[PentaxPoke]

Conclusion: If you own a Pentax DSLR, you need one of these! It is the best investment I have made in my k20d, and is well worth the money I spent. Now let me tell you why:

I have had the Katzeye ( http://www.katzeyeoptics.com/ ) in my k20d for several days now. I shot a variety of scenarios including indoor basketball games, portraits, etc. I have also tested every lens I own with it. I really like the combination of split screen and microprism. For example, if you are looking at a scene that doesn't have an obvious line in it to use on the split prism, the microprism will tell you if it is in focus. There are other times where the split screen is better for focusing than the microprism collar. They complement each other nicely.

Here were my options:
Katzeye for k20d
Optibrite: yes
Grid lines: no

Glossary:
MF means Manual Focus
AF means Auto Focus

View:
Big and bright. If anything, it actually looks better and brighter than the original Pentax viewfinder screen.

Installation:
Simple (as long as you are not the "ham fisted" type that forces things into place. Thank you Pentax for allowing interchangeable viewfinder screens!)

Effect on light metering:
None observed

Split prism screen "blackout":
None observed on any lens (even with max aperture of 6.3 on the Pentax 18-250) note that I wear eyeglasses, and even then I had no problem using this viewfinder.

Advantages:
When using autofocus: Here is a scenario with the standard DSLR viewfinder that always bothered me: How often have you taken a picture (especially indoors, because of lower light) that you thought was in focus because it looked good in the viewfinder, only to find out that the AF missed perfect focus a bit? Modern DSLR viewfinders are just not good enough for us to get confirmation that the AF achieved perfect focus. The Katzeye screen gives us the advantage we had in the MF days on our AF cameras. I now have visual conformation of focus on every shot I take. If your AF is off a bit, you can simply tweak it if you have a quick-shift lens, or you can push the AF button again to tweak. Sometimes I have even quickly switched to MF and used the Katzeye!

The other nice thing is that the Katzeye will make your AF better! Before you jump on me, let me explain what I mean by that. When you look through this type of viewfinder, you will naturally be training yourself to point the camera on key parts of the scene that contain the most contrast. That is exactly what the AF is using, and so you will get a better, faster AF lock.

Also, with a split prism finder, you don't have to use "focus charts" any more to set your k20d AF adjustments for back or front focus. Simply choose a fixed vertical subject, and adjust the AF setting until the prism lines up perfectly. Doing it this way also eliminates the uncertainties in the angled focus chart methods. It is also FAST because you don't actually have to see a picture to know if the setting is correct.

Manual focus: No way can you be as accurate using the factory screen as you can with the Katz screen. If you do any MF at all, you need one of these. Heck, just for grins, I shot part of an indoor basketball game using only MF, and it worked perfectly. If I can focus on a running basketball player using this tool, one can certainly nail the focus on a stationary macro subject!

Disadvantages:
None! (except for cost, but it is worth it to never have a shot out of focus again!)

Bottom line: I wish all Pentax DSLR's came with this type of viewfinder. There are no down sides, and maybe there would be less complaints about Pentax AF because it would subconciously train people to point the camera better so the AF can work the way it is designed!

Now for some pictures. What you will see below are pictures taken with a P&S camera through the viewfinder of my k20d. That is why the image quality doesn't look as good as a shot taken with the k20d itself. Here is the complete set if you want to download larger versions than below:
Katzeye viewfinder test - a set on Flickr

This is a shot with focus on the battery. You can clearly see the split prism as well as the micro prism ring. Anything out of focus on a split prism will be "broken" and anything out of focus in the microprism ring will be "shimmery." It is quite clear to the eye when you look through the viewfinder:


Now the focus is on the house:


Look closely on this shot of the house. You can tell from the microprisms what part of the house is in focus and what is not. Note outside the microprisms the focus looks pretty good, indicating that your eye could not detect the slight misfocus of those areas without microprisms:


Here is the ubiquitous battery test that is often used to determine front or back focus. the focus here is on the center battery:



Now the front battery:


Finally, here is a test that shows how well this tool works for precision focusing. I put two batteries together and took a very close picture. I spaced the batteries so that one of them was only a couple of millimeters ahead of the other one. The camera was also at a vertical angle so that the plane of focus only intersected the battery at one point. I then focused on the "r" of Energizer. Here is the picture through the viewfinder. It clearly shows that the "r" will be in focus, and the top of the battery will be a bit out of focus, as well as the left battery will be out of focus. There is no way I could have seen this difference with my eye on a standard viewfinder:


Now here is the picture taken with the k20d. Note that the parts are out of focus exactly the way that the microprisms indicated:

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Last edited by PentaxPoke; 01-20-2009 at 04:48 PM.

[Buddha Jones]

Interesting....

[ghost]

Great review!!! Where did you get your focusing screen?

[pasipasi]

Interesting....

Yes, makes me want to buy the katzeye - I love split screen focus screen on my mf film bodies.

[YJD]

Wow... I always wondered about split screens and read a lot about it on this forum, but never saw shoots about it.

Thank you!

[PentaxPoke]

Great review!!! Where did you get your focusing screen?

Thank you! Good point. Sorry about that. I just put the link in the original post.

[Shaloot!]

cool to finally see a review like this. I've wondered about the katzeye for awhile, and haven't been too convinced, though this looks to be a game changer...

[stevebrot]

Nice review. The viewfinder images pretty much say it all.

