Wednesday, March 11, 2015

Sony E 16 2.8 Review Part 2: fisheye and ultrawide converters



This is a continuation of our review of the Sony 16 f/2.8 for the E-mount (Part 1 here).  In this part, we will discuss the two converters for the 16 2.8: a fisheye converter (VCL-ECF1) and an ultrawide converter (VCL-ECU1). 

First, I will describe the two converters.  I will then discuss the rationale and performance of each converter, starting with the fisheye, then the ultrawide.

Before we go on to the review, I want to mention a couple of footnotes:

1. If you've tried cheap wide angle converters before, you may think that these converters are just gimmicks.  But these are entirely different and are very good quality converters.

2. When Sony announced their new lenses on March 4, 2015, they also announced "new" versions of the converters, the VCL-ECF2 fisheye and VCL-ECU2 ultrawide.  As far as I can tell, they are identical to the old converters, with the same specs and same optical formulae.  The only difference between the new converters and the old ones seems to be that the new versions are black (matching the finish of the 20 2.8) while the previous versions are silver (matching the finish of the 16 2.8).  The VCL-ECF2 and ECU2 are advertised as being compatible with the 20 2.8, but so are the ECF1 and ECU1.





OVERVIEW
Ultrawides, both rectilinear and fisheye, are challenging - but rewarding - to use well.  They take courage to use for several reasons.  First, it is a specialized lens with a specific "look." If you choose to use an ultrawide, you're making a commitment to search for and use that look.  There will be many missed opportunities, which increases the pressure to find new opportunities to justify having brought this lens. 

Second, when you use an ultrawide, you need a clear artistic intent.  If you don't have a clear intent, an ultrawide will make the image look even weaker by drawing in more elements that don't contribute to the image. 

Third, in order to have a clear intent, the subject usually needs to occupy a significant part of the frame, which for an ultrawide means you often need to shoot very close to the subject -- often well within most people's personal space.  It takes guts to do that, especially if you are a stranger to the subject.

Fourth, assuming your intent is clear, your idea will be very plain to see, with not much room for interpretation, and therefore it will evoke a stronger reaction to your image -- positive or negative. You need a thick face for criticism.

With so many challenges for using an ultrawide, why would you use one?  The simple reason is there is no substitute.  No other lens looks like an ultrawide.  Indeed, even a rectilinear ultrawide and fisheye are very distinct from each other.

Related posts:
How to Bend Spacetime (Tokina 10-17 Fisheye Review)

Conveniently, these Sony converters give you these two ultrawide "looks" (rectilinear and fisheye), in a relatively compact and affordable modular package.

DESCRIPTION
At a casual glance, the converters look very similar from the outside.  Both have the same dimensions, and both have a metal exterior with silver finish that matches the look of the 16 2.8.  To help me distinguish them easily, I put different colored thin rubber bands around them.




Each converter comes with:
•Built-in hood (which cannot be removed).  The shape of the hood is slightly different between the two converters.

•Front cap.  Although they have slightly different lens hoods, both converters use the same cap.  The front cap is a custom Sony design, and to my knowledge there are no 3rd party versions, therefore to avoid losing mine I attached a lens cap keeper.

•Rear cap.  This is a different design from the rear cap for lenses, and is a slip-on.  As with the front cap, there is no 3rd party version for it, although I'm looking for a slip-on cap that can fit.

•Case.  A hard, padded, leatherette case with a zipper.  The case is well made, and looks very protective.  There is a loop for a carabiner.


You attach these converters the same way you would a lens hood.  You position it at 90 degrees, then rotate counterclockwise until it clicks to lock.  A red mark helps to align the converter with the hood, although it can also be mounted upside down.  I just look at the lens hood to help me find the 90 degree angle.  To release the converter, there is a spring-loaded switch which you press then you rotate the converter clockwise to remove it.

Note: When the converters are attached, there is no change to the EXIF data.  Compare this to the SEL075UWC and SEL057FEC converters for the new Sony FE 28 f/2 -- the new converters have electronic contacts that enable the EXIF to correctly show the converted focal length when they are mounted on the 28 f/2.

