[stevebrot]

After many months of wavering, I finally purchased a Katzeye focusing screen for my K10D. Here are a few of my notes and observations:

What I Bought
K10D focus screen with:

• Split image
• Microprism collar
• Ground glass donut
• No OptiBright
• No grid or autofocus lines

Ordering
The item was ordered with standard shipping on December 10 and received in the mail on December 13. I was totally surprised to get it so soon.

What Was In the Box

• A special tool for handling the screen
• A padded plastic jewel case containing the new screen

Installation
The installation was pretty straightforward. The confirmation e-mail included a link to step-by-step instructions specific to the K10D. The instructions were pretty good, though the photos were not particularly clear. Fortunately, the process on the K10D is fairly simple. The whole operation required less than 2 minutes start to finish.

Brightness
As noted above, I opted against spending the additional $49 for the OptiBright treatment. As such:

• Viewfinder brightness is directly related to lens aperture
• With slower lenses or narrow apertures on manual lenses, the viewfinder is distinctly dim...much more so than with the stock screen
• With fast, auto-aperture lenses the viewfinder image is superior in brightness and contrast to the stock screen
• Screen brightness will vary when zooming with variable aperture zoom lenses
• The split image does indeed resist black-out down to f/8 or smaller

Depth of Field
True to the advertised claim, the Katzeye screen gives a much truer representation of DOF at all apertures than the stock screen. I was very impressed.

Auto Focus
Since the auto-focus mechanism is independent of the focus screen, it was no surprise that AF functioned as expected. What was interesting was to see just how accurate the AF is and to see it snap in on the microprism/split image. With all three of my AF lenses, the split image was always on the mark at all subject distances.

Manual Focus
Here lies the reason for the purchase. In short:

• The manual focus experience is immensely improved...What a pleasure!
• Both the microprism and the split image are very effective
• The wide ground glass donut proved to be very useful for evaluating DOF and determining focus for situations where the prisms are ineffective.
• Subjects snap in and out of focus with much the same ease as a good 35mm SLR
• Focus was very accurate and more precise than the camera's focus confirm

A few cautions:

• I did not test focus with bellows, though my expectation would be that the focus aids will be essentially useless (as they are with my film camera)
• I also did not test focus with moving subjects such as motorsports or birds-in-flight, though I also believe that the focus aids will have little value there as well

Metering With "A" Mount Lenses

• Spot metering is not accurate for lenses having a maximum aperture narrower than f/2
• Center-weighted and evaluative metering work as expected for all lenses with maximum aperture of f/5.6 or wider. Apparently the split-image and microprism retain a false brightness at smaller apertures that skews the meter.
• Gray-card series in all modes within the limits noted above produced accurate and predictable meter readings

Edit: Added Flash Section Below 23 Dec 2008
P-TTL Flash
According to the K10D owner's manual, P-TTL flash is supported for DA, D FA, FA, F, and A series lenses. I was able to run simple exposure series using my DA 18-55, FA 35, and A 50 and the built-in pop-up flash to confirm that correct flash exposure was attained at all apertures.

Stop-down Metering With "Non-A" Mount Lenses
As many are aware, stop-down metering may be erratic with the stock screen on the K10D. A few quick tests with my manual lenses indicate that the Katzeye screen may compound an already bothersome issue. Based on gray card series with a few of my manual lenses:

• Underexposure at wider apertures is lessened somewhat with the Katzeye screen to the extent that metering is essentially accurate for some lenses in the range of f/8 and wider. Other lenses showed no improvement at wider f/stops.
• Unfortunately, the "false" brightness of the split image and microprism regions results in underexposure at f/11 (about 0.5 stop) that worsens to 1.5 stops or greater at f/16-f/22. With one of my lenses, the meter reads the same for f/11 through f/32. Not good.

I will have a chance to characterize this issue more thoroughly later this month when I have access to a second K10D with the stock screen for comparison exposures. This issue is not addressed on the Katzeye Web site and I intend to bring it to Rachel Katz's attention once I have some data.

Quirks

• The center AF indicator point is displaced to the side by the split image prism
• There is a circular line at the outside border of the ground glass donut. This line has a purpose on the Nikon screen (K3) that Katzeye machines down for the K10D. I was a little peeved at the extra screen content until I realized that it is useful for adjusting the eyepiece diopter.

Conclusions:

• Great performance for manual focus using relatively fast A-mount lenses
• Dim viewfinder for lenses such as the 18-55 kit
• Severely degraded meter performance for stop-down metering at narrower apertures

I will post additional observations as I see them.

Steve

(Upset about the stop-down metering issues...)

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Last edited by stevebrot; 12-23-2008 at 10:09 PM. Reason: Added section for flash exposure

[dugrant153]

So... if the lens starts at, say F5.6 instead of F2.8, does that mean it will be consistently dimmer in the range? Or does this only apply to lenses with aperture rings?

This part always confused me because I've gotten people saying two different things.

Thanks for the review, by the way It helps as I just ordered one!

[Class A]

Thanks stevebrot, great review!

The center AF indicator point is displaced to the side by the split image prism.

I understand the KatzEye isn't cheap. For a pricey product I would expect flawless alignment.

It also seems that the brighter version of the KatzEye should be preferred, or is there a downside to using that as well?

[Mike Cash]

Mine works fine with a bellows. Of course, the effective aperture is smaller than the selected aperture on the lens and that has a corresponding effect.

[dlacouture]

Great, I can't wait for the Stop-down tests!!!

