New "old Design" from Leica, 50mm F1.4 Summilux

Grok's analysis of the MTFs:

MTF Analysis Report: Lens Performance at f/1.4, f/2.8, and f/5.6
1. Overview
This report evaluates the optical performance of a lens across three apertures—f/1.4 (maximum), f/2.8 (intermediate), and f/5.6 (narrower)—using MTF graphs. The MTF measures contrast (modulation) as a percentage (0–100%) for spatial frequencies of 5, 10, 20, and 40 lp/mm, representing coarser to finest details, respectively. The horizontal axis ("Y'[mm]") ranges from 0 mm (center) to 21 mm (edge), indicating field position across the image. MTF is plotted for sagittal (solid lines) and tangential (dashed lines) structures under white light at long focus distances (infinity).
2. Graph Details
  • Vertical Axis: Contrast (% modulation), from 0% (no contrast) to 100% (perfect contrast).
  • Horizontal Axis: Field position (Y'[mm]), from 0 mm (center) to 21 mm (edge or corner, depending on format).
  • Curves:
    • Solid lines: Sagittal MTF (radial details).
    • Dashed lines: Tangential MTF (perpendicular details).
    • Multiple curves per aperture represent 5, 10, 20, and 40 lp/mm, assessing contrast for coarse to fine object structures.
3. MTF Performance by Aperture
3.1. f/1.4 (Maximum Aperture)
  • Center (0 mm):
    • MTF is near 100% for all frequencies (5–40 lp/mm), indicating excellent contrast for both sagittal and tangential details.
  • Mid-Field (3–12 mm):
    • Coarser details (5, 10 lp/mm) maintain high contrast (60–80%), but finer details (20, 40 lp/mm) drop to 40–60% and below 20%, respectively, by 12 mm.
    • Sagittal MTF outperforms tangential MTF, showing significant astigmatism.
  • Edges (12–21 mm):
    • Contrast drops sharply, especially for fine details: 5–10 lp/mm at 30–50%, 20 lp/mm below 20%, and 40 lp/mm nearly 0%.
    • Tangential MTF lags further, indicating pronounced astigmatism and edge softness due to aberrations (e.g., coma, field curvature) at this wide aperture.
  • Observations:
    • Excellent for low-light or portrait photography prioritizing center sharpness and bokeh, but poor edge performance and fine detail resolution limit its use for wide-angle or high-resolution shots.
3.2. f/2.8 (Intermediate Aperture)
  • Center (0 mm):
    • MTF remains near 100% for all frequencies, matching f/1.4 center performance.
  • Mid-Field (3–12 mm):
    • Coarser details (5, 10 lp/mm) maintain very high contrast (85–95%), dropping slightly by 12 mm.
    • Finer details (20 lp/mm) stay above 60–70%, and 40 lp/mm is around 40–50% at 12 mm, showing improvement over f/1.4.
    • Astigmatism reduces, with sagittal and tangential curves closer, but a gap remains, especially for higher frequencies.
  • Edges (12–21 mm):
    • 5–10 lp/mm retain 70–80% contrast, 20 lp/mm drops to 50–60%, and 40 lp/mm falls to 30–40%.
    • Sagittal-tangential difference persists but is less severe than at f/1.4, indicating reduced aberrations.
  • Observations:
    • Balances light gathering and sharpness, suitable for general photography (e.g., portraits, street) with improved edge performance over f/1.4 but less uniformity than f/5.6.
3.3. f/5.6 (Narrower Aperture)
  • Center (0 mm):
    • MTF is near 100% for all frequencies, consistent with other apertures at the center.
  • Mid-Field (3–12 mm):
    • Coarser details (5, 10 lp/mm) maintain 80–90% contrast, dropping minimally by 12 mm.
    • Finer details (20 lp/mm) stay above 70–80%, and 40 lp/mm is 40–50% at 12 mm, showing the best performance for fine details among the apertures.
    • Sagittal and tangential curves are nearly aligned, indicating minimal astigmatism.
  • Edges (12–21 mm):
    • 5–10 lp/mm retain 70–80% contrast, 20 lp/mm drops to 50–60%, and 40 lp/mm falls to 30–40%.
    • Astigmatism is virtually eliminated, with uniform performance for radial and perpendicular details.
