Lens quality vs size

[Lanark]

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I just watched this video by Tony Northrup       about full frame vs smaller lenses.

He makes some good points about the larger lenses collecting more light due to 'basic physics'

But this also has me wondering about M series lenses which traditionally have very good quality ratings despite their small size - where is the trade off?

I feel like I am missing something in the way that lens size applies to a rangefinder?

 

 

 

[adan]

I didn't watch the whole video, since it was clear he was going to get into things beyond "quality." (crop factor, DoF, etc.)

Key point - some things related to "quality" and size are different when talking about film vs. a digital sensor. This was why, around 15 years ago, Leica was insisting they couldn't make a digital M (until forced by the market) and then had to offer retrofitted 6-bit coding for their legacy lenses, and first dip their toes in the water with the 1.33x crop-factor M8. And why they need to design "special" sensors rather than just buying Sony or Canon or Panasonic ready-mades, and some people report degraded corner quality using the same M lenses on, for example, a Sony with the same sensor size, compared to Leica film or Leica's custom-designed sensors.

However, yes, allowing unrestricted size for a lens give an optical designer more leeway to remove more aberrations and improve quality. Back in the film days, Zeiss was famous for the philosophy of "We will design the best lens possible with current technology, regardless of size." Leading to such monsters as the 21mm f/2.8 Distagon for the Yashica/Contax SLRs, or the 40mm Distagon v.1 for medium format. Either of which can be used as dinner plates .

https://www.clubsnap.com/threads/wtsell-lens-hasselblad-40mm-f-4-distagon-c-t-wiiidddeeeest-hassy-v-lens.1394378/

https://kenrockwell.com/zeiss/slr/21mm-f28.htm

Leica has felt their M lenses must conform to the ethos of "small camera/big pictures," and thus they have tended, historically, to trade off aberrations within a target design size. For example, allowing quite strong vignetting with the 50mm Noctilux f/1.0 in order to retain more resolution in the corners (and to some extent, the same for the 28mm Summicron). Or, in the era when Leicas were seen as "journalistic/documentary" cameras, letting the corner performance slide in some fast lenses, in exchange for maximum resolution in the center of the image.

ASPH elements, since about 1990 (and a very few hand-ground ASPHs earlier) have helped in keeping things small and good. Leica also uses more expensive special-property glass in some cases (one element of the 50 f/1.4 ASPH costs as much as the other seven elements combined, or so the story goes).

Leica has allowed some M lenses to grow a bit over the years. The 35 Summilux ASPH compared to the previous non-ASPH version from 1961, for example, or the new 75 Noctilux (I have medium-format lenses that are smaller ), or the 90 Summicron (the ASPH version front element fills the E55 diameter at the front - the non-ASPH allowed room for an engraved ring around the element within the same diameter, and weighed 20-60 grams less).

And in the SL system, Leica has adopted the Zeiss philosophy ("as large as necessary") - 50mm f/1.4 SL is 4x the volume of the 50mmf/1.4 ASPH for the M (and the M ASPH is slightly larger than the old non-ASPH version). I haven't used any SL stuff, myself - users do report those lenses are even better than the M equivalents.

[adan]

BTW - there is some real-world and up-to-date insight into size vs. quality in our own Thorsten Overgaard's interview with Leica chief optical designer Peter Karbe here (click through to Thorsten's page):

Including details of the trade-offs of using high-refractive-index glass to keep size small (but produce purple fringing) vs. using less exotic glass, but with more elements, to get a better result (but a longer lens structure).

[pico]

This ping-pong discussion encourages me to like my 4/3 Cosina 25mm ƒ0,95 more.

 

[TomB_tx]

This discussion reminds me of how satisfied I've been with my 1969 Summicron 50 v3 and tiny 1970 Summicron 35 v2, that I've used since new. Never had a complaint for decades until I got an M9, and started looking a detailed comparisons to modern lenses. But I've always gone back to these because of the size and familiar handling. In Modern lenses I prefer the 2.5 Summarit 35 & 50 for the same reason - but lately have been using the old ones more, and still love the images. I could have saved a lot by just enjoying the fine performance of what I had instead of getting lost in comparisons to others.

