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Katz-eye focusing screens
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PostPosted: Tue Aug 28, 2007 3:35 pm    Post subject: Katz-eye focusing screens Reply with quote

Hi!

After a failure on trying to use the Virtual Village focusing screen in my Canon EOS 350D, I'm looking now at the Katz-eye ones.
After asking to the Katz people about compatibility of the focus screen between the 350D and the 400D, they have replied this:

Thank you very much for you inquiry. The focusing screens for the Canon
350D and 400D may be interchanged - the physical fit and calibration is the
same. However, the AF sensors are located differently, so the AF markings
on the screen are different between the 350D and 400D. Most people order
the focusing screen without the AF marks (they are additional cost), so in
that case, the two screens are identical.


I enclose it here for the case anyone else is interested.
Best regards,
Jes.


PostPosted: Tue Aug 28, 2007 4:11 pm    Post subject: Reply with quote

As I suggested many times use focus confirmation adapter instead of split screen. I have Katz-Eye screen because I have no other choice on Olympus-E1 , but I like much more better the focus confirmation. Split screen effect the metering you need for every f/stop to adjust metering, not so much fun to use it. In long distance subject difficult to set the focus with split screen if not fully open.


PostPosted: Tue Aug 28, 2007 7:37 pm    Post subject: Reply with quote

Actually, Atilla, at least on the Canon's, metering problem (for me) is not that great. I just bump the exposure compensation up and leave it there.

Sorry, I have no experience with the Katz eye products. Soryy you weren't able to resolve the virual villiiage issue.


PostPosted: Wed Aug 29, 2007 1:50 am    Post subject: Reply with quote

What is the problem with your Virtual Village screen?

I bought one some time back, put it in the camera for about an hour, took it back out again (this was partly because I had spent $80 on an AF confirming lens adapter that was going to be a little pointless without the AF lights) and hadn't used it since.

I put it back in this morning, and after playing with it a bit discovered that it's off a bit in focus: the actual focus point was a little farther away than the finder had indicated.... enough to make it unacceptable.

I thought I had sort of calculated it out to needing an extra .002" added to the brass shim/frame that comes in the camera with the standard screen. As it turns out, Scotch Magic Tape (frosted cellophane tape) is .002" thick, so I added one layer to the shim at each end and tried again. It was better, but still focusing about an inch behind the target at 1 meter, so I went back and added a second layer of Scotch tape. It is now quite good, though I think it could still use maybe another .001" if I can think of something that thin to use. Another .002" would be too much, it's that close.

So, if your focus is off with the VV screen, before you give up and spend a lot of money on a new screen you might want to see if you can adjust yours.

If the actual focus point is FARTHER away than your aiming point, then you need to ADD thickness to the shim. If you have to go the other direction, that's tougher, as you really do want to have that brass frame in there to keep things located correctly. The brass shim itself, in my camera at least, is .005" thick. These may not all be the same, as Canon may use the shim to fine tune their own screens... if that's the case, then no aftermarket screen, however good, could guarantee correct focus out of the box.

Here's a test image after adding the .004" to the shim. It's not quite perfect, but you can clearly see that the focus at the aim point (in the red circle at the center) is much better than on the printed page a few millimeters behind it. This was shot with an Olympus 50/3.5 macro lens, wide open:

http://rick_oleson.tripod.com/400d_vv_focus_check.jpg


PostPosted: Wed Aug 29, 2007 4:33 am    Post subject: Reply with quote

Attila wrote:
As I suggested many times use focus confirmation adapter instead of split screen. I have Katz-Eye screen because I have no other choice on Olympus-E1 , but I like much more better the focus confirmation. Split screen effect the metering you need for every f/stop to adjust metering, not so much fun to use it. In long distance subject difficult to set the focus with split screen if not fully open.

Hi, Attila, thanks for your comments. I was thinking of a split screen because I come from the classic cameras, and that split screen focusing was nice there. On the other hand, I've got 6 manual lenses by now, and my idea was to have each with its own adapter (M42, Contax, adaptall-2) to avoid changing adapters at any time I change the lens. But this may end being expensive if all the adapters are of the focus confirmation ones...
I've got no experience with those adapters, probably I should buy one of them and see. Some colleagues here in Spain have had bad experiences, but it is related to the quality of the focus confirmation adapters. In one case the chip fell down...
Could you please suggest me one that works fine?. Several of my lenses are of the M42 kind, so I would try one of those.
Thanks a lot!
Jes.


PostPosted: Wed Aug 29, 2007 4:41 am    Post subject: Reply with quote

rick_oleson wrote:
What is the problem with your Virtual Village screen?

