Ken Rockwell, Has Posted A Comparison Sharpness Of Leica 35mm Summicron-M Lenses.

[*Mark*]

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Mr Rockwell is often technically accurate in his observations as long as you carefully review the test conditions. This is why I check his site, sometimes there is useful information.

 

His conclusions and analysis however are usually based on the assumption that his priorities and constraints must be everyones. He also changes these priorities daily or varies them according to his bias du jour.

 

I recommend reading his observations, but always draw your own conclusions based on what matters to you, and the conditions under which you operate.

 

Remember. " if you leave your mind sufficiently open, some will fill it with rubbish. "

Maybe even me.

 

Regards ... H

 

 

 

xt

 

Rockwell bashing is normal in online forums- since the days he argues for jpg against raw the the online experts hates him - but the posted picture was to much for my taste - i dont like tastless jockes with children from old men... But maybe this is normal for luf...

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[ho_co]

Some have counted too infinity, maybe even 2 times but Ken is the only one to have counted to infinity backwards...

Best line on the page, jacarape!

 

 

There's no need to dump on Rockwell. Sometimes he's fun to read. In one Nikkor review that I recall, he said something like, "Yes, the lens shows horrible distortion. But the point is, it's a lot less than you'd expect in a lens of this specification."

 

Translated, "Yeah, it's unusable for photography, but it could have been worse."

 

How can you not like a guy with logic like that?

[jaapv]

:confused:In this review I only see images of trees...

[pico]

[...] but the posted picture was to much for my taste - i dont like tastless jockes with children from old men... But maybe this is normal for luf...

 

Consider the eye of the beholder, Mark. It is not all about you.

 

Back to the subject - Rockwell's samples were about 36X, which is ridiculous. The 35mm format was never intended to be enlarged to such a degree and viewed as closely as his presentation. It's rather like viewing your mate with a microscope - how can that tell you anything about the look of the person (or lens)?

[gravastar]

................................. Honestly, how can you take someone seriously when they state...

 

"Even at f/2, everything is pretty much in focus with a 35mm lens"

 

Maybe the commission was for Postage Stamps?

 

 

Bob.

[Xmas]

Hi

 

It is good to have strong opinions and PJs need to make a iving or starve, but -

 

There are MTF charts for these lenses why do we need comparitive photos?

 

Note I'll give you thet a MTF chart is not everything, e.g. veiling flare wont necessarily show, but they are pretty objective.

 

Noel

[lct]

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Would you have MTF charts of v2 and v3 35/2 by chance? Just curious.

[storybrown]

Ken R doesn't write mainly for real foto pros or for artistes (although he often tries to boost some of these) but for a mass middle brow audience most of whom are swamped by market offerings, including many others who know a smattering & want to improve. Most of his pieces on Leica are all good ("best film camera" is a Leica according to him; M9 is wunnerful for what it is, &c), and anyone who is for Leica Inc staying profitable or becoming more profitable ought to be all for him, esp as he is not a fanboy for any maker & holds the shooter is the main thing. Plus, he has more pieces on Leicas than your avg quarter's worth of pop foto mags.

 

His style seems offensive to some, but I increasingly think they are mostly those who, without the audience, would like to believe themselves as much or more an authority for about the same audience as he is (so they take it personally), or who take themselves more seriously than he does. He's not hurting anyone, certainly, and, in the end, his opinion is one among others; who's the final authority? He's not EPuts - yes - but I've seen Puts slimed by wannabe technocrats on the Forum, also - it goes with the territory. Besides, looks like a pretty positive review - so, good for Leica. Be happy & do your own comparisons. Thanks for posting.

[deirdre]

* Ken Rockwell's camera has similar settings to ours, except his are: P[erfect] Av[Awesome Priority Tv[Totally Awesome Priority] M[ajestic]

 

* Ken Rockwell doesn't color correct. He adjusts your world to match his.

 

This was full of awesome and caused me to go into a giggling fit.

 

I have to admit a soft spot for Rockwell because I do completely agree with his review of the Mamiya 6. Well, I haven't tried one since I got my Leica, granted.

[pico]

Hi

 

It is good to have strong opinions and PJs need to make a iving or starve, but -

 

There are MTF charts for these lenses why do we need comparitive photos?

