Glad you agreed after all Richard. ;-) On Mon, Dec 1, 2008 at 1:29 PM, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote: > > ----- Original Message ----- From: "Peter K." <peterk727@xxxxxxxxx> > To: <rollei_list@xxxxxxxxxxxxx> > Sent: Monday, December 01, 2008 10:48 AM > Subject: [rollei_list] Re: Does the Quality of a Lens Affect Grain? > > > Yes, more grainy. It is simply not resolving as well in many instances > a result of not passing enough light (coatings) which can result in > grain. I am sure there are those that may say otherwise, but this is > my opinion. > > On Sun, Nov 30, 2008 at 8:07 AM, Elias Roustom <eroustom@xxxxxxxxxxx> wrote: >> >> I know there's no comparison between the quality of the lens on my Rollei >> 35 >> and my Rollei Giro 90, but is it possible that in addition to difference >> in >> contrast, the cheaper lens would make the images more grainy (or less >> smooth)? >> >> E. > > I think I understand what Peter is getting at but I _do_ disagree with > it. Film does not work that way. While some film as more than one coating, > generally to extend the latitude. More modern emulsions achieve the same > purpose with a mixture of silver particals. Also, generally modern emulsions > are thinner than those of the past mostly to improve sharpness. In the > older, thick, emulsions, the light striking the surface became diffused as > it passed deeper into the emulsion so that the image was sharp at the > surface but became more blurred as it went deeper. Of course, the light also > became attenuated as it was scattered so the overall image remained pretty > sharp. However, sharpness also decreased with increasing exposure. This is > the primary reason the film speed system in use now (ISO standard method) is > designed to give the minimum exposure that will result in good tone > rendition. > Grain also varies with average density becoming greater as the density > increases, another reason for keeping negatives on the thin side. > Now, its also true, and I think this may be what Peter is getting at, > that the sensitivity of the silver halide grains, and the size of the image > silver that develops from them, varies with their size. The finer grains are > less sensitive than the coarser ones. Also, grain tends to increase with > development time. So, an underexposed negative may look grainier than a > properly developed one. If the negatives from a blurry camera are being > developed more than those from a sharp camera in order to increase the > apparent contrast, that would also increase the grain. > > There is something also in the idea that an image which is confined > strictly to the surface may look grainier than one which extends into the > emulsion a bit since what we see as grain is actually the statistical > combination of many silver grains. When there are more to combine the imager > looks less grainy. Individual silver grains are nearly submicroscopic and > are not visible when using a grain focuser on an enlarger. What is seen > there is the "clumping" of grains at various depths in the emulsion. The > fact that visible and printible grain is the result of a stochastic process > also explains why the Callier effect exists. Simply that diffused light > striking the emulsion on one side is less likely to be blocked by the grains > at various depths, that is, by striking the surface at many angles, some > will be scattered and tunnel around the denser areas to wind up going toward > the lens where collimated light will be scattered away from the optical path > to the lens. All this is to say that grain is a physical effect not affected > directly by the nature of the image or lens. > > However, having said all that I agree more with the idea that a blurry > image may _look_ grainier than a sharp one because the eye is more more > likely to detect the grain in areas of continuous tone especially in the mid > grays. > > -- > Richard Knoppow > Los Angeles, CA, USA > dickburk@xxxxxxxxxxxxx > > --- > Rollei List > > - Post to rollei_list@xxxxxxxxxxxxx > > - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the > subject field OR by logging into www.freelists.org > > - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the > subject field OR by logging into www.freelists.org > > - Online, searchable archives are available at > //www.freelists.org/archives/rollei_list > > -- Peter K Ó¿Õ¬ --- Rollei List - Post to rollei_list@xxxxxxxxxxxxx - Subscribe at rollei_list-request@xxxxxxxxxxxxx with 'subscribe' in the subject field OR by logging into www.freelists.org - Unsubscribe at rollei_list-request@xxxxxxxxxxxxx with 'unsubscribe' in the subject field OR by logging into www.freelists.org - Online, searchable archives are available at //www.freelists.org/archives/rollei_list