I've come to the conclusion that for me size and handling are also "quality of use" factors, and are more important that incrementally "better" image quality, considering how well the Mandler lenses perform.

[adan]

I'm with you, Tom. Just today got my lineup back to all-Mandler lenses (including tiny 90mm TE "thin"). Except for an also-compact C/V 35mm f/1.4 Nokton, which as a "modified" 35 Summilux pre-ASPH, gets honorary Mandler status in my book.

Although that does also include the massive 75 Summilux (which is big because, well, it is a 75 f/1.4, not for "quality" reasons as such). And the nearly-as-heavy 135 f/4 in its last version (built-in lens hood).

[Jeff S]

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13 hours ago, adan said:

Leica also uses more expensive special-property glass in some cases (one element of the 50 f/1.4 ASPH costs as much as the other seven elements combined, or so the story goes).

 

More than just a ‘story’ if you trust Peter Karbe...

https://www.shutterbug.com/content/leica-lens-saga-interview-peter-karbe-page-2

Jeff

[Gregm61]

Tony Northeup’s site Is all about.....making more money for Tony Northrup.

I consider people like him and Ken Rockwell as modern/internet versions of The National Enquirer and take what I hear others quote from his articles with about the same amount of seriousness.

”what I hear” from others, as in, I don’t go there/click on links, which is what his often provocative “headlines” are all about.

Edited March 3, 2019 by Gregm61

[earleygallery]

I’ve only ever watched one of his videos & it was so full of misinformation and bullshit I haven’t wasted time looking at any others.

 

[ckuwajima]

M lenses are 100% manual and mechanic, saving significant bulk necessary to accommodate autofocus and aperture control components.

Edited March 3, 2019 by ckuwajima
Clarification

[evikne]

4 hours ago, adan said:

Except for an also-compact C/V 35mm f/1.4 Nokton, which as a "modified" 35 Summilux pre-ASPH, gets honorary Mandler status in my book.

So this lens has a 0.7 m minimum focus distance? How do you think the image quality is at f/1.4, compared to the equivalent Leica lens?

I miss a 35mm f/1.4 lens, but Leica's 1 m focus distance was the reason why I chose the 35 Summicron pre-ASPH instead.

[TomB_tx]

I also use a 35 1.4 Nokton (MC) which I got for low light with my M9. I found at 1.4 the IQ was very similar to my 1970 35 Summicron at 2.0, and the Nokton at 2.0 had less vignetting and better sharpness. (However, I recently discovered my Summicron had slight front-focus - now being fixed by DAG - so that is likely the cause.)

The Nokton has flaws: barrel distortion and focus shift primarily. But I've had some very nice images from it. And the small size and good mechanical build make it a pleasure to use.

[adan]

Tom's CV351.4Nok(MC) description is about right.

It doesn't have exactly the same "dreamy, foggy" look of the 1961 Leica at f/1.4 (a bit more contrast, but still a bit glowy and fuzzy). The single-coated (SC) version probably matches that better.

It's one of those strange lenses where (at large apertures) the contrast makes details and tones "pop" with a 3D look at normal viewing distances - even if zooming in reveals them to be a bit streaky and fuzzy. Seems to be a Voigtlander Classic signature - the 75 f/1.8 has the same effect.

Regarding focus-shift, mine came dialed in for correct focus at f/2, with f/1.4 producing front focus, and 2.8-4 producing back focus, and from 5.6 on DoF hides the issue. So I tend to use it as an f/2 lens, with f/1.4 for "emergency-use only" - although it is not as bad as that may sound. Just depends on the situation (lighting, composition, etc. etc.).

[UliWer]

 

vor 22 Stunden schrieb adan:

...However, yes, allowing unrestricted size for a lens give an optical designer more leeway to remove more aberrations and improve quality. Back in the film days, Zeiss was famous for the philosophy of "We will design the best lens possible with current technology, regardless of size." Leading to such monsters as the 21mm f/2.8 Distagon for the Yashica/Contax SLRs, or the 40mm Distagon v.1 for medium format. Either of which can be used as dinner plates. ...

