All Forum Comments
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 23:20
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 23:09
Principally, the site is about helping and encouraging pentax Users to get the best out of their photography. Hence the exclusion, moslty, of talk of other marques and non-photographic subjects.
One can question things without challenging, which in itself could easily be seen as aggressive.
Anyway, let's not argue about it, so why not show us some of your f1.2 shots Smeggypants? The Your Photos section is ideal, but anything of an adult nature should be in the Gallery and flagged accordingly. That way, those who do not wish to see "adult" photos can exclude them if they wish.
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 23:00
Of course, sometimes the subject wavers about as well, so then it only helps to a limited degree. An example of this would be flowers waving in the breeze.
If I were to be shooting at open aperture then certainly sveral shots would be helpful is ensuring that at least one was spot on.
We rarely see shots at f1.2, so it would be interesting to see some where the extra wide aperture enhanced the image. The SMC Pentax 50mm f1.2 is especialy good for night shots, rendering point light sources as proper points and not smears.
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 21:16
The information about Pentax screens is accurate, and if we think for a moment it would be bizarre indeed if Pentax (or anyone else) made a lens but not a screen to assist in its use.
However, the screens are from the manual focus era, plus some are from the Z series, and may need adaptation.
In the wider sense, this is not too unusual. For example, Zeiss made a special pink-hued screen for thei 18mm lens for use in the Contarex.
These things are not essential, but they do help.
As rgeards the question of lens adjustments, the instructions do stress only do this if absolutely necessary and with my Pentax lenses and bodies I have not so far found it to be. My images are as crisp as anyone else's.
I suppose adjustment is more likely in other makes of lens used on a Pentax body, but even so I would hope that most of them were correctly set up. What concerns me is setting newbies off on a path that isn't needed and could get them into all sorts of trouble. Other marques often don't even offer the option, although incresingly on the higher priced bodies they do.
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 18:23
Comment by johnriley posted on Gallery photos at 28/05/2012 - 16:46
Comment by johnriley posted on Gallery photos at 28/05/2012 - 15:57
Comment by johnriley posted on Dive-bombing Kingfisher at 28/05/2012 - 15:54
It has been suggested that it's difficult to focus the 50mm f1.2 lens accurately, but unfortunately (or fortunately) I can't judge this as I don't have any difficulty focusing any lens. What I can say is the manual focusing is inherently inaccurate. Experiments have revealed (see Photo Technique in the 1970s)that generally people will focus any lens at quite different positions every time. Probably the way the eye adapts very quickly accounts for part of this, and for some a lack of acuity.
There are, however, and have been, various manual focus screens and although they may or may not be usable with DSLRs with adaption, there are some that may be helpful.
SC-26 is extra bright for use with telephoto lenses. SA-23/SA-26?SA-3 feature sharper microprism angles for easier focusing of lenses from f2.8 to f1.2. There are also lots of other options for those specialising in macro, super-telephoto, astronomy, architecture and so on.
Comment by johnriley posted on Focusing Screens at 28/05/2012 - 14:17
Comment by johnriley posted on Pentax Ricoh future at 28/05/2012 - 14:08