When mounted on the 16 2.8, the combined lens looks almost like one piece.  The combined length (including the non-removable hood) is about 2.5 inches, about the same as the 50 1.8 OSS without hood.  It's not compact anymore but it's not too large either.

Although these converters were designed for the Sony 16 2.8, they can be mounted to other lenses.  Both converters mount to any Sony lens with 49mm filter size and a bayonet-type hood, which comprise the majority of Sony's lenses (e.g. Sony 35 1.8 OSS, 50 1.8 OSS, etc.). 

Although the converters can be mounted to other lenses, that doesn't mean the resultant performance is usable.  For example, when the ultrawide converter is attached to the 35 1.8, the resultant image is very hazy at f/1.8, like shooting through a gauze.  In fact, it is so soft that my a6000 has difficulty acquiring focus.  When the 35 1.8 is stopped down to f/4 or so, the image becomes sharper but is still not sharp.  Having said that, there are users who report that they have been able to get good results with the Sony 20 f/2.8, which is an optically superior lens to the Sony 16 f/2.8.  I don't have that lens, so I can't comment but it may be something worth looking into.

FISHEYE CONVERTER
Rationale:
Everyone recognizes the fisheye look, even if they're not photographers, and fisheye lenses have been pigeonholed for comedy effects.  However, I like using fisheye lenses because of the unreal look that they create.  I also like using fisheye lenses because people's faces look *less* distorted than with a rectilinear ultrawide.  Composing for a fisheye lens can be quite challenging but you will be rewarded with an image that looks nothing like what you get on any other kind of lens.


world's largest chocolate fountain
f/2.8, 1/60, ISO 160
There are two kinds of fisheye lenses: a circular fisheye, and a rectilinear fisheye.  With a circular fisheye, it looks as though you are peering through a barrel, and the image is framed by a circle.  A true fisheye lens has a 180 degree field of view.  With a rectilinear fisheye, the fisheye image fills the entire frame.  It is similar to cropping a rectangle out of the circle of a circular fisheye.  A rectilinear fisheye lens is supposed to have a 180 degree angle of view on its diagonal.  The VCL-ECF1 converter converts the Sony 16 2.8 to a 10mm (15mm equivalent) rectilinear fisheye with a 180 degree angle of view (diagonal).  On the 20 2.8, the equivalent focal length becomes 13mm (20mm equivalent) with a 133-degree angle of view.

f/4.0, 1/60, ISO 2000


Performance:

Sharpness: Compared to the 16 2.8 without the converter, sharpness at the center is about the same with the converter.  Sharpness at corners is reduced.  Any area that is outside the field of view of the 16 2.8 looks more blurred with the converter.  At f/2.8, the area that is acceptable is a circle that encompasses the area from the center to about midway to the corner.  Without the converter, there is a significant improvement when stopping down to f/4.  But with the converter, there is no improvement until you stop down to f/5.6, when the circle of acceptable sharpness reaches about two thirds of the way from center to corner.



There is another big improvement at f/8, when the circle of acceptable sharpness reaches about four-fifths of the way to the corner. At f/11, the circle of acceptable sharpness reaches the corner, although it is still not sharp.  There is a very slight improvement of corner sharpness at f/16, although the center becomes less sharp due to diffraction. f/22 looks less sharp than f/8, also due to diffraction.  Here is an album with full resolution test shots from f/2.8 to f/22 (you need to zoom in to see the full resolution).


