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06-06-2014, 06:43 PM   #691
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QuoteOriginally posted by tromboads Quote
just to add more to this ongoing metering sager, well a video might be most useful to explain...

YouTube

Did we previously know about back light, / stray light through the eye piece effecting the metering? Or did we file that under only older cameras were affected by this?
No, that affects all of them, and yes we know about it.

So I've been doing some testing with the K-5 w/ the S-screen with AF frame. I can get discrepancies between live view and viewfinder metering of up to 2 stops with the slowest lenses (f/5.6 or slower) in some conditions with matrix metering. With center-weighted metering, it usually is no higher than .7 EV different, but under rare conditions will go to 1.3 EV. It varies a lot lens to lens. Will provide more details later...

06-07-2014, 11:00 AM   #692
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QuoteOriginally posted by DogLover Quote
Kinda blows my mind that you'd prefer to give that up to get the more predictable (for you) metering of the stock screen. That's certainly your choice to make, but this forum is chock-a-block with folks who feel quite differently. I have one in both my current bodies and will continue to use them for the foreseeable future. They just plain make manual focusing much more precise, something at which the stock screen is woefully inadequate.
At a certain point I ask myself whether it's worth it. My screen makes metering wildly inconsistent, and it's becoming more trouble than it's worth to remember which lens needs how much adjustment. My 35/2.8 needs nothing at all, but my 43 needs -0.7--except for the days that it needs -1.0. I didn't have these issues before installing this screen, and I don't have nearly enough time to play with every pic in RAW. As it stands, my MF glass has been relegated back to my K-01 and I put the stock screen back in the K5. I'm not sure what I'm going to do with it going forward.
06-07-2014, 11:30 AM   #693
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QuoteOriginally posted by vonBaloney Quote
So I've been doing some testing with the K-5 w/ the S-screen with AF frame. I can get discrepancies between live view and viewfinder metering of up to 2 stops with the slowest lenses (f/5.6 or slower) in some conditions with matrix metering. With center-weighted metering, it usually is no higher than .7 EV different, but under rare conditions will go to 1.3 EV. It varies a lot lens to lens. Will provide more details later...
Ah, that might be why I get "just" one stop (or so) underexposure for certain bright scenes with slow lenses - I tend to use center weighted metering. Also a K-5, S-screen w/markings.
06-07-2014, 03:20 PM   #694
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Ok, I just did a quick and dirty test. First of all, turns out the s-screens in both my bodies have the grid lines (rectangles in each corner). I've been saying my K-3 screen had no markings, but I was misremembering. These markings are in different spots, obviously, than the AF-area markings, but they are still in areas where they could affect metering in any mode other than center spot.

First I tried my Zeiss 100/2 and 50/2 and found absolutely no difference between LV and normal VF mode. This was in average light, and center-weighted metering. Tried my 50-135/2.8 and again found no difference at all. Then I tried the 15/4 and did indeed find 1/1.5 stops underexposure on the K-3 and, interestingly, only 1/3 of a stop on the K-5IIs. So there you go.

I gotta say, though, I still don't find this to be a big deal at all for me. I obviously shoot fast lenses the vast majority of the time which are completely unaffected, and when I do use a slower lens I'm not really worried about it because I shoot RAW exclusively and can easily fix underexposure. If it's a sensitive subject or setting where I need to preserve every bit of the bottom end, and I happen to be using one of my 2 slower lenses, then I can dial in some EV Comp. Are you guys all jpeg shooters?

The pros of the s-screen far outweigh this minor (to me) con. I just started (attempting) to shoot hummingbirds at a feeder just outside our window. Within the first couple of shots I could see that this would be impossible for me without this screen, and that's just the latest of many of these instances over the years that I have been using it. I remain committed to it's use indefinitely.

06-07-2014, 04:01 PM   #695
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Yep. And if my K10 breaks it sounds like there will be plenty of second hand screens for me to buy :P
06-07-2014, 08:21 PM   #696
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QuoteOriginally posted by DogLover Quote
First I tried my Zeiss 100/2 and 50/2 and found absolutely no difference between LV and normal VF mode. This was in average light, and center-weighted metering. Tried my 50-135/2.8 and again found no difference at all. Then I tried the 15/4 and did indeed find 1/1.5 stops underexposure on the K-3 and, interestingly, only 1/3 of a stop on the K-5IIs. So there you go.
This matches my results. No impact on fast lenses. Rather significant (1-1.5 stop) on slow lenses. Unfortunately the slow lens impact is somewhat depending on the subject.