  • Observations:
    • Offers the best overall sharpness and uniformity, ideal for landscapes, architectural photography, or high-resolution imaging requiring corner-to-corner detail, though it sacrifices light gathering compared to wider apertures.
4. Comparative Analysis
  • Center Performance: All apertures (f/1.4, f/2.8, f/5.6) perform excellently at the center (near 100% for 5–40 lp/mm), as aberrations are minimal here.
  • Edge Performance: Improves significantly as the aperture narrows:
    • f/1.4 struggles with edges, especially for fine details (20, 40 lp/mm < 20% at 21 mm), due to strong aberrations and astigmatism.
    • f/2.8 improves edge contrast (20 lp/mm at 50–60%, 40 lp/mm at 30–40%), with reduced but present astigmatism.
    • f/5.6 provides the highest edge contrast (20 lp/mm at 50–60%, 40 lp/mm at 30–40%) and minimal astigmatism, balancing aberrations and diffraction.
  • Astigmatism: Most pronounced at f/1.4 (large sagittal-tangential gap), reduced at f/2.8 (smaller gap), and nearly eliminated at f/5.6 (curves nearly overlap).
  • Spatial Frequencies:
    • Coarser details (5, 10 lp/mm) perform well across all apertures, with f/5.6 offering the most consistent contrast.
    • Finer details (20, 40 lp/mm) show the greatest improvement from f/1.4 to f/5.6, with f/2.8 as an intermediate step.
  • Light vs. Sharpness Trade-off:
    • f/1.4 prioritizes light gathering but sacrifices sharpness, especially at edges.
    • f/2.8 balances light and sharpness, suitable for versatile use.
    • f/5.6 maximizes sharpness but reduces light intake, ideal for bright conditions or tripod use.
5. Lens Characteristics
  • Strengths:
    • Excellent center performance across all apertures, making it versatile for centered subjects.
    • f/5.6 offers superior uniformity and edge sharpness, while f/1.4 excels in low-light scenarios.
    • f/2.8 provides a practical middle ground for general photography.
  • Weaknesses:
    • f/1.4 has poor edge performance and significant astigmatism, limiting its use for wide-field or fine-detail work.
    • f/5.6 sacrifices light gathering, requiring brighter conditions or longer exposures.
    • f/2.8, while balanced, doesn’t match f/5.6’s edge sharpness or f/1.4’s light intake.
6. Applications
  • f/1.4: Best for low-light or portrait photography, prioritizing center sharpness and bokeh, but expect softness at edges and for fine details.
  • f/2.8: Ideal for general photography (portraits, street, indoor), balancing light and sharpness with improved edge performance over f/1.4.
  • f/5.6: Optimal for landscapes, architectural photography, or high-resolution imaging requiring uniform sharpness across the frame.
7. Field Size Context
  • The 0–21 mm range suggests the lens is likely designed for a full-frame or similar format. For a full-frame sensor (36mm x 24mm), 21 mm might correspond to the edge or corner diagonally (diagonal ≈ 43 mm). On an APS-C sensor (approx. 23.6mm x 15.6mm), 21 mm could span the diagonal or height. Without the exact format, I assume full-frame, but this could vary.
8. Limitations
  • Exact spatial frequencies (5, 10, 20, 40 lp/mm) aren’t labeled on the graphs, but I’ve matched them to your description.
  • The lens model and sensor size aren’t specified, which could refine field position interpretation.
  • Performance at closer focus distances isn’t shown, only infinity focus.
9. Conclusion
This lens demonstrates strong optical performance, with aperture choice dictating its application. f/1.4 excels in low-light scenarios but struggles with edges and fine details. f/2.8 offers a versatile balance, while f/5.6 provides the best sharpness and uniformity, ideal for high-detail work. Photographers can select the aperture based on lighting, subject, and sharpness requirements.
 
