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Homemade Pentax K10D ground glass screen
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PostPosted: Sat Feb 21, 2009 11:14 am    Post subject: Homemade Pentax K10D ground glass screen Reply with quote
I got a bit fed up with the unusable focusing screen of my Pentax K10D, which made everything look sharp even if it wasn't. So I grabbed a defective Pentax ME-Super which has a nice ground glass screen with microprisms and a horizontal wedge (I don't like the diagonal ones). I did the following:

- Remove the ground glass screen from the ME-Super. For that I had to remove the whole top plate and prism assembly.

- Remove the ground glass screen from the K10D. This is easy through the mirror box.

- Wear a pair of latex gloves, and grind the sides of the new screen on a piece of fine sandpaper. It's impossible to keep the sides 100% straight but it can be done. Do this for all sides until the size of the new screen is the same as the old one.

- Clean the new screen with a can of compressed air (don't move it while blowing, as this will spray moisture on the screen!)

- Put the new screen in the ground glass screen frame of the K10D (notice that the grounded side of the ground glass must be in the UP position), and push it up until it clicks in place.

My first reaction: the screen is not as clean as I thought. But there's not more dust on it than on the original one, so I'm still happy Very Happy

My first reaction when looking through the viewfinder, focusing a 50mm f/1.8 Carl Zeiss Jena Pancolar Zebra: WOW! I've waited for 7 years but I have now my favorite screen back... And focusing is a breeze now, even if I only use the matte part of the screen. No more unsharp pictures from now on unless I want them to.

The screens. The top screen is from the ME-super, already grinded, and the bottom one is the orginal one from the K10D. The tab is not really necessary, it only makes removing the screen easier.




The screen already installed. Who wouldn't love the sight of a really usable ground glass screen




I focused on the "H" here.


The first time with my K10D I got the focus immediately right: perfectly in the middle of the screw.


Razz


PostPosted: Sat Feb 21, 2009 11:54 am    Post subject: Reply with quote
Excellent!


PostPosted: Sat Feb 21, 2009 12:34 pm    Post subject: Reply with quote
Have you used the chinese split screens from ebay or a katzeye? Is the ME-Super screen better?


PostPosted: Sat Feb 21, 2009 12:37 pm    Post subject: Reply with quote
Thanks Carsten!

ovim wrote:
Have you used the chinese split screens from ebay or a katzeye? Is the ME-Super screen better?


I really cannot answer that question because this is the first and only time I replaced the screen. But I supposed it should not be worse as I liked the screen from my ME-Super, which I used until the year 2000, a lot.


PostPosted: Sat Feb 21, 2009 4:49 pm    Post subject: Reply with quote
Nice one! I did use a cheap chinese screen for my K100D and it worked fine, just won't fit the K10D, I use an LL-60 screen for *istD for that, seems to be ok for me anyway, but its a great idea for making an alternative. Very Happy Very Happy


PostPosted: Sun Feb 22, 2009 11:57 am    Post subject: Reply with quote
Great work! You've just given me a another job to do! Smile


PostPosted: Thu Mar 05, 2009 9:15 pm    Post subject: Reply with quote
I have a me super to spare any way to do transplant onto Canon 20D ?


PostPosted: Fri Mar 06, 2009 2:07 am    Post subject: Reply with quote
I have both these cameras and I agree about the useless standard screen. I got one from Virtual Village which has the horizontal wedge etc. and works well, but a very interesting approach you have - I must try that too...

By the way.. this sentence in your piece confused me.. it seems to contradict itself:

".... It's impossible to keep the sides 100% straight but it can be done. ..."

Doug.


PostPosted: Mon Apr 13, 2009 2:05 pm    Post subject: Reply with quote
Very Interesting.

I have looked at the Katzeye - but sooo expensive.

Also I have read conflicting reports about the chinese screens. Ebay feedback implies that many people have problems with them (because people cant use them properly? or poor quality?)

Has anyone done this with an olympus e-1? What donor did you use?

thanks


PostPosted: Mon Apr 13, 2009 4:36 pm    Post subject: Reply with quote
I have a chinese 10$ (incl shipment) screen in my K10D, which seem to look the same as the ME one here. I have no problem with it. However a friend of mine has, from the same seller. Funny part is that we cant tell them apart. But I hear that the thickness can inflict some strange behaviour of them. Dunno really.

What really pains me is the darkness, even though the splitscreen is alot better, it is also alot darker then the original one. This is where Katzeye might be interesting, the matte part of the Katz eye is very bright. According to their site, even the center does not black out until f8. The one I got is near blackout at f4. Basically, i recommend that if you use lenses at f2.8 and lower, a cheap chinese is for you. Slower then that, stick to the original or buy a proper modern made one. I cant really use a few telelenses thats f8 at all. And even the 20/4.5 i have is a pain to focus with the chinese one. The 1.4 and 1.8 lenses I have is a dream come true though.


