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10-19-2013, 05:39 PM   #16
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QuoteOriginally posted by p38arover Quote
Ahh, that's the problem. I studied electronics when electrons were still new.
Me too, just not so much on electron... valves, more on silicon based devices.


Last edited by Ex Finn.; 10-19-2013 at 06:00 PM.
10-19-2013, 05:59 PM   #17
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QuoteOriginally posted by Ex Finn. Quote
Me too, just not so much on electron... valves, more on silicon based devices.
I learned on valves, too. I recall the instructor telling us that transistors were probably a passing fad - the days of the OC71, etc. I still have some OC71 transistors - with the glass case.
10-19-2013, 06:30 PM   #18
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QuoteOriginally posted by p38arover Quote
i learned on valves, too. I recall the instructor telling us that transistors were probably a passing fad - the days of the oc71, etc. I still have some oc71 transistors - with the glass case.
Why!:
edit: I know, for the same reason my dad still has all of his old tubes and tube manuals.

Last edited by Ex Finn.; 10-19-2013 at 06:35 PM. Reason: trying to make the W an upper case.
10-19-2013, 06:40 PM   #19
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Maybe I'm a hoarder.

I just never got around to tossing them out. I wouldn't be surprised to find drawers of transistors I stripped from surplus computer boards I bought from US electronic disposal stores in order to be able to get cheap transistors back in the 60s and early 70s. Heck, I used to buy ICs from the UK and then tested them to see which gates worked, cut off the leads of the faulty gates, and stacked them on top of others to make, for example, a composite quad NAND gate that worked. ICs were just so expensive in Australia in the 70s.

I did give away all my valves - but I still have the Mullard and Philips valve manuals.

10-20-2013, 07:45 AM   #20
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QuoteOriginally posted by p38arover Quote
tested them to see which gates worked, cut off the leads of the faulty gates, and stacked them on top of others to make, for example, a composite quad NAND gate that worked
Now that right there is some serious dedication!. And speaking of NAND gates, I could be a hoarder also because I just pulled this out of my wallet.
I have had it since early 80`s

Last edited by Ex Finn.; 11-11-2014 at 05:45 PM.
10-20-2013, 02:33 PM   #21
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Heaven forbid. I've never seen one of those cards before.
I did go and check my component drawers yesterday and I do have glass-cased OC71 transistors and transistors pulled from old computer cards back in the 70s.

Some of the OC71 have had the paint scraped off to use them as photo transistors. Those ones have the clear silicone grease filler. Some others have a white filler and couldn't be used as photo transistors.
10-20-2013, 03:21 PM   #22
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Mine had the G shim. My Katzeye seems to want something like the A shim. I built one up out of brass and tape which seems to work fine. Some day I'll order the set, US parts are supposed to be in the same town as me.

QuoteOriginally posted by p38arover Quote
Maybe I'm a hoarder.

I just never got around to tossing them out. I wouldn't be surprised to find drawers of transistors I stripped from surplus computer boards I bought from US electronic disposal stores in order to be able to get cheap transistors back in the 60s and early 70s. Heck, I used to buy ICs from the UK and then tested them to see which gates worked, cut off the leads of the faulty gates, and stacked them on top of others to make, for example, a composite quad NAND gate that worked. ICs were just so expensive in Australia in the 70s.

I did give away all my valves - but I still have the Mullard and Philips valve manuals.
I used to have more of that stuff until I moved a few times.
10-20-2013, 03:50 PM   #23
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I think I'll try a few more shots but using a tripod and Yvon Bourque's focus test cards and several lenses. I'll get an email off to Pentax Australia today re the shims.

Re electronics, the trouble is I have moved a few times - including a 3-year overseas posting - and I've still got the stuff.

