I like shooting around the focal length of 35mm so getting the Panasonic LUMIX G Leica DG Summilux 15mm f/1.7 ASPH Lens.
Summilux is Leica's way of naming lens that can gather light at f/1.4, but for this particular lens it's f/1.7.
I have a lot of lens around the 35mm focal length, namely the Panasonic 14mm f/2.5, Olympus 17mm f/1.8, Panasonic 20mm f/1.7 and Voigtlander 17.5mm f/0.95 for the Micro Four Thirds system.
What it comes with
The lens comes with a lens hood and accompanying rubber cap. There's also a lens cap of course, and as usual a Panasonic lens pouch.
The lens weighs 115g. It's light, small and extremely portable.
This is taller than the Panasonic 20mm lens, about twice as tall actually, and after you add the lens hood, it protrudes a bit more.
It's well built with the feel of metal.
At the front of the lens is an adapter ring. You detach the adapter ring to mount the lens hood. It's the click and lock type of lens hood. It might come off when knocked because I feel that it's not quite tight.
Also near the front is an aperture ring that goes from f/1.7 to f/16, with 3 clicks for each full stop. Be careful not to have any stray fingers in front blocking it. Use the lens hood to help avoid that problem.
About the aperture ring, you must be in Aperture or Manual mode to be able to use that. Strangely, when in Aperture mode, even when the aperture dial is to A, you won't get automatic aperture (logically speaking it should go into Program mode).
There's a manual focusing ring, and it's nicely damp, smooth to turn.
There's no image stabilisation for the lens, but wide angle lens generally speaking can do without image stabilisation.
Compared to the Olympus 17mm lens, it's almost the same size and weight. When you mount the lens hood, the Olympus lens is slightly larger.
Note on aperture ring when used on Olympus camera bodies
I've read that the aperture ring only work on Panasonic cameras at the time of this writing. Maybe Olympus might want to update their firmware. If not then, there's seriously no point for Olympus camera users to buy this lens over the Olympus 17mm f/1.8 lens.
Autofocus is snappy. Definitely much faster than the 20mm lens.
There's no focusing noise so there's nothing for the mic to pick up, so it's good for shooting video as well.
In terms of colour and contrast rendition, I feel there's no difference compared to the Panasonic 14mm and 20mm.
Below are photos I shot under the harsh afternoon sun. Colours are adjusted for exposure and minor contrast.
You can click for full size images.
ƒ/1.7 1/800 200
ƒ/1.7 1/1000 200
ƒ/4.0 1/60 320
ƒ/1.7 1/4000 200
ƒ/4.0 1/60 640
ƒ/1.7 1/4000 200
ƒ/1.7 1/400 200
There is slight barrel distortion. Very minor issue.
Shot from near the ground, you'll get the tilting verticals effect.
ƒ/4.5 1/500 200
The effective focal length of 30mm is definitely wider than the 40mm from the 20mm lens.
ƒ/2.8 1/2500 200
ƒ/1.7 15.0 mm 1/2500 200
Colouring fringing is slight to non-visible even when shooting wide open. This may be due to the software-correction of Panasonic cameras. But I do on occasions see that the colour fringing is not 100% corrected. It's not a significant issue. And Olympus cameras do not correct Panasonic lens CA.
There is vignetting and it goes away at f/2.8. Even at wide open, it's not a big issue.
These cropped sections are based on the vignetting examples above.
Corners are a big soft, but relatively speaking compared to other lens, it's quite good. Even stopping down the lens does not improve the corner sharpness by much.
The lens has 7 diaphragm blades and when shooting up close produces a nice smooth bokeh.
As a wide angle lens, it's difficult to get any significant bokeh unless you're shooting real close to your subject.
The minimum focusing distance is listed as 20cm. However, I find out that focus can be locked even at around 15cm away. In other words, you can really shoot quite close up. By comparison Olympus 17mm's minimum focusing distance is 25cm
These 3 photo below are shot at f/1.7.
Personally, I don't feel the magic from this lens.
But having said that, it's still a fantastic lens with great image quality. I prefer the Voigtlander 17.5mm lens even though it's heavier because of the characteristics of its images, but that's just me.
If you're choosing between this and the Olympus 17mm which cost more than $100 cheaper, I would say go for the Olympus lens unless you need the aperture ring. Having the aperture ring is indeed very convenient at times. But the images they produce are the same, so is it worth more the $100 for that aperture ring? Are you comfortable with using the dial on your camera to change aperture?
If you're choosing between this and 14mm. It's a tougher call because the focal length is quite similar the price discrepancy is in favour of the 14mm lens which is almost half the price, albeit for 1 stop slower. If you're primary shooting with good light, it's not a problem. The f/1.7 becomes helpful when you shoot indoors, and when it's even darker, you should get f/1.4 or faster and there's only the Voigtlander lens.
I won't even consider comparing this lens with the 20mm lens. Focal length is quite different, at least to me.
I'll give it 4.5 out of 5 stars. In terms of value, I would give it 4 out of 5 stars.
At a glance
+ Well built, sturdy
+ Small, light weight (115g)
+ Aperture ring
+ Fast f/1.7
+ Great image quality and centre sharpness
+ Silent focusing
+ Comes with lens hood, lens hood cap and pouch
- Aperture ring too close to the front lens element
- Slight corner softness when shooting wide open
- Snappy auto-focus speed
- Slight vignetting from f/1.7 to f/2.8
- Slight chromatic aberration at f/1.7
? Chromatic aberration not corrected on Olympus body
? More expensive than the Olympus 17mm lens with the main difference being the existence of the aperture ring.