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Thread: View Finder-Focusing Screen_removal and cleaning

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    A royal pain in the bum! arthurking83's Avatar
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    View Finder-Focusing Screen_removal and cleaning

    I was blind and now I can see!

    Most people dont' realise it, but you can change the viewfinder screen(normally called the focusing matte screen in your camera. I think there are a few cameras that don't have changeable focusing matte screens though. (an internet search will answer that question, if you're unsure).

    Q; Why would I change the focusing matte screen in my camera?
    A: because!
    Actually because is actually the correct answer! There are many6 reasons why you'd want to change your focusing screen. They can be brighter, better for manually focusing with various visual aides.

    Focusing screen.com has the best site with visual representations as to what, how, and why(a third party matte screen helps).

    THIS webpage has the most comprehensive info and visual comparisons as to what each focusing aid does and how it works. I've been used to the split prism in Nikon's SLR's from way back, and the micro prism to a lesser degree. The biggest dissapointment I found when I first started using a DSLR about 4-5years ago. I didn't realise they don't come with focusing aids through the VF!

    I'm only going to discuss and display the images I took when I recently cleaned out my focusing screen a few months back. Reactions thread twigged my memory about this the past few days, and these images have been sitting idle on my PC since.. got to get my moneys worth out of them before they get deleted in a few months!

    First of all, what is a focusing matte(screen) and why do you need it. Look it up in you're Funk and Wagnell's or believe what I say(possibly at your peril ).
    As I understand it: they're an etched in-between screen overlay that assists the SLR operator in acquiring focus through the vf. They're position is between the lens and the prism(or pentamirror) that directs the image through the lens to your eye. They don't actually make any difference to the image formed on the sensor(or film) not in the same optical path. So with that they only aid you in focusing/seeing the image you want to capture. They don't help the camera(to capture a better pic) one iota!
    So if you were to change yours, then it's for reasons such as 'failing eyesight' more consistent manual focusing(if you do that) and so forth. It's not like a CPL which can alter how an image will be exposed.

    Where is the focusing matte screen?

    Inside the mirror box area of your camera and below the prism area. It's 'easily' removable(on cameras that allow you to do so) and is like a window to the prism area, acting like a barrier. It stops dust and specks getting onto the prism box, but I've found I get specks and hairs in there on the odd occasion. When that happens it's time to pull it out, blow out any crud and give the matte screen a quick clean too.
    The matte screen is the opaque looking window below the lens contacts.

    I give the mirror box area a quick blow out with canned air before I remove the matte screen.
    These images are not how I normally do it though!! These are the single handed versions of how to do it, as it's hard to operate another camera and hold the camera upright at the same time. Normally I hold the camera up in the air to allow any large particles to drop out as they're being blown on with the canned air straw.
    ***Note if you use caned air, never shake the can before use. Propellant discharges lay a white-ish residue. Easily cleaned off, but more work to do later***

    How is the matte screen held in place?

    ... a retaining clip around the perimeter on Nikon DSLR's. Note that it;s flat apart from one small raised bump, which is located conveniently at the front to assist in unclipping it from it's locked position. On Nikon cameras, the clip is almost impossible to see directly due to the foam sponge that runs along the leading edge of the mirror stopping/resting area. That foam sponge must never be damaged, as (I think) it acts a a vibration dampener for the mirror as it swings up and stops against it.
    You do have to rest on it and compress it a little as you release the retaining clip.
    **Note the two small screws near the sponge. They can be removed apparently to give a clear path to the retaining clip. I can't remove them, and I do have enough tools to do that, but I found them to be too tightly locked and risked stripping the cross heads. Easier to leave them and do it the normal way. Those screws hold the sponge in place.

    lever the retaining clip upwards and it swivels up and out of the way to remove the matte screen.

    *note: sometimes the retaining clip comes out of it's dedicated spot, and completely out of the camera. No problem. it's easily located back into it's position to swivel up and down. notice the splayed ends. These ends are located into small holes at the back of the matte screen recess*



    This is the matte screen assembly, with the retaining clip removed. On Nikon cameras there may be a very fine spacer. I've read others reports that their camera didn't have a spacer fitted(?? .. I don't know if this is true or not).
    If this(or more) spacers need to be placed back into the assembly they go in first. They're supposedly spacing washers to maintain the optical path to certain specs.
    Makes sense to me as manufacturing tolerances need to be factored into somehow.
    Both my cameras(D300 and D70s) have only one each. I put them back as I found them.

