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11-15-2011, 11:19 PM - 6 Likes   #1
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The Great Focusing Screen Revelation

Executive Summary
Buy the Canon Ec-A, it is super good.

The Long Version
I've tried the K3 based screen from focusingscreen.com, which is of similar layout and type to the offerings from KatzEye, and the Ec-A is absolute night-and-day better than that screen.

I there is a certain romance about manual focus lenses. The well-damped focus rings, the now (mostly) absent depth-of-field scales, the built-like-a-tank-ness of the old Taks and the new Zeiss and Voigtlanders. It's a wonderful experience.

That is until you try to focus them.

Now I knew what I was getting into when I went mostly manual, and I was proactive and got myself a screen. Did some reading and found that the K3 seemed like a popular option. It had the split prism and microprism collar I grew familiar with in an old Olympus OM-4T. And I got some great pictures. The K3 was miles ahead of the ME-60 or whatever comes stock in the K5.

But recently I've done a couple of photo shoots. Engagement pictures. Some newborn pics. Stuff where timing is everything and sharp focus is critical. Needless to say, my keeper ratio was disappointingly low. Pictures that I thought were in focus were ever so slightly, but ever so critically, out of focus. Despair! I love my lenses (especially the Zeiss 85 (holy man!)), but how could I continue with such a hit or miss keeper ratio?

I thought about it. Selling them. All of them. But, I decided to hold off and purchase the Ec-A. I had done some reading and stumbled across some information on it. It was a microprism spot only. No split prism. This was just fine with me. I always had better results with microprisms anyway. More importantly, it does not use a micro-array of honeycomb shaped lenses, it has a true matte (ground glass) finish. This is huge for anyone using fast primes. It gives a much, much stronger impression of what in focus is. It is like night and day between the K3 and Ec-A.

Now I bought mine off of ebay (uncut) and cut it myself, which was a bit of a harrowing experience, but focusingscreen.com also carries precut ones (provided they are in stock). Either way, if you are in the market for a new screen, I'd put my money on the Ec-A.

You can check out more technical information on the matte area of the Ec-A here and the more traditional micro-array (often called precision matte) here.


Last edited by feilb; 11-16-2011 at 08:39 AM.
11-15-2011, 11:28 PM   #2
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Thank you for this excellent post!
I will most certainly give the Ec-A a try in my K-5. - sounds exciting.

Having said that, I have a few questions that you may be able to answer.

1. Any idea how good focusing accuracy is with the faster lenses(f/2 and wider)?
2. Do you know what the differences are between the Ec-, Ec-B and Ec-L screens?
3. Do these screens affect metering?

Thanks again for sharing this with us btw.

Last edited by JohnBee; 11-15-2011 at 11:35 PM.
11-16-2011, 12:16 AM   #3
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1. The accuracy is excellent. Even my 55/1.2 is accurate with the screen. That to say, I can get accurate focus off of the matte part of the screen even at f/1.2.

2. I believe that the B and L have the same matte area, the primary difference being the split prisms.

3. It does have an effect on spot and center weighted metering for lenses with max apertures of f/4 or greater in my experience. In practice, the only way i run into this is with the 55/1.2, which uses stop-down metering. That being said, frame averaging appears unaffected.
11-16-2011, 01:52 AM   #4
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How does it compare to the canon EE-S? That has an ongoing thread here about how good and accurate the metering is with it. Does the micro prisms in the EC-A affect spot metering for you?

11-16-2011, 05:45 AM   #5
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Thank you for the post. Any idea if this can be used in a k20d? Edit: Nevermind the qn. I see that focusingscreen.com does list a custom version of this for k20d
11-16-2011, 06:38 AM   #6
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QuoteOriginally posted by gtl Quote
How does it compare to the canon EE-S? That has an ongoing thread here about how good and accurate the metering is with it. Does the micro prisms in the EC-A affect spot metering for you?
Seconded Especially how does it compare with your f1.2 lens? The reason people are interested in the EE-S is that it will enable you to check focus on very fast lenses. The stock screen (and presumably the K3 too?) supposedly only resolve up to about f2. The EE-S thread is here.
11-16-2011, 07:36 AM   #7
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QuoteOriginally posted by thoughton Quote
Seconded Especially how does it compare with your f1.2 lens? The reason people are interested in the EE-S is that it will enable you to check focus on very fast lenses. The stock screen (and presumably the K3 too?) supposedly only resolve up to about f2. The EE-S thread is here.
I can't speak directly to the EE-S screen as i have not personally used it. That being said, the links i posted above (the last line of the original post) have some more detailed information about both the EE-S and EC-A screens (someone over at dpreview had done extensive research into both). Fundamentally, the EE-S screen has a very uniform honeycomb-array of small, domed, hexagonal lenses cut into the surface. The EC-A has a very fine ground-glass texture to it.