As far as I think I know, the V2 summilux was the first Leica original design, while the original V1 wasn’t a Leica design. In this light, it would be somewhat of a nonsense for Leica to reissue a design that was never theirs.

I’m personally a big fan of the V1’s character/optical signature.
 
Pretty sure I have a v2 version got it for really cheap 10+ years ago $400. The body is beat up but the glass is clean. Sometimes I like the color it produces other times not so much... The B&W tones are amazing and is the reason I kept it and got a 50 1.4 ASPH v1 which I really love its its all around rendering color in particular...
 
Interesting.

I have several 50mm lenses that I can use on the M ... Elmar 5.0cm f/3.5 (with adapter), Color-Skopar 50mm f/2.5 (with adapter), Summicron-M 50mm f/2, and Heliar Classic 50mm f/1.5. They are all good lenses, and all make satisfying photographs. And I have four M bodies that I can use them on (and an LTM body). Never mind a Summicron-R 50mm f/2 (with adapter).

So I wonder that I am curious about yet another 50mm lens... 😵‍💫 I think it's addiction.

G
 
Ororaro said:
As far as I think I know, the V2 summilux was the first Leica original design, while the original V1 wasn’t a Leica design. In this light, it would be somewhat of a nonsense for Leica to reissue a design that was never theirs.

I’m personally a big fan of the V1’s character/optical signature.
Click to expand...
The Xenon 5cm F1.5 was "outsourced". The Summarit 5cm F1.5 was close to it, but the "exact optical prescription" is different, and it is coated. The v1 Summilux has the same basic 1-2-2-1-1 5/7 configuration, but is recomputed. It's like comparing the Nikkor-SC 5cm F1.4 to the Nikkor-SC 5cm F1.5, all new calculations required.

I would have liked to see a modern implementation of the Summarit 5cm F1.5. Multi-coated optics, and an improved formula for the 1-2-2-1-1 configuration. So many Summarits suffer from coating loss and damaged glass. We're lucky to have our good examples of it.
 
Given that this is potentially the first lens in their “Classic” re-issue series that already has an allocated 6-bit code, it will be interesting to see whether they’re going to re-use it or give this lens a new code. If it’s sufficiently different to the previous V3 lens because of modern coatings then it doesn’t sound like they have a choice but to give it a new code.
 
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The coatings are not very important, they were already very good in the early sixties. The Summilux 50mm v2, so the one from 1962, suffered from barrel distortion, that was the big problem. The v1, designed by TTH, but made by Leitz and made from 1959, was distortion free.
 
Lotsa illogical infos on the internet from this lens

First of all, it’s suuuuper fat. Nothing even remotely close to the original V1/2 in size. This reissue is a FAT AND HEAVY lens.

Secondly, no, the focus throw is not as long as the original, it is shorter. From infinity to 1m it is much shorter than the original from infinito to 1m. It seems long because 0.7 to 1m has been added. Basically, from infinity to 1m the focus throw is normal, nothing to cry about.

Very nice lens, but much more into noctilux 1.2 territory than into summilux territory, size and weight-wise.
 
simonOWO said:
What was negative MTF supposed to mean?🤣

Coma?

View attachment 4857416
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There is no negative MTF, although I sort-of like the idea (it could explain the behaviour of one Hanimex lens I had when I was starting out). MTFs are either modelled or measured at some points (this could be why some peaks on the curve are sharp) and then a curve is fitted to join them. The negative area is an artefact of the model or the algorithm that is used to fit the curve.
 
Sonnar Brian said:
leica-camera.com

Summilux-M 50 f/1.4 | Leica Camera US

A reinterpretation of a legendary, fast M-Lens combining a classic vintage look with state-of-the-art technology.
leica-camera.com leica-camera.com

I was expecting a v1 Summilux, which basically tracks for formula back to the Xenon.
"Not that one".
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Possibly a good thing all in all. I have a Summarit (also based on the Xenon) and wide open it is slightly soft and very low contrast. Stopped down a little it improves remarkably though. I like it but I bet many would not. Interestingly I also have a Schneider Kreuznach Xenon (slightly later I think, and in Exacta mount and it is very well behaved - sharp and contrasty at all stops. (Admittedly though it is an f1.9 not an F1.4 or 1.5).
 
peterm1 said:
Possibly a good thing all in all. I have a Summarit (also based on the Xenon) and wide open it is slightly soft and very low contrast. Stopped down a little it improves remarkably though. I like it but I bet many would not. Interestingly I also have a Schneider Kreuznach Xenon (slightly later I think, and in Exacta mount and it is very well behaved - sharp and contrasty at all stops. (Admittedly though it is an f1.9 not an F1.4 or 1.5).
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Summarit needs a cleaning. All of them have suuuuuper foggy elements 1 and 2. They dont seem fogged until you wipe them. The difference is drastic.

Clean summarit are not low contrast wide open. They are superb lenses throughout.
 
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