I bought one some time back, put it in the camera for about an hour, took it back out again (this was partly because I had spent $80 on an AF confirming lens adapter that was going to be a little pointless without the AF lights) and hadn't used it since.

I put it back in this morning, and after playing with it a bit discovered that it's off a bit in focus: the actual focus point was a little farther away than the finder had indicated.... enough to make it unacceptable.

I thought I had sort of calculated it out to needing an extra .002" added to the brass shim/frame that comes in the camera with the standard screen. As it turns out, Scotch Magic Tape (frosted cellophane tape) is .002" thick, so I added one layer to the shim at each end and tried again. It was better, but still focusing about an inch behind the target at 1 meter, so I went back and added a second layer of Scotch tape. It is now quite good, though I think it could still use maybe another .001" if I can think of something that thin to use. Another .002" would be too much, it's that close.

So, if your focus is off with the VV screen, before you give up and spend a lot of money on a new screen you might want to see if you can adjust yours.

If the actual focus point is FARTHER away than your aiming point, then you need to ADD thickness to the shim. If you have to go the other direction, that's tougher, as you really do want to have that brass frame in there to keep things located correctly. The brass shim itself, in my camera at least, is .005" thick. These may not all be the same, as Canon may use the shim to fine tune their own screens... if that's the case, then no aftermarket screen, however good, could guarantee correct focus out of the box.

Here's a test image after adding the .004" to the shim. It's not quite perfect, but you can clearly see that the focus at the aim point (in the red circle at the center) is much better than on the printed page a few millimeters behind it. This was shot with an Olympus 50/3.5 macro lens, wide open:

http://rick_oleson.tripod.com/400d_vv_focus_check.jpg


Hi Rick, thanks for answering!
My problem with the virtual village screen is that I cannot get it to focus properly. Even with Peter's indications, (that allowed me to improve a lot the issue) the final foxusing was almost accurate in short distances but not in the far ones. So after many tests, I gave up. I tried to take out the shim at all, but it was even worse.
Anyway, I'll give it another try following your indications.
Thanks a lot!
Jes.


PostPosted: Wed Aug 29, 2007 6:51 am    Post subject: Reply with quote

Jes, I suppose Orio has several focus confirmation adapter and they are works fine. I don't have Canon,so I can't suggest any trust able one.Orio or somebody else can be suggest to you.


PostPosted: Wed Aug 29, 2007 7:08 am    Post subject: Reply with quote

Attila wrote:
Jes, I suppose Orio has several focus confirmation adapter and they are works fine. I don't have Canon,so I can't suggest any trust able one.Orio or somebody else can be suggest to you.


I buy my chipped adapters from this seller:
http://feedback.ebay.it/ws/eBayISAPI.dll?ViewFeedback2&userid=www_nikon-discount_com&ftab=AllFeedback

They cost more than from Hong Kong, but there's no customs fees and no mail delay. I am unable to tell which brand they are though (they look identical to those sold by Roxsen, Hong Kong).

One suggestion to make the most out of chipped adapters: make some tests to find out where your AF central sensor exactly is. In theory it should be centred inside the central square, but it isn't always like that. With my former 300D camera, for instance, it was close to the top left corner of it.
Once you know exactly where the sensor is, you will greatly increase the percentage of properly focused images.


PostPosted: Thu Aug 30, 2007 11:44 pm    Post subject: Reply with quote

Hi - just an update on my Virtual Village screen adjusting project.... I think I've got it about right now, it seems to turn in good results. With the Nikkor 50/1.2 wide open, I think the wedge is just not steep enough to be able to discern the split within the limits of the DOF when it's wide open, so when I shoot at f/1.2 I get kind of random errors in either direction. Once I get down to f/1.8 or so, things seem to work pretty well.

As for metering, I use the "limited area" metering pattern most of the time on the Canon (400D), which should be a worst case if the prism is going to screw it up. I have not been able to detect any problem at all with metering, the histograms on the exposures look very normal and correct.

I don't get AF lights, but I think with a manual focus lens I'm probably better off with the split image than with the lights anyway; AF still work s with the AF lenses, of course, and since I only use the center focus spot, I know where that is without a little LED in the screen to tell me. I'm not 100% sure yet, but I'm thinking I may leave it this way.

If I do, I will probably be willing to part with my AF-confirming Nikkor adapter at a pretty reasonable price if someone wants it....

: ) =


PostPosted: Fri Aug 31, 2007 3:20 am    Post subject: Reply with quote

rick_oleson wrote:
Hi - just an update on my Virtual Village screen adjusting project.... I think I've got it about right now, it seems to turn in good results. With the Nikkor 50/1.2 wide open, I think the wedge is just not steep enough to be able to discern the split within the limits of the DOF when it's wide open, so when I shoot at f/1.2 I get kind of random errors in either direction. Once I get down to f/1.8 or so, things seem to work pretty well.

