NikonGear'23
Gear Talk => Camera Talk => Topic started by: Øivind Tøien on June 29, 2015, 11:32:30
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Being able to evaluate proper focus on the matte area of the focusing screen can be very useful, both for those of us who like to use manual focus lenses and do not want to care about the green dot or do not want to use a central focusing aid that forces re-framing after focusing, and also as an aid to evaluate proper focus when depending on auto focus. The problem is however that the stock screens are too transparent to make them optimal for visual focus evaluation. In the following I am trying to visualize what alternative focusing screens more close to the classic ground glass screens can do.
Sadly one of the main suppliers for alternative focusing screens, Katzeye Optics, http://www.katzeyeoptics.com/ (http://www.katzeyeoptics.com/) , has closed business as the founders wanted to move on to other ventures and they were not able to get anyone to take over the business. Any of their purchasing pages will take you to a notice about this. All the informative pages regarding installations etc. are still kept active.
In a previous thread in the old forum started 30 December 2011 I made a comparison between two different types of Katzeye focusing screens, both with and without Optibrite treatment, and the stock D5100 screen and and Nikon F4 type E screen. As the Optibright treatment (which is optimized for lenses with smaller max aperture opening) is unique to the Katzeyes, I will here only show the Optibrite treated screen and the F4 screen for the 50mm f/1.8 lens. The one remaining major supplier for alternative focusing screens currently appears to be http://www.focusingscreen.com/ (http://www.focusingscreen.com/). The alternative to the Katzeye all-matte special order version I am using in my three DSLR bodies would be their S-screen, which appears to use Canon Super precision matte screen as a starting point. It would be interesting to hear from anyone using this type of screen. They do show some example shots on their web pages. However there is no comparison with the stock screens, so I am going to show that in the following for the Katzeyes as an example of what alternative all matte screens can do for you.
Focusing screen comparisons.
I used an old Nikon Coolpix 3700 in macro mode (only mode that still works...) to capture the viewfinder views of the tripod mounted DSLRs. At the time I had a stock focusing screen in my D5100 and a KatzEye standard all matte focusing screen in my D40x (and Katzeye Optibright in D200) The viewfinder shots had to be cropped quite a bit to only include the actual viewfinder view. (No magnifiers or other accessories were used on any of the viewfinders). The subject, my wax bear, was placed in front of a lot of rubble from the lab located at different distance to obtain a good background to evaluate.
First out, 50mm f/1.8 G wide open, compared at the end to D5100 shots at apertures from f/1.8 to f/5.6.
Stock screen, D5100 50mm f/1.8 G
(http://otoien.zenfolio.com/img/s9/v17/p1286245087.jpg)
KatzEye standard matte D40x, 50mm f/1.8 G
(http://otoien.zenfolio.com/img/s9/v2/p1286245101.jpg)
KatzEye w/ Optibright D200, 50mm f/1.8 G
(http://otoien.zenfolio.com/img/s3/v45/p1286245091.jpg)
Stock E-screen Nikon F4, 50mm f/1.8 G (image sized according to viewfinder magnification)
(http://otoien.zenfolio.com/img/s11/v27/p1286245113.jpg)
D5100 Capture 50mm @ f/1.8
(http://otoien.zenfolio.com/img/s12/v177/p1286245125.jpg)
D5100 Capture 50mm @ f/2.8
(http://otoien.zenfolio.com/img/s6/v143/p1286245133.jpg)
D5100 Capture 50mm @ f/4
(http://otoien.zenfolio.com/img/s9/v90/p1286245145.jpg)
D5100 Capture 50mm @ f/5.6
(http://otoien.zenfolio.com/img/s4/v9/p1286245165.jpg)
From these it looks like the D5100 stock screen corresponds to something closer to f/5.6.
Next 105mm f/2.5 AIS wide open
Stock screen D5100, 105mm f/2.5
(http://otoien.zenfolio.com/img/s1/v20/p1286245267.jpg)
KatzEye standard matte D40x, 105mm f/2.5
(http://otoien.zenfolio.com/img/s3/v44/p1286245291.jpg)
D5100 capture 105mm @ f/2.5
(http://otoien.zenfolio.com/img/s6/v146/p1286245317.jpg)
105mm f/4 AIS micro wide open
Stock screen D5100, 105mm f/4
(http://otoien.zenfolio.com/img/s3/v41/p617970616.jpg)
KatzEye standard matte D40x, 105mm f/4
(http://otoien.zenfolio.com/img/s11/v31/p1286245419.jpg)
D5100 capture 105mm f/4
(http://otoien.zenfolio.com/img/s5/v126/p1286245443.jpg)
AF 300mm f/4 wide open + TC-14 = f/5.6
Stock screen D5100 300mm/TC-14 f/5.6
(http://otoien.zenfolio.com/img/s9/v90/p1286245616.jpg)
KatzEye standard matte D40x, 300mm/TC-14 f/5.6
(http://otoien.zenfolio.com/img/s7/v153/p1286245627.jpg)
D5100 capture 300mm+TC-14 @ f/5.6 (exif does not reflect the TC)
(http://otoien.zenfolio.com/img/s3/v40/p1286245689.jpg)
In all of these it looks like the Katzeye standard all matte screen gives a depth of field/background blurring very close to the captured image. Our ability to accurately focus the lens is also affected by magnification of the details. This is the same issue as when Bjørn keeps telling us that we cannot use depth of field tables, we need to consider magnification and viewing distance (if a print). A DK-17M on or DK-21M a DX viewfinder is a great help in this respect. The FX viewfinder already has a big advantage here although with my DK-17M my D200 viewfinder is very close to my F4. (Of course the FX finder can be further approved by with a magnifier). Unfortunately the magnifiers do not match well with wearing glasses.
