That would introduce the debate of whether it should be on the front or the rear of the lens.
There's a technical solution for everything. Just put vaseline over the enlarging lens front element and be done with it !
Is it ironic, or foreshadowing? I found them in the old card file where I keep pieces of paper to use under the grain focuser.
Is it ironic, or foreshadowing? I found them in the old card file where I keep pieces of paper to use under the grain focuser.
Are you sure it isn't a conspiracy?I'd be inclined to call that coincidental.
will Bill be honest and not biased?
Fine with me. Start a new thread. The debate will really heat up once we start discussing the merits of smearing vaseline over the lens versus applying a nylon stocking.
What about K-Y jelly instead of Vaseline?
Whatever you happen to have on hand....
Ah that picture, backyard with my best friends Tom and Jim.Look at his picture. You can clearly trust him.
Your methodology of evaluation...arriving at 0.076" or 1.93mm (which is less than the computed DOF value stated earlier in this thread)My conclusion is the range of sharp focus is 0.076 inches. Six sheets in the middle of the test reveal low contrast detail that is camouflaged in noise on the outside sheets.
I'm not sure I understand this. Does the position of the eye to the focuser affect the grain as seen through the focuser? Can it be in focus (when the focuser is properly adjusted, using the reference line) through the instrument and not at the surface the focuser is resting on?It is the "eye to the grain focuser" part that I have been posting about in this thread.
It is much simpler than that.I'm not sure I understand this. Does the position of the eye to the focuser affect the grain as seen through the focuser? Can it be in focus (when the focuser is properly adjusted, using the reference line) through the instrument and not at the surface the focuser is resting on?
If I try to paraphrase what I think you're asking, "If you put the grain focuser on the top layer, as you removed each of the layers of double-weight paper, would you be able to detect increase/decrease in focus accuracy as you passed thru the ideal focus plane?" (finding out if the 25X grain focuser would reveal what the naked eye would be fooled as 'in focus')It is much simpler than that.
The distances we are talking about here - changes in position of the grain finder one sheet of paper at a time - give results that we are unable to differentiate between, because we can't see a change when the grain focuser moves that small distance.
It is like trying to measure milligrams with a postage scale.
For me, the grain "snaps" into focus when using a magnifier. So, basically you are saying that when I see that sharp grain in the magnifier, when the lens is stopped down it is sharp over a depth of 3-5mm perhaps. I am surprised because there does not seem to be that much leeway when focusing, even stopped down. Disclaimer: I develop in Rodinal and use a condenser enlarger, so grain is quite apparent.It is much simpler than that.
The distances we are talking about here - changes in position of the grain finder one sheet of paper at a time - give results that we are unable to differentiate between, because we can't see a change when the grain focuser moves that small distance.
It is like trying to measure milligrams with a postage scale.
IIRC, Bill did in his testing.Who uses double-weight paper?
Remember, you are focusing by moving the lens (or the negative), not the easel/paper.For me, the grain "snaps" into focus when using a magnifier. So, basically you are saying that when I see that sharp grain in the magnifier, when the lens is stopped down it is sharp over a depth of 3-5mm perhaps. I am surprised because there does not seem to be that much leeway when focusing, even stopped down. Disclaimer: I develop in Rodinal and use a condenser enlarger, so grain is quite apparent.
I believe his point was to reduce the number of layers in the test, to offset the same vertical distance....removal of 0.015" per layer to have a 0.150" stack takes fewer layers than 0.008" per layer. As it was, he had to do 19 layers...your suggestion would double that count, and only improve the apparent precision of the test by 0.008"Well perhaps Bill should test using single weight paper?
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