The "street lens"
Adapting old "legacy" lenses to the Sony NEX cameras is a lot of fun. In my previous article in this series, I've exalted the qualities of the fast 50mm f/1.4 lens. This positive first experience led me to seek other Zuiko OM "prime" lenses to complement the 50mm. Because of the 1.5x "crop factor", a 50mm lens is 'equivalent' to a 75 mm (in 35mm film terms). This makes the 50 mm f/1.4 an excellent portrait lens on the NEX system, but not a very good "street photography" or landscape lens. Enter the 24 mm f/2.8. This is a "wide" lens in 35 mm terms though more of a "normal", slightly wide lens when mounted on the NEX (24 x 1.5 = 36 mm equivalent). It's a focal length well suited to both street / candid photography and landscape work.
Figure 1 shows the G-Zuiko 24 mm f/2.8 mounted on the Fotasy OM-NEX adapter. The build quality is once again excellent, featuring all-metal construction, a nice aperture ring and very "smooth" focus ring. This lens is also very compact, even accounting for the NEX adapter. This is probably better seen in Figure 2 (without an adapter) sitting next to the 200 mm f/4 lens (the latter will be the topic for a future article in this series).
Figure 1 - G-Zuiko 24 mm f/2.8
Figure 2 - G-Zuiko 24 mm f/2.8 and 200 mm f/4
The filter size in this lens is also 49 mm. As noted in the previous article, this is very convenient because it matches the filter size of most NEX lenses, including the 18-55 mm kit lens. And last, but not least, this lens is black! Though not likely to make a difference in the quality of your photos, this is an important aesthetic consideration when "pairing" it with a black NEX-5N body. Photography is an aesthetic pursuit after all:). As seen in Figure 3, this is a very nice match indeed.
Figure 3 - Zuiko 24mm f/2.8 on Sony NEX-5N. A very nice match.
The fridge test
So how does this lens perform? It is time for the famous "fridge sharpness test". I was curious to see how this lens compared to the standard 18-55mm kit lens set at 24 mm. After all, this is a prime lens, so it should do better than a zoom lens where compromises are necessary to cover a wide focal length range. Actually, there would be no reason to buy such a prime lens, apart from the 1-stop speed advantage, if it didn't surpass the kit lens... Figures 4 and 5 tell the story. Figure 4 is a crop from the center portion of the photo (where most lenses fare pretty well) whereas Figure 5 is a corner crop (where lenses tend to "struggle" for sharpness).
Figure 4 - The "Fridge Test"
G-Zuiko 24 mm f/2.8 lens vs Sony 18-55mm. Center
Figure 5 - The "Fridge Test"
G-Zuiko 24 mm f/2.8 lens vs Sony 18-55mm. Corner
Here are my conclusions after closely examining both pictures:
- Somewhat to my surprise, in the center crop, the Olympus is actually worst than the Sony at f/4. It only gets better than the Sony at f/5.6 and above. However, this is not the end of the story. Let's look at the corners:
- In the corners , the Zuiko is clearly superior to the Sony lens (always sharper). The difference is obvious at f/4, and remains noticeable throughout the aperture range. This is an important advantage for landscape work where "corner-to-corner" sharpness is a key consideration.
- With both lenses, loss of sharpness due to diffraction effects is only noticeable at f/16 (f/11 is still quite good).
- The Zuiko lens exhibits some cyan fringing in the corners as shown in Figure 5. Fortunately this is easily corrected in post processing (especially if shooting raw) but is a slight annoyance nonetheless.
- As expected the Zuiko shows some vignetting at f/2.8 (notice how the "corner" crop at f/2.8 is darker than the photos at smaller apertures. This is normal behavior for most fast lenses when wide-open, and can be easily corrected in Photoshop.
An important consideration for architectural photography using "wide" lenses (and this was a pretty "wide" lens in its days), is distortion. An easy way to assess lens distortion is to shoot a man-made structure, like the brick wall shown in Figure 6. There is a noticeable amount of barrel distortion here. Nothing that the "Lens Correction" filter in Photoshop can't handle, but I was expecting a better showing from a dedicated "prime lens".
Figure 6 - The Wall
Sony NEX-5N, G-Zuiko 24 mm f/2.8 lens
In summary, I would say that the lens fared well in these "technical" tests though I was expecting a better showing, especially considering that this lens is not very cheap, as used lenses go (a little over $200 at KEH.com). However, it still beats the Sony kit lens in most aspects, and is of course a whole stop faster which is a real advantage for low-light shooting.
A lens test wouldn't be complete without some real-world examples. The Zuiko 24 mm seems well suited for landscape photography, so naturally I took it with me on a recent trip to Point Reyes National Seashore in California. Figure 7 is actually an "auto-stitched" photo using the in-camera "sweep-panorama" feature (for more on that, see this article). I set the sweep-panorama feature orientation to "vertical" and the aperture to f/8. It's hard to judge sharpness in a small, web-sized jpeg as in Figure 7, but to my eyes, this is a very sharp photo, taking oadvantage of the lens' optimum aperture of f/8.
Figure 7 - Drake's Beach, Point Reyes, California
Sony NEX-5N, OM Zuiko 24mm f/2.8, shot at f/8
I shot the photo in Figure 8 during the Sacramento "Second Saturday Art-Walk". This is an example of street-photography in a low-light environment. The f/2.8 aperture was welcomed in this situation, though I wouldn't necessarily say this is an optimum lens for low-light work. If your primary useage mode is in low-light situations, then go for a f/2 or f/1.4 lens. However, because the Sony NEX-5N is a very capable camera at high-ISOs (ISO 3200 is very good), you can easily capture scenes with minimum light and still get acceptable results.
Figure 8 - Chairs and Alien
Sony NEX-5N, OM Zuiko 28mm f/1.4, shot at f/2.8
In conclusion, I would say that the Zuiko 24 mm is a good choice as a "walk-around" lens for street photography due to its's compactness. It is also a very good landscape lens when stopped down to f/5.6 or f/8, offering corner-to-corner sharpness and good contrast. The "value for money" is not as good as with the 50 mm f/1.4 reviewed earlier in this website, but it is still a good choice in this focal range if you get to know it well, and work around its limitations.
UPDATE: Check my video review on the PAULORENATO.COM Photography YouTube channel:
Comments, questions, suggestions? You can reach me at: contact (at sign) paulorenato (dot) com