PostPosted: Mon Apr 13, 2009 4:54 pm    Post subject: Reply with quote
The real problem lies not in the screen but rather in the mirror.
Modern AF cameras have a semi-silvered Mirror that allows light to pass thrugh it to the AF/metering module mounted below.
This Mirror does not send a full transmition of light to the prism or thrugh the focus screen.
To use a light hungry matte screen with a semi-silvered mirror you will have a darker VF.
Katzeye and some others machine their screens from old Eos-1 screens (at least in the case of canons).
These screens are less light hungry but also have less contrast for manual focus use (they were made for AF use originally).

Sorry guys. There is no perfect solution to the focus screen problem.
The AF cameras are designed for AF. There is no way around it Rolling Eyes


PostPosted: Mon Apr 13, 2009 5:05 pm    Post subject: Reply with quote
My Pentax ME Super has a Split image screen but many Pentax SLRs had the ground glass one.
To state the obvious you can use any screen from any old SLR you can find, there are many at car boot/garage sales. The last one I tried was from a Praktica.
It’s a straight forward job but I found a good timesaver was to use an orbital sander in a jig to grind the screen to size. To clean the screen leave to soak in warm water with a little washing up liquid then rinse off with clean water, the final rinse should be distilled water or use tap water with just a drop of wetting agent in it. Leave to dry naturally.

This really is a good alternative to the screens on sale at an often over inflated price.


PostPosted: Mon Apr 13, 2009 5:12 pm    Post subject: Reply with quote
F16SUNSHINE wrote:

Katzeye and some others machine their screens from old Eos-1 screens (at least in the case of canons).


I was under the impression that they had their own production?

Quote:

NOTICE - Katz Eye™ focusing screens are custom made to order and are usually not available to ship the day the order is placed. As of 04/13/2009 production is slightly delayed due to heavy order volume and most orders are being completed in 4-6 business days from the date the order is placed.


I can't see how they can do custom etchings for focuspoints etc if it is grounded old screens?

Quote:

For those users that wish to have the focus area brackets marked, this is available as an option. If you want the AF area markings, please be sure to select the focus area bracket pattern when adding the screen to your cart.


Also there is the "Optibright treatment".

Quote:

The OptiBrite treatment is a brightness enhancement for the matte portion of the screen (outside the prism) and is unrelated to the prism function.


And they have some "magic" prism version that is supposedly brighter aswell.

Anyways, not arguing, just asking Smile. You ever seen any Katzeye in real life? I am curious, because I am considering to get one myself, with the plus/optibright and some rules of thirds markings.

(quotes from http://www.katzeyeoptics.com)


PostPosted: Mon Apr 13, 2009 5:26 pm    Post subject: Reply with quote
zewrak wrote:
F16SUNSHINE wrote:

Katzeye and some others machine their screens from old Eos-1 screens (at least in the case of canons).


I was under the impression that they had their own production?

Quote:

NOTICE - Katz Eye™ focusing screens are custom made to order and are usually not available to ship the day the order is placed. As of 04/13/2009 production is slightly delayed due to heavy order volume and most orders are being completed in 4-6 business days from the date the order is placed.


I can't see how they can do custom etchings for focuspoints etc if it is grounded old screens?

Quote:

For those users that wish to have the focus area brackets marked, this is available as an option. If you want the AF area markings, please be sure to select the focus area bracket pattern when adding the screen to your cart.


Also there is the "Optibright treatment".

Quote:

The OptiBrite treatment is a brightness enhancement for the matte portion of the screen (outside the prism) and is unrelated to the prism function.


And they have some "magic" prism version that is supposedly brighter aswell.

Anyways, not arguing, just asking Smile. You ever seen any Katzeye in real life? I am curious, because I am considering to get one myself, with the plus/optibright and some rules of thirds markings.

(quotes from http://www.katzeyeoptics.com)


Yeah, There is some confusion. I did inquire with them one time and they told me the screens are old canon eos 1 screens that they re-surface. This is one of the reasons that shims are required during installation to make up for lost material.
So in other words. They make them. But from old stock.
As for the opti-bright treatment. I bet it is a different screen that has lower contrast and therefore is brighter.

Did I ever see one? No, they did not make a 5D screen at the time. Maybe now they do.

I plan to try and refit an old Contax RTS screen into my 5D.
Alex (hk300) has it in his 40D. It should work for me also with the fiver.
Of course I do expect the VF to become much darker.