[Wheatfield]

Thanks stevebrot, great review!



I understand the KatzEye isn't cheap. For a pricey product I would expect flawless alignment.

It also seems that the brighter version of the KatzEye should be preferred, or is there a downside to using that as well?

Ummm, the AF indicator is projected onto the screen by the camera. If it is misaligned, it is a camera problem, not a screen problem.
I ordered my Katz-Eye with the Optibrite coating. It is a lot brighter than the stock screen, and much easier for manual focus.
Center weighted metering seems unaffected, I don't use any other metering mode, so can't comment on them.

[Mechan1k]

tempted ... so tempted.
Might even opt for the Opti-Brite screen as well.

[Ratmagiclady]

Ummm, the AF indicator is projected onto the screen by the camera. If it is misaligned, it is a camera problem, not a screen problem.
I ordered my Katz-Eye with the Optibrite coating. It is a lot brighter than the stock screen, and much easier for manual focus.
Center weighted metering seems unaffected, I don't use any other metering mode, so can't comment on them.

I'm not sure what this displacement looks like, but could it be just part of the nature of split prisms? Those have a bit of a cant to each surface of the split part: it could be that whatever projects that indicator just isn't designed to account for this...

[stevebrot]

So... if the lens starts at, say F5.6 instead of F2.8, does that mean it will be consistently dimmer in the range? Or does this only apply to lenses with aperture rings?

This part always confused me because I've gotten people saying two different things.

Thanks for the review, by the way It helps as I just ordered one!

My experience with DA lenses is limited to the 18-55 kit. It is quite dim at 55mm and not so bad at 18mm. Basically, brightness is directly related to the viewing aperture. At least this is the case for my screen without the OptiBright treatment. The claim is that brightness is enhanced at smaller apertures with the OptiBright, but I can't confirm.

Steve

[stevebrot]

Thanks stevebrot, great review!



I understand the KatzEye isn't cheap. For a pricey product I would expect flawless alignment.

It also seems that the brighter version of the KatzEye should be preferred, or is there a downside to using that as well?

The displacement of the focus mark is not a matter of alignment. The split in the split-image runs true to the center of the lens. So does the focus mark. As a result the focus mark "falls" to the side of the prism.

I don't know about the OptiBright treatment, though at this point I wonder if it might be advisable.

Steve

[Mechan1k]

Well ... I have decided to order a screen with the Opti-brite treatment ... wo will see what it is like when it arrives here in Australia.

[emalvick]

Steve, here is a question and brainstorm out loud, if you will...

In the review you talk about the underexposure in "Non-A" lens, apparently because the screen is "too bright" in the center portion. What I am wondering is that if the Katz-Eye is already compounding a problem, would the opti-bright compound the problem more since it would theoretically be "brighter".

I am just wondering. Right now I have one of the Chinese split screens, and I've been pretty happy with it except that it isn't very bright. I'm not sure it is worse than what came with the camera, but I wouldn't mind brighter. In terms of function, the one I have works well...

What I notice on mine is that I seem to have problems with my M50 lens in that the split screen goes black on one half at apertures at f8 and smaller. I don't use the lens in these aperture ranges often as my M50 is usually dedicated for when I need an aperture faster than f2.8. Never-the-less, I think the blackening leaves me with over-exposed images at smaller apertures (not sure if I am remembering right as I don't often test these things and still chalk up some exposure problems to inexperience).

It looks like there might be a bit of a catch 22. I'm interested in your comparisons when you get them. Thankfully, I find my results are much more consistent with all my A setting lens, perhaps because they all open to a nice constant f2.8. I guess it makes my use consistent without much thought to the lens speed.

[afs760bf]

I have been using a Katz-eye for about a year, and I love it. I got the optibright, the split ring, and lines for 8X10 frame. Works great.

[Big Dave]

emalvick,
I think that one factor causing loss of brightness, is screen thickness. I use a 1.3mm thick screen from a Olympus OM-2N, instead of the 1.4mm Pentax screen. I find the OM screen brightness to be about the same as the stock dslr screen. My split image does darken at F8 and above though. If you move your eye in the finder, you can use it at F8 sometimes. Works fantastic.

Dave

Steve, here is a question and brainstorm out loud, if you will...

In the review you talk about the underexposure in "Non-A" lens, apparently because the screen is "too bright" in the center portion. What I am wondering is that if the Katz-Eye is already compounding a problem, would the opti-bright compound the problem more since it would theoretically be "brighter".

I am just wondering. Right now I have one of the Chinese split screens, and I've been pretty happy with it except that it isn't very bright. I'm not sure it is worse than what came with the camera, but I wouldn't mind brighter. In terms of function, the one I have works well...

What I notice on mine is that I seem to have problems with my M50 lens in that the split screen goes black on one half at apertures at f8 and smaller. I don't use the lens in these aperture ranges often as my M50 is usually dedicated for when I need an aperture faster than f2.8. Never-the-less, I think the blackening leaves me with over-exposed images at smaller apertures (not sure if I am remembering right as I don't often test these things and still chalk up some exposure problems to inexperience).

It looks like there might be a bit of a catch 22. I'm interested in your comparisons when you get them. Thankfully, I find my results are much more consistent with all my A setting lens, perhaps because they all open to a nice constant f2.8. I guess it makes my use consistent without much thought to the lens speed.

[Kerrowdown]

I have the Katzeye with OptiBrite since May last year, for me with fast manual glass, it just does not get better, it reminds my of my days with LX's.