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02-07-2014, 07:50 PM   #16
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See my comment (#3) on that thread.


Steve

---------- Post added 02-07-14 at 07:05 PM ----------

As for appropriate focus system, the AF focus confirm may be adequate with maximum apertures to about f/2.8 using center focus point. You can expect lower precision and uncertain accuracy with lenses faster than that. Live view with focus peaking will provide a much better option on the order of what can be attained with a well-calibrated split image focus screen. I consider both to be equivalent, though it is hard to use focus peaking off tripod.

In any case, I think I can safely state that fine focus with lenses faster than f/2.8 provides a significant challenge to the AF system as well as to manual focus with the stock focus screen*. I can also relate my personal experience of not being able to reliably attain accurate focus with faster lenses until I replaced the stock screen with the Katz Eye product.**


Steve

* The stock screen has DOF no less that for about f/4 regardless of a faster maximum aperture of the lens mounted. Attempts to manual focus a fast 50mm or 85mm lens is an exercise in frustration. The situation is not much better at the wide end where the small viewfinder frame provides a miniature view of the subject.

** I have been active on this forum for a number of years and am of the opinion that most of the complaints regarding "soft" lenses are the result of missed focus.

03-09-2014, 03:36 PM   #17
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QuoteOriginally posted by stevebrot Quote


As for appropriate focus system, the AF focus confirm may be adequate with maximum apertures to about f/2.8 using center focus point. You can expect lower precision and uncertain accuracy with lenses faster than that. Live view with focus peaking will provide a much better option on the order of what can be attained with a well-calibrated split image focus screen. I consider both to be equivalent, though it is hard to use focus peaking off tripod.

In any case, I think I can safely state that fine focus with lenses faster than f/2.8 provides a significant challenge to the AF system as well as to manual focus with the stock focus screen*. I can also relate my personal experience of not being able to reliably attain accurate focus with faster lenses until I replaced the stock screen with the Katz Eye product.**
...........

* The stock screen has DOF no less that for about f/4 regardless of a faster maximum aperture of the lens mounted. Attempts to manual focus a fast 50mm or 85mm lens is an exercise in frustration. The situation is not much better at the wide end where the small viewfinder frame provides a miniature view of the subject.

** I have been active on this forum for a number of years and am of the opinion that most of the complaints regarding "soft" lenses are the result of missed focus.

Thanks for your input.
Well... you suggest that most "problems" with the image quality of old MF lenses are due to poor focusing.
I guess there is some (much?) truth in what you wrote. You seem quite experienced, and you seem to know a lot about operativity of vintage MF lenses, used with recent (Pentax) digital bodies.
So i am going to ask you something more...

First, an update:
i decided to go for an "exibition" K-5 II body, equipped with the standard WR zoom.
It is like new, and was used for demostrations in a swiss shop. The shutter count is 1200 ca. I bought it for a nice price, and the parcel was posted from Germany, hence i had to pay no extra taxes.
I am just getting acquainted with the camera, and at the same time i am rushing a couple of lens purchases, cause i am leaving for South East Asia for a long vacation, and i don't want to bring with me some of my valuable A and A* lenses, which are weighty and too expensive (to be hauled around in a cloth bag, with little care, and subject to high risk of theft).
I think i will bring with me a cheap Tamron 90mm Macro, and a Pentax 50mm f/1.4 M. Probably i'll take the 1.7x AF converter as well (though i would hate to damage it, or have it stolen!!).
All the other lenses must be zooms, and for good reasons:
1) less lens exchanges = less dust on the sensor
2) worth LESS money = less paranoia, and more likely to have the stuff with you (and not in the hotel room) in "complicate" circumstances
3) reduced bulk and weight (see the previous line)
4) easier operativity, cause all the zooms i'll bring have electric contacts and AF