    Always try to keep the matte screen clean as you can. Try not to touch it. although you can handle it with care by holding it in your fingertips at the very edges of the screen without damage. Apparently oils in your skin can mark the screen. I guess if that happens, a solvent can clean it.
    If I have to handle it all over, I wrap it in a PecPad. I do this to clean it too, rubbing it carefully between my fingers. After that, I'll blow it off with a burst of canned air again.

    some side notes:
    Apologies for some of the images being either dark/blurry/not particularly interesting in an arty sense. Next time I'll add some HDR/ToneMapping/copper toning effects via Nik software's Color Efex Pro
    I have to leave this one here for the moment. I'll tend to the kids for a while and coem back after lunch. Doing the laundry too as we speak

    .../2
    Nikon D800E, D300, D70s
    {Nikon} -> 50/1.2 : 500/8(CPU'd) : 105/2.8VR Micro : 180/2.8ais : 105mm f/1.8ais : 24mm/2ais
    {Sigma}; ->10-20/4-5.6 : 50/1.4 : 12-24/4.5-5.6II : 150-600mm|S
    {Tamron}; -> 17-50/2.8 : 28-75/2.8 : 70-200/2.8 : 300/2.8 SP MF : 24-70/2.8VC


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    So it seems!
    The matte screen is optimised for a good balance of both some DOF and brightness.
    if you look through the vf with the matte screen removed you notice two things. Instantly brighter and clarity, and virtually no DOF separation.
    So why would you want to change it?
    I'm only cleaning my D300 screen ATM, and have plans to change it to a 'better one' one day soon. I've already changed the D70s's screen and installed an ebay($35) screen with a split prism. The D70s does have live view for static manual focusing assistance(or calibration/testing) and I had a difficult time focusing both the 500/8(mirror) and 50/1.2 lenses on it. The split prism helps immensely with getting a consistently good focus point, more so on the 50/1.2 as the split prism blacks out at f/8.. but is still usable. Have at least got closer to acquiring good focus manually with it than without it.
    But it seems that opting for a brighter matte screen means lowering the DOF virtualisation. That is the DOF that you think that you see through the vf.
    To see the apparent DOF that you see through your vf an easy test is performed at home.
    Take some random images at various apertures below f/5.6 and have easy access to the PC.
    Compare the images captured at various apertures to what you see through the vf. There;s a very high probability that the images captured at f/5.6 will approximate the image through the vf more accurately
    It seems that as you optimise the screen for faster lens, and hence better DOF perception through the vf, the image becomes darker through the vf becomes if you use small aperture lenses. Makes sense, because there will be more opaqueness to the matte screen to give that DOF separation. More opaqueness will mean less light transmission through the matte screen.
    I have no idea on how much difference this wil make, but I suspect that If I choose the faster lens screen from Katzeye, then subsequently using the 500 mirror will be fraught with a virtually black vf image!
    (I may have to live with this issue tho).

    See HERE for some more info on this issue.
    I did have a web site bookmarked with more detailed info about screen differences and perceptions of DOF.. etc.
    As far as I know, only the D3 series and Canon 1Ds series offer factory options for differnet screens. All others may only be via third party vendors, such as focusin screen.com and KatzEye, among others.
    I'm leaning towards the KatzEye Optibright and Plus additions to any screen I order for my D300(which I'll probably do right after I finish this, if the AUD-USD ratio is acceptable )


    note how the screen is positioned in the camera. For non Nikon cameras I can't help with info, but with most Nikon cameras, I suspect they all work in a similar fashion.

    Note that in the images where the matte screen is clearly visible there is a small tab on one of the long edges. That's where you 'capture' the screen from...