Screen brightness
So what is the penalty? Instead of presenting the somewhat shaky comparison in my previous presentation, and since the Optibrite treatment is out out the reach now that Katzeye is not operating any longer, I will just state that there is a penalty with respect to brightness with the standard Katzeye screen. This is not too noticeable at f/2.8 and wider, but at apertures beyond f/5.6 the viewfinder gets markedly darker. And then comes the influence of brightness for acuity, which under bright conditions might not be that much of an issue but very dim viewfinders like with the standard KatzEye screen at 300/4+TC-14 at f 5.6 may be so, not to talk about a f/8 mirror lens with an effective aperture of 10... . After this was written in the original post I ended up installing a standard Katzeye in my D5100, and it has served me very well, even with my 300mm+TC-14 when light is not too dim.
Focusing screen calibration
In the original thread I asked the question:
"If you bought a KatzEye and installed it yourself, did you experience manual focus shifts (to the worse or to the better)?
In case to the worse, what did you do about it?" My own answer to this question is:
D200: No shift (or a very moderate shift that improved manual focus, not sure), focus on the matte area perfect after installation.
D40x: Noticeable shift (front focus as I recall), fixed by adjusting mirror with hex key, manual focus on the matte area perfect after adjustment. However autofocus has as a consequence become less accurate; I have not bothered trying to adjust the secondary mirror.
D5100: Marked error, corresponded to 0.1mm travel of the lens barred. Fixed by installing a shim (see below).
The installation of the screen in my D5100 itself went pretty smoothly except for the usual struggle with the shim wanting to come out with the original screen. This KatzEye screens has a nice handling notch that makes them very secure to handle opposed to the original that only have a small handling tab at the side. Also a nice tool to open and close the focusing screen catch is supplied and the catch was unproblematic.
After the install I did however as noted above experience a considerable back focus in the image when the focusing screen image was focused correctly. Thanks to my experience with a misaligned mount in a D5100 body that was replaced, I estimated that the screen would have to come ca. 0.1 mm closer to the mirror. I emailed KatzEye, and the suggestion was either to do a main mirror adjustment (my approach to correct a similar problem on my D40x) or to make up for the distance by applying a couple of layers of 3M tape to the short edges, or to make a shim out of printing paper which is about 0.1mm think.
Regarding the main mirror adjustment, the saying out there (including KatzEye's) seems to be that the AF adjustment (position of secondary mirror) is unaffected. However I wonder if this is the whole story, as the secondary mirror is attached to main mirror, and that point will theoretically form an arch on adjustment. The AF on my D40x was never very accurate after the adjustment - perhaps it never was, I am not sure, and I never bothered with the secondary mirror adjustment. Here is a simple schematic of how the mirrors are supposed to work:
(http://otoien.zenfolio.com/img/s4/v11/p1286311981.jpg)
The black circle is the AF adjustment screw that in this "experiment" is untouched while the effective position of the main mirror adjustment screw is moved, here shown for two theoretical extreme adjustments, and it clearly affects the angle of the secondary mirror. So may be the the correct phrase should be that AF is minimally affected when the main mirror is adjusted. Of course this might be a simplification and the mechanics more sophisticated. Since AF on my D5100 seems perfect, I felt that is was better to do something about the shims. Here is a view with the focusing screen removed showing the single shim already in place and below it the viewfinder mask which also can come out:
(http://otoien.zenfolio.com/img/s3/v26/p1286312005.jpg)
As Nikon USA refuses to sell spare parts like shims the only option for a fairly quick solution was to manufacture my own. This is not really rocket science, so I found a sheet of old used overhead transparency plastic sheet that seemed to be about 0.1mm thick and cut out a shim.
(http://otoien.zenfolio.com/img/s9/v89/p1286312018.jpg)
Not so pretty, but as long as it does not come in the way, and has reasonably uniform thickness, that should not matter. I placed it between the mask and the existing shim. Now the screen was going to go in again, and in a moments panic, I could not understand why the matte surface was going towards the pentamirror. (The tab has to go to the left in the body's notch of the image above.)