PostPosted: Tue Apr 14, 2009 1:35 am    Post subject: Reply with quote
zewrak wrote:
I have a chinese 10$ (incl shipment) screen in my K10D, which seem to look the same as the ME one here. I have no problem with it. However a friend of mine has, from the same seller. Funny part is that we cant tell them apart. But I hear that the thickness can inflict some strange behaviour of them. Dunno really.


You're correct. Many low cost ebay screens use poor focus screens and poor QC. If the thickness of the sides are not consistent, front and/or back focus will occur.

zewrak wrote:

What really pains me is the darkness, even though the splitscreen is alot better, it is also alot darker then the original one. This is where Katzeye might be interesting, the matte part of the Katz eye is very bright. According to their site, even the center does not black out until f8. The one I got is near blackout at f4. Basically, i recommend that if you use lenses at f2.8 and lower, a cheap chinese is for you. Slower then that, stick to the original or buy a proper modern made one. I cant really use a few telelenses thats f8 at all. And even the 20/4.5 i have is a pain to focus with the chinese one. The 1.4 and 1.8 lenses I have is a dream come true though.


The cheaper splitscreens do not allow enough light to pass, thus are darker. There is a difference around f2.8 and up. That is why i use a Contax screen.
However, I doubt that the Katz will be useable at f8. Most screens were not designed with that in mind.


PostPosted: Tue Apr 14, 2009 1:46 am    Post subject: Reply with quote
zewrak wrote:
F16SUNSHINE wrote:

Katzeye and some others machine their screens from old Eos-1 screens (at least in the case of canons).


I was under the impression that they had their own production?

Quote:

NOTICE - Katz Eye™ focusing screens are custom made to order and are usually not available to ship the day the order is placed. As of 04/13/2009 production is slightly delayed due to heavy order volume and most orders are being completed in 4-6 business days from the date the order is placed.


I can't see how they can do custom etchings for focuspoints etc if it is grounded old screens?

Quote:

For those users that wish to have the focus area brackets marked, this is available as an option. If you want the AF area markings, please be sure to select the focus area bracket pattern when adding the screen to your cart.


Also there is the "Optibright treatment".

Quote:

The OptiBrite treatment is a brightness enhancement for the matte portion of the screen (outside the prism) and is unrelated to the prism function.


And they have some "magic" prism version that is supposedly brighter aswell.

Anyways, not arguing, just asking Smile. You ever seen any Katzeye in real life? I am curious, because I am considering to get one myself, with the plus/optibright and some rules of thirds markings.

(quotes from http://www.katzeyeoptics.com)


Most focus screen sellers are customizing existing screens.
I had mine made of a Contax RTS, but others have theirs made out of Leica screens, or Nikon screens, or Minolta screens, ...

Katz-eye is making theirs out of Canon 1D FF film screens, I can do that as well. Their price is expensive, since their labor is expensive (in the USA). Also, i bet that a certain percentage of the screens are unusable/unsellable after customization, which adds to the cost.

The optibrite is perhaps a chemical which they put on their screens to make it brighter. I do not know what they are using.


PostPosted: Tue Apr 14, 2009 1:50 am    Post subject: Reply with quote
F16SUNSHINE wrote:

Did I ever see one? No, they did not make a 5D screen at the time. Maybe now they do.

I plan to try and refit an old Contax RTS screen into my 5D.
Alex (hk300) has it in his 40D. It should work for me also with the fiver.
Of course I do expect the VF to become much darker.


Andy ... i can get 5D screens ... i will send you a pm.


PostPosted: Tue Apr 14, 2009 3:41 am    Post subject: Reply with quote
As I have been interested in a split-prism focusing screen, I have been
following this thread with much interest.

In spite of all the pros and cons mentioned about the cheaper screens
and the expensive screens, I just have to ask:

Are these no longer being installed in modern film cameras?
Sure, film cameras are mostly auto-focus nowadays. But are they
being shipped with the same or similar screens that digital SLRs
are shipped with?

There's got to be at least one maker of quality film SLR cameras
shipping their products with a quality focusing screen, right?
If so, why aren't Haoda Fu, Katz Eye, and others using those
screens for their re-works?

But if such screens do not exist for modern film cameras, then
why is the issue such a debated one? Please forgive my ignorance here,
but it seems to me that we're already using various methods with our
MF lenses to achieve acceptable results when used with our digital
camera bodies, and many of you who frequent this forum seem to be
realizing truly exceptional results.