Other observations:
  • The fisheye converter reduces the minimum focus distance from 9.6 inches (24cm) to 5.1 inches (13cm).
  • The fisheye converter seems to decrease vignetting.  Without the converter, a manual correction of vignetting on Lightroom 5 requires a +50 correction at f/2.8.  With the converter, a manual correction requires about +35 correction at f/2.8.
  • Greatly increases barrel distortion.  Just kidding :-)
  • No significant increase in chromatic aberration.
  • Slightly more vulnerable to flare.  Increased ghosting.  When there is a bright light source in the center of the frame, there is a very large prominent green ring in addition to other ghosting artifacts.
  • No effect on autofocus performance.
  • No effect on exposure.

f/2.8, 1/60, ISO 1000
Alternatives:
The most popular alternatives to the 16 2.8 with fisheye converter are probably the Samyang 3.5 fisheye and Samyang 2.8 fisheye (both are also re-branded as Rokinon, Bower or other brands).  The Samyang 3.5 is the older lens and is quite large.  The Samyang 2.8, on the other hand, is very compact.  Both are manual only lenses.  You focus manually and change the aperture using the aperture ring.  Manual focus on the a6000 is easy thanks to focus peaking.  As for exposure, you can still get automatic exposure by switching to shutter priority.  Although manual focus is easy on the a6000, I still find the 16 2.8 fisheye combo's autofocus ability useful for capturing quick candid shots.
Both Samyangs have reportedly good sharpness.  I haven't tried either of them but it appears that the Samyangs have pretty good sharpness in the middle but the Sony 16 2.8 + fisheye has a sharper center.  On the other hand, the Samyangs have good sharpness at the edges whereas the 16 2.8 fisheye combination has poor sharpness at the edges.

The minimum focus distance of both Samyangs is 12 inches, which is significantly longer than that of the 16 2.8 fisheye combination.  Having a shorter focusing distance with the 16 2.8 fisheye combination is very useful for fisheye photography because it can create a more exaggerated fisheye effect by moving the lens closer to the subject.  On a related note, something to consider is that the Samyangs produce less distortion compared to other fisheye lenses, even though they also provide a 180 degree field of view.  That can be an advantage or disadvantage, depending on how you use fisheye lenses.

For me, the most significant advantage of the 16 2.8 + fisheye combination is the incremental cost (see below).  The Samyangs are reasonably priced for fisheyes, but the VCL-ECF1 converter is still much cheaper.  On the other hand, if you plan to use only the 16 2.8 with fisheye combination, and you don't care about 24mm equivalent or the ultrawide, then it may be more fair to compare the cost of both the 16 2.8 with fisheye converter, in which case the Samyangs may cost less.

ULTRAWIDE CONVERTER
Rationale
Whereas the fisheye bends lines, an ultrawide keeps lines straight but stretches the image.  The closer to the edge of the frame, the greater the stretching effect.  I use the stretching effect to exaggerate angles, leading lines, or the direction of motion.



Performance

Surprisingly, sharpness is better with the converter than without (??).  On my copy of the 16 2.8 and converter, I get better edge-to-edge sharpness with the converter than with the 16 2.8 by itself.  Check out this comparison of the same part of the frame, both at f/2.8: 


It makes me wonder whether the lens was originally designed with the ultrawide 12mm 2.8, then Sony got the idea that they could make it do double duty as a 16mm 2.8.  

When stopped down to f/4, the ultrawide combination becomes acceptably sharp except at the corners.

To get acceptable sharpness at the corners, you need to stop down to f/8.  Corner sharpness peaks at f/11.  f/16 is almost as sharp as f/11.



Here is an album with full resolution test shots from f/2.8 to f/22 (you need to zoom in to see the full resolution).

Other observations:
  • Reduces the minimum focus distance to 7.1 inches (18cm).  Strangely, I can get larger magnification with the ultrawide than without.
  • Increases vignetting.
  • Increases distortion.  Without the converter, there is slight barrel distortion.  With the converter, there is slight moustache distortion.
slightly increased vignetting and distortion with the ultrawide converter
  • Increases chromatic aberration
  • Slightly more vulnerable to flare.  Increased ghosting.  When there is a bright light source in the center of the frame, there is a very large prominent green ring in addition to other ghosting artifacts.
  • No effect on autofocus performance.
  • No effect on exposure.

The a6000 was able to focus quickly enough with the ultrawide combination to grab focus while we were going down this giant slide.

