Using grains focuser with or without paper on the easel

[Don_ih]

Now that's what you call coming full circle.

 

[Bill Burk]

https://www.photrio.com/forum/threads/grain-focuser-recommendation.178580/

In that thread I did a different test and estimated a tenth of an inch range of sharpness at f/5.6 viewing through the grain focuser. But my butterfly test showed that on prints, the estimated range of sharpness is a quarter inch at f/2.8 which is more I think because you cannot see the grain.

A test I did today, mounting an SLR with no lens on a microscope stage and racking it up and down looking through a reflex magnifying viewer, also comes in near a quarter inch at f/2.8

The next test I do will span a half inch, I don’t think I will use single weight paper but am entertaining the idea “because I can”. It will take a sharper negative with fine detail. I have some ideas of what negatives might work.

 

[Bill Burk]

Another check using the grain focuser on a microscope stage. I racked the focuser up and down then came to the best focus 10 times, calipering the stage height after each best focus.

The results varied, as expected. The standard deviation was 0.076 - inch.

Average missed the original mark by 0.07 inches - about 1 standard deviation low.

 

[MattKing]

Bill,
Does all of this remind you of your work in radio?

 

[wiltw]

Another check using the grain focuser on a microscope stage. I racked the focuser up and down then came to the best focus 10 times, calipering the stage height after each best focus.

The results varied, as expected. The standard deviation was 0.076 - inch.

Average missed the original mark by 0.07 inches - about 1 standard deviation low.

Error of 0.07", far greater than one thickness of double weight paper at 0.015"

 

[faberryman]

Error of 0.07", far greater than one thickness of double weight paper at 0.015"

Depth of field covers a multitude of sins.

 

[Bill Burk]

Bill,
Does all of this remind you of your work in radio?

Kid of, like planning for another four hour show.

 

[Lachlan Young]

Error of 0.07", far greater than one thickness of double weight paper at 0.015"

And that says it all - as ever people get themselves wrought into the most extraordinary shapes over notional 'precision' that is so far within the tolerances of the system as to be less than irrelevant, yet cannot manage to control the basic parts of the process that demand nothing more than very moderate & reasonable levels of care/ precision.

 

[faberryman]

And that says it all - as ever people get themselves wrought into the most extraordinary shapes over notional 'precision' that is so far within the tolerances of the system as to be less than irrelevant, yet cannot manage to control the basic parts of the process that demand nothing more than very moderate & reasonable levels of care/ precision.

I might take issue with the suggestion that someone who rests his grain focuser on a sheet of enlarging paper when making a print is likely to be the type of photographer who does not exercise very moderate and reasonable levels of care and precision in other areas of the process. I would have come to the opposite conclusion. Of course, I am not an expert on human behavior.

 

[Bill Burk]

Bill, you used a focuser that is 10x, I used a 25x model. Do you feel the greater magnification may reduce the margin for error any?

Greg, I think absolutely you will have better repeatability and precision with 25x vs my 10x.
Give it a shot, even if you don’t have calipers you probably still are going to miss repeatability by a sixteenth of an inch.

25x is good for your way of working. Since I work the other way I don’t normally try to move the easel into focus. I have to Jerry rig to focus at the easel. My normal steps are to locate the negative a fixed distance from the easel (22 3/16 inch for 11 x 14) then I focus the lens. For this, my 10x is sufficient and quick.

The next part is an order of magnitude less precise. The results, when you can tell the difference in an 11x14 silver gelatin print from 35mm negative. My last test spanning a quarter inch didn’t find the range. I think it is the range but with nothing outside the range I couldn’t tell.

So I am going to try more like 50 sheets. I will try a different negative too because my butterfly is a little unsharp.

 

[Bill Burk]

I might take issue with the suggestion that someone who rests his grain focuser on a sheet of enlarging paper when making a print is likely to be the type of photographer who does not exercise very moderate and reasonable levels of care and precision in other areas of the process. I would have come to the opposite conclusion. Of course, I am not an expert on human behavior.

I can say that if you are going to take two shots of something important to get it right, it makes sense to go through each setting independently instead of just firing twice.

How I missed the focus of the photographer couple so badly at the wedding I will never know. I took two out of focus shots of them.

Maybe I did better in another roll but I sure can mess up the basics.

