Viltrox AF 25 mm f/1.7 Air
4. Image resolution
Let’s remind here that the best fixed focal length Fujifilm X lenses, tested that way, can reach as high as about 90 lpmm and the decency level is situated near 44-45 lpmm. So far the best resolution we measured while testing the Fujinon XF 18 mm f/1.4 R WR (93.5 ±0.9 lpmm), the Viltrox AF 27 mm f/1.2 (97.5 ±1.5 lpmm) and the Viltrox 75 mm f/1.2 (99.8 ±1.2 lpmm).
Let's check how the Viltrox AF 25 mm f/1.7 Air compares here – its results in the frame centre and on the edge of the frame presents a graph below.
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When it comes to the frame centre, it's obvious that the performance is a tad weaker than in case of the model tested by us earlier, the Viltrox AF 15 mm f/1.7 Air. Still, before you start to pick holes in this performance let's glance at a graph below that shows you a comparison of resolution values in the frame centre between the Viltrox, tested here, and the faster and four times more expensive Fujinon XF 23 mm f/1.4 R LM WR.
It's obvious that both lenses fare very similarly at their respective maximum relative apertures and, at the same time, they show very good results, reaching almost 70 lpmm. Then by f/2.0 the Fujinon prevails slightly but by f/2.8 and f/4.0 the cheap Viltrox puts to shame its more renowned rival. We don't doubt that the performance of the Viltrox are brilliant and allow you to get very sharp images across the whole aperture range.
In order not to make a situation too rosy we should also glance at the same comparison but for the edge of the frame – an appropriate graph you can find below.
Here the faster and much more expensive Fujinon shows what it is capable of, outdistancing the Viltrox distinctly. It's evident that, when it comes to their cheaper constructions, Viltrox optimizes them in the frame centre and neglects a bit the edges. Of course we should mention the fact that, overall, the performance of this cheap lens is hardly weak. After all by f/1.7 and f/2.0 you get results reaching 43-44 lpmm so, within the margin of error, on a decency level. On a more significant stopping down MTFs increase to a good level of over 50 lpmm.
To sum up once again you get a lens of a rare price/performance ratio, with an excellent resolution in the frame centre and no slip-ups on a demanding edge of the detector.
At the end of this chapter, traditionally, we present crops taken from photos of our resolution testing chart, saved as JPEG files along with RAW files we used for our analysis.
| Fujifilm X-T2, JPEG, f/1.7 |
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| Fujifilm X-T2, JPEG, f/2.8 |
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