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Thread: Brightscreen diagonal split report

  1. #1
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    Brightscreen diagonal split report

    After a long delay I finally got the brightscreen diagonal prism screen I ordered in February. It works well though I probably should have gotten either a horizontal or vertical split. It's very hard to see the split and then line it up. It is accurate however.

    The screen was just a little too wide out of the box but with the permission of brightscreen to whittle it down a bit and still be able to return it I took about 1/2mm or so off the left side with a jewelers flat file. After doing so it fit fine.

    The screen does not have the two little pegs that are on the bottom of the original sony screen but still registers the same and no diopter adjustment was necessary.

    The screen consists of the split prism in the middle surrounded by two more circles then the rest of the screen. I've found that the outside circle is the best way to focus. I open the lens to full aperture, 3.4 for the contax 35-70 variogon and 4.0 for the leica 35-70 and focus using the outside circle by stopping where there is no shimmer or distortion on the short or the long side. As long as the light is reasonable this works well.

    I'm finding that the contax has a very wide variation of being in focus using the focus confirm on the chip. I doubt the chip has anything to do with it but maybe it does. The chip I'm using is the one with the variable aperture that is set by the aperture knob on the camera. (Aperture does appear to affect metering btw and it shows up correctly in the exif info.) I think this variation was true of the leica as well but I don't recall for sure. At some point I will play around with the different chips I have to see if it is a problem with all only one or two.

    The contax conversion is via a Leitax mount; I also did a 21mm distagon.
    The two leicas are via ebay bought adapters.

    Best,

    Mike

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    Re: Brightscreen diagonal split report

    Mike:

    I am surprised the screen had to filed to fit. I was considering getting the horizontal split screen but decided to get the Sony matt instead after reading some posts here saying it is much brighter than the stock screen and causes exposure issues. Do you have any problem with exposure?

    Alan

    Quote Originally Posted by docmaas View Post
    After a long delay I finally got the brightscreen diagonal prism screen I ordered in February. It works well though I probably should have gotten either a horizontal or vertical split. It's very hard to see the split and then line it up. It is accurate however.

    The screen was just a little too wide out of the box but with the permission of brightscreen to whittle it down a bit and still be able to return it I took about 1/2mm or so off the left side with a jewelers flat file. After doing so it fit fine.

    The screen does not have the two little pegs that are on the bottom of the original sony screen but still registers the same and no diopter adjustment was necessary.

    The screen consists of the split prism in the middle surrounded by two more circles then the rest of the screen. I've found that the outside circle is the best way to focus. I open the lens to full aperture, 3.4 for the contax 35-70 variogon and 4.0 for the leica 35-70 and focus using the outside circle by stopping where there is no shimmer or distortion on the short or the long side. As long as the light is reasonable this works well.

    I'm finding that the contax has a very wide variation of being in focus using the focus confirm on the chip. I doubt the chip has anything to do with it but maybe it does. The chip I'm using is the one with the variable aperture that is set by the aperture knob on the camera. (Aperture does appear to affect metering btw and it shows up correctly in the exif info.) I think this variation was true of the leica as well but I don't recall for sure. At some point I will play around with the different chips I have to see if it is a problem with all only one or two.

    The contax conversion is via a Leitax mount; I also did a 21mm distagon.
    The two leicas are via ebay bought adapters.

    Best,

    Mike

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    Re: Brightscreen diagonal split report

    Alan, Exposure is all over the place. Sometimes it's 1 or 2 stops from what is metered and other times 3 or more. I'm sure there is probably a pattern to be discerned but I usually shoot initially where I think it should be then adjust. In addition the need to drop back to wide open to focus sometimes leads me to waste a shot because I forget to move the aperture back to where it should be. Fortunately the camera is pretty forgiving for up to two stops if light is sufficient so exposure can be adjusted in post.

    As far as the screen goes I have also noticed that it is now offset slightly to the left and also slightly higher in the center of the screen as compared to the middle metering square. The left offset is probably due to filing but I didn't touch the vertical orientation at all.

    Mike

    Quote Originally Posted by apsheng View Post
    Mike:

    I am surprised the screen had to filed to fit. I was considering getting the horizontal split screen but decided to get the Sony matt instead after reading some posts here saying it is much brighter than the stock screen and causes exposure issues. Do you have any problem with exposure?

    Alan

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    Re: Brightscreen diagonal split report

    Mike, Unfortunate the screen still fails to hold registration. I had one of the pre-tab versions that shifted, and I'd hoped the tabbed version had cured that problem.

    I returned mine for the exposure inconsistency. I was considering giving the tabbed version another try, mainly for macro, but the failure to maintain registration would drive me up the wall.

    I could probably forgive the Brightscreen's registration and exposure inconsistency, and just use the screen on occasion, if it was a cheaper. Frankly, it would bother me to have a $175 bit of plastic being used only on occasion.

    Although not perfect, the type M and an angle finder at 2x does the job. I'd still like the occasional split screen, so I'm thinking of ordering a Hasselblad split-screen off ebay for $20 and cutting it down, although it would probably be too thick. I sent an email to the Chinese vendor/manufacturer for specifics.

    Graham

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    Re: Brightscreen diagonal split report

    I had earlier converted an old canon FD or FA screen for a sigma SD10/SD9 with success and have contemplated doing the same now. I may yet return this screen but I'm not giving up yet.

    The metering issues are not really screen related. They happen with the sony screen as well. Not sure what is going on but it could be that the difference in interior diameter of the tunnel inside the lens affects the meter much like a bellows does. There could be information passed from a sony lens to the camera to meter correctly that isn't passed by a converted lens. all the lenses I have converted, a 21mm distagon, contax 35-70, leica 35-70, leica 80-200 and a flektogon 50 have not metered consistently.

    The screen may alter metering but I would expect it to be consistent independent of lens issues and it does seem to be consistent with the 70-400 which is he only sony lens I am currently using on my trip.

    Mike

    Quote Originally Posted by GrahamB View Post
    Mike, Unfortunate the screen still fails to hold registration. I had one of the pre-tab versions that shifted, and I'd hoped the tabbed version had cured that problem.

    I returned mine for the exposure inconsistency. I was considering giving the tabbed version another try, mainly for macro, but the failure to maintain registration would drive me up the wall.

    I could probably forgive the Brightscreen's registration and exposure inconsistency, and just use the screen on occasion, if it was a cheaper. Frankly, it would bother me to have a $175 bit of plastic being used only on occasion.

    Although not perfect, the type M and an angle finder at 2x does the job. I'd still like the occasional split screen, so I'm thinking of ordering a Hasselblad split-screen off ebay for $20 and cutting it down, although it would probably be too thick. I sent an email to the Chinese vendor/manufacturer for specifics.

    Graham

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    Re: Brightscreen diagonal split report

    Mike,

    Regarding your screen movement, double check the screen tray. I recall the tray will stay closed, but an additional push will fully latch the tray.

    Graham

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    Re: Brightscreen diagonal split report

    I tried the focusingscreen.com screen on my A700, and it too shifted all over the place. It has no registration pins.

    Exposure was fine, but having a shifting screen and a prism full of dust now isn't what I bargained for. At least it was only $50...save your money.

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