That being said, the matte area on the EC-A is the best way to focus my f/1.2. I can reliably get spot-on focus from the impression using the matte area (I find microprisms more useful for quickly focusing, matte area for precision focusing). With the K3, there was simply no way to get reliable focus confirmation at 1.2.

Last edited by feilb; 11-16-2011 at 07:51 PM.
11-16-2011, 07:41 AM   #8
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QuoteOriginally posted by gtl Quote
How does it compare to the canon EE-S? That has an ongoing thread here about how good and accurate the metering is with it. Does the micro prisms in the EC-A affect spot metering for you?
The microprisms do not affect spot metering as long as the lens is f/4 or faster. I've found that at f/5.6, the screen causes over exposure, likely due to the darkening of the prisms. This is not a substantial issue with frame-averaging metering.

I wish I would have done a more scientific study on exposure with the stock screen. I could swap and do an experiment, but my shims are placed perfectly and there is no dust on the screen at present .

11-16-2011, 11:20 AM   #9
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Great thread by the way!

This type of focusing screen might solve the problem I am having with focusing acurately, wide opened, with those lenses I have:

Zeiss T*Planar 85/1.4
Vivitar 135mm f/2.8 1:2 Close Focusing
Cosina 55/1.2

I usually use the K7 with those lenses. Once installed, would the EC-A screen also work accurately with ANY lens, even AF ones?

If I decided to install such a screen on the K5 as well, should I expect focusing/metering problems while using other lenses such as DA*16-50, DA*300, FA Limited's (43, 31) ... etc. ?

Is this a tedious job to install the said screen? Do you need to be experienced as to avoid any fitting issues?

Thanks.

JP
11-16-2011, 11:59 AM   #10
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QuoteOriginally posted by jpzk Quote
Great thread by the way!

This type of focusing screen might solve the problem I am having with focusing acurately, wide opened, with those lenses I have:

Zeiss T*Planar 85/1.4
Vivitar 135mm f/2.8 1:2 Close Focusing
Cosina 55/1.2

I usually use the K7 with those lenses. Once installed, would the EC-A screen also work accurately with ANY lens, even AF ones?

If I decided to install such a screen on the K5 as well, should I expect focusing/metering problems while using other lenses such as DA*16-50, DA*300, FA Limited's (43, 31) ... etc. ?

Is this a tedious job to install the said screen? Do you need to be experienced as to avoid any fitting issues?

Thanks.

JP
JP, I've had great results with 2 of the 3 lenses you mention (I have the Zeiss 85 (great lens by the way), and the Ricoh 55/1.2, which is fundamentally identical to the Cosina). The 3rd i haven't had experience with, but if you can accurately hit the 55 and the 85 wide open, the 135 will be easy.

The focusing screen has no impact on autofocus. There is a separate sensor used to detect focus that does not depend on the screen. As a result, you could theoretically put a black piece of plastic in for a screen and still achieve auto-focus.

Your success in metering properly will depend on the max aperture of the lens. Specifically, lenses f/4 or faster will likely not experience any ill-effects (based on my test, f/5.6 starts to cause issues). All of the lenses you listed above are f/4 or faster and shoudn't have an issue. Lenses slower than f/4 will require exposure compensation.

As far as installing it, I would say the thought of opening up your camera and fiddling with the internal bits is much more nerve-wracking than the actual experience. In reality, there is one tab you push and the focusing screen pops right out. Probably the most challenging part of the ordeal is shimming the screen to provide proper focus. This isn't difficult if you use thin strips of tape on the very edges of the screen, but if you use clear plastic spacers like those provided by focusingscreen.com, alignment can be a challenge. All in all, its not to difficult. I'd recommend a rocket blower to get the dust out.
11-16-2011, 01:03 PM   #11
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I experimented with a lot of focus screens in my K7, even cut some screens of a Pentax MX, a Pentax MV, some Nikon and some Canon screens. And i have bought a screen at focusscreen.com. But none of them did what i tought they should do and they all forced me back to the original screen with all the none problems with manual settings.
So i ordered a screen again at Katzeye. It is in the mail right now, but my former experiances with my K100D are superb.

Last edited by Sakura; 11-16-2011 at 01:15 PM.
11-16-2011, 01:19 PM   #12
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QuoteOriginally posted by feilb Quote
JP, I've had great results with 2 of the 3 lenses you mention (I have the Zeiss 85 (great lens by the way), and the Ricoh 55/1.2, which is fundamentally identical to the Cosina). The 3rd i haven't had experience with, but if you can accurately hit the 55 and the 85 wide open, the 135 will be easy.