QuoteOriginally posted by DogLover Quote
I gotta say, though, I still don't find this to be a big deal at all for me. I obviously shoot fast lenses the vast majority of the time which are completely unaffected, and when I do use a slower lens I'm not really worried about it because I shoot RAW exclusively and can easily fix underexposure. If it's a sensitive subject or setting where I need to preserve every bit of the bottom end, and I happen to be using one of my 2 slower lenses, then I can dial in some EV Comp. Are you guys all jpeg shooters?
I am only shooting RAW. Just like not having the benefit of the focusing screen, the 1.5 stop in critical situations may make the difference between a OK photo you can mostly save or a really great photo that preserves critical details. In short this screen has pluses and minuses: I have not been able to use manual focus lenses until now, but considering I have a number of slower AF lenses this screen is definitely a comprise. I hope I can use the screen on my backup K-5 where the impact might be less (I'll find out) and I can make that camera my goto for manual focus lenses for now.

I do think it is critical that people are aware of the short comings of this screen as well as the advantages, and allow everyone to make an educated decision as to whether it will work for them or not.

Last edited by HenrikDK; 06-07-2014 at 08:32 PM.
06-07-2014, 08:28 PM   #697
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QuoteOriginally posted by HenrikDK Quote
This matches my results. No impact on fast lenses. Rather significant (1-1.5 stop) on slow lenses. Unfortunately the slow lens impact is somewhat depending on the subject.


I am only shoot RAW. Just like not having the benefit of the focusing screen, the 1.5 stop in critical situations may make the difference between a OK photo you can mostly save or a really great photo that preserves critical details. In short this screen has pluses and minuses: I have not been able to do use manual focus lenses until now, but considering I have a number of slower AF lenses this screen is definitely a comprise. I hope I can use the screen on my backup K-5 where the impact might be less (I'll find out) and I can make that camera my toto for manual focus lenses for now.

I do think it is critical that people are aware of the short comings of this screen as well as the advantages, and then make educated decision as to whether it will work for them or not.
I really wish Pentax would offer a similar screen or adjust the firmware for it. The EE-S is just fantastic for focusing.
06-07-2014, 08:39 PM   #698
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QuoteOriginally posted by tromboads Quote
Did we previously know about back light, / stray light through the eye piece effecting the metering? Or did we file that under only older cameras were affected by this?
It is a problem with all SLR cameras with built-in TTL metering. That is why the camera ships with an eyepiece cover. My late-70s Ricoh XR-2s even has a nifty eyepiece shutter. In general the effect is fairly small, but when doing stop-down metering it can cause a huge bias. I was careful when I did my testing to make sure that the eyepiece was covered.


Steve

---------- Post added 06-07-14 at 08:43 PM ----------

QuoteOriginally posted by DogLover Quote
I'm not really worried about it because I shoot RAW exclusively and can easily fix underexposure.
I shoot RAW exclusively as well and can guaranty that the 1.5-2 stops of shadow detail lost are quite irretrievable for a full-range subject. Ditto for the lost contrast. I am pretty handy with the PP, but was unable to salvage several shots from my final outing with the S type screen.


Steve

06-07-2014, 10:33 PM   #699
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QuoteOriginally posted by stevebrot Quote
It is a problem with all SLR cameras with built-in TTL metering. That is why the camera ships with an eyepiece cover. My late-70s Ricoh XR-2s even has a nifty eyepiece shutter. In general the effect is fairly small, but when doing stop-down metering it can cause a huge bias. I was careful when I did my testing to make sure that the eyepiece was covered.


Steve

---------- Post added 06-07-14 at 08:43 PM ----------



I shoot RAW exclusively as well and can guaranty that the 1.5-2 stops of shadow detail lost are quite irretrievable for a full-range subject. Ditto for the lost contrast. I am pretty handy with the PP, but was unable to salvage several shots from my final outing with the S type screen.


Steve
I think that depends. I don't doubt that some shots that are 2 stops underexposed are ultimately not "fixable," especially if your final image size is inordinately large or contains a heavy crop of the affected area, but many are absolutely usable, and I'm quite picky. The sensor in the K-3 (and really, even the K-5) is nothing short of remarkable when it comes to retaining shadow detail. Indeed, I get giddy sometimes when I see what it can do.

What I'm getting at is that for some people, myself included, we keep getting into smaller and smaller subsets of instances where the s-screen might cause an annoyance. For me in particular the subset is pretty danged tiny. I realize that not everyone is like me and I'm not even trying to say that there are more like me than there are like you, I just don't want everyone trying to make a decision on this issue to think that the s-screen is automatically going to underexpose every image to an untenable level. I know that's not what you said, but that's what some people will take away from your post. Just trying to provide a yin to your yang.