Alternatives
There are a few alternatives for a rectilinear ultrawide for Sony E-mount.
1.  Samyang 12 f/2 for E-mount.  This is a manual only lens, so the same considerations apply as the Samyang fisheyes with respect to focusing and exposure.  This lens has excellent sharpness, and is sharper at all apertures, whether at the center or at corners, than the Zeiss 12 2.8 below, which costs 3 times as much.  Needless to say, it is sharper than the 16 2.8 ultrawide combination.  As with the fisheye converter, comparing the cost of this lens to the 16 2.8 ultrawide combination depends on whether you plan to use the 16mm by itself, and whether you plan to get a fisheye.  In my case, I love ultrawides but I rarely make large prints, so I couldn't justify the additional cost of the Samyang, modest though it may be.  I also want the autofocus of the 16 2.8 ultrawide combination for quick captures.

2.  Sony 10-18 f/4 OSS.   The 10-18 covers a greater range of focal lengths, even taking into account the 16 2.8's optional converters. On the other hand, the 10-18 doesn't have the option of a fisheye.  The 10-18 is optically better, has image stabilization, and is compatible with Fast Hybrid autofocus.  The 16 2.8 ultrawide combination has a wider aperture, is more compact, and is much cheaper, even if you factor in the cost of an ultrawide converter.  For shooters wanting an ultrawide, the Sony 10-18 provides a wider field of view compared to the 16 2.8 ultrawide combination (130 degrees vs. 122 degrees diagonal).  If optical performance is a priority (e.g. landscape or architecture), or for a wider field of view, the Sony 10-18 is the better choice.  The advantage of the 16 2.8 is the much lower cost, the option to get a fisheye, and the smaller size.

3.  Zeiss Distagon Touit 12 2.8.  This lens is sharper than the 16 2.8 ultrawide combination but also costs considerably more.

 
 


INCREMENTAL COST/BENEFIT
Notwithstanding the foregoing comparisons, for many users, there may be no competition for these converters, and here's why: in my opinion, the genius of these converters is their unbeatably low incremental cost, not just in money but in terms of opportunity cost.  If Sony offered a fisheye lens that was optically "meh" and cost $370, probably no one would care.  But if they said they had a $250 16mm, $120 fisheye converter, and by the way a $100 ultrawide converter, the package has better value.  And on the second hand market, it's even cheaper.

Separate from the monetary considerations, the split design also reduces the opportunity cost.  As I mentioned above, the choice to use an ultrawide lens requires commitment because it creates a very specific look.  Most people are probably interested in taking a few shots with an ultrawide, but to ask someone to shoot with an ultrawide the whole day, weekend, or vacation is a tall order. Almost any other lens is more "useful".  For that reason, as much as I love ultrawides, I often choose to bring another lens for vacations.

However, the split design changes the opportunity cost equation.  Each component takes only a small space in my camera bag, such as a side pocket, or I can clip on the dedicated converter case to the strap of my bag.  That means I can bring a 2- or 3-lens ultrawide combo in addition to the other lenses I would normally bring, and it effectively costs me nothing in opportunity cost.

To me, this unique quality more than makes up for its optical shortcomings.  Of course, if you are determined to take ultrawide shots on a given day (e.g. for a project or assignment), then you should take a lens with higher optical performance, regardless of size.  On the other hand, for casual shooters, who most likely don't know ahead of time if they will need an ultrawide, and also don't have such a stringent need for sharpness, this modular combination is well suited -- even ideal.
 
 
 


CONCLUSION
For some people, this lens will be terrible, while for others it will be exactly what they need. How well this modular lens combination fits your needs depends on what you plan to use it for:
  • LANDSCAPE / ARCHITECTURE PHOTOGRAPHY: 1 star.  Poor sharpness at the corners.  You won't get pixel-level sharpness at corners at any aperture.
  • PHOTOJOURNALISM: 4 stars.  Compact size and wide aperture with decent focusing speed to capture subjects candidly, with acceptable sharpness in the middle areas.
  • CASUAL ULTRAWIDE USERS: 5 stars.  Small enough to bring anywhere and everywhere.