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03-25-2013, 05:03 PM   #1
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jinfinance focusing screen

Hello guys, so i finally got the opportunity to buy this screen but before i press the click and confirm the sale, i would like some input....
k20d is the camera to use, and smc-m 50mm f1.4 and smc-m 35mm f2.8 are my all around lens....
so, there is no way i can affor the type S screen from canon /katseyes/focusing screen.com

i've read some problems about being able to see with it on higher aperture values, but... since i'll only use those in broad daylight, i dont that will be a problem to me

i also read about messing up metering.
i ask if anyone can help me out with this and tell me how my camera will work with auto focus lens (the kit lens) with this screen.

thank you very much in advance for your support

http://www.ebay.co.uk/itm/Dual-Split-Image-Focus-Screen-4-Pentax-K10D-K20D-i...item518dbb4028

and
Diagonal Split Image Focus Screen Pentax k10D k20D DS | eBay




Last edited by Akarak; 03-25-2013 at 05:31 PM.
03-25-2013, 06:07 PM   #2
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I have the (k20d) K3 focusing screen w/ grid. I only use with manual focus lenses so cannot say about AF.
Spot metering is affected--but the amount is predictable--just test your lenses. e.g.,

0 e.v., at f/2
+1/2 e.v. at f/2.8
+2 e.v. at f/4
+3 e.v. at f/5.6 and above

I bought it about 1 year ago--at the time they were very responsive/helpful. I think it is well made.
Only 1 minor item--I wished the grid lines were darker. Hardly show in my faster lenses.
03-25-2013, 07:24 PM   #3
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I have their screen on my K10D. It does darken at small apertures, but in daylight is OK to f5.6. It hasn't affected my autofocus or exposure at all. The only regret I have is that I put it in myself and scratched it.
03-25-2013, 08:54 PM   #4
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but what do you guys recommend for most accurate focusing? diagonal or horizontal? what about dual prism? i honestly don't understand the differences but the diagonal and horizontal (i learned photography on a p30 and it had an horizontal focusing screen)

I don't care if it gets darker as i twist the aperture ring, it doesn't turn the blades until i click (or dof preview of course) so i honestly don't care if it's dark above f5.6 or 3.5 even!!

i just really don't want miss shots because of focusing issues (i photograph some concerts and besides not being able to use a flash, i'm not even allowed to) so i don't want to carry on this stock focusing screen "hit or miss" quest for photographs, it is really frustrating

03-25-2013, 10:26 PM   #5
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I prefer horizontal because that's what every manual focus camera I've ever had, except for one, was equipped with. The one I had that was diagonal was quickly replaced. My favorite though is horizontal split with a micro prism collar.

Another nice thing about manual focus screens is that they also give you a quick confirmation of your AF. This is another reason I prefer horizontal because I usually try to choose a vertical line to focus on if possible, whether I'm using AF or MF.
03-25-2013, 10:48 PM   #6
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It really comes down to personal preference. I have both the single diagonal split image screen and the dual split image screen (one in K10 the other in my *istD. I think the dual split image screen gives a betters indication of when things are out of focus, because the screen shows a complete wedge out of alignment as opposed to a single discontinuity in the image. Also note that in discussions with Rachel Katz she indicated that the most accurate indications are achieved when the split is at right angles but unless you are always shooting vertical lines iris somewhat irrelevant because nothing is ever perfectly ati right angles any ways
03-26-2013, 07:21 AM   #7
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QuoteOriginally posted by Akarak Quote
I don't care if it gets darker as i twist the aperture ring, it doesn't turn the blades until i click (or dof preview of course) so i honestly don't care if it's dark above f5.6 or 3.5 even!!
This is true for all k-mount lenses, but not M42 lenses. They don't have the aperture lever your camera requires to hold the aperture open while focusing. I actually prefer M42 to K- and M- series lenses, since they don't require stop-down metering.

I have a 1000mm mirror lens with a fixed aperture of f/10 which would be nearly unusable with a regular split-prism. Heck, it's nearly unusable no matter what equipment you have.

If you plan on sticking to your two lenses, go for it. That looks like a tremendous deal. However, if you save up some money in the future and find yourself considering a new lens, I'd get the KatzEye with OptiBrite first. It costs about the same as a very good old lens (or very cheap new lens), and it will help you take better pictures with the lenses you already have, especially in a dark concert hall.
03-26-2013, 08:22 AM   #8
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QuoteOriginally posted by Akarak Quote
i've read some problems about being able to see with it on higher aperture values, but... since i'll only use those in broad daylight, i dont that will be a problem to me

i also read about messing up metering.
i ask if anyone can help me out with this and tell me how my camera will work with auto focus lens (the kit lens) with this screen.
I have one in a K-x & it works about as good as the KatzEye in my other K-x. Doesn't seem to affect the center-weighted metering, which is what I usually use. It does start to suffer from prism blackout around f:5.6, but most split-prism screens do. (The KatzEye starts blacking out around f:8) I think you'll be fine with it.

