Just Published - Rediscover Understanding MTF Charts

[TommyWeir]

Re: The actual article - very useful and a clear cogent explanation.  I've always wondered about them and was glad of the Cliff's notes approach.  Very good.   Contrast vs resolution, another decision range to add to the many that seem to define photography.

[Bart_van_der_Wolf]

Re: The actual article - very useful and a clear cogent explanation.  I've always wondered about them and was glad of the Cliff's notes approach.  Very good.   Contrast vs resolution, another decision range to add to the many that seem to define photography.

Exactly, and that why it should be relevant for many types of photography. It also explains part of the Medium Format 'look', which has to do with larger detail (more magnified in the sensor plane), and thus higher MTF/contrast in the microdetail (more realistic at larger magnification output sizes, and because usually less magnification is required).

Subjects like MTF and limiting resolution were mandatory parts of my official education to obtain a license as Professional Photographer when such licenses were still required in my country.

Cheers,
Bart

[TommyWeir]

It also explains part of the Medium Format 'look', which has to do with larger detail (more magnified in the sensor plane), and thus higher MTF/contrast in the microdetail (more realistic at larger magnification output sizes, and because usually less magnification is required).

Ah.  Thank you.  The few times I've used Medium Format I've always had this sense of being 'in' the optics, like I'd dipped my head into the lens itself. Your note points to part of why, the lens is more enveloping given its relative scale to my eye, but it's the contrast in the microdetail that hooks you in.

[KLaban]

I have to admit that I find MTF charts very useful when buying lenses: better a review of the data than a very expensive mistake. Having bought the lens I do of course test to confirm there are no unexpected behaviours.

[digitaldog]

Re: The actual article - very useful and a clear cogent explanation.  I've always wondered about them and was glad of the Cliff's notes approach.  Very good.   Contrast vs resolution, another decision range to add to the many that seem to define photography.

+1. This isn't a topic on my radar but I read it anyway and learned some new concepts. Even if I never use them, I'm glad I spent the minor amount of time reading the article! It's kind of shocking that people feel the need to spend time bitching about a piece that does nothing but add to one's understanding of the topic of photography. I guess such people practice the 'ignorance is bliss' approach to life and learning and other's have to spend more time replying in agreement than just reading the piece and learning. Sad but so common these days.
This seems so appropriate in light of the complaints:


Learning is not attained by chance. It must be sought for with ardor and attended to with diligence. -Abigail Adams

"It is better to say nothing and be thought a fool than to open your mouth and remove all doubt".- Abraham Lincoln

[Mark D Segal]

Andrew, I gotta start collecting these quotes of famous authors ending some of your posts; they're classics.

[jeremyrh]

Yes, the forum elicits responses.  His seemed devoid of much of anything beyond snark and when asked to clarify, he descended into name calling.

Not really, he made a joke based on the beginning of Michael's article, and when confronted with a holier-than-thou response from one of the forum "big hitters" declined to comment further. Then he got banned.

[jeremyrh]

Andrew, I gotta start collecting these quotes of famous authors ending some of your posts; they're classics.

[Mark D Segal]

Not really, he made a joke based on the beginning of Michael's article, and when confronted with a holier-than-thou response from one of the forum "big hitters" declined to comment further. Then he got banned.

Nope, please re-read Replies 7, 8, 9, 10 for the correct sequence of the conversation and the real (and only) reason the Moderator intervened.

Anyhow, the constructive side of this discussion is that there are members who still believe (a) that MTF charts can be useful, and (b) the reposting of this article of Michael's was appreciated. It's not to say that every member has to agree with every editorial decision made on this website - that would indeed be a real impossible stretch, but good to know what clientele there is for what kinds of material.

[Eric Myrvaagnes]

Just imagine what the forum would be like if every member posted "I'm not interested in this" in every thread in which he/she had not interest.   

If I did that, I'd never have time for photography!

[jeremyrh]

Just imagine what the forum would be like if every member posted "I'm not interested in this" in every thread in which he/she had not interest.   

If I did that, I'd never have time for photography!

And yet, here you are.

[SteveArnold]

I am an optical engineer and photographer, but my specialty is not imaging optics. I learned quite a bit from this post about reading lens manufacturer's MTF charts, but MTF itself was not really defined.

In a line pattern, modulation is the ratio min/max of brightness. An imaging lens transfers the object line pattern to its image line pattern with some loss of modulation. Thus "Modulation Transfer.

Modern lens design software can produce theoretical MTF charts for free with a keystroke. Theoretical MTF is useful for comparison, but as-built MTF can never be as good as theoretical.  MTF is degraded by lens manufacturing tolerances, assembly tolerances and AR coating performance. It also depends on focus and zoom position.

P.S. I am also a mathematician, which is a requirement to pass LULU's Turing test.