Leica has felt their M lenses must conform to the ethos of "small camera/big pictures," and thus they have tended, historically, to trade off aberrations within a target design size. For example, allowing quite strong vignetting with the 50mm Noctilux f/1.0 in order to retain more resolution in the corners (and to some extent, the same for the 28mm Summicron). Or, in the era when Leicas were seen as "journalistic/documentary" cameras, letting the corner performance slide in some fast lenses, in exchange for maximum resolution in the center of the image. ...

A main factor for the size of a lens is the diameter of the exit pupil; it does not only determine the lenses diameter but also its length. For optical design the exit pupil should be large enough to ensure the light hits the whole image format at an angle of 90°.  This would have been good even during film times, but for a digital sensor it's essential if one does not want to take the pains Leica took to design the sensor with a special microlens structure. Though an angle of 90° for the whole image format is not possible if the camera's bayonet is smaller. The M-mount, which was designed to allow to use the old screw-mount lens designs, is too small to allow an ideal angle for the light.

When Zeiss is mentioned one may have a look at the lenses for the original Zeiss Ikon Contax rangefinder. The Contax had an even smaller bayonet: ca. 36mm. When you compare the lenses for the Contax to contemporary Leitz lenses, one does not get the idea that Leitz lenses were very small. This is not only true for Contax 50mm-lenses which could be way smaller as they used the camera's focussing mechanism. Also Contax lenses with own focussing were significantly smaller than the Leitz equivalents: e.g. the 85 or 135 Sonnars compared to the 90mm Summicron or the 135mm Hektor or Elmar. The 1:2.8/35mm Biogon's housing was even much smaller than the very compact 1:2,8/35mm Summaron, so small that it's awkward to use - but it needed a huge rear lens element to "squeeze" the wide angle perspective on 35mm film. The rear element is so big that it won't fit into a digital M body, but the lens you see on the Contax is just 20mm long 

So the "ethos" of small lenses reflected a serious downside: the lens design had to "squeeze" the light though the small hole in the camera. To achieve this the lenses could be small, perhaps they even had to be small. 

[lct]

2 hours ago, adan said:

It doesn't have exactly the same "dreamy, foggy" look of the 1961 Leica at f/1.4 (a bit more contrast, but still a bit glowy and fuzzy). The single-coated (SC) version probably matches that better.

Yes but it has less glow (halos around highlights) and more flare than my Lux 35/1.4 v2. Adding to this focus shift, it's a lens i can hardly recommend except for its speed and size on mirrorless cameras. Other 35/1.4's are more expensive though. I would welcome a new version with same qualities as the new CV 35/2. FWIW.

[pgk]

6 hours ago, earleygallery said:

I’ve only ever watched one of his videos & it was so full of misinformation and bullshit I haven’t wasted time looking at any others.

Well, it appears that the link is another then, so just in case you are tempted, I wouldn't bother.

[mike3996]

I like how people bash Ken Rockwell but then take Tony Northrup's words as gospel

[SMAL]

vor 23 Stunden schrieb evikne:

So this lens has a 0.7 m minimum focus distance? How do you think the image quality is at f/1.4, compared to the equivalent Leica lens?

I miss a 35mm f/1.4 lens, but Leica's 1 m focus distance was the reason why I chose the 35 Summicron pre-ASPH instead.

The Lux ASPH has 0.7m close focus distance.

[evikne]

1 hour ago, SMAL said:

The Lux ASPH has 0.7m close focus distance.

I know. I had it for a short time, but I sold it. Because of the size, and because I now prefer the "Mandler-look". 😊

Edited March 4, 2019 by evikne

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Hallo,

Look here: Leica M

[SMAL]

vor 2 Stunden schrieb evikne:

I know. I had it for a short time, but I sold it. Because of the size, and because I now prefer the "Mandler-look". 😊

I don´t think you could call the FLE ASPH big and look wise the old pre ASPH are not pleasant imo. They are just too soft.