    I use long nose very fine(jewlers) pliers. It's recommended to use protective coverings on the tool so as to not damage the matte screen surface.
    In all the years I've been doing this(and I've been doing this on a regular basis for the past 4 years, I've never damaged the screen surface due to handling!
    I did however scratch the D300's screen with the pliers as i was too rough in trying to get the retaining clip off one time. having done this many times before, I guess I was too blaze about it.... whoops!... scratch . No biggie! There is a mark and it's annoying, but no big deal.. I'm wanting a new screen anyhow. I just hope the standard screens are not too expensive if I ever want to revert again(for the purpose of selling the D300 only).
    Also notice that the fine shim is located around the matte screen here. That's how it sits, with the shim in the camera first and then the screen is placed on the shim.

    Notice the texture of the screen. It has a very fine etched surface on one side and smooth on the other. The fine etching creates the illusion of DOF. Light transmission is an inevitable consequence! In that image the screen was removed and then turned to reveal the spacer shim.


    Screen removed camera upright, I blow out the prism box with canned air. I give the prism box more caned air time, as there is no way to physically clean it out, aws you can with the sensor, or mirror..etc. There is limited access, and I won't use cotton buds as some people have suggested they do. All I want is the crud out and the screen back in cleaner than when I pulled it apart.

    Here's another angle of the matte screen being held by the tab with the fine nosed pliers:

    Note this side is the glossy side. The non glossy side produces no reflections at all.

    (if you do this at home) when you refit the screen the matte side is facing the mirror, and the glossy side is hidden and facing the hidden prism. That's how it came out of my (Nikon)cameras, that's how I put them back in. Makes sense too. Minimises the risk of reflections within the camera.


    Now I've got big Phat Phingers, so the fine nosed pliers is a must. I could do this by hand, there is just enough room, but if you have supermodelling hands with long thin fingies, then you could do it by hand. Long-ish fingernails also helps to get a fine grip of various bits and pieces too. I find that handling the shim by hand is a great lesson in origami with fine metal spacer parts from Nikon. Too fine to pick up and place accurately. I always use a pair of fine pliers.

    For Nikon owners contemplating this, you may forget how to orient the screen back into the camera, after you've cleaned it. Because of the small grab tab, it can only be placed back in one position. The tab must be closer to the menu button side of the camera, not the shutter release side. This info will be invaluable to those folks that took their time and forgot how to put it back(as I did ).

    That's about it I guess.. but only because I've run out of images to upload

    Any question or further information is welcome.

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    OH! It seems I've re-invented the wheel!(doofus!)

    It seems that KatzEye have a installation tutorial page on their site with clear(clearer than mine!) images, for many makes and models.

    See HERE. Click your model and it opens as a PDF(or download it to your PC).

    I think I'm about to order the OptiBright Katzeye for my D300 I reckon.

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    So tell me , have you ordered and fit to your camera the optibright and what are your thoughts regarding it as i'm in the same boat as you regarding eyesight..
    We didnt inherit this land, we merely borrow it from our Children

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    My eyesight is currently 99% fine.

    I did only just order the Optibright version of KatzEye's screen.
    They say that it should work ok with slow lenses, and I really don't want to make the vf too much darker with a faster matte screen and this lens mounted.

    Hopefully the screen will come in a few days(a week or so), they are manufactured to order and with postage.. anyhow.. we'll see.

    I'll be sure to add to this thread when I have it fitted, and whether it's worth the effort and expense.

    if anyone has any idea on how to capture an image through the viewfinder, I'd be interested to know.
    I've tried to use my 105Vr macro lens in an as close as possible position(all tripod mounted and all) but it don't work!)
    I'd like to get a set of non subjective images through the vf if that's possible to do.

    I did seriously contemplate getting the cheaper focusing screens.com variants, but if they darken the screen by any amount the 500/8 becomes useless, even in bright summer daylight!

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    wow, that's more fiddling inside my cam than I have courage for!!
    still reeling after sensor 'cleaning' using Visible Dust swabs which deposit more crap than they clean..

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    Yeah! At first it looks 'daunting' but really it's quite simple and easy to do.

    The trick is to know how much force to use with releasing the retaining clip, but as I see it you can't really do any damage(unless you slip up).

    The D90 looks easier to unclip the retaining ring going from the instructions on the KatzEye site.

    now I just have to wait for my new screen to come, and hopefully it'll make a world of difference to the 50/1.2 with respect to more consistent focusing, as it's very hit and miss as it currently stands.