I personally have no real issue with focusing wide-open, then stopping
down for metering, then finally adjusting exposure as needed or desired
for the shot I'd like. At the same time, I admit, I do not tend to try shots
that require me to be very quick with focus and metering.

Am I the odd man out?

I'm still interested in replacing my camera's focusing screen in favor of a
split-circle type, as I believe it will help me to achieve more-accurate
manual focus. But if a replacement screen will sacrifice the ability of my
auto-focus lenses to do their job correctly, it looks like I should stay with
the screen I already find so lacking in performance. I'd like a nice balance
between MF and AF, though.


PostPosted: Tue Apr 14, 2009 3:49 am    Post subject: Reply with quote
SkedAddled wrote:
As I have been interested in a split-prism focusing screen, I have been
following this thread with much interest.

In spite of all the pros and cons mentioned about the cheaper screens
and the expensive screens, I just have to ask:

Are these no longer being installed in modern film cameras?
Sure, film cameras are mostly auto-focus nowadays. But are they
being shipped with the same or similar screens that digital SLRs
are shipped with?

There's got to be at least one maker of quality film SLR cameras
shipping their products with a quality focusing screen, right?
If so, why aren't Haoda Fu, Katz Eye, and others using those
screens for their re-works?

But if such screens do not exist for modern film cameras, then
why is the issue such a debated one? Please forgive my ignorance here,
but it seems to me that we're already using various methods with our
MF lenses to achieve acceptable results when used with our digital
camera bodies, and many of you who frequent this forum seem to be
realizing truly exceptional results.

I personally have no real issue with focusing wide-open, then stopping
down for metering, then finally adjusting exposure as needed or desired
for the shot I'd like. At the same time, I admit, I do not tend to try shots
that require me to be very quick with focus and metering.

Am I the odd man out?

I'm still interested in replacing my camera's focusing screen in favor of a
split-circle type, as I believe it will help me to achieve more-accurate
manual focus. But if a replacement screen will sacrifice the ability of my
auto-focus lenses to do their job correctly, it looks like I should stay with
the screen I already find so lacking in performance. I'd like a nice balance
between MF and AF, though.


Quote:
Modern AF cameras have a semi-silvered Mirror that allows light to pass thrugh it to the AF/metering module mounted below.
This Mirror does not send a full transmition of light to the prism or thrugh the focus screen.
To use a light hungry matte screen with a semi-silvered mirror you will have a darker VF.


That is really the bottom line and you nailed it. With very tiny few exceptions.
All modern screens are designed to work with semi silvered mirrors. so they will be darker or less contrast.
Even true for the opti-bright.


PostPosted: Tue Apr 14, 2009 5:20 am    Post subject: Reply with quote
SkedAddled wrote:

I personally have no real issue with focusing wide-open, then stopping
down for metering, then finally adjusting exposure as needed or desired
for the shot I'd like. At the same time, I admit, I do not tend to try shots
that require me to be very quick with focus and metering.

Am I the odd man out?


Nono. I have no problems with that either. The problem is when you use lenses that have, say f4.5 or f8 or something as maximum aperture. Looking into the viewfinder of a f8 lens to focus is like looking into a brickwall. And usually the f8 lenses are hard enough to focus being very long telelenses and what not. Smile

I do all my shooting by wideopen focusing and then stepping down to meter. It's a pain sometimes, but you get used to the procedure quite quickly.


PostPosted: Tue Apr 14, 2009 8:27 am    Post subject: Reply with quote
zewrak wrote:
I do all my shooting by wideopen focusing and then stepping down to meter. It's a pain sometimes, but you get used to the procedure quite quickly.

+1 It's much more accurate too.


PostPosted: Tue Apr 14, 2009 9:25 am    Post subject: Reply with quote
F16SUNSHINE wrote:


Quote:
Modern AF cameras have a semi-silvered Mirror that allows light to pass thrugh it to the AF/metering module mounted below.
This Mirror does not send a full transmition of light to the prism or thrugh the focus screen.
To use a light hungry matte screen with a semi-silvered mirror you will have a darker VF.


That is really the bottom line and you nailed it. With very tiny few exceptions.
All modern screens are designed to work with semi silvered mirrors. so they will be darker or less contrast.
Even true for the opti-bright.


What about the Autofocus film slrs? Presumably they would make the best donors then? Or has there been a different AF mechanism of some sort?


PostPosted: Wed Apr 15, 2009 12:49 am    Post subject: Reply with quote
I have a Olympus screen spare which has no split circle, just a central microprism (type 1-2). Now, having experienced the darkening of the split on typical MF use when I tried a Virtual Village s/c screen in my Canon, I think I might modify the old Oly microprism screen for the K10D and see how it goes.


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