As for metering, I use the "limited area" metering pattern most of the time on the Canon (400D), which should be a worst case if the prism is going to screw it up. I have not been able to detect any problem at all with metering, the histograms on the exposures look very normal and correct.

I don't get AF lights, but I think with a manual focus lens I'm probably better off with the split image than with the lights anyway; AF still work s with the AF lenses, of course, and since I only use the center focus spot, I know where that is without a little LED in the screen to tell me. I'm not 100% sure yet, but I'm thinking I may leave it this way.

If I do, I will probably be willing to part with my AF-confirming Nikkor adapter at a pretty reasonable price if someone wants it....

: ) =


Thanks for the update, Rick!
I'm looking forward to the week-end to try your tape tricks Wink
Best regards,
Jes.


PostPosted: Sun Sep 02, 2007 2:46 am    Post subject: Reply with quote

OK, I think I'm done testing now. I don't know if this is the appropriate place for it, but if anyone wants an AF confirming Nikkor/EOS adapter in good but used condition, let me know. I paid $80 for the thing, but it looks like they're a lot cheaper now (figures). It's a Roxsen adapter, chrome plated brass in a vinyl case to protect it when it's not in use.

The Virtual Village screen looks like it's going to work fine for me, and in my situation (adapters for 4 different mounts, can't afford them all in AF form) I think it's a better solution. Since the AF lights don't work with the VV screen, the AF chip in this adapter is useless to me. If any of you can use the adapter, I'd rather let you have it than put it up on eBay. If $25 sounds fair to anyone, I'll pay the postage to wherever you are.


PostPosted: Sun Sep 02, 2007 9:15 pm    Post subject: Reply with quote

Rick I "think" I sent you an email. If you don't get it send me a line

fourfortyroadrunner (the at thing) yahoo.com


PostPosted: Sun Sep 16, 2007 2:23 am    Post subject: Reply with quote

That's interesting. From my experience and what I've been hearing from others here, it sounds like the error of about .005" is consistent from one example to another with the Virtual Village screen in the 400D.... maybe the screen is right for the 350 but not for the 400.


PostPosted: Sun Sep 16, 2007 6:14 am    Post subject: Reply with quote

Hi
The image you see trough the viewfinder is created on the matte part of the screen who is toward the viewfinder.
It doesn't matter how fat is screen. The only important is to have the same distance (mirror-sensor) = (mirror-matteofscreen) and only shim can adjust that.


PostPosted: Sun Sep 16, 2007 3:05 pm    Post subject: Reply with quote

poilu wrote:
Hi
The image you see trough the viewfinder is created on the matte part of the screen who is toward the viewfinder.
It doesn't matter how fat is screen. The only important is to have the same distance (mirror-sensor) = (mirror-matteofscreen) and only shim can adjust that.


With these screens, that's not quite true. The thickness of the screen itself doesn't matter, but the edge of the screen has been machined to a different position for the mounting (shim) surface. The amount of material that has been removed from the matte surface to the mounting surface is critical. It could be different from one model of camera to another (which wouldn't be very smart, but it still could be the case), the aftermarket screen maker might have the dimension wrong, or, since the machining is a secondary operation on the aftermarket screens, it could vary from one screen to another from the same maker.


PostPosted: Sun Sep 16, 2007 3:43 pm    Post subject: Reply with quote

Wow! I won't touch my screen. You know, when a tolerance of .002 has considerable effect, I would just mess the whole thing up, if I tried.
I use some AF-confirm adapters (one Nikon adapter that works perfectly, another Nikon one that sometimes has to be mounted again and one EOS-model that sometimes produces ERR99... so not perfect, really!) and normal adapter plus my (fortunately very good) eyesight.


PostPosted: Sun Sep 16, 2007 3:47 pm    Post subject: Reply with quote

rick write

Quote:
but the edge of the screen has been machined to a different position

True I miss that Embarassed

Ok Jes buy a katz-eye and if you get good result without shimming I will replace my haoda Idea


PostPosted: Sun Sep 16, 2007 4:36 pm    Post subject: Reply with quote

poilu wrote:
rick write

Quote:
but the edge of the screen has been machined to a different position

True I miss that Embarassed

Ok Jes buy a katz-eye and if you get good result without shimming I will replace my haoda Idea


Now I'm pretty close to fix the Virtual Village one. I've seen that adjusting the shim one gets frontfocus instead of backfocus... It's a matter of finding the appropriate shim thickness.... Now I'm cutting a alu foil shim to put under the brass one. I'm hopeful in getting an accurate focus this time. Anyway, I'm convinced that screen focus brand doesn't matter, you can have frontfocus/backfocus problems even with the Katz-eye...

