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11-12-2013, 04:10 PM   #16
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Ok - this might be useful for either OP or someone else anyway. I used original screen as a template. To prevent a new screen from scratching I put on both side of it a thick, good quality transparent 3M tape. To cut I used very sharp surgical scalpel - repeatedly I sliced along the lines I drew with moderate pressure - and it simple cracked along the cut line. Cut it with slight margin and file it down with fine nail file. Note on my screen small crack on bottom edge - it happened when I did first cut - too much pressure ends in nasty cracks. Fortunately this is on the outside and its covered fully by retaining frame.. so my viewfinder is perfect. Just patience and slow motion - it took me about an hour to make it fit. If screen doesn;t fit - simple stick the tape again, cut excess of the tape on edge to be filed down - and adjust the size carefully by sliding that edge on a nail file placed flat.

I managed to create screen that is absolutely perfect - my focus now is so accurate that I can focus with macro lens on single PIXEL on my screen and it will be in perfect center of the sharp area. Also tested with telephoto lens - and what a breeze now. With my approach and good quality thick 3M tape you will not scratch your screen and furthermore - when you remove the tape you will also remove from the screen all the particles and craps that will get glued to the tape.

Good luck --manntax

This is how the focusing screen looks like :



and installed :



11-12-2013, 04:19 PM   #17
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QuoteOriginally posted by manntax Quote
Ok - this might be useful for either OP or someone else anyway. I used original screen as a template. To prevent a new screen from scratching I put on both side of it a thick, good quality transparent 3M tape. To cut I used very sharp surgical scalpel - repeatedly I sliced along the lines I drew with moderate pressure - and it simple cracked along the cut line. Cut it with slight margin and file it down with fine nail file. Note on my screen small crack on bottom edge - it happened when I did first cut - too much pressure ends in nasty cracks. Fortunately this is on the outside and its covered fully by retaining frame.. so my viewfinder is perfect. Just patience and slow motion - it took me about an hour to make it fit. If screen doesn;t fit - simple stick the tape again, cut excess of the tape on edge to be filed down - and adjust the size carefully by sliding that edge on a nail file placed flat.

I managed to create screen that is absolutely perfect - my focus now is so accurate that I can focus with macro lens on single PIXEL on my screen and it will be in perfect center of the sharp area. Also tested with telephoto lens - and what a breeze now. With my approach and good quality thick 3M tape you will not scratch your screen and furthermore - when you remove the tape you will also remove from the screen all the particles and craps that will get glued to the tape.

Good luck --manntax

This is how the focusing screen looks like :



and installed :
Hats off to you sir. I tried it once and it didn't work out nearly as well for me. I much prefer to buy screens already pre-cut.
11-13-2013, 02:56 AM   #18
J2R
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Yes, an impressive bit of work! I realize I have neither the dexterity nor the patience to do this, and know full well that if I attempted it, half way through I'd be wondering why on earth I didn't just pay the extra for the pre-cut one from focusingscreens.com.

I'm very interested in your use of tape there, both as a protection layer while cutting and as a means of removing dust. I have read so much of the delicate nature of these screens that I would not have been bold enough to do this, but your experience suggests there's no problem.

I'd be interested to hear how the new screen affects metering with the older lenses. My primary motivation for changing the screen was not, in fact, to do with focusing issues, but to improve exposure metering. I believe my screen (from the *ist DL) has indeed helped with this, making it much more linear than it was with the stock screen, although it's still not perfect. The curious thing is that it is now 'wrong' in the opposite way from with the stock screen, in that my M50 1.7 now underexposes slightly at f22 and overexposes slightly at f1.7.

Oh, and I believe my fears about needing to shim my screen were unfounded. The severe back-focusing problem I was seeing was, I think, user error! There is a tiny range through which I can turn the focusing screen and still have the centre point in focus, and when I tried it at the other end of this range, focus was spot on in the resultant image, so I think it's more to do with the tiny depth of field at f1.7.
11-13-2013, 05:06 AM   #19
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QuoteOriginally posted by DogLover Quote
Hats off to you sir. I tried it once and it didn't work out nearly as well for me. I much prefer to buy screens already pre-cut.
QuoteOriginally posted by J2R Quote
Yes, an impressive bit of work! I realize I have neither the dexterity nor the patience to do this, and know full well that if I attempted it, half way through I'd be wondering why on earth I didn't just pay the extra for the pre-cut one from focusingscreens.com.
Thank you both for the kind words.. I was always sort of DIY person so whenever I am in the need of something it always triggers in me that sort of skills. Besides - what else I had to lose anyway - I have a brand new LL-80 bought years ago and never used - so if I failed I could always have it installed Plus I saved about $100 and that is substantial to me being LBA victim :P


QuoteOriginally posted by J2R Quote
I'm very interested in your use of tape there, both as a protection layer while cutting and as a means of removing dust. I have read so much of the delicate nature of these screens that I would not have been bold enough to do this, but your experience suggests there's no problem.
Yes, but since the original focusing from Super A was larger - I had it tested on edges before I attempted it - and I didn't notice *any* change on both shiny and matt surfaces at all - so I went ahead.However, the tape I used was known to me as of very high quality that would for certain not lose the glue and left it behind. Below you can see how it looks like :



