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Thursday, 12 September 2024

Leica D-Lux 8 Multi part user review Part 4 About the lens

 



The unique selling point of the Leica DL8 and its precursors,  the DL7, LX100 and LX100.2 is the Leica DC Vario-Summilux f1.7-2.8,  10.9-34mm  Asph zoom lens.   

Designed by Leica in collaboration with Panasonic, the lens first appeared on the LX100 in 2014. With a focal length range of 10.9-34mm, it covers an image circle of 19.2mm on a standard 4/3 sensor which has a diagonal of 21.6mm. As there is no lens mount and no focal plane shutter, the rear element of the lens can be placed very close to the sensor. These design features enable the lens to have an unusually small f-number range of 1.7-2.8 and the camera to have a multi-aspect ratio feature in which 4:3, 3:2 and 16:9 ratios all have the same effective 19.2mm diagonal on the sensor.

These two features continue a theme which has characterised PanaLumix and Leica D-Lux models for almost 20 years. Prior to 2014 smaller sensors were used, making the lens designers task a bit easier but lacking the image quality of the 4/3 sensor.



I am a long time user of these cameras. I bought the LX100, LX100.2 and D-Lux 7 as each came onto the market and took them around Australia and several other countries including Iceland.

I experienced two problems with each of these cameras. The first is unreliable autofocus in low light and when the camera is presented with bright specular highlights.  The second is inconsistent lens sharpness. Each of my cameras suffered from problematic softness in some or several parts of the zoom range and some or several parts of the image frame. This was frustrating to put it mildly especially as nobody else seemed to be reporting these problems.

So it was with some trepidation that I decided to get the DL8.

As to the autofocus I have to report that while the DL8 is more reliable than previous models, it is not perfect and in the course of a photo session I still see several mis- focussed frames in low light and when there are bright or specular highlights under the AF area.

The lens has provided a more positive experience. My copy of the DL8 lens has no obvious faults. It is well centered throughout the zoom range. It is consistently sharp in a large central area of the frame at all focal lengths with evenly distributed mild softness in the periphery most noticeable at the wide end of the zoom range.

The optimum aperture for sharpness is f5.6 at all focal lengths.

I suspect that  problems with the lenses on my previous cameras are related to quality control not design. Both Panasonic and Leica have been a bit coy about revealing the design details of the lens but as described in the DPR review of the LX100 in 2024, it appears to have 10 elements in 6 groups, with each group being able to move separately during zooming. In addition the lens has a double extending barrel design which sees it almost triple in length from 27mm at 10.9mm focal length  to 80mm at a 34mm focal length.

So we have a lot of parts moving in complex fashion and a requirement that each of those parts must be located with near-microscopic accuracy for the lens to perform as designed.

My guess is that Leica might have spent more resources on lens construction and quality control for the DL8 than has been the case with the three previous models which use this lens.


So I subjected the lens on my DL8 to more rigorous testing than usual. I photographed my usual test chart, pointed it at the sun and  gave it many different and challenging types of subject to reproduce. I also compared it to several other lenses in my ongoing investigation of compact cameras from different brands.

My overall impressions of the lens are positive. It is entirely usable at the widest aperture at each focal length.

Optically my copy is very good to excellent at focal lengths of 35-75mm (FFE) and good to very good at 24-28mm (FFE) focal lengths.

Resistance to flare from the sun in or just outside the frame is very good. I can induce a bit of veiling and color flare with the sun in the right location but in most situations sun flares are not a problem.

The lens/sensor/processor combination  is prone to color fringing in some situations. With the aperture at or near the widest available and the focal length towards the wide end of the zoom I frequently see red color fringing around bright highlights. I notice this quite often indoors with bright sources of artificial light. This is difficult to correct and is different from the blue/green color fringing which I see on high contrast edges such as foliage against a hot sky outdoors.


The built-in profile corrects Raw files well for distortion and peripheral shading.

The image stabiliser works well, allowing slow speed hand held photos indoors if desired.

Single shot autofocus is fast and usually but not always accurate. Dark subjects with a bright background and bright or specular highlights under the AF area box can produce misfocussed frames. We need to be aware of this when using the camera and check focus to see if a re-shoot is required.

The lens can focus very close but only at the wide end of the zoom,  with the front element almost touching the subject at 24-28mm (FFE). This limits the lens’ usefulness for macro work but can be handy for occasional close-ups when a macro lens is not available.

I include here the issue of moiree although it is not a lens problem but a phenomenon seen with some cameras which lack or have a weak anti-aliasing filter on the sensor. I noticed when testing that fine print on my test chart is reproduced by the DL8 with false color moiree and lorikeet (bird) feathers are reproduced with a false pattern. I have not seen the problem in general photography but it can occur whenever the regular pattern of a subject generates interference with the regular pattern of the Bayer filter array on the sensor.

I assume the DL8 has no AA filter or a very weak one.

This does enhance the ability of the camera to reproduce fine subject  details but also increases the risk of moiree.


Comparisons

I have been running a multi-camera comparison between the DL8, Lumix G100 with Lumix 12-32mm f3.5-5.6 and  Canon R50 and Canon R10, each with the Canon RF-S 18-45mm f4.5-6.3. The DL8 has the obvious advantage of a 2-2.5 stop wider aperture than the kit lenses, but when compared at the same apertures and output size there is very little difference between them although on my tests the kit lenses are marginally sharper with less color fringing. Even the much derided Canon RF-S 18-45mm is actually very good within the constraints of its focal length and aperture range.

A few years ago low f-stop numbers would have given the DL8 a big advantage as it can usually operate at a wider aperture and therefore lower ISO sensitivity setting producing less noise than cameras with small aperture kit lenses.

But noise reduction using artificial intelligence has changed the game. With Adobe>Enhance>Denoise AI   I am now getting clean, sharp results from the crop sensor Canons and the Lumix G100 at ISO 12800.

Summary

The lens is the most distinctive feature of the Leica DL8 and one of the more interesting consumer camera lenses to have been produced over the last 20 years or so.  It is very good but not perfect although I think we can probably agree that perfect is the enemy of good.

It allows the DL8 to be used at low ISO sensitivity settings indoors and permits greater foreground<>background separation than is possible with kit zoom lenses.

 

 

 

 

 

 

 

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