 

[Pieter12]

Time would be better spent making sure everything is in alignment, including the easel.

 

[pentaxuser]

Greg, your video convinced me that it makes no difference whether there is a sheet of paper in the easel or not but others appear to be convinced that it does.

I'd suggest that those who feel( they might say they know rather than feel) that it does make a difference then here's a suggestion: They should continue to use a sheet of paper and others who find no difference need not bother

After 13 pages it would seem likely that the only reasonable consensus possible here is that we are not going to get to a consensus

pentaxuser

 

[wiltw]

Greg, your video convinced me that it makes no difference whether there is a sheet of paper in the easel or not but others appear to be convinced that it does.

I'd suggest that those who feel( they might say they know rather than feel) that it does make a difference then here's a suggestion: They should continue to use a sheet of paper and others who find no difference need not bother

After 13 pages it would seem likely that the only reasonable consensus possible here is that we are not going to get to a consensus

pentaxuser

Bill appears to have convincingly determined, "It does not matter to have paper under focuser", and with 10X focuser there is 0.076" typical error that is often not detected even at f/2.8 The only remaining question is "if using 25X grain focuser, is the margin of detectability reduced?"
The methology of test would merely entail someone with an enlarger and using 25X grain focuser, and doing 50 trials of repositioning enlarger to identical elevation using the grain focuser, and putting 50 marks on the enlarger column, for each attempt to bring enlarger back to position. No paper need to be exposed.
I would offer to do it, but I sold my Beseler 45V-XL and my 25x grain focuser a few months ago, after being in storage for 20 years. the demise of Cibachrome/Ilfochrome paper was the beginning of the end to any thought of setting up a darkroom in our current home.

 

[RalphLambrecht]

Well stated,
If, when shooting a photo of flat art, my subject is at exactly 10', I would not think it optimal to set focus at 9' with the knowlege that 'f/8 DOF covers it just fine'. So why apply that line of thought in the darkroom, if that previous sentiment (about focus accuracy on flat art) applies to your thinking while shooting?! That would seem to be inconsistent.

It may be true 'The eye will never know the difference', but in such a case we are knowingly accepting imperfect blur circles as a substitute for perfectly reproduced points of light. The print is inherently less sharp than it could be.
About striving for excellence (not 'perfection') in what we do in photography....

• Some folks obsess about not using filters when shooting because the photo is 'not as sharp as it could be'.
• Some folks obsess about AF calibration for their camera and each lens because the photo is 'not as sharp as it could be'.
• Some folks will not use a teleconvertor on a long lens because the photo is 'not as sharp as it could be'.
• Some folks always mount the camera on a tripod because the photo is otherwise 'not as sharp as it could be'.
• Many folks use the magnifier in the waist level finder of medium format cameras and most use magnifiers on the large format focusing screen, to improve upon their focus accuracy,
• Most folks use the focus aid in the center of the 135 SLR viewfinder rather than merely relying upon the ground glass area because the photo would be 'not as sharp as it could be'.
• When the exposure is somewhat long, most use mirror lockup, because otherwise the photo is 'not as sharp as it could be'

So why not use that same thinking in the darkroom? If you have a piece of photo paper in the easel to make it easier to frame the projection, one merely needs to put the grain focuser on top of the paper, and then remove both after verification of focus. No added effort because the paper is already there, it is merely a question of WHEN the paper is removed, so one does not need to be OCD about focus accuracy.
You already are using a grain focuser...why did you purchase one, if 'good enough' focus is all you want?! You could have saved yourself that expense, and the bother of using it to focus. And why care for it and not simply throw it around, if its accuracy is 'it does not really matter, I cannot see the difference'.
There is apparent inconsistency of thought seen in some of the responses...that, or there seem to be a lot of photographers who settle for 'good enough' in all their methods throughout photography?

It is not being 'dogmatic', it is merely consistency of approach.

sharpness is poorly defined and overrated.

 

[faberryman]

I can say that if you are going to take two shots of something important to get it right, it makes sense to go through each setting independently instead of just firing twice.

How I missed the focus of the photographer couple so badly at the wedding I will never know. I took two out of focus shots of them.

Maybe I did better in another roll but I sure can mess up the basics.

I did not intend to suggest that people who are conscientious don’t make mistakes from time to time.

