In my last post I tested the accuracy of the FujiFilm XE-1's spot meter and ISO values. Today I'm interested in exploring the exposure range. Can the XE-1 handle the full range of Ansel Adams' Zone System? I'll put the camera to the test with a few exposure test sequences and some quick portraits.
THE ZONE SYSTEM
Sure, a digital camera's histogram will show if parts of your scene are clipping above white, but it won't tell you which parts and by how much. The zone system is a helpful way of mapping the proper exposure of the scene using a spot meter. Eleven "zones" range from pure black (O) to pure white (XI), with middle gray in zone V. Each zone represents a stop - with five stops from middle gray (zone V) to pure black (zone 0), and five to pure white (zone X). Zone I and IX contain discernible tone, but no texture. Texture is seen only in the three stops above and below middle gray (between zones II an IX). There are many excellent resources which explain the zone system, including this wikipedia article: http://en.wikipedia.org/wiki/Zone_System
Here's an example of how I would utilize the zone system in a scene with bright clouds:
- Set the f/stop and ISO as desired, put the shutter in 'A' mode and ensure the camera is in spot meter mode.
- Set the center of the frame on the brightest cloud that I want to the retain texture of. Half-press the shutter and the spot meter will give a reading that would make that cloud middle gray (zone 5) - say 1/2000 second.
- Use the zone system to map that tone. in this case I want that cloud to be bright but retain texture, so I need to move it into zone VIII, or three stops above what the camera metered.
- Set the actual shutter speed and take the shot. In this case I'll open up the shutter speed by three stops to 1/250 second. My clouds will be nice and bright, but still retain texture and color.
The zone system can also be used to map out shadows to ensure they don't fall into blackness.
ZONE SYSTEM FOR FUJIFILM XE-1
Does the XE-1 have the range to support the breadth of the Zone System developed for old school negatives? Some say it doesn't work in the digital world, that digital cameras just don't have the latitude.
The XE-1 sports a "Dynamic Range" mode and I would like to know just what that setting does. Does DR400 put the XE-1 closer to the tonal curve of negative film? I'm hoping to answer each of these questions with a test exposure sequence.
I'm starting with an exposures sequence of sandpaper, boring, but it contains both tone and texture - I'll be able to identify when either one is no longer visible. I'll shoot one sequence at the camera's base ISO (200), one at ISO 800 with the DR mode turned off (DR100), and one at ISO 800 with the DR mode turned on (DR400). The aperture was adjusted to achieve proper exposure (0 EV) at a shutter speed of 1/125 second. The numbers in each of the squares are the L value (Lab) sampled at the center of the square.
This isn't a controlled lab setting, so there is a bit of variance to be expected. And with full stop increments it's hard to tell exactly where we hit pure white. But there are some interesting patterns here:
- For the brights, +3 EV is the last safe tone and texture zone. +4 EV goes to white, and it clips pretty hard as typical for digital.
- For the shadows, -4 EV still has visible tone and texture. -5 EV goes to black, but the roll to black is very smooth. The XE-1 has excellent shadow detail.
- The DR400 mode doesn't change the shadows at all, but it does extend the whites by an additional zone, maybe slightly more. But, and this is a big one caveat, there seems to be little texture in the extra zone, only tone. +3 EV is still the last safe zone for texture.
Here are the L values plotted against EV:
Focusing in above the 85% value, you can really see the different curve of the DR400 mode:
I shot a second test sequence containing a gray card, white cloth and black cloth. It's not as accurate as the first, the sunlight changed a bit during this test, but it does reinforce the results - you can see the loss of texture in the over and under exposures:
Charted we can see the same subdued rolloff curve of the DR-400 mode.
With DR400 active the exposure curve seems pretty close to that of the Zone System, though I'm not convinced there's much texture up there in zone VIII. And, to shoot at ISO 800 outdoors with wide open apertures I would need to throw a pretty heavy ND filter on the front in order to keep shutter speeds lower than 1/4000 second - not too practical.
Without DR, the XE-1's exposure range matches up well with the dynamic range of slide and cine films. These films, and the XE-1, have one less stop in each direction from center gray. Brightest safe texture at zone VII, brightest safe tone at zone VIII, darkest safe texture at zone III, darkest safe tone at zone II.
It was a typical drab Oregon day with bright backlit sky and dead shadows - perfect for trying the XE-1's different metering modes in a harsh lighting condition.