You can also see below that the screen is very clean - I can see only several microscopic spots that I didn't bother to remove. I took the photo of my K10D viewfinder with my K01 during focusing :



And my main goal was to achieve focusing accuracy with my newly acquired SMC A 50mm 1.4 - now I am very happy to be able to focus perfectly even in macro mode - here is the crop of a central area of the shot from the focusing above



QuoteOriginally posted by J2R Quote
I'd be interested to hear how the new screen affects metering with the older lenses. My primary motivation for changing the screen was not, in fact, to do with focusing issues, but to improve exposure metering. I believe my screen (from the *ist DL) has indeed helped with this, making it much more linear than it was with the stock screen, although it's still not perfect. The curious thing is that it is now 'wrong' in the opposite way from with the stock screen, in that my M50 1.7 now underexposes slightly at f22 and overexposes slightly at f1.7.
I didn't notice much difference in exposures with non A lenses and the currently applied compensation looks like they were before , with stock screen (K10D is known for that issue with manual lenses ) :

APERTURES : COMPENSATION :

1.4 - 1.8 + (0.7 ~ 1.0) EV
2.0 - 5.6 - (0.7 ~ 1.0) EV
6.3 - 22 - (1.0 ~ 1.7) EV

so basically I go from +0.7 EV to -1.7 EV. There are some odd exceptions but these can usually be addressed in PP

A and AF lenses are as they were perfectly exposing.

hope it helps!--manntax

DISCLAIMER :
I take no responsibility for any damage or losses that might be resulting after attempting any of the methods and/or using tools described above.. so please apply common sense first


Last edited by manntax; 11-13-2013 at 11:15 AM.
11-13-2013, 11:59 AM   #20
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QuoteOriginally posted by J2R Quote
I'd be interested to hear how the new screen affects metering with the older lenses.
QuoteOriginally posted by manntax Quote
APERTURES : COMPENSATION :

1.4 - 1.8 + (0.7 ~ 1.0) EV
2.0 - 5.6 - (0.7 ~ 1.0) EV
6.3 - 22 - (1.0 ~ 1.7) EV

so basically I go from +0.7 EV to -1.7 EV. There are some odd exceptions but these can usually be addressed in PP
Hmm looks like my initial tests were wrong.. I tested now with borrowed Takumar 50mm 1.4 and it looks like my compensation needs to be consistent +0.7 wide open and slowly goes up to +1.7 EV at f16. Previous tests were done with my SMC A in manual mode and sadly I did them outside and simple estimated exposure from the sample - it turned that they were JPG's and I had brightness up. Now re-did them looks like camera is simple underexposing but slightly less at wide open and more at full closing with intermediate values in between
.
I need to recheck my lenses because I also have a suspicion that it might be somehow lens- related. --manntax
11-13-2013, 12:09 PM   #21
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Interesting that you're not seeing linear metering either. For my part, I'm kind of resigned to the fact that accurate exposure metering with manual lenses is always going to be difficult on my K20D, whatever focusing screen I end up with. I just want to get it to the point where I don't actually miss any quick shots through gross exposure errors. I shoot RAW so normally if I'm there or thereabouts, I can tweak the exposure in post-processing and get the result I need. And if I have time, I can apply compensatory EV - I just need to get to know and remember where the errors are with each lens. And if I have even more time, I can simply resort to chimping!
03-10-2014, 11:55 AM   #22
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QuoteOriginally posted by manntax Quote
Thank you both for the kind words.. I was always sort of DIY person so whenever I am in the need of something it always triggers in me that sort of skills. Besides - what else I had to lose anyway - I have a brand new LL-80 bought years ago and never used - so if I failed I could always have it installed Plus I saved about $100 and that is substantial to me being LBA victim :P




Yes, but since the original focusing from Super A was larger - I had it tested on edges before I attempted it - and I didn't notice *any* change on both shiny and matt surfaces at all - so I went ahead.However, the tape I used was known to me as of very high quality that would for certain not lose the glue and left it behind. Below you can see how it looks like :



You can also see below that the screen is very clean - I can see only several microscopic spots that I didn't bother to remove. I took the photo of my K10D viewfinder with my K01 during focusing :



And my main goal was to achieve focusing accuracy with my newly acquired SMC A 50mm 1.4 - now I am very happy to be able to focus perfectly even in macro mode - here is the crop of a central area of the shot from the focusing above





I didn't notice much difference in exposures with non A lenses and the currently applied compensation looks like they were before , with stock screen (K10D is known for that issue with manual lenses ) :

APERTURES : COMPENSATION :

1.4 - 1.8 + (0.7 ~ 1.0) EV
2.0 - 5.6 - (0.7 ~ 1.0) EV
6.3 - 22 - (1.0 ~ 1.7) EV

so basically I go from +0.7 EV to -1.7 EV. There are some odd exceptions but these can usually be addressed in PP

A and AF lenses are as they were perfectly exposing.

hope it helps!--manntax

DISCLAIMER :
I take no responsibility for any damage or losses that might be resulting after attempting any of the methods and/or using tools described above.. so please apply common sense first
Thanks for all your suggestions. Lots of good ideas for a decent focusing screen. DIY is probably beyond my competence so will send my K10D away for installation.. Exposure issues are not likely to be an issue as I shoot Raw.
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