So by now I'm quite disenchanted with focusing screens, so by now I'll keep trying the VV one.

Best regards,
Jes.


PostPosted: Mon Sep 17, 2007 4:19 pm    Post subject: Reply with quote

Hi Jesito,

Jesito wrote:
My problem with the virtual village screen is that I cannot get it to focus properly.

I got a similar problem with mine (bought from virtual village too, on a 350D too).

I have solved the problem by puting back the thin copper frame I had left, as mentionned in some online howto notices. Now it focuses the right way.

The stack is now the same as with originnal Canon screen :

Sensor - Copper frame - Screen - black metal presure frame

The screen is placed as the shinning face facing outside - the sanded face facing the sensor.


PostPosted: Tue Sep 18, 2007 12:04 pm    Post subject: Reply with quote

Flor27 wrote:
Hi Jesito,

Jesito wrote:
My problem with the virtual village screen is that I cannot get it to focus properly.

I got a similar problem with mine (bought from virtual village too, on a 350D too).

I have solved the problem by puting back the thin copper frame I had left, as mentionned in some online howto notices. Now it focuses the right way.

The stack is now the same as with originnal Canon screen :

Sensor - Copper frame - Screen - black metal presure frame

The screen is placed as the shinning face facing outside - the sanded face facing the sensor.


FLor, thanks for the info, but even with the shim in place, I get the image out of focus. After the last experiments past weekend, I'm pretty sure I need some more thickness on the shim, so I'm trying to setup an additional shim made on alu foil. Difficult to cut, so I'm looking for new sharper blades for my cutter.

Best regards,
Jes.


PostPosted: Tue Sep 18, 2007 6:45 pm    Post subject: Reply with quote

Jesito wrote:
I'm looking for new sharper blades for my cutter.


Hi Jes. In jmy job I have to sometimes do accurate cutting of paper, film, card etc. The best tool is a surgical scalpel like this:
Click here to see on Ebay.

I have a box of 500 blades which will last me until at least 2100, so if you need one just PM me with your address. I can send you a roll of Magic Tape at the same time! Smile


PostPosted: Tue Sep 18, 2007 9:39 pm    Post subject: Reply with quote

peterqd wrote:

Hi Jes. In jmy job I have to sometimes do accurate cutting of paper, film, card etc. The best tool is a surgical scalpel like this:
Click here to see on Ebay.

Nice!... Quite cheap, it may be a good add-on to my toolbox Smile

peterqd wrote:
I have a box of 500 blades which will last me until at least 2100, so if you need one just PM me with your address. I can send you a roll of Magic Tape at the same time! Smile


Hi Peter!,
Thanks a lot!.
I see you plan to have a really long life!. Smile
I did something similar with the solder tin, when lead was proscribed. I do very little soldering, and I would'nt like to have to change my current solder irons, so I stocked enough tin to last as long as your blades.
Let's talk around 2070, maybe we can trade some blades for tin, if you're interested... Wink

This afternoon I've been at a toy shop where they sell small ship models to build. I've got a pack of small cutter blades that I want to try. If they aren't useful (i.e. they do tear the alu foil as do the other ones) for sure I'd accept your kind offer. Wink

I'm pretty convinced the focusing screen can be tuned.
Thanks again,
Best regards,
Jes.


PostPosted: Wed Sep 19, 2007 10:43 pm    Post subject: Reply with quote

Much better with the tiny blades...

Now I can cut a narrow band without tearing the foil.


Best regards,
Jes.


PostPosted: Sun Sep 23, 2007 12:30 am    Post subject: Close to success Reply with quote

I've been all the afternoon/evening up to now cutting shims on different matterials: First the alu foil one, (too thin), afterwards paper (Thin as well), and finally back to cello tape... This time I tried with three different brands. One of them has left the focus almost in place. I'll leave the VV focusing screen installed by now, tomorrow I'll do more testing and add further height if necessary, maybe the alu foil...
Thanks to everybody that gave me clues, specially to Peter, that took so much trouble doing testing and suggesting ideas.
The sun light will tell how far I'm now of the perfect focus...
Best regards,
Jes.


PostPosted: Sun Sep 23, 2007 8:47 am    Post subject: End of the process Reply with quote

Now, wth some sunlight, I've repeated the tests. After putting a paper shim behind the brass one, pictures seemed to be slightly fronfocused. I've taken out the paper one and put the alu foil one, but no improvements.

So I left the brass shim with the bare cello tape, and this time the focusing was almost perfect...

If you're interested, I put some shots both short range (macro) and long range with the Tamron 35-175 and the Helios 44-2.

http://jespicturesite.blogspot.com/

Best regards,
Jes.