10-20-2013, 05:57 PM   #24
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QuoteOriginally posted by p38arover Quote
Heaven forbid. I've never seen one of those cards before.
You had to be a Matsushita trained warranty tech. to get one.
Anyhow, back to your quest for those elusive shims.
10-21-2013, 10:13 AM   #25
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QuoteOriginally posted by p38arover Quote
My K-7 was second hand when bought and there were scratches around the clip so I assume the screen had been changed back and forth. The clip isn't very secure. I once dropped the camera a short distance onto the carpeted floor when the strap came off and the screen came unclipped.
It does that - I have battle scars on my EE-s screen to prove it. Mine was a drop from about a metre onto a marble temple floor

Basically you want to start with live-view - that comes off the sensor so get that in focus first. Use the live-view magnifier to get a distant object well in focus, ignore everything else for now. Then check that the viewfinder (phase detect) focus agrees. A bit of trial and error twiddling with the fine tuning offsets may be needed depending on the lens mount. The bleep and flash run off this and have nothing to do with the focusing screen. Then adjust the diopter slider until any graticules (or bits of crap) on the focus screen are sharp. Lastly shim the focus screen until the image through the viewfinder is also sharp when the other two methods show focus. There are two separate clip frames there so make sure that you are placing the right shim in the right place.

The stock screen is rubbish with fast lenses (faster than about f2.8) - basically you can't tell when things are in focus. And some old lenses do refuse to focus to infinity and may need a bit of mechanical tweaking of their focus end stop - ideally I like my manual lenses to turn just a little bit past infinity.
10-22-2013, 09:11 AM   #26
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Shims

QuoteOriginally posted by p38arover:
Does the (XXXX) normally have a focusing screen shim?
Yes. And in general, the presence of a shim is a 'good' thing. All bodies are designed for a 'medium' shim as the default configuration to allow the assembly process to correct for the normal variances in components. Manufacturing each body with the precision needed to eliminate minor assembly adjustments would be extremely expensive.

I consider it a good thing to discover a new body had a shim other than the norm provided focus is OK, as it would indicate that during assembly or QA sample testing someone checked and an adjustment was determined necessary to meet PASS/FAIL criteria.

If there was any indication that an non-normal or no shim was present or that the screen was miss-handled in a 'pre-owned' body I'd consider it cause to suspect there had been other than 'skilled hands' involved -- especially if it was not acknowledged during a sale. (There's ample evidence on-line that folks that don't understand the process are messin' with focus screens -- cheap third party screens make the process too tempting to resist. I've got two bodies picked up VERY cheap from people that tried to 'improve' focus and finally just gave up. Both were offered with an aftermarket split image screen as a upgrade! )

Shims don't fix lens issues, they match the VF focus screen to the sensor surface. Auto focus doesn't involve the VF screen image -- and a miss-adjusted diopter setting doesn't affect AF.

H2
10-22-2013, 02:32 PM   #27
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QuoteOriginally posted by kh1234567890 Quote
The stock screen is rubbish with fast lenses (faster than about f2.8) - basically you can't tell when things are in focus. And some old lenses do refuse to focus to infinity and may need a bit of mechanical tweaking of their focus end stop - ideally I like my manual lenses to turn just a little bit past infinity.
Strange - I expected that focussing would be easier with a fast lens. What focussing screen do you use in place of the stock screen?
10-22-2013, 03:37 PM   #28
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QuoteOriginally posted by RobG Quote
Strange - I expected that focussing would be easier with a fast lens. What focussing screen do you use in place of the stock screen?
https://www.pentaxforums.com/forums/pentax-k-5/142241-best-screen-ever-manual...anon-ee-s.html
10-22-2013, 07:21 PM   #29
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So is this screen what you're talking about? Looking at the options for the K5 I am actually more interested in a split-focus screen, but I suspect that it may not work well with my f5.6 mirror lens, which is the main reason I'd want one. The mirror lens is not AF so I need to be able to set the focus manually - which is difficult with the stock Pentax screen. However, if the type-S screen gives a better idea of focus without needing a split, that would be worth considering.
10-23-2013, 05:12 AM   #30
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QuoteOriginally posted by RobG Quote
So is this screen what you're talking about? Looking at the options for the K5 I am actually more interested in a split-focus screen, but I suspect that it may not work well with my f5.6 mirror lens, which is the main reason I'd want one. The mirror lens is not AF so I need to be able to set the focus manually - which is difficult with the stock Pentax screen. However, if the type-S screen gives a better idea of focus without needing a split, that would be worth considering.
That was my exact problem - focusing with a 300mm f5.6 mirror and the stock screen was very difficult and with my mirror lens the viewfinder phase detect focus assist did not work. I tried a viewfinder magnifier, this was a bit of an improvement but was difficult to use when wearing glasses. Changing to the Canon EE-S screen solved the problem completely.
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