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03-01-2020, 01:27 AM   #1
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K3 and KP and focus screen choice

As a happy owner of both the K3 and KP, and fortunate to have many legacy MF lenses in addition to modern AF primes, I have decided to insert a split image K3 screen from Focusing Screen .com into either the K3 or KP, probably the K3. Before I go ahead and order one though I would like some feedback about using the screen with slower lenses. My most used MF lenses are the K 50mm f4 Macro, M 100 f4 Macro and K 28mm f 3.5. Many (but not all) older film cameras would have the split image black out at f4, will the newer K3 screen suffer the same issues, and if so might there be a better choice?
Any advice would be most welcome.

03-01-2020, 01:56 AM   #2
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and ...

Have you tried either O-ME53 or focus peaking? The "edge highlight" feature in KP works pretty well.
03-01-2020, 02:09 AM   #3
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Here's another vote for the O-ME53 Viewfinder Magnifier and/or focus peaking in LiveView. Also, the Ref A right-angle viewfinder has a 2x magnifier built in and can be useful, especially in some macro situations, where reflections make the rear screen difficult to see.

If I understand correctly, one issue with a split-image screen in an a/f camera is that some of the light from the lens is "lost" through a half/silvered mirror (or similar), which is used for the a/f system, leaving an inherently dimmer image at the viewfinder screen anyway, so the split-image has even less light to work with than it would have done in a totally m/f camera.
03-01-2020, 02:42 AM   #4
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QuoteOriginally posted by kypfer Quote
Here's another vote for the O-ME53 Viewfinder Magnifier and/or focus peaking in LiveView. Also, the Ref A right-angle viewfinder has a 2x magnifier built in and can be useful, especially in some macro situations, where reflections make the rear screen difficult to see.

If I understand correctly, one issue with a split-image screen in an a/f camera is that some of the light from the lens is "lost" through a half/silvered mirror (or similar), which is used for the a/f system, leaving an inherently dimmer image at the viewfinder screen anyway, so the split-image has even less light to work with than it would have done in a totally m/f camera.
I hold the camera to my eye much of the time, so focus peaking, which does work very well on both the K3 and KP, is not the solution I want. I already use the magnifying eyecup, which is nice but really is not as good as a proper screen designed for MF.

You are correct in that some light is lost through the mirror for the AF system, but this has long been the case also for OTFP metering going back to pre-AF film days. Many film cameras still gave a perfectly good split image at f3.5 and a usable one at f4, others less so. For slower lenses, traditionally ground glass was preferred for accurate focus. For faster ones the split image or microprism collar was better.

Hence I am looking for answers from people who have used after-market screens, but thank you and others anyway for your suggestions. I should have made my requirements clearer in my original post!

03-01-2020, 02:44 AM   #5
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and I will further the vote for the O-ME53 viewfinder...

I don't have the benefit of an education/experience with film SLR's, so cannot comment on a change in focus screen...
03-01-2020, 03:31 AM   #6
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QuoteOriginally posted by richard0170 Quote
I hold the camera to my eye much of the time, so focus peaking, which does work very well on both the K3 and KP, is not the solution I want. I already use the magnifying eyecup, which is nice but really is not as good as a proper screen designed for MF.

You are correct in that some light is lost through the mirror for the AF system, but this has long been the case also for OTFP metering going back to pre-AF film days. Many film cameras still gave a perfectly good split image at f3.5 and a usable one at f4, others less so. For slower lenses, traditionally ground glass was preferred for accurate focus. For faster ones the split image or microprism collar was better.

Hence I am looking for answers from people who have used after-market screens, but thank you and others anyway for your suggestions. I should have made my requirements clearer in my original post!
Personally I also have an experience with another split K-3 screen on K10D and the difference was not so significant. It was much more convenient to use the focus-trap confirmation and recomposing.
03-01-2020, 04:25 AM   #7
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Although I use a split prism focus screen in one of my bodies, I find the impact it has on metering to be too much hassle - especially spot, and to some extent, centre-weighted. I can usually estimate EV compensation fairly reliably for matrix metering, but still end up having to chimp the image and - quite often - making further adjustment and re-taking the shot.

The O-ME53 doesn't guarantee absolute accuracy, I find it's sufficient for most manual focusing purposes. With practice, it's almost as good as focus peaking in Live View (magnified Live View is the most dependable, but not always practical)...
03-01-2020, 05:30 AM   #8
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QuoteOriginally posted by BigMackCam Quote
Although I use a split prism focus screen in one of my bodies, I find the impact it has on metering to be too much hassle - especially spot, and to some extent, centre-weighted. I can usually estimate EV compensation fairly reliably for matrix metering, but still end up having to chimp the image and - quite often - making further adjustment and re-taking the shot.
At what f stop does the split image blacken out? If it blackens out at f3.5 or 4, I would put a screen in the KP for use with faster MF primes. If f4 is still usable it would go in the K3, which would be used predominately for MF lenses.
I had not considered the impact on exposure, so thanks for the heads up. I am using the green button for most of my MF lenses and am OK with exposure compensation when necessary. Some of my MF lenses are already unreliable when it comes to accurate meter readings, so any further metering inconsistencies will not effect me too much. Indeed, it may just encourage me to use my handheld meter, which would be better practice in any event.