I'm going for worst case scenario, so don't expect these to look anywhere close to fabulous - I'm purposely not adding any reflector, fill, shade or flash. Miriam's face is lit by featureless dim light and the clouds behind her are bright. I'm displaying these shots as they appeared straight out of the camera in .jpg format.
Portrait 1 - Incident Meter
In this first shot I have used the Minolta Auto Meter IVF to take a reading of the light falling on Miriam's face. Nothing surprising here, the skin is properly exposed but the bright clouds are blown out and there is no separation between the backlight on top of her head and the clouds behind her. ISO 200, 1/1000s, f/3.2.
Portrait 2 - XE-1 Multi-Segment Metering
For this shot I set the XE-1 to "multi-segment metering", with the exposure compensation dial at +0EV. The XE-1 does a pretty good job of bringing the clouds down to the exposure ceiling, and no further down than necessary. The backlight on Miriam's hair is still clipped, but that's a very small part of the scene and the algorithm likely tossed it as unimportant. Yes, it is underexposed overall, but a curves adjustment would bring the mid-tones up to make this image look decent while still retaining cloud tone. ISO 200, 1/1600s, f/3.2
Portrait 3 - Canon Digital Elph
As a comparison I brought along my wife's totally automatic, totally pink, Canon Elph. I pointed it at Miriam and clicked. The Elph clearly found Miriam's skin tone and exposed properly, and then took the brightest details and cranked down hard to get them into Zone VIII. An aggressive curves adjustment is happening in-camera, automatically for us, because that's what a point-and-shoots should do. Today's point-and-shoots change the tonal curve for every shot to automatically maximize the brightness of faces and snap the dynamic range perfectly to the histogram. Camera and magic darkroom in one! ISO 160, 1/1000s, f/2.8:
Portrait 4 - XE-1 Average Metering
I've never found the average meter particularly useful. As expected, the top third of the frame being bright clouds completely underexposes this image. If I pointed the camera even slight higher it would have underexposed even more. ISO 200, 1/2700s, f/3.2
Portrait 4 - Zone System with XE-1 Spot Metering
In this shot I'm trying a zone based exposure. I spot metered on the bright clouds behind Miriam's head and opened up an additional three stops. This shot is still dark, but I know the exposure is as bright as possible while retaining tone in the clouds behind her head, as well as the separation between the clouds and her hair. ISO 200, 1/1800s, f/2.8:
Using a curves adjustment in post production I can easily bring the low mid-tones up - not too bad for unflattering light with bright backlighting:
I was surprised that the multi-segment metering chose an exposure very close to my own zone system based exposure. Yes, the skin was underexposed in both cases, but for good reason: the important highlights were preserved and a curves adjustment brought the skin back up to proper levels. In daily use though I have found the multi-segment metering to be inconsistent, slight framing changes alter exposure changes dramatically - I would rather use the spot meter and apply the zone system rules to know I have details where I want them.
The FujiFilm XE-1 does seems to have a similar dynamic range to that of slide film, maybe even a bit more range. I measure 3 useable stops above (zone VIII) and 4 stops below middle gray (zone I). DR400 mode gets us one more stop into the brights (zone IX) but in this case zones VIII and IX seems to be predominately tone, not texture.
Does the XE-1 underexpose compared with other cameras? I believe that is a yes and no.
In my last post I tested the XE-1's ability to shoot an accurate exposure, and yes, an XE-1 exposure at 1/200s f/2.8 ISO400 will be identical to a Nikon or Canon DSLR at the same exposure settings. As for automatic exposure mode, the XE-1's multipoint metering doesn't seem as advanced and consistent as that of the Nikon D7000 I shot previously, though when the XE-1 seems to underexpose it does so in order to preserve highlights.
All that aside, I think that the biggest frustration for those starting out with any pro-grade camera is that the camera doesn't tinker with the curves after the shot has been taken. Today's consumer cameras are getting pretty darn good at in-camera post-processing - just look at some of the shots from an iPhone 5, they are beautiful! We can easily take for granted how much darkroom magic these cameras are doing. They make skin tones bright, sharp, and push warm colors to the extreme. But the XE-1 is definitely not a point and click, we are rightly left to our own post-processing style after the shoot. Compared to a good point-and-shoot, the XE-1's out-of-camera shots may appear dull, even improperly exposed - simply because these shots haven't been pushed to their potential yet.
Please leave feedback! I would enjoy hearing your thoughts on this topic.
By Adriel Henderson