Diffraction Limit

Started Aug 28, 2013 | Discussions thread
GeorgianBay1939 Veteran Member • Posts: 4,044
Re: Diffraction Effects in a Real Lens-Camera System

Anders W wrote:

Detail Man wrote:

LTZ470 wrote:

Know a lot or think they "know" a lot? Love it when the school boys come out to play!

The usefulness of the above "calculator" has been debunked a multitude of times on DPReview Forums. The most recent example of that was on this particular recent Open Talk thread here:


... on which I posted this (if you really want to get into the numbers that actually matter):


It is a mistake to assume that some given website (including "Cambridge In Color" and "Luminous Landscape" must surely define shining "absolute truth". In fact, there are certain posters on these (as well as the LL) forums who actually understand these subjects well, and in fact know a lot more about these subjects than the offerings of many, many web-sites and web-blogs.

Complicated subjects cannot be easily simplified - and it is thus a mistake to wrongly assume so.

It is possible to better understand these subjects - but it is necessary to make the (non-trivial) effort of reading and thinking about and trying to understand what these folks are actually talking about.

I have myself provided you with a huge amount of specific and accurate information in the last few days, and linked you to even more reliable information. What Anders and Joe are saying to you is not untrue (though I do indeed think that there are just a few things in Joe's method of explanation that are well served by some further surrounding facts also being mentioned).

All in all, there is much to learn before one can even imagine to begin to "teach" others about complicated subjects. Humbling it can be. It has been for me. It likely is for any intelligent participant.

One of the most important aspects of learning, perhaps the most important of all, is to learn what it is worth paying attention to (and not) for the purpose of learning more. As an educator, I have long considered the stage where a person is capable of further learning without the aid of a designated teacher to be the ultimate objective of education. Consequently, I try to teach my students in such a way as to eventually make myself superfluous (at least in my capacity as their teacher). It gladdens my heart to see such a fine exposition of this (I am sure) shared philosophy of ours.

One of the things that sometimes makes me scared is when students start treating me as some kind of authority whose every word they will dutifully note no matter what. In such cases, I sometimes make a conscious effort to get them to challenge me in order to understand that they should never listen to me for whom I am (except, possibly, as a temporary short-cut) but only for what I can deliver in the way of valid arguments in support of my claims.

Well said, DM and Anders!

As an old f@rt learning how to take better pictures I found your contributions to this thread (and the locked one) to be very instructive and helpful.   So to you two, GB, PDB  and others ... Thank you for taking the time and making the effort to share your expert knowledge with us.   I suppose I should also thank the OP for prolonging the discussion. 

It is refreshing to see some disciplined discussions of complicated and difficult topics.  Some time ago I became quite disinterested in this forum because of the high incidence of opinion being presented as (false) fact and the puerile ad hominem attacks.   But then I started to be a bit more selective in what (and who) I read (and ignore) and now find great value in spending some time here.

Many thanks,


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