(http://otoien.zenfolio.com/img/s7/v164/p1286312027.jpg)
(Note the nice handling notch on the matte side).
All my older cameras like F2 had the ground glass towards the mirror, and a bulging surface towards the prism. However it was only one way to put it in and the original screen looked similar to the KatzEye in this respect. This was rewarded with success. Manual focus is now spot on without any further adjustment with all tested lenses and seems uniform across the screen, so this was a pretty lucky choice of shim. (Nikon's own shims come in 0.5mm steps from 0.05 to 0.2 mm so it is a fairly coarse adjustment.) I talked to Rachael at KatzEye and she confirmed that modern screens form the image on the prism side and has the Fresnel lens towards the mirror. So I learned something new. My guess is that this is necessary to let the eye focus at the screen image and the viewfinder info at the same time.
And here is the obligatory proof in the pudding: While testing focusing on some branches, a small bird that I believe is a Chestnut-backed Chickadee showed up in a small neighbor tree (view large). These birds quickly move around with only one second at each spot, but focus was still nailed with the correctly adjusted KatzEye focusing screen.
(http://otoien.zenfolio.com/img/s3/v39/p1286312055-6.jpg)
105mm f/2.5 AIS @ f/2.5, 1/800s ISO 100.
Another one, a Northern Harrier shot from a moving vehicle on a bumpy gravel road with my 300mm f/4 lens!
(http://otoien.zenfolio.com/img/s5/v122/p1286495362.jpg)
300mm f/7.10 1/2500s ISO 400 (manual focus on D5100):
One final comment on the D5100 viewfinder: While one cannot expect too much from a penta-mirror, I find the D5100 viewfinder image slightly dimmer and with a warmer tone than the similar constructed D40x viewfinder in spite of the magnification of the D5100 finder being smaller. Also I think the D40x viewfinder is somewhat crisper with the exception of a blurry line going down the middle, which is not noticeable in the D5100. As I also understood from Rachael at KatzEye, they used to check each body they install with a collimator, and she thought there has been a steady decline in precision of the Nikon bodies starting from D300 on. There is a possibility that a body could come with a maladjusted mirror, so that a mirror adjustment would improve its position. The question is how much (if) that would affect AF if the adjustment is large. The screens from http://www.focusingscreen.com/ seem to standard come with a selection of shims. That could perhaps indicate that they are less standardized with respect to the thickness of the standard screen on the host body, or they could have a realistic relationship to the tolerances in general. Experiences from users of those screens would be very valuable now that Katzeye is out of the picture.
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Thanks Øivind for reposting this very interesting topic. Lots of food for thought and valuable practical observations.
As to finder brightness, we are facing the same dilemma as elsewhere in real life: you can have one or the other, but not both concurrently. Meaning if you want brightness, focusing accuracy with a screen will be lower. If the screen is coarse it will allow precise focusing, but now brightness suffers.
At this point, if opportunity arises, put a fast lens on a Nikon F2 and notice how seemingly dark the finder image is. However, the image simultaneously literally pops in or out of focus with authority. The problem with the current 'modern' screens are they are too bright and therefore too fine-grained, so the aerial image projected by the lens simply won't break up in a satisfactory manner to allow proper visual focusing. These screens are made for viewing with AF doing the dirty job of getting the lens into focus.
Somewhere in my drawers I have stacks of specialised finder scrrens for nikon F, F2, F3, F4, ... so perhaps shall investigate whether any of these can be grafted onto my current cameras. The B type screen of my Df cameras is pretty good, but improvement is always possible.
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I did install a type S from focusingscreen.com in my Df and it made a big difference to nailing focus manually.
I am still thinking about returning to the Df (currently in Fujiland) and if I do I will reinstall the S.
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Sten, did you do the installation yourself and if so, were there any obvious issues to watch out for?
If I am to have a screen replaced on any of my Df bodies, my trusted repair shop should do it for me. They can also do any fine-tuning with shims if required plus verify that visual and actual focus planes coincide.
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I believe its quite straight forward to exchange the focus screen and get MF correct, what could turn out to be tricky is to get AF to work as well with the new screen.
I know that's not your concern Bjørn...
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I did the installation myself. The most critical part of the operation is to make sure that the tool of choice to open the retaining steel spring doesn't slip so the screen is scratched. Other than that the shims are somewhat delicate and one should take care not to damage it/them. Oh, and use medical globes...any grease from one's fingers will fill the incredibly fine grooves in the Fresnel side and/or the satin side of the screen. Cleaning a focusing screen is not a trivial task.
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Well, even with the Nikon Df I'm not firmly set *against* using AF on occasion. So prefer also AF to function perfectly after such a surgery and that is why I'll leave the task to a qualified repair shop.
For now I am postioned on the side line and taking notes.