 

[dkonigs]

Speaking of grain focusers with different magnifications... All the ones I've tried (Bestwell Microsight, Paterson Micro, Peak 2030) all seem to magnify about the same. Sure, their stated magnifications may be different, but this just seems to manifest as a larger or smaller field of view in the eyepiece. Of course this could just be my perception, and I might be wrong, but after trying all of these I didn't actually find one to usefully magnify more than the other. (So I mostly just use the Peak now.)

This difference, or lack thereof, kinda reminds me of back when I tried using different eyepieces (with different stated magnifications) on my stereo microscope. At the end of the day, the only difference was field of view, so I stuck with the ones that had the largest FOV.

 

[Bill Burk]

I did not intend to suggest that people who are conscientious don’t make mistakes from time to time.

I didn’t take it that way, your comment just prompted a thought… it reminded me of a couple weeks back when I failed to pay even the least bit of attention.

 

[MattKing]

Time would be better spent making sure everything is in alignment, including the easel.

And time is always well spent in coming to an understanding of the limits inherent in the precision of the equipment and techniques we rely upon.

 

[Nicholas Lindan]

sharpness is poorly defined and overrated.

Bringing to mind one of my favorite web sites: https://www.junkstorecameras.com/ "Because Focus is Overrated."

 

[Lachlan Young]

I might take issue with the suggestion that someone who rests his grain focuser on a sheet of enlarging paper when making a print is likely to be the type of photographer who does not exercise very moderate and reasonable levels of care and precision in other areas of the process. I would have come to the opposite conclusion. Of course, I am not an expert on human behavior.

I've found it to be a warning flag of someone having taken too many confidently asserted myths at face value without meaningful or adequate testing - let alone any realistic consideration of what bits of the process really matter.

 

[faberryman]

I've found it to be a warning flag of someone having taken too many confidently asserted myths at face value without meaningful or adequate testing - let alone any realistic consideration of what bits of the process really matter.

1. A warning flag for what?
2. Have you determined which myths are myths?
3. How many myths is too many myths?
4. What constitutes meaningful or adequate testing?
5. Meaningful to whom?
6. Which bits of the process really matter?
7. What constitutes a realistic consideration?

To be honest, I am a little surprised you didn't mention actually looking at the work product of the person under scrutiny, you know, the photographs he has made. I don't think any of that vague mumbo-jumbo you rattled off is of any consequence in comparison.

Poor old Ansel Adams. A warning flag must be issued. From The Print at page 34:

"Since you wish to determine focus accurately on the enlarging paper, it is best to rest the magnifier on a scrap sheet of enlarging paper in the easel."

God knows what other myths this poor guy confidently asserted. More like talking through his hat. And I fell for it. In retrospect, the deception is so obvious. Post hoc ergo propter hoc.

A complete evaluation of my photographic technique is necessary. First up, determining whether you actually have to pull the dark slide before you make your exposure. I have read reports of photographers forgetting to pull the dark slide before making their exposure and being disappointed with the results, but I have never verified the phenomenon for myself. I was young and naive when I first started, so I just followed the instructions. It worked as advertised, so I blindly accepted it as fact.

Speaking of actual experiences, I once attended a large format workshop. To speed things up, on the second day, an assistant loaded the film holders for us since we had spent who knows many hours doing it ourselves the first day. So everybody experimented with tilts and swings and focus all morning, and exposed some negatives, and then came back to the darkroom to develop and print. Everybody thought the results looked great. Come to find out that the assistant loaded the film backwards. Sometimes just reading the instructions rather than conducting your own tests has its advantages. On the other hand, maybe owing to the miracle of depth of field and the limited acuity of the human eye, it doesn't make any visible difference which way you load the film. Anyone tested that recently?

 

[pentaxuser]

Nice offer, wiltw, but it might be a blessing in terms of your time, that you no longer retain the 25x grain focuser as, frankly, I see all the signs on this thread that it would make no difference to those who have already decided that Greg's test was flawed anyway

pentaxuser

 

[focus_on_infinity]

I'm thinking of just gluing a piece of paper to the bottom of my grain focuser.

Or maybe the grain focuser manufacturers already thought of that.

 

[Craig75]

Are some people not able to watch a 10min video and understand it without being auto triggered into their own mind garden