Archived posting to the Leica Users Group, 2003/11/20
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Peter, boke is, I believe, a Japanese word referring to the quality of the out of focus areas of a picture. Clearly boke is of little concern to photographers who are intending to maximise depth of field and shoot heavily stopped down as a consequence. However those liking to exploit DoF effects and users of wide aperture lenses find it to be extremely important. Lets face it if you are shooting 3 dimensional subjects with a lens at f1.4 over 90% of the negative area is likely to be out of focus and, if this huge OOF area contains harsh distracting blobs it draws attention away from the subject. Those using M lenses wide open are an important and extreme example of this type of photographer they probably chose Leica lenses for their superiority wide open. Some photographers consider it unimportant (but I suspect they are the ones who own lenses which are good in this respect;-)) There are many subjective and objective explanations of what makes good and bad boke, a web search of boke and bokeh should find a few. FWIW my experience would indicate that the Canon statement that the quality of the OOF background can be judged from the closenes of the saggital and meridional lines on the lens' MTF curve is spot on. There are lots of other theories but that is the one that agrees with my experience. Several manufacturers publish MTF curves for their lenses and there are several sites on the net with MTF curves. My experience is that lenses which show the two MTF lines close at maximum aperture produce the best boke - obviously having this characteristic optimised at smaller apertures is relatively less important simply because at the apertures less of the film area is OOF and the DoF effect will not have been a crucial part of the image in the mind of the photographer if he/she has chosen a small aperture. Other people's opinion will cerainly vary! There are already large digital sensors available at fantastic cost. Their superiority over smaller sensors is just as one would expect from the superiority of 35mm over minox or MF over 35mm. My opinion is that since the quality of the existing minute digital sensors is so high it is evident that the digital sensors are superior to an equal area of film. This means that in order to equal 35mm quality a sensor of 24x35mm dimensions will not be necessary. OTOH to mimic 35mm effects in depth of field a 24x35mm sensor will be necessary and these are still rather expensive! cheers Frank > from: Peter Dzwig <pdzwig@summaventures.com> > date: Thu, 20 Nov 2003 10:10:38 > to: leica-users@mejac.palo-alto.ca.us > subject: Re: [Leica] Digital Leica? > > Thanks, Frank, that's a clear, sensible answer. I wasn't thinking it > through. But, yes, what I ultimately want is 35mm DOF, anything else > doesn't make digital a substitute for film. The potential is however > huge. Yes, and I suspect that the yield figures for such chips would be > terrible at least at first...of course if the feature size were driven > down and the effective pixel count driven up as a consequence.... Does > anyone know what the current feature size is on these chips? > > BTW, all, since I don't parse "bokeh" I didn't understand most of the > previous comments - probably I don't want to :-) Save me - and all of us > - from 2000 emails explaining the meaning though ;-) > > Peter Dzwig > > Frank Dernie wrote: > > > Sorry Peter, > > Not on digitals with minuscule sensors (less than 3/8" wide) because > > f11 is already causing serious deterioration due to diffraction on 7mm > > focal length lenses (and must be difficult to manufacture an iris with > > an accurate aperture less than .025" diameter)! These sensors are a > > fraction of the size of minox film never mind 35mm, depth of field > > effects we are used to are impossible on them. It is surprising how > > good the enlargements are from such tiny "negatives" but if you want > > 35mm type DOF you will need a 35mm size sensor - very expensive at > > present, thought the "in betweens" (Nikon, Fuji and most Canon digi > > SLRs and Leica in a year or so) are an excellent compromise IME. > > cheers > > Frank > > > > On Wednesday, November 19, 2003, at 08:25 pm, Peter Dzwig wrote: > > > >> Looks like what I want, but I still want head-up info - and PLEASE > >> can we have a minimum stop smaller than f11. > >> > >> Peter Dzwig > >> > >> <big snip> > > > > > > -- > > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html > > > > > > -- > To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html