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Øivind, regarding adjusting the main mirror: According to Bjørn & Bjørn's favourite camera repairman the main mirror can be adjusted to a certain degree without affecting the secondary mirror. If you go pass a certain amount of adjustment the secondary mirror will also be affected. (This was on my D3X that has misalignment between visual focus and AF. It may be different on other cameras). He also said that on the D3X they never put shims on the screen, but instead they shim the prism itself if adjustment is needed after changing screen. On other cameras they place shims under the screen.
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Thanks Bjørn J that is valuable information indeed!
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The question is, hombres, should I leave the Fuji and get back to the Df?
(its soothing shutter sound I cannot forget).
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It's like when you go to your car dealer... Never ask for price on the car of your dreams... Just pay! ;)
Seriously, I have seen some amazing quality files from the Df (and D4/D4s btw) similar look to what I'm used to from Leica M9 and D3X it's just that the Df is capable to deliver those files at insane ISO values that I can only dream about...
Only real competition for me to the Df would be to go for one of the Leica M Monochrom cameras but only since I have Leica M lenses already...
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Only your heart and soul can answer that question, Sten.
I think personally you should have both and save yourself a lot of troubles and money wasting. Going back and forth cannot be cheap in the longer run.
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I know you guys are outside EU - But have you seen the brand New prices for Df in UK, it's 1,500.- £
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I have the chance to get a mint Df w/the lens for 19000,- NOK.
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That seems to be a great deal in Norway, the kit lens is remarkably good as you know... :)
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My focus screen experiences have been:
first attempt for a better alternative on the D70s, a cheap .. and definitely nasty! .. ebay product.
While $30 wasn't a huge hit to my pocket, it certainly wasn't worth that amount(other than if one ever needed replacement).
moral to that story is if you want a better focusing screen(ie. experience) avoid the cheap ebay products. If you have somehow managed to damage the focus screen and simply need a replacement at $30 they're ok.
My next experience was with the Katzeye with optibright fro my D300.
In hindsight I should have also purchased one for the D70s, only because(with hindsight) it's too late now as they no longer exist. The hope being that an enterprising person may take up such a challenge one day.
In a word, the Katzeye with optibright on the D300 was, for all intents and purposes, perfect.
It's easy to focus at the periphery using just the matte even with such lenses as the 50/1.2(wide open) and even the dingy dark old 500/8.
A small amount of darkening is apparent with the 500/8, and any other smaller than f/5.6 lens(ie. lenses with teleconverters, etc).
My other lens that pertains to this point is an old Tamron 300/2.8 for which I have both a 2x and 1.4x T/C and can confirm that is still bright enough to use easily and still coarse enough to focus accurately too.
My katzeye had both microprism and split prism focus aides. I was a bit weary of Katzeye's marketing about their unique split prism design, in that black out is delayed till very late in the small aperture range .. but my fear was unfounded.
Where the relevance to the Tamron lens comes into it, is that it's my only lens that I can test at small apertures(eg. f/11 or f/16) and still get a shallow DOF to test both focus accuracy and split prism blackout.
Blackout begins to appear at about f/16 on the Tamron lens with both T/Cs attached(ie. at 840mm and f/16 and close range focus)
Even in such conditions, while the vf is significantly darker due to f/16, and the split prism is only slightly blacking out .. focus with the split prism is still easily achieved on good subject matter.
I couldn't give an accurate assessment of the brightness difference between the stock D300 screen and the katzeye with optibright, but the katzeye is most certainly brighter to begin with .. maybe 0.3 to 0.7Ev(possibly more) AND more accurate to focus faster lenses.
Manual focus has never let me down, other than for my inability as a practitioner. That is, with a stable camera and static subject matter, I can hit focus 99.99% of the time with the D300 + Katzeye.
In give and take situations where fast focus is required(of a manual lens) it's most certainly my inability that misses the shot.
My third experience with another focus screen is as Sten, with the S Type from focusingscreen.com for my D800E.
Accuracy is superb.
As above in terms of capability in ideal conditions and situations. I can hit focus easily due to the coarse nature of the screen.
Only problem is the darkness through the vf.
Once again .. one word .. massive!(darkness).
With fast f/2 or faster lenses it's not a huge problem. in fact, barely a problem. But with an f/2.8 lens of any type ... 300mm or 24mm! .. the vf is darkened enough to notice it.
Add an f/4.5 lens and it's almost a pain in low light.
Add a 500/8 and it's murderous(the darkness through the vf) .. except in very bright light.
While the stock D800 is brighter than a stock D300, with the aforementioned screens fitted now, the D800 is now a few Ev darker at f/2.8 than is the D300 + katzeye(optibright version).
So much so that the D800+S-Type with a 24-70/2.8 mounted and zoomed in to 70mm is about as dark as the D300+Katzeye with the 500/8. Both setups pointed at a blank pale wall/screen to replicate the same lighting for each focal length.
if I switch the lens/camera combos(ie. D800 with 500/8 and D300 with 24-70/2.8) it's like having one eye closed(obviously the D800 eye) where by comparison to the D300 eye, a blank white PC screen is a very very dark grey and the D300 is bright enough for anyone to consider white.
