Article Index

Resolution

Please note that MTF50 results for APS-C and Full-Frame cameras are not cross-comparable despite the same normalized [0:1] range used to report results for both types of cameras.

 

Leica APO Telyt-R 180mm f/3.4 showed a very good overall performance in controlled environment. Performance across different cameras as well as picture frame was fairly consistent as well. Here the lens actually benefits from its rather slow maximum aperture - while most lenses, even telephotos, would show somewhat weaker results with wide open apertures and then pick up by f/4, for APO Telyt f/4 is (almost) the widest aperture. The lens shows very strong center image resolution throughout all aperture settings and all cameras, APS-C or FF. Border resolution remained also quite good, although you might notice a minor drop off in quality at f/3.4 on full frame cameras. The difference is quite small and by f/4 it disappears almost completely. One has to wonder though, how much such a small difference in MTF is going to make in real life situations.

 

Canon 400D (10Mp)

Canon 5D (12Mp)

Canon 5DMk2 (21Mp)

 

Looking at the chart crops, you will notice that there is basically no difference in border image quality from f/3.4 to f/8 on an APS-C body. The difference in quality becomes more noticeable on FF Canon 5D and 5DMk2 cameras, but again, the difference is quite subtle, and hence is unlikely to cause major problems in real life. But let's double-check.

 


Canon 400D (10Mp)


Canon 5D (12Mp)

Canon 5DMk2 (21mp)

 

The crops below compare image quality in a more natural setting. The images were taken using focus bracketing at around 50m with Canon 5DMk2 camera, which, with its higher res full frame sensor, should provide the higher levels of stress on the lens. Image resolution in the center is quite good, but this is not even interesting at this point, given how the lens performed in the lab. Borders show very minor difference here and there, but you really need to squint to notice them and most users will probably be completely indifferent to this. While I do not conduct particularly comprehensive tests to detect field curvature of a lens, the bracketed shooting gives at least a hint of whether the lens suffers from it or not. Given Telyt's performance and its focal length, the probability of image quality actually suffering from field curvature was already low, and after eyeballing the bracketed images I can't detect any noticeable shifts.

Note that the images below do not include crops from the top right corner - these were excluded on purpose for not confusing the readers, as the object in that area was located about a dozen feet further from the point of focus and so the image in crops looked softer because of that.

Interestingly, there are a lot of online discussions where users of APO Telyt-R 180mm f/3.4 swear that the lens performs noticeably worse at close focusing distances. Of course, the term 'performance' can mean many things, but in my experiments I did not notice significant resolution degradation at close distances. As a matter of fact, the MTF50 resolution tests that I recorded at distanced from ~3m to ~10m did not show significant variation. However, images recorded at closer distanced did have different character, with less definition, but we will cover that in the next section.

 

Center

f/3.4, Canon 5DMk2

f/8, Canon 5DMk2

L.L.Corner

f/3.4, Canon 5DMk2

f/8, Canon 5DMk2

R.L.Corner

f/3.4, Canon 5DMk2

f/8, Canon 5DMk2

L.U.Corner

f/3.4, Canon 5DMk2

f/8, Canon 5DMk2

 

Color Reproduction

The lens showed pretty good handling of lateral chromatic aberration, which was pretty minimal on all types of cameras. CA in the center never exceeding 0.4px across all aperture settings, while border CA hit about 0.5px at wider apertures and hovered at about this level through most other aperture settings. The levels of CA are so low that they should not even register in real life photography and hence should not be a concern.

 

Canon 400D (10Mp)

Canon 5D (12Mp)

Canon 5DMk2 (21Mp)

 

Color reproduction, under normal lightning conditions, was fairly good, with well balanced and saturated color palette. Images carried good amount of global contrast and tonal reproduction in midtones and shadows was fairly good as well. Generally, images looked perfectly fine, although I can't say that the rendering was particularly unique in any way. For my personal taste, the pre-APO Elmarit-R 180mm f/2.8 E67  produces rendering that is at least as good as with the APO Telyt-R lens, yet offers an extra strop when I need it. As mentioned earlier, there is one exception, when the APO lens seems to falter a little bit. The rendering at focusing distances up to about 5m seemed to carry less definition.  The lack of  definition  however was actually due to lower contrast levels rather then lower resolution per se.


ISO 100, 1/800, f/3.4, 180mm (100% crop)
ISO 100, 1/800, f/3.4, 180mm (100% crop)

DOF & Bokeh

When it comes down to DOF, there's one factor that works against APO Telyt-R 180mm f/3.4 more then anything else, and that is the 2.5m minimum focusing distance. As I have demonstrated with a number of slower lenses, the minimum focusing distance is more influention in rendering smooth OOF background then the maximum aperture - and even an f/4 lense can perform fairly well, if you manage to get it very close to the subject, There are obviously other factors that influence how the lens renders the background, specifically the aperture level used and the distance to the OOF background subjects. In Telyt's case, the 2.5m minimum distance and not so fast maximum aperture ultimately result in a bokeh that does not feel particularly special. The background is blurred, but not quite enough and so the background objects by large retain their shapes even at f/3.4. With smaller apertures and extended DOF the lens brings even more detail in and the bokeh starts to feel pretty busy. And at longer focusing distances the feeling of bokeh does not improve (I'd even say gets worse) as more and more backkground items start to pop into focus.

 

DOF @ 2.5m

ISO 160, 1/1250, f/3.4, 180mm (Canon 5DMk2)

ISO 160, 1/250, f/8, 180mm (Canon 5DMk2)

DOF @ 5m

ISO 160, 1/1600, f/3.4, 180mm (Canon 5DMk2)

ISO 160, 1/250, f/8, 180mm (Canon 5DMk2)

 

Aside from the somewhat iffy background rendering, as mentioned earlier, you should expect somewhat lower contrast when shooting with the lens at close focusing distances. This is not necessarily a bad thing if you're trying to make your subject pop out as a high contrast foreground against lower contrast background will accentuate the feeling. Aside from that, I see minor double contouring in the background, but it does not create too much distraction. OOF highlights have neutral; to neutral/smooth edge transitions and uniform fill. Overall, I can't say that this is the lens to use if you're trying to get the absolutely best bokeh and make your subject breathe with life, but you might be able to achieve decent results under right circumstances.

 

ISO 320, 1/320, f/3.4, 180mm (Canon 5DMk2)