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    looking forward to see how you go with it and hear your results regarding improved focussing(visually offcourse).
    You know once upon a time ago a lot of makers had the split focausing screens in the camera(I Think) as i had yashika that did and it did make manual focussing so much easier to see when it snapped into focus.
    Why dont they install these screens nowadays if they are so much better i wouldlike to know ey??..

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    Quote Originally Posted by Papou View Post
    looking forward to see how you go with it and hear your results regarding improved focussing(visually offcourse).
    You know once upon a time ago a lot of makers had the split focausing screens in the camera(I Think) as i had yashika that did and it did make manual focussing so much easier to see when it snapped into focus.
    Why dont they install these screens nowadays if they are so much better i wouldlike to know ey??..

    They thought that replacing the split screen with a single green dot was a easier and quicker to get focus! Go figure.

    Curious to know how much light through the VF is lost with the split though

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    the split prism itself doesn't lose light, except at apertures of f/5.6 or smaller.

    The matte screen I got for my D70s way back when, didn't lose any light in an overall sense through the matte screen, but when mounting the f/8 lens(stuck at f/8 of course) the split prism did 'semi' black out. In good light you could move your eye around in the vf and get half an image formed, but in lowish light(say close to sunset) it would totally black out.
    I suppose it begs the question.. why use an f/8 lens in semi darkness?... where likely exposure values would be in the order of 1/50s and ISO200? Surely that'd be a recipe for disaster.. and you now it usually was! But occasionally you could get lucky and get a single shot.. out of 12 or 15 attempts
    The KatzEye is said to delay split prism blackout to over f/11.
    (That would be a problem with a non CPU'ed lens in LiveView mode ... but you don't use a vf and it's split prism in Lv mode!... did you now that if you use a non CPUlens in Lv mode the aperture works in real time? ie. stopped down! But you can't use DOF Preview with a CPU lens! )

    The problem with loss of light is when you install a more contrasty matte screen whichgives a better snap in as you focus. That is the matte screen is more opaque to simulate a wider(than f/5.6) aperture, and as the Katzeye site says is optimised for f/2.8 or faster lenses.
    The higher contrast of the matte screen, means that less light is transmitted through it, but that's compensated for with the faster lenses.
    The problems come into play when you mount a slower lens to the camera with this faster type of matte screen fitted.
    Katzeye say that their Optibright treatment counters that issue, and that as the max aperture value gets smaller the difference in brightness with the Optibright treatment becomes more obvious(works better).

    I guess that matte screens with micro prisms and split prisms costs money, and that's money saved by the manufacturers. AF systems generally mean that they are no longer required. Manufacturers probably assume that those(of us) that still use MF lenses will put up without, or seek alternatives.

    LOL! on the green dot. I hardly ever look for it in the vf info screen, but when I do, it tells me porky pies... so I recalibrated the MF system in the camera to teach it a lesson. No more lies!

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    hi would you guys know where i could localy purchase a OEM focusing screen for my d90?

    Cheers

    Steve

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    Locally.. no!

    Nikon don't make them available as an optional extra for the likes of a D90.
    As far as I know the standard screen should be available as a service item, but I think that would entail getting it replaced by a Nikon service department.

    IF any retailer does offer aftermarket focusing screens, I would like to know about them too, but it's too late for me. My Katzeye has been sent, and is probably 50,000 feet over the Pacific(if not already landed ) as I type.

    Nikon do have optional focusing screens available for the top end pro series camera bodies tho.

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    KatzEye fitted

    The screen came yesterday(15-07), and was of course immediately fitted, but after a few shots of it:

    This is what you get from KatzEye:
    DSG_1525.JPG
    The screen will come vacuum sealed in a bag.
    I remember them saying somewhere they supplied a pair of tweezers too... but maybe that was a long time ago??
    The supplied tool for unhooking the (Nikon) retaining clip is perfect, and I should have thought of making something so simple myself!
    I used to use a pair of pliers and slipping once caused me to scratch the original screen. Not by much, but a scratch none the less! This tool is basically a two pronged fork looking thingie, where you hook into the retaining clip at the most accessible point(the raised triangle in this case), you give it a slightly backwards(into the camera) push and then upwards. Unless you're a chainsaw masochist from Texas you really shouldn't be able to stuff this operation up! Reversal is similar except that you push in and then down to seat the clip into is locked position. Easy as!