 

Note I'll give you thet a MTF chart is not everything, e.g. veiling flare wont necessarily show, but they are pretty objective.

 

Noel

 

MTF cannot show a lens' particular look, rendering, drawing. MTF metrics are misleading in other ways, for example they cannot show focus-shift because the lens is re-focused at each aperture (in real measurements, however not all MTF charts are from real tests - many are calculated theorems.) Nor can MTF show distortion and it disregards light fall-off.

 

Further, MTF is largely a measure of contrast rendition, which also has a lot to do with resolution, however even a lens that has relatively poor resolution can have an excellent transfer function across a reasonable aperture range, resulting in pleasing OOF or bokeh. For wide aperture shots at less than infinity, MTF cannot describe the rendition of the aperture in OOF highlights.

 

Finally, MTF is pretty much meaningless to large formats, or possibly reconnaissance and survey lenses which are qualified by other means - for example, they are always certified at widest aperture, even if they can stop-down.

[Xmas]

Would you have MTF charts of v2 and v3 35/2 by chance? Just curious.

Hi

 

Sorry no - Put's little hand book only provided one (MTF) for 'both' lenses he 'implies' they would be the same, and does not indicate a # for change over,

 

I'd have expected that if they changed the optics there would be a change in performance, so I'd be suspicious, though it would not normally be a large difference as both are double Gauss, a few years apart, - the glass catalogue did not alter much.

 

SInca I have use a J12, CV f/2.5 or preasph lux interchangably I'd not loose sleep on V2 versus V3 cron.

 

Noel

P.S. Don't have a scanner to hand - this is a web book, and the book is copyright...

[Chistoso]

I, for one, could not live through the day without informing myself with all the verifiable expert opinions expressed here by the elite group of experts who mostly verify their own expertise by assumption (our assumption that they are experts, they assume) as they attempt to negate anything anyone else might have to contribute that might be helpful to those, like me, seeking information and capable of evaluating its usefulness, but that might be new or different, thus threatening, to the self-proclaimed experts.

[stunsworth]

Sorry Chistoso, but that's not the point. Look at the time and effort someone like Puts or Reid puts into a review, and then compare it to the "review" by KR. It's not a question of self appointed "experts" pouring cold water on anything someone else might have to say, it's a case of a very shoddy, superficial review being promoted. If you find KR useful, fine, but don't mistake what he writes for the real thing.

[Xmas]

MTF cannot show a lens' particular look, rendering, drawing. MTF metrics are misleading in other ways, for example they cannot show focus-shift because the lens is re-focused at each aperture (in real measurements, however not all MTF charts are from real tests - many are calculated theorems.) Nor can MTF show distortion and it disregards light fall-off.

 

Further, MTF is largely a measure of contrast rendition, which also has a lot to do with resolution, however even a lens that has relatively poor resolution can have an excellent transfer function across a reasonable aperture range, resulting in pleasing OOF or bokeh. For wide aperture shots at less than infinity, MTF cannot describe the rendition of the aperture in OOF highlights.

 

Finally, MTF is pretty much meaningless to large formats, or possibly reconnaissance and survey lenses which are qualified by other means - for example, they are always certified at widest aperture, even if they can stop-down.

 

Well I not sure about your sympathy, e.g. when you have built your prototype (lens) as well as the normal MTF at infinity it would be normal to do variations, as well as taking photos. You would not necessarily refocus off axis or at different apertures.

 

They dont normally publish the variations, but the designer would look at them, think Zeiss describe some of this on their site.

 

Bokeh is subjective... The design software will do plots of this, and they could publish the signatures, perhaps if we asked them.

 

The MTF at the largest aperature is meaningful, the variation off axis is most significant.

 

Noel

[Xmas]

Would you have MTF charts of v2 and v3 35/2 by chance? Just curious.

Hi

 

Sorry no - Put's little hand book only provided one (MTF) for 'both' lenses he 'implies' they would be the same, and does not indicate a # for change over,

 

I'd have expected that if they changed the optics there would be a change in performance, so I'd be suspicious, though it would not normally be a large difference as both are double Gauss, a few years apart, - the glass catalogue did not alter much.

 

SInca I have use a J12, CV f/2.5 or preasph lux interchangably I'd not loose sleep on V2 versus V3 cron.