The method used for the above comparison is to hold the two camera/lens combinations at each eye at the same time, in a sort of binocular manner.
Both pointed to the same PC screen, with a blank white page.
The same method used with no lens mounted on either camera produces near identical brightness levels.
For accuracy in observation, the D800 vf is significantly larger by comparison to the D300, and with the two respective screens fitted, (D800 + S-Type) and D300 + Katzeye) there are colour balance differences too. S-Type is more red cast and Katzeye is more green cast.
I can't remember there being any colour cast to either of the stock screens, and it's fiddly to replace and check this without a direct comparion.
Next time I catch up with anyone with either a D300 or D800, I will try to remember to check for this colour cast difference.
If I can work out an accurate method to capture this with consistent and accurate exposure levels to indicate the differences, I'll reply once again with those results.
But needless to say that S-Type screen at f/2.8 is approximately 3Ev darker.
You don't see this at f/2, it may well be darker than even a stock screen with an f/2 lens but it's not a noticeable. Neither is it a notable difference compared to the katzeye.
One last point, if you can bear with me.
Even tho I have commented that this S-Type screen from focusingscreen.com produces a darker vf, focusing is still somehow possible even in very dark conditions.
The other day when out with some friends, I had the opportunity to have one final play in the dark, and the thought of manually focusing the D800 in the dark crossed my mind for no obvious reason.
I mounted the Sigma 50/1.4 I have(old model) as the other thought was for how well AF would work.
AF in this dark situation was out of the question.
Couldn't give an accurate estimate of an Ev level, other than barely anything other than a well lit ferris wheel was visible through the vf. Seeing in this dark was easy enough with the eye, but not so much through the camera .. nor Lv mode(it was all noise or too dark too). You could make out shapes via Lv mode, but the noise levels with the increased gain of the Lv system made focusing on anything impossible.
YET! somehow I still managed to focus accurately in this darkness ... manually. And not only once(by luck) but consistently once I got my eye in.
Out of 4 frames, the first attempt was missed(frontwards).
Once I got my eye in(to the light conditions), the next 3 shots were all focused. At 50mm with an acceptably sharp lens(not the sharpest at f/1.4) in almost total darkness.
So on one hand the S-Type sounds like a major liability, yet even with that obvious liability it still allows accurate focus.
I've never experienced either AF issues, nor metering issues with either focus screen fitted.
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Thanks for the heads up!
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Thanks for the response all of you, and Sten and Arthur in particular for sharing your experiences.
Sten, It is encouraging to hear that you would go for the S-screen again.
Arthur, it sounds to me like the brightness of the non-Optibright Katzeye is in many ways close to the S-screen. I think my experience is similar, that it is possible to focus in pretty low light even with these not so bright screens - I would like to add - as long as wide optics is not involved (although I have sometimes success with that too, but then far from 100%).
I now and then surprise myself by doing these super fast manual focus captures in the blink of a second in not so favorable conditions, and with no chance of rocking focus back and forth. I think that the brain perhaps after a while learns to stop at just the right point, decision taken before the image looks crisp (there is a little reaction time before stopping movement of the focusing ring). But then it is essential to have a realistic blur of out of focus subjects relative to the final capture.
I likewise use the amount of blurring to estimate how much I need to compensate for IR shots (Particularly with my 105/2.5) after obtaining sharp focus on the screen. This is just a minor twist of the focusing ring toward closer focus.
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One more aspect to take into account when seeking to get the plane of sharpness correct is that for some lenses that plane moves as the lens is stopped down, you dont see that on the matte screen of a DSLR, until you hit the aperture stop down, but you will see it in live view and on an EVF that works with lens stopped down...
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I have a Katzeye split/screen and prism combo screen here for my D7000 which I don't have anymore. Anyone want it?
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I became recently aware that a last batch of Katzeye screens was announced at the Katzeye web site in September. I got an answer from Rachael this morning:
"It is good to hear from you. We are still collecting orders for the final production batch, though not for much longer. We are within a couple of weeks of closing off the order-taking process. I would have to check inventory to see if we have any of the all matte material left in stock. My sense is that we probably don’t, but I will check into it and let you know."
So if anybody are in the market, there might be a possibility, but one will have to act rather soon. I will update when I hear back regarding the all matte screen.
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Now that the screens from Katzeye and those are ridicously expensive, I looked into alternatives and ended up buying a Canon EG-S for my D700. Well, it doesn't fit to begin with but after filing it down a bit it will ;) Just use the old screen as an example.
I paid about 30 euros if I'm not wrong. The screen is getting quite a bit darker but manual focussing get's easier, especially if you use fast primes which I do most of the time.
I ended up make a few very small scratches on the screen while filing down... But I can live with that, especially at that price point!
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Now that the screens from Katzeye and those are ridicously expensive, I looked into alternatives ....
.... The screen is getting quite a bit darker but manual focussing get's easier, especially if you use fast primes which I do most of the time.