03-26-2013, 08:26 AM   #9
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Keep in mind that you will most probably need to change the shim for the focus screen as well ... or else you will be front/back focusing when using the viewfinder.
What size you need now ... depends on the focusing screen you get ... you have to try with different sizes until you find the right one.
03-26-2013, 08:40 AM   #10
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QuoteOriginally posted by Akarak Quote
tell me how my camera will work with auto focus lens (the kit lens) with this screen.
Autofocus is a completely separate system, located underneath the mirror. The focusing screen has no effect on it whatsoever. That said, you will have a little difficulty seeing your subject when zoomed all the way in, as the max aperture on the kit lens at 55mm is f/5.6.
03-26-2013, 10:45 AM   #11
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QuoteOriginally posted by Akarak Quote
but what do you guys recommend for most accurate focusing? diagonal or horizontal? what about dual prism? i honestly don't understand the differences but the diagonal and horizontal (i learned photography on a p30 and it had an horizontal focusing screen)

I don't care if it gets darker as i twist the aperture ring, it doesn't turn the blades until i click (or dof preview of course) so i honestly don't care if it's dark above f5.6 or 3.5 even!!

i just really don't want miss shots because of focusing issues (i photograph some concerts and besides not being able to use a flash, i'm not even allowed to) so i don't want to carry on this stock focusing screen "hit or miss" quest for photographs, it is really frustrating
I am used to horizontal and just turn the camera if the subject only has horizontal edges.

The "darkness" problem happens to all focus screens in some way - they all compromise. It's an aperture problem, not a low light problem. When the lens maximum aperture is not that big (large f number), half of the split-prism will turn black. You can sometimes adjust your eye position slightly and the blackout stops. My P3n is pretty bad here even at f5.6, I don't know why, but with a Katz-Eye on my DSLR I can usually use my mirror lens with a 2x converter, which is f16. That shouldn't work either. The stock focus screens get dark but black out well beyond where you'd ever use them. The Canon EE-S just gets darker and darker.
03-26-2013, 12:48 PM   #12
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QuoteOriginally posted by mrNewt Quote
Keep in mind that you will most probably need to change the shim for the focus screen as well ... or else you will be front/back focusing when using the viewfinder.
What size you need now ... depends on the focusing screen you get ... you have to try with different sizes until you find the right one.
but im getting a focus screen to fix that.... :|

that's what happens with my stock screen!!! the subject is in focus, i click and the backround is focused....


damn.. getting this screen is worthless then?.... i just want to pop it in and go.
03-26-2013, 12:54 PM   #13
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QuoteOriginally posted by Akarak Quote
but im getting a focus screen to fix that.... :|

that's what happens with my stock screen!!! the subject is in focus, i click and the backround is focused....


damn.. getting this screen is worthless then?.... i just want to pop it in and go.
Ummmm ... a new focus screen will NOT fix your problem ... ...
Unless you are extremely lucky and find one that has the right thickness to compensate for your back-focus.

Invest in shims - cheaper too if you are in US.
03-26-2013, 01:36 PM   #14
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... damn, it's like i've been researching to fix my focusing problems with my 50mm f1.4 and now people are sugesting diferent solutions... i feel so lost now, and really sad.

i dont know what to do...!
03-26-2013, 02:24 PM   #15
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Don't dispair! All is not lost.

A shim is just a tiny sliver of metal that acts as a spacer for your focusing screen. If the screen is not in exactly the right place, it will cause front/back focusing, and you need to add or remove shims to get it to the correct position. They only cost a couple $s (or or or whatever).

I doubt your stock screen is back/front focusing. If you're shooting your 50mm f/1.4 wide open, the focal plane is tiny. If you're not spot on, it's not in focus at all. The stock focusing screen doesn't make the distinction between in-focus and out-of-focus clear enough for you to nail it at f/1.4.

In other words, your stock focusing screen is probably accurate, but not precise. An aftermarket focusing screen which is not shimmed properly would be precise, but not accurate. Don't worry! Installing a focusing screen is not difficult. Getting the shims right isn't hard, either. It's just tedious. You can't just "pop it in and go," but it's not brain surgery, either.
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