I have watched videos on all kind of stuff. Who knows which ones are true. Take the History Channel for example. Did you know aliens built the pyramids?
Are some people not able to watch a 10min video and understand it without being auto triggered into their own mind garden
I have watched videos on all kind of stuff. Who knows which ones are true. Take the History Channel for example. Did you know aliens built the pyramids?
In this particular case, Adams made this statement without providing proof and I decided to test the claim. Independently, Bill also tested it, and I have since seen that ic-racer has also tested it in a separate thread. All three of us have found that the sharpest focus has a margin of error far thicker than a single sheet of photo paper and the statement by Adams doesn’t hold up.
probably best if you are kept away from videos if thats your level of discrimination
The mentalité that holds Adams' words on technique to be somehow inerrant is a big (and persistent) problem. In a reasonable world, three independent tests that disprove his statement should be enough to dismiss it completely.
Thinking more about this question, I concluded that a drawing might better convey what is happening, in comparing the ideal focus with starting off a paper thickness low (no paper on easel). So I made this drawing...And if it is impossible to see any difference between the two, which one has the built in error?
Is there some individual or organization that vets the accuracy of YouTube videos, because it pretty much seems to me that the only requirement is that you have a video camera (or cellphone) and that you know how to upload. I uploaded a video once. It may still be up. Everything in the video is true. Trust me.
So would it not make sense to start at the 'ideal focus' level, rather than starting with one sheet error (bare easel)?!
Fair point.If you’re going to get technical, the diagram does not illustrate the real situation because you cannot assume the paper plane = the actual focal plane unless everything else in the system is perfect (enlarging lens, grain focuser). What you’d need to do is add two more lines for actual focal planes, each displaced from the “focus” lines. It might turn out focusing without paper ends up putting the actual focal plane closer to the ideal plane than focusing with paper.
And how do you know that you can ever determine (i.e. actually see) which focus is ideal, and which ones are not ideal.Thinking more about this question, I concluded that a drawing might better convey what is happening, in comparing the ideal focus with starting off a paper thickness low (no paper on easel). So I made this drawing...
The drawing was entirely a conceptual model for discussion purposes. The paper plane is considered the 'ideal' level since the emulsion coated on the paper is the image formation location. Given the very thin thickness of the emulsion (one paper spec states a thickness of approximately 245 µm), it did not really need to be factored into the discussion, especially when 0.070" range of undetectable error has been determined in Bill's testIf you’re going to get technical, the diagram does not illustrate the real situation because you cannot assume the paper plane = the actual focal plane unless everything else in the system is perfect (enlarging lens, grain focuser). What you’d need to do is add two more lines for actual focal planes, each displaced from the “focus” lines. It might turn out focusing without paper ends up putting the actual focal plane closer to the ideal plane than focusing with paper.
yes there is; this site - bill and ic-racer have peer reviewed it.
And how do you know that you can ever determine (i.e. actually see) which focus is ideal, and which ones are not ideal.
You can assume that the grains focuser accurately positions the image in relation to the image at the paper itself, and that assumption is a reasonable one, but it still is an assumption, which might very well be off slightly.
The "system" (enlarger plus grains focuser plus visual acuity) doesn't permit us to accurately determine where the range limits of your diagram are. In order for the system to do so, it would have to be accurate enough to permit us to see the effect of the sheet of paper.
As warden posted, both with and without paper is equally ideal.
So insert the paper if you like inserting the paper (or not) and use the grains focuser to maximize the accuracy of focus, within the limits that the "system" permits.
The drawing was entirely a conceptual model for discussion purposes. The paper plane is considered the 'ideal' level since the emulsion coated on the paper is the image formation location. Given the very thin thickness of the emulsion (one paper spec states a thickness of approximately 245 µm), it did not really need to be factored into the discussion, especially when 0.070" range of undetectable error has been determined in Bill's test
That is left as an exercise for the student. QEDYou might want put one of those plus or minus symbols in front of that 0.070" since the accuracy of Bill's vision is an unknown. Wouldn't want any false precision sneaking in. I am not saying it would change the result, so everyone can calm down.
The other thing you might want to do is add a couple of green lines on each side of the paper/non-paper lines representing the near and far distances from Bill's depth of field calculations.
As restated countless times by many, "you cannot tell the difference, so it does not really matter"!One point that has not been raised is, how accurate is a grain focuser? It seems to me it depends on how well it has been made so the mirror image actually represents the image projected on the paper surface. The peak magnifiers have front-surface mirrors so they won't introduce errors from the mirror glass, I don't know if that kind of care is found in others or if it is even all that necessary.
I can certainly tell the difference when using an enlarger that is not aligned or a lens that has poor definition at the edges. Why shouldn't I be able to tell if a faulty grain focuser results in a soft image?As restated countless times by many, "you cannot tell the difference, so it does not really matter"!
That is left as an exercise for the student. QED
You cannot tell, if the "fault" in the grain focuser is of an order of magnitude less than the thickness of a few sheets of paper.I can certainly tell the difference when using an enlarger that is not aligned or a lens that has poor definition at the edges. Why shouldn't I be able to tell if a faulty grain focuser results in a soft image?
Left hand doesn’t know what right hand is doing.
Butterfly in my series was shot on Double-X not TMY-2.
It makes me happy to realize I cannot see the grain of Double-X on my standard 11x14 enlargements because that was the entire goal of my idea to try Double-X in the first place.
But next test is going to be from TMY-2 because that’s what I had intended to test. Hang tight, we might see the grain.
Bill's test (and other tests by posters here) showed that some degree of error cannot be identified, either by naked eye or by 10X grain focuser. If the alignment is bad enough, or if the elevational error is large enough, it can be visualized, as shown in Bill's testing. So within the zone of undetectability, 'it does not really matter'I can certainly tell the difference when using an enlarger that is not aligned or a lens that has poor definition at the edges. Why shouldn't I be able to tell if a faulty grain focuser results in a soft image?
We've really got to see the grain. Comparing flower stems seems a little iffy to me.
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