....
I suppose the term ridiculously expensive needs to be predefined accurately.
While they are pricey, I actually didn't find them expensive, and would gladly pay that price again simply for the sheer quality.
My two main cameras are D800E and D300. D300 has the Katzeye and D300 uses the S screen from Focus Screen Dot Com.
FSDC is good, but the Katzeye is clearly a lot better .. by a few orders of magnitude. The primary difference is in the brightness level comparison.
I would assume that with normal screens fitted, the D800 would offer a brighter more accurate screen to the D300's vf.
The Katzeye is so much brighter now, and a little more accurate to focus, but that's mainly due to the split prism option I ordered from Katzeye.
In my testing, I think Katzeye claimed that split screen was good down to about f/11 or so before blackout, and I can confirm that .. I think down to about f/16 even!(that is f/11 is still usable)
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Are you comparing to the Optibright treated version of the Katzeye?
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Yes .. Optibright version for D300(I forgot to mention)
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Thanks Arthur, the Optibright version is about midway between a stock screen and the one without the treatment with respect to transparency/realistic depth of field per my previous experiments (as mentioned earlier I have one in my D200). I have been communicating with Rachael at Katzeye about their final production run, however things have been delayed because they moved to a new facility and have not gotten inventory unpacked yet. She estimated that material for 0-2 all matte screens would be available. Because of this uncertainty and because I was pretty much geared towards the non-Optibrite treatment all matte version for more realistic depth of field view (as in my D40x/D5100), I went ahead with an order of an S-screen from focusingscreen.com for my new D7100. it is already on its way to me so we will see how that works out. One thing I like about that alternative is that there is no engraved circle, which could become a slightly messy on top of the marked oval for the extent of the focus area.
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I just thought it is worth mentioning that the images for the D7100 install on focusingscreen.com's web site are incorrect. They assume D7100 and D7000 have the same layout. Inspection of my D7100 (below) shows that it is similar to D300, which is correctly used as example for the D7100 install at the Katzeye site. On the images showing D7000 in Focusingscreen's instructions, and D90 on Katzeye's site, the retaining wire has to be pulled towards the mount to be released, while on the D7100 (and D300) it is pushed towards the screen for release. The retaining wire has a bump to make it easier to release it.
The D7100 focusing screen retaining wire and catch (reflected in the mirror):
(http://otoien.zenfolio.com/img/s9/v17/p1678127533-4.jpg)
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I received the S-screen from focusingscreen.com just before Christmas and installed it yesterday without getting a single dust spot. So far it does not seem necessary to install any additional shims or remove the one present; focus seems accurate. My initial impression reflects those of Arthur with respect to brightness, although not quite as dramatic as he describes :) : "But needless to say that S-Type screen at f/2.8 is approximately 3Ev darker" (perhaps a printing error for f/8?)
Focusingscreen.com S-screen (FS) comparison to D7100 stock screen with 105/2.5:
f/2.5: FS is 0.66 stop dimmer than the stock screen, depth of field realistic.
Stock screen depth of field as an exposure at f/4.5-5.6
f/2.8: Both about the same brightness as at f/2.5
f/4: FS 0.66 stop dimmer than at f/2.5, ca. 1.5 stop dimmer than the stock screen.
Stock screen about the same brightness as at f/2.5
f/5.6: FS 1.66 stop dimmer than at f/2.5, ca 1.75 stop dimmer than stock screen
Stock screen 0.75 stop dimmer than at f/2.5
f/8: FS is 2.3 stop dimmer than at f/2.5
Stock screen 1.3 stop dimmer dimmer than at f/2.5
(Results obtained using constant exposure of viewfinder with AW1 as recording instrument, using adjustment sliders in CNX2 to judge exposure of selected points in image. I also did a series with the FS screen where I adjusted exposure according to the aperture used on the lens.)
In conclusion I must admit that the screen is dimmer than I really wish for. If one depends on frequently using lenses with max aperture of f/8 I would think twice about installing the screen. However I am presently testing under worst case conditions with very little daylight or even night scenes(need to turn off the viewfinder O-LEDs for framing then...) , so I think it will work for me with my Nikon 12-24mm and the 300PF with 1.4 converter. The 105/2.5 is unproblematic.
Unfortunately I forgot to do systematic before - after meter tests with different lenses. Results so far indicates that metering needs exposure compensation of at least -0.3 to -0.7 EV .
I do not have access to my other camera bodies right now, so comparison to the all-matte Katzeye screens with and without Optibright will have to wait.
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I do not have access to my other camera bodies right now, so comparison to the all-matte Katzeye screens with and without Optibright will have to wait.
