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02-05-2016, 04:52 AM   #16
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Thanks for all your help!

I always focus manually. I've never tried auto-focusing my film or digital cameras.

How difficult is it to replace the focusing screen? I looked up KatzEye, and discovered it's gone out of business, so I'd have to use something else. I'm leery of doing something major to my K10D - though it may be necessary. Before I go ordering any focusing screens, though, I'm going to experiment with my film lenses.

02-05-2016, 06:02 AM   #17
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You can get something like Pentax A 50mm f1.7 or Pentax A 28mm for very reasonable prices. These are manual focus lenses, good image quality.
Samyang also currently makes manual focus lenses, which have very high image quality.
Regarding focusing screens, there are a couple of threads and even youtube videos. I remember one youtube video where the guy made a bunch of mistakes as he went along. Definitely more of a "how NOT to" than a "how to" video.
With focusing screens you have to be careful not to touch anything with your bare hands, as it can leave a lasting mark. Only use tweezers and only hold the screen on the edge, where it won't be seen through the viewfinder anyway. You can get some focusing screens from places like Jin Finance, Focusing screens com, or even on ebay (these are usually really cheap, and some people have good experiences with them). Note that a focusing screen may darken the viewfinder if you are using slow lenses (slow lens=lens with a high minimum f-number, like f4 or f5.6 and higher), as most of these manual focus screens are made for fast lenses (f2.8, f1.4)
02-05-2016, 08:16 AM   #18
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QuoteQuote:
The focus seems just a bit off. Not enough crispness to the photos.
  1. The original 18-55 was designed for the use with the 6MP sensors of its time. I think with the 10MP sensors of the k10/K200/K-m it is resolutionwise at the limit. For the 12/14/16MP sensors, Pentax changed the optical design. I don't know whether you use the first or the second version.
  2. Even the second version lacks a bit of sharpness used fully open. Aperture closed down 1-2 steps, it can deliver quite sharp/crisp pictures. My K200D (about the same firmware as the K10D) in P or GREEN mode tends to prefer fast exposure times. This means, in conditions not a bright summer day at noon, it will most likely work fully open or 1/2-1 step down. This should not be a problem for you, as you told you work in M mode most of the time.
02-05-2016, 08:53 AM   #19
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OK - let's make sure this is clear. If you manually focus you rely on the focusing screen being the exact distance needed from the lens that the focal plane of the sensor is. Shimming is used to ensure this but with autofocus it is less critical that it is "exact" and the screens lack the level of critical resolution that older style screens have. This results in 'close enough' syndrome - where the shims may not be exact and the focusing screen gives acceptable looking focus that is misleading. In addition, the focus confirmation system has to be fine tuned as well - often per lens to get the exact results needed. Last but not least the Diopter correction on the eyepiece needs to be correctly set. I recommend something at infinity focus for initial setting of the diopter.

Once you understand this - you understand why a replacement screen may be a better choice if you do a lot of manual focusing. This is particularly true if the camera does not support focus peaking in live view.

However it also points out that replacing the screen means trying to ensure that the focusing screen is at the exact correct distance (which may mean experimenting with shims and looking at test shots).

As someone else pointed out, one of the reasons for this is that traditional split prism screens tend to darken in the center as the lenses get slower. Even f/3.5 may be too slow for some screens.

02-06-2016, 02:22 PM   #20
osv
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QuoteOriginally posted by Photogoof Quote
I always focus manually. I've never tried auto-focusing my film or digital cameras.

How difficult is it to replace the focusing screen? I looked up KatzEye, and discovered it's gone out of business, so I'd have to use something else. I'm leery of doing something major to my K10D - though it may be necessary. Before I go ordering any focusing screens, though, I'm going to experiment with my film lenses.
i swapped out the focus screen in my k10d, which still wasn't accurate, i figured out that the new screen needed to be shimmed, which i tried to do with paper strips, it turned out to be a disaster

if you have the budget for a dslr with liveview, or better yet, a mirrorless camera with a good evf, it'll revolutionize your manual focusing experience.
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