Were you able to evaluate metering with your screen using non-A lenses? As you are probably aware, stop-down metering on the K10D and K20D with the stock screen is not accurate. I have the KatzEye screen without Optibright and noticed that while accuracy is better at the wide end, there is a new tendency towards underexposure at narrower apertures that is not present with the stock screen. There was some discussion on this forum that the Optibright might help with this problem.

To test, you could do an exposure series with your FA 35/2 in AV mode and repeat the same series using the aperture ring and green button in M mode. The variance between modes indicates the exposure error.

Steve

(Thinking about sending the screen back to KatzEye to have the Optibright treatment applied...)

[PentaxPoke]

Nice review. The viewfinder images pretty much say it all.

Were you able to evaluate metering with your screen using non-A lenses? As you are probably aware, stop-down metering on the K10D and K20D with the stock screen is not accurate. I have the KatzEye screen without Optibright and noticed that while accuracy is better at the wide end, there is a new tendency towards underexposure at narrower apertures that is not present with the stock screen. There was some discussion on this forum that the Optibright might help with this problem.

To test, you could do an exposure series with your FA 35/2 in AV mode and repeat the same series using the aperture ring and green button in M mode. The variance between modes indicates the exposure error.

Steve

(Thinking about sending the screen back to KatzEye to have the Optibright treatment applied...)

Thank you Steve. I will be happy to do that test. I have shot manual quite a bit, but I have never actually used the aperture ring on any lens with my k20d. When I am able, I will try and do that tonight.

[stevebrot]

Thank you Steve. I will be happy to do that test. I have shot manual quite a bit, but I have never actually used the aperture ring on any lens with my k20d. When I am able, I will try and do that tonight.

Thanks. I have never used the aperture ring on my FA 35/2, but I believe that doing so will trick the camera into thinking that it has a non-A mount lens.

Steve

[kristoffon]

After using a katz eye on my K200D for 3 to 4 months I took it off and put the original screen back. I found the katz-eye no help for the following reasons:

1 - unless your subject has VERY clearly defined vertical lines or edges it's useless
2 - if your subject is moving it's useless
3 - the ring of microprisms is completely useless, period
4 - in cases 1 or 2 when the subject was in the center of the frame I had to move the camera so I could focus on the plain part of the viewfinder, then recompose

Overall, I guess I just have good vision and can see clearly when things are in focus with just my eyes and don't need this aid. I'm much happier with the stock screen back which is also brighter than the standard katz eye (not much though). I don't regret buying it but will definitely NOT equip any future bodies I purchase with split screens.

[PentaxPoke]

After using a katz eye on my K200D for 3 to 4 months I took it off and put the original screen back. I found the katz-eye no help for the following reasons:

1 - unless your subject has VERY clearly defined vertical lines or edges it's useless
2 - if your subject is moving it's useless
3 - the ring of microprisms is completely useless, period
4 - in cases 1 or 2 when the subject was in the center of the frame I had to move the camera so I could focus on the plain part of the viewfinder, then recompose

Overall, I guess I just have good vision and can see clearly when things are in focus with just my eyes and don't need this aid. I'm much happier with the stock screen back which is also brighter than the standard katz eye (not much though). I don't regret buying it but will definitely NOT equip any future bodies I purchase with split screens.

I guess you didn't read the text of my review then. Each of your 4 points and the brightness are addressed in the text, and demonstrate just the opposite.

[sinus007]

Hi PeentaxPoke,
thanks for the review - great job.
Questions:
Did you try or anybody else, to see if this Optibright enhancement worth it?
Does Katzeye affects the select focus?
thank you very much,

[PentaxPoke]

Hi PeentaxPoke,
thanks for the review - great job.
Questions:
Did you try or anybody else, to see if this Optibright enhancement worth it?
Does Katzeye affects the select focus?
thank you very much,

Thanks. I have only read that people with Optibright really like it, so I thought it would be worth it. On the other hand, some people without it also like the screen so I don't know what to tell you. I can only speak for the screen with the treatment, and it is fantastic. I have never seen the view without it. The manufacturers seem to recommend it if you shoot with a wide range of zooms, especially if they have smaller max apertures. This link may help you decide: http://www.katzeyeoptics.com/page--OptiBrite-Brightness-Enhancement--optibrite.html

The Katzeye has no affect on the auto focus whatsoever. Auto focus does not go through the screen.

[stevebrot]

...Overall, I guess I just have good vision and can see clearly when things are in focus with just my eyes and don't need this aid...

Sorry you had a bad experience with the split-image screen. Many of us have a long history using this type of viewfinder on film cameras and usage comes as second nature, I guess.

In regards to the stock screen, good vision, etc...

The stock screen is indeed fairly bright. In fact, it appears brighter than it has the right to with most slower lenses. It has micro-lenses (or something like that) as part of the design that create a view with greater overall brightness. The stock screen also has a very even ground-glass field that should be excellent for manual focus. The problem is that it is not very good at all.

That sounds like a pretty blunt statement, but it is based on my personal experience with fast manual focus lenses that I own. Other users on this forum have a similar opinion. The problem is that the apparent depth of field in the viewfinder with the stock screen is greater than the actual depth of field provided by the lens. At taking apertures wider than f/4, the stock screen may present an in-focus image, while the actual final image is clearly out of focus. This issue is present on all of my lenses faster than f/4.

You can demonstrate this by putting a fast manual aperture lens on the camera. Start at the widest aperture and stop down until you see a change in depth-of-field. Typically, you will not see any change until about f/4. Ditto for apparent brightness. Repeat the same test with the KatzEye and you will see what I mean.

Simply put...The stock screen is not optimized for manual focus, nor can you really use it to evaluate DOF prior to exposure.

Steve