    I'm thinking for non Katzeye owners a very small jewellers flat screwdriver with a notch ground dead smack in the centre of the face would work exactly the same. The forks on this tool may only be 3mm apart so that the notch is only about 1, maybe 2)mm wide. Perfectly fits the 1-2mm thickness of the retaining clip.

    as for the screen itself and how it compares to the standard screen:

    DSG_1537.JPG

    Standard screen on the left, KatzEye on the right.
    You can see that the Katz is blurrier tan the standard screen, seen in the more blurry rendition of the foam backing. Focus is on the LH edge of the katz screen. At the split prism(which is HUGE!!) you can see a less blurry rendition of the foam backing. Very bright large centre circle micro prism surrounding the split prism.
    There is a large circular marking, that's just a marking and doesn't seem to actually make any difference other than mark your vf with another marking! .. BUT in that circle is a smaller Prism area. Outer area is a micro prism type and the inner circle is split prism type.
    The screen type therefore looks like what Focusing Screen.com call the K6 type(Nikon FM3 type).
    I encourage you to have a good look at their website too, for a good visual representation of how the darkness of the screen can become!!

    Of all the screens, from what I can tell on my screen, the FSX screen images closely resemble the darkness I now get with the f/8 mirror lens mounted, and maybe even darker in my case. I believe that without the Optibright enhancement on the Katz, an f/5.6 lens may produce the kind of screen darkness seen in that FSX screen image!
    As it is tho, this Optibright screen looks a lot like F6-J, but brighter at the edges.
    The beauty of variable aperture lenses is that at the wide end they are faster.
    So with the Katz screen installed you can literally see the difference in corner brightness form wide to zoom(where the f/5.6 aperture kicks in). It gets darker(only just) but it's really at the very extreme corners is where you notice the extreme vignetting. The last 55 of the corners are now getting very dark by comparison to the rest of the image seen through the vf.

    if you have only fast lenses, this is not going to present itself as a problem.

    So far I've had variable results in the camera's metering system. I'll check this out after I sort out the MF alignment I'm now having. AF is working spot on, but shows a slightly disconnected split prism image. Aligning the split prism is slightly front focused. I can't remember if I adjusted the MF system forwards or backwards last time.. but it's an easy fix(if I can find my allen keys! ).

    Question remains: Should you get one? ..

    Yes??... maybe no!
    If you rely heavily on slow lenses you'll hate the darker vf.
    If you don't opt for KatzEye's brightness enhancement, which adds a considerable cost to an already expensive accessory, you'll probably end up hating the vf darkness. If you shoot in dark environments(sunsets, night, etc) it'll be dreadfully dark. Be warned.
    Remember that there may be a hit in brightness with your faster(f/2.8 and wider) lenses too, but it's not going to concern you as they're bright enough already!(an non issue in that respect).

    the $200+ that the KatzEye cost me is worth the money, I reckon, and will allow me to use my Manual lenses easier.. ie. less guesswork in acquiring focus in fast paced situation.

    50/1.2 is now back in the good books!
    Haven't yet mounted the 300/2.8 nor the 180/2.8 but these lenses were both relatively easy to use without the screen anyhow, where the hit rate with those two were higher than with the 500/8 and the 50/1.2.

    As it stands, my only concern with the KatzEye screen is that, now that I have a visual reference point for the centre of the vf screen the central AF square is just off centre!
    Whether this is due to the screen itself, or some alignment issue in the D300 is unknown. But, I suspect that it's an alignment issue with my D300's vf, but that's only a guess because I see less of the LHS of a given scene than I get on the right looking through the viewfinder as compared with what I get in my images(what the sensor captures).
    This still doesn't add up, as the central AF square is just to the left of centre, and therefore I should see more of the RHS of the scene, not the left.. unless there is some reversal of the AF squares when projected onto the vf image.
    I have no idea if this is servicable at all.. but not really a big issue.

    Focusing perfectly is!... I'm off to fix it.

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