Grain Focusing - discrepancies

[Bill Burk]

The only adjustment on the Peak 1 is the viewfinder diopter adjustment. If it is not set correctly and you have presbyopia (inability to alter the focus of your eye), then your prints will be blurry.

The optical components are easy to disassemble and there is always the possibility that someone took it apart and buggered it up by not putting the focusing reticle in the correct location.

Oh! maybe they put the reticle in UPSIDE DOWN after cleaning! Thus making the focus off by the thickness of that piece of glass.

I just looked at my Micromega under a microscope. The reticle is on the outside surface of the lens. (You could put a fingerprint on the silver painted double rectangle if you touched it).

Also, by design I believe the visual projection of the reflection of the reticle should appear to be at the same plane as the paper surface, if you look down at the mirror with both eyes, so your left eye sees the reticle and the right eye sees the baseboard... I drew a rectangle on paper same size and placed it underneath so my eyes believed they were seeing one rectangle. The visual appearance was as if they are on the same plane. Parallax would show if they are out of place. Moving my head, the rectangles seem to stay visually in place. I suspect if the reticle was upside down (inside out), you might visually notice they are not in the same plane, and parallax would make the images move relative to each other when you move your head.

[pentaxuser]

The thing is Bill It seems as if all 4 of the OP's focusers are off compared to each other and his eye. It is very strange and I wonder as you will see from my previous post what were the circumstances of the OP's discovery of these faults.

pentaxuser

[DREW WILEY]

Of course there are ways to precisely calibrate such things, but is it worth it to set up instruments far more expensive than the only you're trying to fix? Been there, done that. I'm nitpicky, but at a
certain point, things can become overkill. Some of these magnifiers had paper shims in the base as
well as under the mirror. All it takes is a little bit of sloppiness in either and you've got an issue.
In most cases the casting aren't precise enough to dispense with the need of some manual adjustment during final assembly. And I never ever assume that a piece of equipment is precise without first checking it - well, maybe a machinist's quality instrument from Starret or Mitutoya
accompanied by a regiesterd certificate of accuracy - and I they'd have made on of these devices
it would have cost a lot more than what you paid for Peak. In fact they make instrumentation which
will read that front surface mirror and make a countour map of it several feet wide in millionth's of
an inch, just in case you need to see how flat it really is!

[ic-racer]

I'd put my Peak 1 focusers up against a Mitutoya any day. I'm surprised to hear so many people having trouble with them. I'll take any that are not wanted.

[Michael R 1974]

For what it's worth I've never had a problem with my Peak 1 either. When I bought it (new) years ago I tested it to see if any calibration was needed and found it was dead on. Then again, the plastic Paterson I used for years before that was just as accurate. Maybe I got lucky on that one. I invested in the Peak so I could see further away from the center, but I'm not sure I'd do that now. They're damn expensive and my prints were already as sharp as they could get from a focusing perspective.

[scheimfluger_77]

Have a look at page 76 here:

http://ctein.com/PostExposure2ndIllustrated.pdf

What? This book is available in PDF? Darn and I purchased a used one on Amazon.
Steve

[michaelbsc]

What? This book is available in PDF? Darn and I purchased a used one on Amazon.
Steve

Thinking out loud, I started building a collection of PDF and Kindle texts, but it's not the same without margin notes.

I know the electronic dodads let you "make notes" for a file. But it just isn't satisfactory in the end. At least not to me.

Luddite I guess.

[DREW WILEY]

What th' .... Ice Racer? Mitutoyo makes the instruments that measure the dies and machinery that
make things like Peak in the first place. They're a precision instrument and optics mfg - and obviously
have to been of a far higher quality control standard than the thing itself being made. I don't know what you're thinking of. You can buy something as simple as a digital caliper from them (and they
make some of the very best) or some advanced instumentation that will measure in angstroms!

[Steve Smith]

What th' .... Ice Racer? Mitutoyo makes the instruments that measure the dies and machinery that
make things like Peak in the first place.

Indeed. The manufacturer of the Peak focuser (do they make it themselves?) probably has some Mitutoyo equipment!


Steve.

[Nicholas Lindan]

My experience parallel's Marco's: I can focus more accurately [and far more quickly] without a grain focuser. It helps that I am terminally myopic. If you are far sighted I am sure a focuser is a great help.

The magnifiers' adjustment isn't for calibration but for adjusting to your eyesight so as to bring the reticle into focus. But you aren't making a print of the reticle. The proper calibration is to either move the reticle or to shim the focuser.

The Ctein article on focusing was discredited long ago.