Last edited by DogLover; 06-07-2014 at 10:43 PM.
06-08-2014, 06:02 AM   #700
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I would STILL like to see results from someone with an unetched screen. Anyone?
06-08-2014, 06:06 AM   #701
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Haven't we been over this already? Oh you mean on a K5 / K5ii / K3.

For a screen that is designed to make manual focusing easier, for me it does just that. I = happy.

I'm sorry there have been a few of you whom have been mucked around by metering issues, it must be frustrating knowing they won't honour a refund
06-08-2014, 07:59 AM - 1 Like   #702
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QuoteOriginally posted by HenrikDK Quote
I would STILL like to see results from someone with an unetched screen. Anyone?
Unetched S-type screen on K-5

With the A50/1.2, using spot metering, Av mode, Live View (LV) consistently chooses a shutter speed one increment faster (I have the camera set to 1/3-stop increments) than with LV off. That is, VF metering overexposes 1/3 of a stop compared to LV. Whether or not the VF cap is in place doesn't make much difference (maybe a slight one). With matrix metering, there is no difference between VF and LV metering.

With the A400/5.6, spot metering again gives 1/3-stop overexposure using VF metering (as compared to LV). No difference with or without VF cap. Matrix metering gives a very different result. Without the VF cap, VF metering overexposes by a full stop. With the cap, the overexposure is reduced to 2/3 of a stop.

Addendum:

The above testing was with a uniform gray wall as a subject. Using a high-contrast scene, matrix metering, now the A50/1.2 overexposes by 1/3 stop, but the A400/5.6 exposure is correct. Go figure.

Last edited by baro-nite; 06-08-2014 at 08:08 AM. Reason: Addendum
06-08-2014, 08:22 AM   #703
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QuoteOriginally posted by baro-nite Quote
Unetched S-type screen on K-5

With the A50/1.2, using spot metering, Av mode, Live View (LV) consistently chooses a shutter speed one increment faster (I have the camera set to 1/3-stop increments) than with LV off. That is, VF metering overexposes 1/3 of a stop compared to LV. Whether or not the VF cap is in place doesn't make much difference (maybe a slight one). With matrix metering, there is no difference between VF and LV metering.

With the A400/5.6, spot metering again gives 1/3-stop overexposure using VF metering (as compared to LV). No difference with or without VF cap. Matrix metering gives a very different result. Without the VF cap, VF metering overexposes by a full stop. With the cap, the overexposure is reduced to 2/3 of a stop.

Addendum:

The above testing was with a uniform gray wall as a subject. Using a high-contrast scene, matrix metering, now the A50/1.2 overexposes by 1/3 stop, but the A400/5.6 exposure is correct. Go figure.
Well, I think all tests should be done covering the viewfinder -- not doing so will mess things up with any screen (how much so being highly dependent on how much light is hitting the back of the camera). I'd be most interested in results with matrix metering with lenses f/2.8 or slower...that's where I'm seeing the big differences with the etched screen on the K-5, all underexposed with VF compared to LV with the exception of one lens which consistently would be exactly opposite.
06-08-2014, 08:25 AM   #704
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I did a lot of testing, but I got to say I generally found some inconsistencies that align with HendrickDK's. Hardly a big deal, being that I don't have very many slower lenses and I am quite prepared to use exposure compensation in any case. Thinking back to before I had the screen, I still had to use exposure compensation with some lenses and shooting scenarios.

I also didn't try a proper test with the original stock screen. So for me, I have never actually really proven how much of this is the ee screen, and how much of it is simply due to differences between VF and LV metering.

Did anyone try the stock screen with LV and viewfinder metering? I would be really surprised to hear that it is not possible to see some difference between the two methods using the stock screen under some circumstances. I think that most people with more than a couple of lenses (especially slower, older or third party) who can't find some requirement to compensate with some of them.

For me, the MF performance of the screen outweighs any issues with metering. And I am not expecting perfection 100% of the time even if I put the stock screen back in! YMMV, of course.
06-08-2014, 08:33 AM   #705
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I used the ees on my K-5 for a long time, it was a big improvement over the stock screen. The K-3 viewfinder is much better; I can focus my 1.4 50. I shot f2.8 and f4 long lenses, 300mm and 400mm with this screen without a problem. The exposure was consistent, slightly underexposed. In low light conditions the screen darkens; it is not linear, but exponential, at one point it goes black.

To reiterate. The purpose of this screen is to allow you to manually focus a lens faster than f2.8. If you shoot with anything slower than f4, don't. It doesn't work well, and sometimes it doesn't work at all. The benefits in the K5 are worth the restrictions, but with the K-3 only someone who shoots f1.2 or f1.4 lenses manual focus all the time may benefit.

Wade through the thread. All these issues have been discussed in detail.
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