03-01-2020, 05:46 AM   #9
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QuoteOriginally posted by richard0170 Quote
As a happy owner of both the K3 and KP, and fortunate to have many legacy MF lenses in addition to modern AF primes, I have decided to insert a split image K3 screen from Focusing Screen .com into either the K3 or KP, probably the K3. Before I go ahead and order one though I would like some feedback about using the screen with slower lenses. My most used MF lenses are the K 50mm f4 Macro, M 100 f4 Macro and K 28mm f 3.5. Many (but not all) older film cameras would have the split image black out at f4, will the newer K3 screen suffer the same issues, and if so might there be a better choice?
Any advice would be most welcome.
I recently got back into photography (circa October 1919) after leaving it altogether back in the very early 1980s while still in film photography.

I started out with the Pentax K2, which had a microprism focusing screen. I found this almost never let me down, even when hand-holding an F5.6 400mm lens with a shoulder brace, shooting model aeroplanes (and the occasional bird) in flight. When, while twisting the focus ring of whatever lens I was using, the "bubbles" in the microprism suddenly "popped" clear, I knew I had focus, and could click.

When my K2 was stolen, and I tried to replace it, I found it was out of production, and I had to buy a Pentax ME (after which, of course the Pentax ME Super came out - grrrrr!). The ME unfortunately came with a split screen focusing system. I never completely got used to it. Often, one of the half-circles around the split would go black, and if too much of the content I was trying capture had vertical instead of horizontal lines - or was a flat surface without lines, the split screen left me stranded.

Now that I have gone digital (first a K50, now, joyfully, a KP), and even with the 1.2 viewfinder magnifier, I found I rarely achieve spot-on focus with my old legacy manual lenses. This is more so with the 135mm F3.5 and the 200mm F4. Not so bad with the 28mm 2.8 , the 50mm Macro F4, and the 85mm F2. As a result, I rarely use them, which is sad, because they were good lenses, and were part of the reason I returned to Pentax when I returned to photography.

But the main point of all this rant - if you are going to take the (financial) gamble on a focusing screen, I would seriously suggest you consider the focusingscreen.com EC-A microprism focusing screen.
Focusing Screen

Not that I have tried it, but I believe it has been tried by other pentax forum members on other pentax dslr cameras. When I first realized my problems with manual focus, I did a fair bit of "search" through the forums - and I suggest you use the forum search functions too, to check out the viewpoints and experiences of other members.

Why haven't I followed my own recommendation? Mainly financial - I am a 76 yr old pensioner with limited funds, and no experience of meddling with the insides of camera old or new, so I would not only have to buy the focusing screen, but pay someone reliable to install it.

OK - you have my 2c worth. In truth, I am very interested in this topic - I have read, searched, and re-searched, and posted, on it on more than one occasion in these forums. so would be most interested in other people's reactions to this point of view. And also, much interested to see if you take the leap, and if so, which way you go, and your assessment of the success or otherwise of your choice.


My only other comment - I did recently mount my 135mm manual lens, and switched on "catch in focus" just to see how well that would work. I only tried it in-doors, in relatively low light, so not a truly fair trial, but I got some respectable results. But trying to hold the camera still, while trying to twist the focusing ring smoothly while holding down the shutter button had its challenges
03-01-2020, 06:06 AM - 2 Likes   #10
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Not sure if I've got much to add..... but I fitted a S screen in my K5II to use with some K lenses.... sold the camera a few years ago.... and I have just purchased and fitted a S screen in a K1 a few weeks ago. I chose the S screen so the metering works ok still. I also have used 1.22x eyepieces with both. Anyway... the S screen does show the focus plane snaping in and out of focus better with both cameras. I've not had any real metering issues. The other day I had my DFA 150-450 on a tripod.... and swapped several times between my 2 K1 bodies (one with a S screen and one stock) and to my eye I could see about one stop or so of less light through the viewfinder with the S screen..... but it was still fine to use. Fitting the screen and shimming it was ok to do.

FWIW.... I'm hitting focus ok with my K50/1.2 most times with the S screen.

With the S screen I like that you don't need to centre things, focus and then reframe.... you can see focus off centre.

Manual focusing the 150-450 worked well chasing birds in follage as well..... I may even add a S screen to my second K1.