I'd like to have with me a couple more MF lenses, but i prefer to have one more body instead.
That body will be the K200D, cause i have a cheap third party battery grip, and two sets of Eneloop batteries. It would be a life saver, if the K-5 II charger goes bust, or the battery can't be recharged because of no electricity. AA batteries can be found everywhere, and charged Eneloops last for very long!
The K200D would be a perfect body for old MF lenses (though it lacks the second wheel, which would be a bonus), but i found out that the focusing screen i bought LONG time ago, and which was never mounted, is actually made for the K10D, NOT the K200D. That's al least what's written on the label.
The focusing screen is a cheap chinese-made one, which looks exactly as an old time screen, with split-image and micro-prisms.
I guess that the K10D and the K200D have different screens, so i doubt i could install it on the other camera.
Using the K10D as second body is out of question, as the choice is based on the fact that the K200D uses AA batteries, and has a grip (which balances the camera, and makes the use in the field more comfortable, especially with the leatherette side handle i use).
Unfortunately i have a few days left. I'll leave in a week. No time to buy anything else on Ebay :-(
I just hope to get the new Sigma 10-20 f/4-5.6, and (at least one of) the two used "long" zoom, before i go.
Should have done it in time, but i wanted to get my hands on the K-5 II before committing to further purchases...

Now i have explained what's going on on my side, so that you (and other forum members) can give me a more informed advice.
Here are a few questions:
1) what's your experience with focusing screens dedicated to MF lenses? Did you buy a "brand" one because you know that cheap chinese ones are not_so_good, or just to be on the safe side?
2) how a replacement focusing screen affects the operativity with AF lenses? AFAIK the standard focusing screen, dedicated to AF lenses, is a lot brighter than an old-school screen, which has coarser grinding. Am i missing something?
3) Your answer seems to imply that the problem lies with the electronics of the camera as well. You wrote that with fast lenses the camera can't focus accurately. That's what i understand: the standard screen isn't good for manual focusing, AND the AF system has a kind of "sweet spot", when it comes to the max aperture of lenses: slow lenses hunt back and forth in low light, at the opposite side, lenses faster than f/2.8 have focusing problems too. If i correctly understand what you mean, the green focus-confirm light can't be always trusted, if a very fast lens is used.... Am i right? Is there anything i didn't get?

I'm stopping here... as we use to say in Italy, there is already too much meat roasting on the barbecue
Just a quick hand-on advice:
is it easy to exchange the focusing screen yourself (be it a K200D, a K10D, or a modern K-5)?
With a Pentax LX it was very easy.

cheers

P
03-09-2014, 04:58 PM   #18
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The focusing screen doesn't affect AF. A microprism or split screen focusing screen will only affect exposure (especially with spot metering) due to the "blacking out" part of the screen with "smallish" opening of some zoom lenses.

The AF sensor itself is located in the bottom of the lightbox and receives the image via a semi silvered part of the main mirror and a secondary mirror behind the main mirror.
03-09-2014, 05:35 PM   #19
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My old screw mount 55mm f1.7 is a stellar performer on my K5 and K5-IIs.

03-09-2014, 07:54 PM   #20
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Cyberjunkie, Since you're going on a trip far from home - I thought I would mention this: it is important to adjust the time on a digital camera to the correct local time. The computer in the camera uses the time to do daylight white balance; it knows what the color temperature should be on a cloudless day from where the sun is in the sky. I learned about this when I lent an Isd* to a friend for a trip to Africa from the US. He didn't adjust the time on the camera and his pictures just looked awful - all the wrong color temperature. When he got back to Houston the camera worked great. His Nikon did the same thing to him.

Since the US went on Daylight Savings time today everyone in this country needs to check the clock on their cameras. All my Pentax cameras had the right time - but the Canons and Kodaks were wrong.
03-10-2014, 08:02 AM   #21
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QuoteOriginally posted by HoustonBob Quote
Cyberjunkie, Since you're going on a trip far from home - I thought I would mention this: it is important to adjust the time on a digital camera to the correct local time. The computer in the camera uses the time to do daylight white balance...
Good to know about it.
I have seen that the K-5 II has two settings for date/time: "Home" and "Destination".
I'll check how you can switch from one to the other.

ciao

Paolo
03-10-2014, 08:54 AM   #22
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I checked my K10D, and the time did not change. I'll check again when the old daylight saving time date arrives. It must be hard coded in the firmware.
03-10-2014, 09:13 AM   #23
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Here's a shot with the K17mm fisheye at f/8 using a K-x (12mp). This lens isn't regarded as the sharpest lens, yet you can clearly see it is out-resolving the sensor. See that dot in the middle? Here's a crop of that. This is a JPEG right out of the camera. Your lens collection will function spectacularly on your K5 ii.

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03-10-2014, 10:44 AM   #24
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Hmmm. K-3 and S-M-C Takumar 85mm f/1.8, 1/15 @ f/2.8, natural light, no PP.
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