There's a mark on the K-5 for the sensor position. It's the same
as on all film cameras an "O" with a line through it "--"
All measurements need to be from there and you need to go to
RH site again and follow the procedure exactly.

The marks on the right side of the camera by the LCD. It
almost lines up with a line on the LCD.

The flat area of the graph at the bottom of this page shows quite
clearly that there are several positions of the camera where
electronically the camera looks in focus due to DOF. It
covers about 4 rail positions.

The article also explains why non of the methods are reliable.

http://www.slrgear.com/articles/focus/focus.htm

I did ask blob if he could come back in 20 years....

-

OK you say you focus by looking at the screen. I presume that
if you were using a preset 85mm f/1.4 lens you would open it
up to wide open to focus, but would be quite happy to frame
the picture at say f/8..... Why don't you also focus at f/8
Could it be that the DOF is too great at f/8 to focus properly?

People even change their screens for the Canon Ee-s screen
because you can't see the DOF with the standard Pentax
screen with a f/1.2 - f/1.4 lens.... This is similar to
the problem with LV... It all looks in focus.

Canon_Screens
-

Anything optical has a DOF even your eyes Look at an
object on the horizon with one eye and then hold a finger an
inch in front of your eye and it won't be in focus. Your eyes
have a greater DOF during the day than at night.

It really is very basic optics.... any lens can only focus
on one point/distance.... all other points are OOF.

Your camera particularly film cameras had a lever called
a DOF lever..... What do you think that did?
What can you see when you press it down?

Why doesn't AF work properly with lenses of
f/8 f/11 aperture?

It's very easy to check any of these focusing
methods. Just focus on something a meter away
and then move the camera (or object) 20mm at
a time and see if it still looks in focus.

Last time I tried on a small rack LV looked in
focus over a range of about 150mm.... Ouch!


-

Like all things LV has a DOF and the aperture changes depending
on the light level. Most of the time I have about +/- 20mm or
40mm total DOF and by definition (of DOF) it will look in
focus anywhere within that DOF. It was the same using enlargers
until someone invented grain magnifiers.

The Green Hexagon/Beep also has a DOF and will be in focus at
a different point if you turn the lens from INF or from MIN
FOCUS. Then you have the problem of no micro adjustment to the
focus on the lens.

Last time I looked at split image finders I looked at the
corner of a box and it showed 3 corners (couldn't see the
4th) in focus even though there was about 75mm difference....
so they are quite crude and are also independent of the
camera electronics, so lenses may need to be mechanically
tweaked.

A reversing ring is by far the cheapest

-

I understand now

The Green Hexagon/Beep will work in a fashion with most lenses.
It's been there since the ME-F came out in 1981 so only 31 years
old and far too young an implementation for any Pentax user to
know much about it.... Can you come back in 20years?

From tests I've done recently it seems to need a lens that is very
good lens wide open to work accurately. The in camera micro-focus
adjustment has to be done for the lens first. I'm currently
trying a Pentax_A 50mm f/2.8 Macro lens and I think I have
it set right. The biggest problem is getting the lens exactly
in focus to set the adjustment. Even LV manual focus isn't
exact. I usually set it on a rack and move in about 5mm
increments until I get the best shot and then try to
match up the in camera micro-focus adjustment.

I'm working at 1M it might be OK at 3M without too much
fiddling.

-

What do you mean?

You were annoyed that you got a focus confirm indication when
using a manual focus lens on an Olympus camera?

-

What next Ansell Adams Macros of Spiders

What a con.

Most people think that there were just TWO versions of this
lens.... but there were actually at least THREE.

This is the very early version that won all the awards in
tests, Best Standard Lens Ever Made etc. I have the same one.

The next version came out around the time of the 31mm and 77mm
and had the Green Wart on the side.

The final version was the Vietnam one, but there could have been
others in between.