Last edited by noelpolar; 03-01-2020 at 06:19 AM.
03-01-2020, 08:56 AM   #11
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QuoteOriginally posted by K2 to K50 Quote
Why haven't I followed my own recommendation? Mainly financial - I am a 76 yr old pensioner with limited funds, and no experience of meddling with the insides of camera old or new, so I would not only have to buy the focusing screen, but pay someone reliable to install it.
I have changed screens on other cameras - Nikon FM2 and Pentax MX. It is not job which requires a technician, just a little bit of care.
03-01-2020, 10:57 AM   #12
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QuoteOriginally posted by richard0170 Quote
Before I go ahead and order one though I would like some feedback about using the screen with slower lenses. My most used MF lenses are the K 50mm f4 Macro, M 100 f4 Macro and K 28mm f 3.5.
If you are considering a screen cut down from the Nikon K3 (same as in the FM2?), it will resist blackout to about f/8. Note that any split-image screen will effectively make spot metering unusable on the K-3 or KP.


Steve

Last edited by stevebrot; 03-01-2020 at 11:19 AM.
03-01-2020, 11:29 AM   #13
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I would advise against a split image screen for your slower lenses.

These screens are cut down FF screens, so the focus aid portion is proportionately BIGGER on a crop camera. Bigger and really dark. Makes it hard to properly see the image you're composing. I'm speaking of my experience with a KatzEye screen and f3.5 lenses.

IMHO you're better off with the "S" type screen.
03-01-2020, 02:05 PM   #14
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QuoteOriginally posted by johnyates Quote
These screens are cut down FF screens, so the focus aid portion is proportionately BIGGER on a crop camera. Bigger and really dark. Makes it hard to properly see the image you're composing. I'm speaking of my experience with a KatzEye screen and f3.5 lenses.
On the table behind me is my K-3 with Katz Eye screen installed mounted to an SMC Tak 28/3.5. The split image does appear larger than that on my Ricoh XR7* (also on the table behind me), but the degree of darkness/dimness is the same on both cameras.** Stopping down to f/11 with A/M switch on M, the split-image is still not blacked out and remains usable. I would expect a K3-derived screen from focusingscreen to be similar in performance since that is one of that screen's signature features. An f/3.5 lens will appear dim with even the best screens, but that is just how it is.

So...respectfully, not my experience.

As for use of slower lenses with an S-type screen, Canon does not recommend for maximum apertures narrower than f/2.8 and neither do I (again, personal experience with an Ec-S).


Steve

(...used the DA 18-55/3.5-5.6 on my K10D with a Katz Eye for several years...)

* Comparable to the excellent ME Super viewfinder

** In all fairness, the SMC Tak 28/3.5 truly sucks with the viewfinder on my Spotmatic F, a body supposedly designed for use with that lens.

Last edited by stevebrot; 03-01-2020 at 02:17 PM.
03-01-2020, 03:10 PM   #15
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QuoteOriginally posted by richard0170 Quote
At what f stop does the split image blacken out? If it blackens out at f3.5 or 4, I would put a screen in the KP for use with faster MF primes. If f4 is still usable it would go in the K3, which would be used predominately for MF lenses.
I had not considered the impact on exposure, so thanks for the heads up. I am using the green button for most of my MF lenses and am OK with exposure compensation when necessary. Some of my MF lenses are already unreliable when it comes to accurate meter readings, so any further metering inconsistencies will not effect me too much. Indeed, it may just encourage me to use my handheld meter, which would be better practice in any event.
It's a while since I shot my body with the split prism focus screen, however... I don't recall running into blackening-out of the split image with any of my lenses wide open, up to and including those with f/4 maximum aperture. I do have a vague memory of experiencing it with an older manual aperture or preset lens, stopped down considerably.

Regarding the metering, I think the general consensus is that matrix metering will either be largely unaffected or out by a small, fairly consistent EV correction (say, 1/3 EV), centre-weighted should be similar, but spot metering is unpredictable and therefore not recommended. In practice, I remember having problems even with centre-weighted, so I ended up shooting in matrix metering all the time. And then, as I recall, the EV adjustment required seemed to differ lens to lens, depending (I believe, but can't be certain) on maximum aperture. Then again, even without a split prism focus screen, it can be necessary to compensate for EV differently for individual lenses, so perhaps that problem wasn't entirely down to the screen in my case.

The other potential gotcha to think about is "shimming". Due to minor differences in thickness of individual focus screens and manufacturing tolerances in the camera, it can be necessary to add shims to achieve the correct distance for the focusing screen to the mirror. This can be done with pre-made shims, but I've never been fortunate enough to own any of those. Scotch tape, cut into thin strips, is a fiddly but practical alternative.

I'm tempted to shoot with mine again soon to see if I get along with it better...

Last edited by BigMackCam; 03-01-2020 at 04:43 PM.
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