The focusing screen has no impact on autofocus. There is a separate sensor used to detect focus that does not depend on the screen. As a result, you could theoretically put a black piece of plastic in for a screen and still achieve auto-focus.

Your success in metering properly will depend on the max aperture of the lens. Specifically, lenses f/4 or faster will likely not experience any ill-effects (based on my test, f/5.6 starts to cause issues). All of the lenses you listed above are f/4 or faster and shoudn't have an issue. Lenses slower than f/4 will require exposure compensation.

As far as installing it, I would say the thought of opening up your camera and fiddling with the internal bits is much more nerve-wracking than the actual experience. In reality, there is one tab you push and the focusing screen pops right out. Probably the most challenging part of the ordeal is shimming the screen to provide proper focus. This isn't difficult if you use thin strips of tape on the very edges of the screen, but if you use clear plastic spacers like those provided by focusingscreen.com, alignment can be a challenge. All in all, its not to difficult. I'd recommend a rocket blower to get the dust out.
Thanks a whole bunch!

This would actually help me a GREAT lot with those manual focus lenses then! And, as you say, it would work with my existing other (AF) lenses.

So, I went and Google'd a bit to find detailed instructions regarding the installation of the screen but did not come across much at all in terms of "visual"instructions and "shimming" aid !
This here: --Pentax K5/K7/K10D/K20D/ISTD Focusing Screen Installation Instruction-- shows basic instructions (visually, thank God) but nothing about shims.
I also did find out that there were two different types of those screens as shown in this link, which I gather would work on either the K7 and/or K5 (which one is the one you have?):
Focusing Screen

You mention "Probably the most challenging part of the ordeal is shimming the screen to provide proper focus. This isn't difficult if you use thin strips of tape on the very edges of the screen"

I am looking for a visual "help" regarding this bit!

Yeah, I think I am a bit reluctant to attempt a screen fit on my camera(s) ... I am perhaps afraid to do something which I would regret later. That is why I am asking so many questions.

Thanks again!

JP
11-16-2011, 02:20 PM   #13
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I have the EC-A in my K10D, and I find it very helpful for focussing with the Tamron SP 2,5/90 (with 1,4x TC) and the Pentax DA* 4/300 (with the 1,4x TC the microprism don't work very well, and with a 2x TC they are useless). Spot-metering is very off, at least with the 300.

I just bought a K5 and a EC-S screen, but I don't have it cut down yet. I will try within some time (very occupied right now).

Cheers - Klaus
11-16-2011, 02:22 PM - 1 Like   #14
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JP, have a look at this link, which explains (in rather broken english) why shimming may be necessary and where the shims go.

Basically, the distance light travels when it enters the lens and hits the focusing screen must be identical to the distance light travels when it enters the lens and hits the sensor (when the mirror is up) in order to indicate accurate focus. Placing spacers (shims) to adjust this distance is likely necessary to get the distance just right.

The screens from focusingscreen.com come with 2 small rectangles of clear plastic that sit between the screen and the flange the screen sits on. The stock screen has a metal spacer that must be removed and these two spacers put in its place (at least in my case, both were necessary).

Placing the spacers and the screen isn't too difficult. The problem is that the spacers can slide when you snap the screen into place. The result will be that the edges of the spacer are visible in the view finder. Fixing it isn't much of a big deal, just pop out the screen and adjust them. I find that holding the camera upside down and setting the screen on top of the spacers helps.

The reason I say it's the most challenging part is that any time you take the screen out, you risk a spec of dust landing on the screen. This is where the rocket blower comes in. Put the spacers in, give a couple light blasts of air, place the screen in, snap the holder down, and blast a couple of more times. Works effectively. In reality, you may repeat this process a couple of times to get things just right, but after the first time you put the screen in, taking it out and making adjustments won't feel like that big of a deal, just a bit fiddly.

For those that cut their own screen, you can place scotch tape as a spacer on the very outline of the screen and then trim it so there is no extra tape extending past the edges of the screen. A couple of layers would probably work. This would probably be easier as the tape won't slide around.
11-16-2011, 03:43 PM - 1 Like   #15
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Here's a couple diagrams to offer some help.

The first shows the relative positions of each relevant part.



The second shows the flange where the spacers get placed. The screen is then placed on top of the spacers (assuming you are holding the body upside down).


Last edited by feilb; 11-16-2011 at 07:49 PM.
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