Great information. Thanks! Paul
> On Oct 5, 2020, at 1:10 PM, Igor PDML-StR <[email protected]> wrote: > > > Toine, > > First, let me say that you've got a very nice image! > > Paul has given a very simple explanation for the visual effect you (we) > observe. The further difference is (as Paul and a few others pointed out) > comes from the quality of the bokeh for the particular lens. > > As you probably know, the lead (actually, lead oxide!) in the lens glass > raises its refractive index. This allows for thinner lenses for a given focal > length. However, glass with a higher refraction index has higher dispersion > that needs to be corrected to make the lens achromatic (i.e. to minimize > chromatic [and spherical] abberations). > So, the combination of these factors *can* affect the bokeh. > > I've found this informative write-up on B&H website: > https://www.bhphotovideo.com/explora/photography/tips-and-solutions/understanding-bokeh > It gives a nice overview of what and how plays a role in the bokeh - with > some nice illustrations. > In particular, I didn't know that there are lenses with adjustable bokeh. > > Now, I was curious about how much is known scientifically about bokeh. > It is clear that at least some lens manufacturers pay attention to it. > > While I didn't do a deep comprehensive search in the scientific literature, > it seems, - not much seems to be published on that topic. > I've been able to find a few research articles adressing the theory and > theoretical calculation of the bokeh, but there are literally handful of > those. (And there was some research on how to fake bokeh, - I assume aimed at > creating "creative filters" for the phone-shooters.) > > Of those, one paper I looked at was Viktor P. Sivokon, Michael D. Thorpe > Optical Engineering, 53(6), 065103 (2014). > https://doi.org/10.1117/1.OE.53.6.065103 > (Sorry, it requires paid access. Feel free to contact me directly for detail.) > They were able to model bokeh mathematically (analytically) and compare > to the actual bokeh produced by lenses with a reasonable accuracy. > Here is one of their results: > http://42graphy.org/misc/BokehCalculated-SivokonThorpe.jpg > > Cheers, > > Igor > > > Toine Sun, 27 Sep 2020 10:56:03 -0700 wrote: > > Yes I agree thats the main effect. However this guy even includes lead in > glass as a pop factor. The rendering of bokeh also adds to the effect. > Zooms have a busy bokeh. > > > https://photographylife.com/the-death-of-beautiful-rendition-and-3d-pop-on-modern-lenses > > I can hardly see the difference in his before after shot with the slider > >> On Sun, 27 Sep 2020, 18:46 Paul Stenquist, <[email protected]> wrote: >> >> What is seen as 3D “pop” is just limited depth of field. And because >> primes generally have a larger app wide open than zooms, they give you > more >> control over DOF. >> >> Paul >> >> > On Sep 27, 2020, at 10:44 AM, Daniel J. Matyola <[email protected]> >> wrote: >> > >> > That certainly does "pop"! >> > >> > Dan Matyola >> > *https://tinyurl.com/DJM-Pentax-Gallery >> > <https://tinyurl.com/DJM-Pentax-Gallery>* >> > >> > >> > >> >> On Sat, Sep 26, 2020 at 2:54 PM Toine <[email protected]> wrote: >> >> >> >> I read a lot about primes vs zooms and old designs of primes. That >> >> should result in something like 3D pop. Never noticed it until today: >> >> >> >> > https://www.repiuk.nl/albums/new/#&gid=1&pid=005-899-20200926-imgp3095-edit >> >> >> >> I find myself lugging the DA*300 around on a daily basis. Maybe > because >> it >> >> pops. >> >> >> >> Do I need new glasses? >> >> >> >> Toine > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
