Katz Eye Split prism

When I am using my A_lenses, I have a problem defining the exact focus.
My previous cameras had a split screen prism. This helped a lot.

Question: Does fitting a split screen prism affect the autofocus?
If not, is it very hard to fit?

Regards, Horst

The first thing to check is that the eyepiece dioptre is correctly adjusted. To do this, point the camera at a plain subject such as a white wall or blue sky and then adjust until the etched lines in the viewfinder are sharp.

If still a problem, then there are other screens, but since the advent of AF spilt images have not been fitted as standard.

Personally, I prefer the plain screen.

No, it does not affect autofocus. The main downside is that it does affect metering. Spot metering will no longer be accurate - possibly a couple of stops out.

It is not at all hard to do, unless your hands are shaky - in which case it's impossible.

Andrew

Ditto what Andrew says - mine is only a cheap Chinese screen but I find it helps loads (complete with confirmation of the green af hexagon/bleep )with manual lens.

I fitted a katzeye screen to my K20D. The best thing I ever did.

K.

Really!!

In terms of photographic gear...

I had one for a k10d and it was great! Helped a lot with manual focus lenses.

Hi, thanks for all your comments.
it seems the majority of you think it helps, but the bit about the exposure metering worries me somewhat.

The eyepiece is correctly adjusted. First thing I did when I bought the camera.

I think I will order one of the Katz-Eye jobs on my next payday, end of ther month.

Thanks, Horst

Ditto with my K200D. Manual focusing was impossible without it, unless stopped down very far.

Exposure was not affected in the slightest.

This is something I also sometimes consider as I tend to use MF predominantly. Focussing fast lenses at max apertures can be a pain - you think it's in focus, it looks in focus, but it's not! Algi sold me a 1.3x eyepiece which helps a lot, but I still find it difficult when dof is very thin.

Aside from a split-screen, there are also ES type focus screens available. I wonder if anyone has been able to compare both?

The Green Hexagon/Beep which has been on Pentax cameras since
the MEF is the most accurate method of focusing as long as
you do the micro-AF adjustment.

Any other method of focusing you can move the camera back and
forth 6" and it still indicates in focus. The Green Hexagon/Beep
is usually +/-5mm at 900mm with an f/2.8 lens.

Catch in focus is good, but the camera is actually moving which
can cause shake.

A focusing rail preferably with a mm scale on it is essential
to get the AF/Beep adjustment right.

MF just by looking at the screen can only indicate that your
within the DOF at screen size.

I find that the green hexagon usually comes on, stays on, then goes off, as I move the focus ring. I think this may be because the focus sensor picks up other objects in it's range. Say if you want focus on the *front* of one particular apple on a tree, there may be other things (twigs, leaves, other apples, the back of the apple, the side of the apple etc) within the focus sensor area which keep the green hexagon lit.

Tommy Cooper would have advised... Don't focus on the *front* of one particular apple on a tree then!

As a rule, the green hexagon comes on and stays on if the split screen suggests that a shot is in focus, which I guess is what you would expect if everything is working OK. For me, the big advantage of the split screen is not that is makes focussing more accurate - but that it makes it much faster to achieve accurate focus with a manual lens.

Andrew