I finally got to compare the S-screen from focusingscreen.com in my D7100 to my all matte non-optibright Katzeye screen in my D5100. To make comparison even with respect to viewfinder image size I used a magnifier on the D5100 while not on D7100, and a 55mm f/3.5 simultaneously on each body. The consensus is that the S-Screen is much darker than a similar Katzeye screen in spite of the inferior viewfinder of the D5100. This was quite a bit of a disappointment as I thought the differences mentioned above by Arthur could have been due to comparing an Optibright treated screen to a standard screen with less transparency. With 105/2.5 mounted on D7100 and compared to 55/3.5 on D5100, the D7100 viewfinder was still less bright, probably by 1/3 to 1/2 a stop. Actually 50mm/1.8 on D7100 was about the same brightness only slightly brighter than 55/3.5 on D5100. So too bad Katzeye is ending production. Perhaps one will have to find a source for the FM3A all matte screens and have it cut oneself...
I wonder why the screen is less bright? could it be that the fresnel lenses of the Canon S-screen is not well adapted to Nikon's register distance/typical exit pupil location? Or perhaps the screen is just even less transparent, althogh both screens do seem to provide a pretty realistic view of the background blurring. I do also have a feeling that contrast suffers somewhat. The FM3A etc. was known to have a quite big and bright viewfinder.
I wonder what size/shape the D500 screens will be?
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Your finding makes it clear (no pun intended) that the Optibrite from Katzeye is more friendly for MF.
If I get the D500 I don't think I will replace the screen as I would use it for AF work. But popping the screen out to check its dimensions will be easy.
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Your finding makes it clear (no pun intended) that the Optibrite from Katzeye is more friendly for MF.
.....
Actually, I'm finding it the other way around, but with a caveat.
The Katzeye I have has the two focus aides in the split prism and the microprism collar around that.
The microprism collar is quite large through the D300, which I guess is due to the smaller overall size of the screen itself relative to the size of the microprism etching.
In this instance, my guesstimate is that the microprism circle covers roughly 1/3rd of the size of the whole screen, so that if the subject is within the 1/3rd area of the vf near the centre, then it will be in range of the microprism area.
But, the D800's S-type screen is usually more accurate if I'm manually focusing from only the matter areas(that is not using the focusing aides of the Katzeye's screen)
So if the subject is in the periphery, where you can't use the centralised focus aides of the katzeye screen, I find that the S-Type is more accurate.
All this assumes fast lenses too tho. 50 @ f/1.2, 105 @2 f/1.8, 24 @ f/2.
The 24/2 is where the accuracy difference is blurred a bit tho..
I assume that it could be due to both the f/2 aperture and the shorter focal length(which probably means deeper DOF, and hence more forgiving allowance of errors).
The 105/1.8 is the harder of the above lenses to focus, and of course the the differences between an Fx and Dx FOV also come into play.
The test target I used was a test pattern I found on the internet with stars and stripes printed on a white sheet.
I had to change distances to try to overcome any undue softness the lens may have at it's periphery too. So for the D300 I set the focus target at the periphery of the frame, and IIRC at just a very slightly longer distance(less than about 1m) whereas with the D800, I set the same target at about the 2/3rds range in the viewfinder area(ie. not right at the very edge).
My assumption here was that if the lens is less acute in it's drawing at the very edge, it'd have skewed the result a bit in favour of the D300 no matter the screen used!
While I did end up taking some images, my primary concern was on the liveview images, once I focused via the respective viewfinders.
My hit rate with the D800 setup was 'more often than not' .. in that reviewing the D800 liveview image, if I tried to tweak the image to a more focused one, it would tend to blur out of focus instead .. so I assume that focus was hit via the vf.
I do remember that the D300 usually could do with a slightly better focus point with a slight tweak more often that not, but that focus was still more than good enough tho for an image.
(the 105/1.8 has a hazy rendering wide open(up to f/2) for this area of the scene. The focus tweak was minimal, but to my eyes on the D300's Lv screen it seemed that I could do a little better.
Using the focus aides on the katzeye screen, all MF attempts were 100% spot on all the time if I allowed myself a second or so to process the scene.
In give and take situations, where only a split second is offered to get the shot(eg. a kid momentarily stopping for a photo, but with the impatience to get back to the game! ;)) my hit rate with the D300 was impacted a little, even tho it has the focus aids. I usually get it, but I still need multiple exposures to be sure to get one image at an acceptable level.
If I had the funds .. I would have jumped at the opportunity to acquire the Katzeye operations.
They certainly do have great products.
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"Your finding makes it clear (no pun intended) that the Optibrite from Katzeye is more friendly for MF."
.....
.. Actually, I'm finding it the other way around, but with a caveat. ...
The Katzeye Optibrite screen is more transparent (have it in my D200, check the beginning of this thread), and I agree that would make it more difficult to determine focus with a wider aperture lens compared to one without Optibrite (although I would say my all matte D200 screen "snaps" pretty easily into focus compared to stock screen). My comparison above was to the Katzeye all-matte non-Optibrite screen, which would be my choice if available. I am not a fan of screens with the split/microprism aids, as I think that an important point of manual focusing is to be able to focus and compose at the same time. Thus I see those screens as an entirely different class of screens.
