Very helpful, Paul. Thanks for the (excellent/detailed) reply! Other approaches are welcome as well.
On Sat, Sep 6, 2014 at 5:36 PM, Paul Stenquist <[email protected]> wrote: > Hi Dareen, > > Answers interspersed. > On Sep 6, 2014, at 5:05 PM, Darren Addy <[email protected]> wrote: > >> I've never messed with the AF Fine Adjustment before, but I think I >> need to on the K-3. So those of you that have experience in this >> area... >> >> First, I'm wondering if the procedure is the same on K-3 as it has >> been for other Pentax models? If so, I don't need to limit my Googling >> to the K-3. > > It’s basically the same. There may be some slight differences in the menu > access, but the nuts and bolts of it are the same. >> >> Secondly, this works with third party lenses also, right? I've got 3 >> Sigma EX to 2 Pentax in the AF department. > > I don’t know. I don’t own any third party autofocus lenses. But if the camera > recognizes them for shake reduction, I would think autofocus adjustment would > work as ewll. > >> >> Thirdly, am I correct in thinking that this is of no use on manual focus >> glass? > > You are correct. It merely fine tunes autofocus to eliminate backfocus or > frontfocus conditions. > >> >> Fourth, what is your procedure? I'm thinking camera should be locked >> down on a tripod and I'm wondering what you use for a target. I've >> seen scales (like a tape measure or yardstick) angled at a 45 degree >> angle, with a vertical target that is perpendicular to the sensor >> plane at the focal point. At what distance do you do the measurement? >> Minimum focus distance? Medium focus distance? I'm also guessing you >> do this with the lens wide open so as to be able to most accurately >> define the in-focus point. What is your procedure on zooms? > > I use a 13 x 19 sheet of good paper, printed with a scale of lines > approximately 3/8-inch apart. The lines cover the middle 2/3 of the sheet, > but right in the center there is a blank area of about three inches square. > In the center of the blank square is a single red dot of abotut 3/16 inch > diameter. This is the focal point. I set the paper on the floor of my deck in > bright shade. Then I mount the camera on the tripod. I place the camera about > three feet away for a wide lens like the 16-50 and about 7 feet away for a > long lens like the 60-250. I use single-point focus with the center dot > active. I elevate the tripod head so the camera is looking at the focus dot > at an angle of about 45 degrees. I test most lenses in the middle of the > focal length range, but check at the wide and long ends as well. Generally, > they’re very close. If there’s a discrepancy I’ll favor the focal length I > use most. I look at the results on a large monitor and try to judge how many > lines on each side of the dot are in focus. The forward lines won’t look the > same as the rearward lines even when the focus is about the same. So you’re > looking for sharpness. I try to count out which line is definitely out of > focus. For example, for the 60-250 at 150mm, it might be line three or four. > For the 16-50 at 35mm, it might be line six. Hope this helps. > > BTW, it’s worth the effort. >> >> I'll stop with the questions now. Any light that you can shed... >> thanks in advance! >> >> -- >> Photographers must learn not to be ashamed to have their photographs >> look like photographs. >> ~ Alfred Stieglitz >> >> -- >> 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. -- Photographers must learn not to be ashamed to have their photographs look like photographs. ~ Alfred Stieglitz -- 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.
