. The zoom should have the advantage as in no aperture interfering with anything.
Both are pretty great given ones a zoom and ones a wide angle. I've had many zooms and many wide angles that OOF rendition was such a mess it was very distracting. Toss a coin, I happen to like the 18mm f/2 prime a hair better but you may like the way the zoom falls off with almost no transition in that middle band. The sparkly-ness gives you an idea about how highlights render.
Still Not The Full Story
So we've taken a look at the center and the corner now we know everything right? Not so much. I used my XT-1 for this, I could have used the XPro-2 but either is good enough. More megapixels make both lenses better while highlighting the differences even more. The center performance of the 18mm really does walk away at any moderate aperture's from the zoom. The corners are almost always better with the zoom at moderate apertures (say ummm wide open thru f/5.6 at least.
There's way more to it than that though. The lenses behave differently at various close/mid/long distances and what's more is that the zoom cleans up in the corners real fast when stopping down. The 18mm f/2 prime cleans up slowly with that center performance becoming more and more of the frame but not extending to the corners ever for moderate apertures and by the time it does you actually see it evening out due to diffraction. Also note that the 18-55mm has this strange dip in performance before it gets to the corners and then gets better again where the 18mm f/2 is far more traditional in it's behavior. I walked thru that way back in another post.
The Bottom Line
In my estimation the 18-55mm is not better than the 18mm f/2 at 18mm as is overly stated out there. It certainly is different and behaves differently. For my use I use the 18mm f/2 way more for a lot of reasons.
- Works way better with my preferred OVF on the XPro-2
- I like the rendering slightly better
- That killer bite and center performance is more useful to me than corner performance, especially at larger apertures I work with. (Don't forget the center is actually pretty big)
- It focuses really close
All images made with the XT-1. Processing via Lightroom CC with the Astia profile applied.
Stay tuned, next up we'll be comparing the 35mm f/2 WR, the 23mm, the 56mm etc.