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10-03-2008, 06:20 PM   #16
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"and I can assure you the stock screens are accurate for manual focusing and AF. "

Sloppy reply there no, i don't think they are, as critical focus on the focus screen does not match focus on the sensor. They are only good *enough* to help in composition.

And he can check his diopter adjustment easily by taking off his lens, aiming at a white wall and then focusing his eye on the black frame lines and adjusting diopter until they are as crisp as can be, if that helps him, i'd be glad for him, but i lost my faith in focus screen accuracy, and i do not have a supply of shims to pick the correct shim, and if i did i am 100% sure the correct shim will be thinner than the one i have in my K20D. I just gave up properly seating screens with selfmade shims

If i had said set of shims, i would fit me a split prism screen instead of the original screen, for ultimate aid, the crazy thing is if i could get those shims, i think my AF zooms would be in grave danger of making it to market place :/

10-03-2008, 06:20 PM   #17
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QuoteOriginally posted by IsaacEastgate Quote
1. The camera has started frontfocusing while using manual lenses and shake reduction. It doesnt seem to affect digital lenses, but my 50mm suffers from just a smidge of disagreement between the sensor and viewfinder which seems irreparable. Very annoying, just as i got good at fast focusing i can no longer trust my viewfinder (i cant just compensate, the amount of front focusing is random, sometimes non at all if i point the camera down or something)
To me it seems like the sensor is moving forwards or backwards because the shake reduction has done something bad.

2. No temporary raw file in live view mode. You know how when you take shots and then go into white balance, the last shot is there for a reference? Not in live view mode it seems... more evidence of an ill thought out function
So, if the viewfinder shows the correct focus or not, even though it is not agreed with the sensor. Which one is correct? Does the AF system right?

As for the LiveView, the K20D is only partially implemented and is one of the weakest designs on the market, Tv and Av cannot be changed after entering the mode, there is no AF operation indication, there is not Live Histogram for viewing and of course you cannot change WB in the LiveView mode. According to the user manual, it cannot be used in hot weather for long and operation would be terminated if the camera feel it to be too hot..
10-03-2008, 07:07 PM   #18
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QuoteOriginally posted by IsaacEastgate Quote
1. The camera has started frontfocusing while using manual lenses and shake reduction. ...
OK, so you could focus accurately with this camera before, so something has changed.

Has the focusing screen come lose? It is hinged at the back and could perhaps have moved a trifle downwards at the front where it is (supposed to be) clipped in place?
10-03-2008, 09:10 PM   #19
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QuoteOriginally posted by creampuff Quote
C'mon, the OP did not indicate if he had changed his focusing screen from the original one that came with the camera, so where can the error arise, when we're talking about manual focusing?
It could have been poorly adjusted at the factory.

Also, as I've observed several times, the default focus screen shows too much DOF with fast lenses. this is trivially easy to demonstrate: aim mount a lens with f/2.0 or better, set it wide open, point at some text at a 45% angle, count how many lines are in focus in the viewfinder, then take the picture and count again. It's going to be off by a *lot*.

10-04-2008, 05:22 AM   #20
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Thanks for all your replies! I have removed the focus screen once for dust blowing so ill check whether its in the right place.

I did a shoot yesterday around a disused hospital (quite dark for most of it, very quick shots), and after a while of focussing i got pretty fast and accurate (HSM hands?), i think they were in line as i got some pretty perfect hits.

Very confusing. If it is the focusing screen that is out then AF should be fine, i am just worried whether it is possible that the shake reduction system is accidentally allowing the sensor to move forward and backward.

I'm going to take a look at some of the test charts and see at least if the AF confirm is correct.

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