Dedicated to Charline Norgrove, a dear fellow m43 user who was always the first to champion my posts.
The Leica/Lumix 10-25mm f/1.7 lens has been greeted with universal acclaim, even though its bigger than many expected and its price is a little eye watering. What is a person to do when he’s also trying to save for the Zuiko 100-450 mm f/4.5 coming out later this year? Then I viewed an interesting review adapting the current Sigma 18-35mm f/1.8 in EOS mount with a 0.71x focal reducer which yields an effective 13-25mm f/1.4 lens. The reviewer found that the combination did not perform as well as he hoped and that agreed with my expectations. This lens was designed specifically for APS sized sensors and the use of a focal reducer will not yield a true increase in one aperture stop and can degrade its optical quality. This is what I encountered when testing a Sigma 30mm f/1.4 ART lens (https://jimchungblog.com/2018/06/24/sigma-30mm-dc-hsm-f-1-4-art-lens/).
The idea still has merit when considering full frame lenses in EOS mount and here are a couple of options that I was eager to test.
The Tokina AT-X PRO FX SD 16-28 mm f/2.8 (IF) is the older generation of the current Tokina 16-28 f/2.8 Opera which appears to have the same optical design. The Tamron SP AF 17-35mm f/2.8-4 Di LD Aspherical (IF) is also an earlier version of the current Tamron 17-35 mm f/2.8-4 Di OSD. The benefit of choosing an earlier generation lens is that its used street price falls precipitously when its no longer a current model. I also tried out a new photo and video gear rental company named Movri based in Surrey, B.C. just outside of Vancouver (http://movri.ca). I was not able to rent the new Leica lens in Toronto, but the folks at Movri were so accommodating that they went and purchased a Leica lens just to solicit my business! It arrived a few days later via FedEx.
The resolution tests were performed on my E-PL5 body (ISO200, tripod mounted with IS turned off) with a professionally printed ISO12233 resolution chart and HYRes3.1 software as described in an earlier blog. The 5 element Metabones Speedbooster Ultra did not work properly with the Tokina lens (but did work with the Tamron) on the E-PL5 body so I used my 4 element Vitrox reducer with it. The Leica would not step down past f/9 on the E-PL5. The Tamron at shortest focal length would not stop down past f/9 on the E-PL5. All the lenses performed normally on a modern body like the E-M1.2
All three lenses perform similarly well and each zoom shows similar center performance in either the long or wide end of the focal length. The long focal length tends to also have better edge performance than the wide end. The Leica lens does show it’s something special by reaching peak resolution after stopping down only a half f/stop and then holding that peak resolution until diffraction sets in. At 25mm, its edge performance is nearly as good as its center performance.
The quality of the background bokeh is similar in all three with perhaps the Tamron showing the most attractive out of focus circular spots of point light sources.
With each lens manually focused to its closest distance at its highest focal length, the Tokina took 1.7 seconds to focus and fire, the Tamron took 1.5 seconds, and the Leica was instantaneous when aimed at Paddington Bear, and mounted on an E-M1X. The E-PL5 is substantially slower.
When taken all together, the Tamron is my choice to keep since the price is absurdly low, it is in fact more compact and light weight than the Leica while delivering center resolution better than the Leica. The Tamron is not as wide as the Leica but there is very little difference between f/2 and f/1.7. Even at 25 mm, the subject isolation at f/2.8 is really not that different from the Leica at 25 mm f/1.7. The big difference is edge sharpness which is much softer in the Tamron. The Tokina is simply too big and too heavy to be anybody’s choice in this shootout. I also have primes that cover the range between 10-20 mm so I’m not anxious to spend $1600 USD (street price) on the new Leica, even though it is a very nice performing zoom and might indeed be the perfect wedding photography lens.
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