Again, with 105/2.5 the dimness of the S-screen is not a problem. But it would be a lot more comfortable to use for focusing and framing with my dimmer lenses if it was as bright as the Katzeye all-matte non-Optibrite, as much that if I could get one I wold be inclined to take the cost on top of the S-Screen, and in particular if the Katzeye screen later could be transplanted to the D500 if I decide to eventually go for that...
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Lo and behold, Katzeye had one remaining piece of the the all matte material left so I went ahead and ordered, although it is a bit crazy using even more funds on this. On the bright side (no pun intended) I got the D7100 for a good price. It also seems to me that Nikon has kept the same standard for screens from D300 up to D7200, so perhaps there could be a slight hope that the Katzeye could one day be transplanted into a D500 if I go for that. I will hold off selling the S-Screen for now.
Further comparison at f/4 and f/5.6, using the AW1 as instrument again, indicates that the D5100 all matte (non-Optibright) Katzeye is a little over 1EV brighter than the S-Screen on D7100 at f/4 and a little under 1EV brighter at f/5.6; tested with 300/4 PF with and without TC-14E, DK21M on D5100 and no magnification on D7100 to keep image sizes as similar as possible.
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In another thread, http://nikongear.net/revival/index.php/topic,8300.msg134877.html#msg134877 (http://nikongear.net/revival/index.php/topic,8300.msg134877.html#msg134877), we discussed the stock focusing screen of D500 vs. other alternatives. The issue at hand is that all screens from D200 through the 7000 series to D500 are called Type B BriteView Clear Matte Mark II, but manual focus with D500 is reported to better than the other bodies with stock screen. As I now have the D500 available, here is a comparison to my D200 Katzeye screen with Optibrite and the D7100 Katzeye without Optibrite, recorded with the AW1 with 10mm f/2.8 lens. While I could have put the stock screens back into the other bodies, I did not want the extra risk of getting them scratched or loaded with dust, so the D500 screen is rather compared to what is presumed to be better alternatives (KatzEyes, although not available any longer). All captures were done with a DK-17M in place (the need to use a modified adapter might be the reason the two older bodies shows more vignetting). Since these were handheld, the comparison is not valid for crispness of the viewfinder images.
First with 55mm f/3.5 at f/3.5
D200 KatzEye screen with Optibrite:
(https://otoien.zenfolio.com/img/s/v-3/p3306150415.jpg)
D500 stock screen:
(https://otoien.zenfolio.com/img/s/v-3/p3306150411.jpg)
D7100 KatzEye without Optibrite:
(https://otoien.zenfolio.com/img/s/v-3/p3306150412.jpg)
Then with 50mm f/1.8 at f/1.8 (this was a new setup so although I tried to keep distances and framing the same, it should primarily just be compared between cameras, not to the f/3.5 images):
D200 Katzeye screen with Optibrite:
(https://otoien.zenfolio.com/img/s/v-3/p3306150413.jpg)
D500 stock screen:
(https://otoien.zenfolio.com/img/s/v-3/p3306150414.jpg)
D7100 KatzEye without Optibrite:
(https://otoien.zenfolio.com/img/s/v-3/p3306150442.jpg)
Interestingly, the D500 stock screen is less transparent/more matte than the D200 Katzeye screen with Optibrite at both apertures, providing more background blurring. The effect is most pronounced with the wider aperture lens. This is quite unexpected as manual focusing improved from the D200 stock screen when the Katzeye screen was installed, and the D200 stock screen is supposed to have the same properties as the one in D500. So may be there has been variations in stock screen with similar designation, or there is something about the optics in the D500 that makes the screen provide a more realistic rendition.
Anyway my conclusion is that with the D500 screen being better than the Katzeye in my D200, there is little reason to replace it with a third party screen. It provides a very crisp and large viewfinder image with DK-17M that snaps easily into focus. It is possible that in situations with bright light and where one has to focus very fast, the Katzeye without Optibrite in my D7100 might provide somewhat higher hit rate, but the viewfinder is much darker than that of the D500 with stock screen.
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Thank you, Øivind for the comparsion. I would be interested in whether the ground glass or the VF construction make the difference for secure manual focus operation.
After some time now with the replacement F6J type screen in the D850 which is significantly better than the original, I still rate the D500 higher in manual focus support.
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Thank you, Øivind for the comparsion. I would be interested in whether the ground glass or the VF construction make the difference for secure manual focus operation.
After some time now with the replacement F6J type screen in the D850 which is significantly better than the original, I still rate the D500 higher in manual focus support.
Thanks for the comment, Frank. We would not really know for sure whether Nikon has tweaked the the ground glass properties of Type B BriteView Clear Matte Mark II screens without being able to transplant the same screen between a D200/D7000 series body and D500. However the screens are not compatible between these bodies and D500 (judged from drawings of the screens at focusing screen.com). The viewfinder optics certainly contributes to the crispness of the viewfinder.