 

Noel

P.S. Don't have a scanner to hand - this is a web book, and the book is copyright...

[!Nomad64]

Ken Rockwell Facts....

 

* Ken Rockwell is the Chuck Norris of photography

 

 

Wrong, mate! Ken Rockwell is not the Chuck Norris of photography. It's Chuck Norris to be the Ken Rockwell of martial arts!

 

Bruno

[pico]

I probably erred when I wrote that the lens is refocused in MTF tests. I was thinking of the old military resolution test chart method.

[redbaron]

Just remember people, KR doesn't get paid for his knowledge or skill, but for how many clicks he generates.

 

Click, click, ker-ching...

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Hallo,

Look here: Interesting Leica gear

[ho_co]

EDIT--

Drat! I see at http://www.l-camera-forum.com/leica-forum/customer-forum/160965-ken-rockwell-has-posted-comparison-sharpness-2.html#post1580234, Noel has already said almost everything I do below in far fewer words while I was typing this!

 

 

 

MTF cannot show a lens' particular look, rendering, drawing....

Correct.

 

 

MTF ... cannot show focus-shift....

Nor can any other single-shot method.

 

 

... not all MTF charts are from real tests - many are calculated theorems....

No, not "theorems." Leica's MTFs are calculated from the lens designs; Zeiss's are measured. See Puts on the topic. Properly built lenses will be virtually identical to the calculated outcome.

 

If one feels that measuring is better than calculating a lens' performance, one would logically want to test each sample rather than relying on a single test.

 

 

... Nor can MTF show distortion and it disregards light fall-off....

Red herring. It isn't designed to do so; those tests are separate, just like focus-shift, color transmission, etc.

 

 

... Further, MTF is largely a measure of contrast rendition, which also has a lot to do with resolution, however even a lens that has relatively poor resolution can have an excellent transfer function across a reasonable aperture range, resulting in pleasing OOF or bokeh. ....

Complete muddle. MTF graphs relate contrast to a given resolution. "Pleasing OOF or bokeh" can't be graphed. It's in our own interpretation.

 

 

... For wide aperture shots at less than infinity, MTF cannot describe the rendition of the aperture in OOF highlights....

I think that's totally meaningless. As I understand it, MTF does not in any case "describe the rendition of the aperture in OOF highlights." If I'm right, your initial clause could be replaced by any other clause and the sentence would maintain the same meaning: "For blondes on sunny days..." or "For political leaders with no foreign policy experience...."

 

 

...Finally, MTF is pretty much meaningless to large formats, or possibly reconnaissance and survey lenses which are qualified by other means - for example, they are always certified at widest aperture, even if they can stop-down.

You may be right. Tell me about how lenses are "certified" or "qualified by other means." An MTF curve can tell you that a lens is diffraction-limited, which is what you want in cases like this.

 

 

Don't misunderstand, pico; what you're saying is mainly accurate but beside the point IMHO. It seems to me you're trying to condemn MTF by listing things it doesn't do.

 

MTF isn't a single number to compare all aspects of an optical design. MTF is the single simplest form (so far) to sum up a lens' performance. You're right, it doesn't include everything. But up till the middle of the 20th century, there was no way to tie 'resolution' and 'contrast' together to give an idea of how a lens' output looked. That's all MTF is: One quick and efficient way to tie together resolution and contrast. Unfortunately, discovery of the MTF concept has meant that today every manufacturer has the same goal in lens design, so we've lost the splendid distinction we had when Zeiss designers had one way of approaching things and Leitz designers had another.

 

 

Zeiss offers a good MTF primer in their "Lens Notes" from Dec 2008 and Mar 2009. I have a horrible time trying to negotiate their site, but maybe someone else can post the URLs.

 

Erwin Puts has an excellent and much more general page on the topic at lens testing.

[tdtaylor]

I'm not a KR fan, but if you take it tongue in cheek, and pass through the self promotion and hyperbole, his comparisons can be informative. And everyone has to admit, he is fabulous at getting people to view his site - by now, all of us And man, does he know how to fuel the fire.

 

I also do believe that those with much experience have the ability to separate out the chaff from the wheat, and many held in high acclaim, such as Mr. Reid and Puts have their detractors. After all, they both endorse Summarits, yet I would venture a large number of members would debate these finding.