[vladimiroltean]

I am about to purchase a 3rd party screen for my M42 converted K-x, and based on the two topics in this forum, I have to decide between the Canon Ec-A and the Ee-S. I would prefer the Ec-A myself, but I am curious whether I would actually like the Ee-S more. My current lenses have an aperture range from f/1.4 to f/4. What is your experience using these screens with slow lenses?

[Jean Poitiers]

Bonjour,

FYI - Thought that my old thread might be useful ... https://www.pentaxforums.com/forums/pentax-k-5-forum/179076-change-k-5-focus-screen.html

Salut, J Frog

[Transit]

I am using the Ee-s makes precision focus of 50/1.2 very easy

[vladimiroltean]

I am not concerned that any of these can provide accurate focus at large apertures, but actually that they may be too dim for me to focus my Industar 50mm f/3.5, Jupiter 135mm f/3.5 and Takumar 200mm f/4. So my question really is which one of these is better in this regard. Sorry for not explaining more clearly.

[lammie200]

I am about to purchase a 3rd party screen for my M42 converted K-x, and based on the two topics in this forum, I have to decide between the Canon Ec-A and the Ee-S. I would prefer the Ec-A myself, but I am curious whether I would actually like the Ee-S more. My current lenses have an aperture range from f/1.4 to f/4. What is your experience using these screens with slow lenses?

There is a lot info in past threads, but if you want my opinion here it is:

From what I know the super precision matte Canon S-type will not affect metering. I have found this to be true. However, I don't know if it is actually a Ee-S type as you wrote, or just a Canon S-type as the focussingscreen.com site shows. (I don't even know if there is a difference between the two, if there are actually two different types.) Screens like the Ec-A microprisms and split image types will affect metering. I think that you will mostly lose spot metering. Personally I wouldn't want metering affected.

I have found the Canon S-type screens to be fine up until about f5.6 as far as viewfinder brightness, so your lenses should work fine for you if they are automatic lenses. (Automatic meaning the diaphragm will be wide open for focusing, as opposed to automatic meaning A lenses that will allow your camera to actually read the aperture setting.) You will then need to stop it down (green button) to get the metering correct. You probably already knew that though. If your lenses aren't automatic then you will need to have them open to at least f4 or f5.6 to focus, and then set the aperture that you want, and then stop down so you can set the shutter speed and sensitivity setting that you want.

Focusing Screen

[vladimiroltean]

From what I understand, a screen that does not affect metering means that it has perfectly linear response in brightness to the lens aperture. This means that lenses with f/4 as their largest aperture will be significantly darker than ones at f/1.4. Personally, I'd rather sacrifice the metering a little so I have a brighter image to focus. The stock screen is optimized for the kit lens, which is f/3.5-f/5.6, so these 3 lenses actually focus best right now. I'd prefer not to change that.

[jeffshaddix]

I have both screens. IMO, the Ec-A would be best for studio work, as it's easier to focus and you have time to recompose. The Ee-S is better for everything else. If you're shooting anything that moves, or timing is important, the "recompose" time necessary for Ec-A use is frustrating, not to mention viewfinder composure is harder when there is a flashy dot in the center of your view. Those are just my experiences, YMMV.

[lammie200]

From what I understand, a screen that does not affect metering means that it has perfectly linear response in brightness to the lens aperture. This means that lenses with f/4 as their largest aperture will be significantly darker than ones at f/1.4. Personally, I'd rather sacrifice the metering a little so I have a brighter image to focus. The stock screen is optimized for the kit lens, which is f/3.5-f/5.6, so these 3 lenses actually focus best right now. I'd prefer not to change that.

You are probably correct. However, I didn't think that f4.0 was too dark in comparison. I have an f1.4 50mm and a ton of f4.0's. Maybe by the numbers a 4.0 is roughly 3 times darker than a 1.4, but it still seems plenty bright to focus. You may get different results, I suppose.

[vladimiroltean]

Regarding the Ee-S, I really don't know if I would regret buying it, as it has no focusing aid. I am used to the microprism aid from the Spotmatic, but when using slower lenses, I tend to use the matte surface even on the SP. So I think it boils down to what is the performance of this screen at f/1.4. Can you always tell if you are in focus, both at close distances and at infinity?

[lammie200]

...Can you always tell if you are in focus, both at close distances and at infinity?

I would say that you can to both. It also makes AF'ing look little better from a visual standpoint. Of course the screen needs to be shimmed correctly. That in and of itself is challenging. You might want to read up on the related threads. There are genuine Pentax shims, metal shims, softer-thinner plastic shims, harder-thicker plastic shims, post-it notes, scotch tape, etc. It was pretty easy for me, but I think that shimming can differ even within the same model of camera.

[lammie200]

...not to mention viewfinder composure is harder when there is a flashy dot in the center of your view...

I think that he said he wants it for a K-x. Not sure, but I think that it doesn't have the red dots.

[vladimiroltean]

Please tell me more about the shimming process. What happens if I cannot achieve perfect focus with the ones supplied? Should I ask for more when I buy the screen, or make them myself?

[jeffshaddix]

I think that he said he wants it for a K-x. Not sure, but I think that it doesn't have the red dots.

By flashy dot I meant the shimmering microprism spot. On old film SLR's the VF was bigger, thus the spot was smaller. On our cam's, that spot takes up a good bit of space.

[jeffshaddix]

Please tell me more about the shimming process. What happens if I cannot achieve perfect focus with the ones supplied? Should I ask for more when I buy the screen, or make them myself?

The Ec-A fit my K-7 perfect with no shims. The Ee-S required me to remove all shimming. A good trick is to use small strips of scotch tape if you need more shim, for less I recommend calling Pentax USA parts and ordering a pack of shims for cheap.

[lammie200]

By flashy dot I meant the shimmering microprism spot. On old film SLR's the VF was bigger, thus the spot was smaller. On our cam's, that spot takes up a good bit of space.

Got it.

Please tell me more about the shimming process. What happens if I cannot achieve perfect focus with the ones supplied? Should I ask for more when I buy the screen, or make them myself?

The main issue is that shims are difficult to place without having them move around and not align with the edges of the screen. As you try to put it all together and snap the retainer back in place the shims slide around. I mean really difficult to place. They are flimsy. At least the plastic ones are that way. Someone has said the Pentax shim kit is all metal. The shim that is in your camera right now is probably metal. And I would bet that there is a shim in camera since the stock screens seem to be fairly thin themselves. I would also bet that the shim that is in your camera right now is too thick to work with a Canon screen.

Although I didn't need to do it, I imagine that the best way is to use thin strips of scotch tape along the two side edges. Your screen will either fit without shims or you will need to shim. They way I see it is that scotch tape is thinner than any shim that you can get. You can build up the tape to get the correct thickness. Using scotch tape is not as rinky dinky as it sounds. Once the retainer clip is snapped back into place nothing can move. If everything is properly aligned you shouldn't see the tape, or any light gaps at the edges of the VF.

There is a video on another recent thread that someone made while installing a screen on their K-r. Check it out if you haven't already. One thing about that video though is that the guy that made it first assumed that every bit of the instructions would apply, i.e., using the supplied tool, needing shims, etc. In reality not every bit of the instructions will apply, and even so, some parts of the instructions may be a little difficult to understand. Take your time and do a couple of dry runs first. If you have done anything remotely similar, i.e. small motor skill oriented, it will be relatively easy.