Grain Focus

[Pieter12]

There is not much I dislike more than a soft print. Even if the focus is soft or there is motion blur, I want the grain to be razor sharp (and I develop in Rodinal). I try to get the best lenses I can for my cameras and enlarger. Using a grain focuser is just another part of ensuring the final print is as sharp as possible. It is also handy to check at what aperture the enlarger lens starts to introduce softness through diffraction.

 

[Sirius Glass]

I do not know about you, but I use grain focusers when I am printing using an enlarger. I have never used a grain focuser while taking photographs.

I am sorry. I guess I was not as clear as I might have been, but thanks for responding. What I meant to say was that if a person could focus a camera unaided that it was likely they could focus an enlarger without having to use only the very best aid.

With a camera I can usually get the focus correct by focusing back and forth quickly or using the depth of field with zone focusing, I cannot consistently achieve sharp focus without a grain focuser.

 

[Mick Fagan]

In other words there is a demonstrable difference?

Thanks

pentaxuser

Demonstrable difference, is the best description.

I didn't use that word as there will most likely be some people who with English as a second or third language may have difficulty with that word.

I have a Patterson unit, as well as a few others of similar design, they all work well, but if you focus with the Patterson unit, then switch to the Peak unit, then you will not reach for the Patterson unit again, unless you cannot find the Peak unit.

This is consistent with people who have been enlarging in my darkroom. Once they have used the Peak unit, the inevitable question is; "how much does this cost?".

It is, that much of a difference.

Mick.

 

[Stephen Prunier]

Like a lot of others, I purchased the Paterson version when I was starting out. I now have the Peak 2030 model and there is a noticeable difference. I have a question for those using the Peak unit for B&W printing. Do any of you have and use the optional BG filter with it? What does it do?

 

[logan2z]

Like a lot of others, I purchased the Paterson version when I was starting out. I now have the Peak 2030 model and there is a noticeable difference. I have a question for those using the Peak unit for B&W printing. Do any of you have and use the optional BG filter with it? What does it do?

I have the filter but haven't used it. I've read that it doesn't make much difference but I should try it and see for myself.

 

[pentaxuser]

Thanks both in #28 and#29. You mention a clear difference but not how this is "seen" by the user Does the grain somehow become even clearer i.e. what I think is sharp grain with the Paterson is not as sharp as it can be, there is a level of sharpness that until you see it under a Peak you are not aware is possible?

Forgive me but I always get a bit concerned when something that can be seen has not been quantified.

Thanks

pentaxuser

 

[Stephen Prunier]

Thanks both in #28 and#29. You mention a clear difference but not how this is "seen" by the user Does the grain somehow become even clearer i.e. what I think is sharp grain with the Paterson is not as sharp as it can be, there is a level of sharpness that until you see it under a Peak you are not aware is possible?

Forgive me but I always get a bit concerned when something that can be seen has not been quantified.

Thanks

pentaxuser

It could be psychological but to my eyes, the image appears more clearly/brighter? before I start to adjust the focus knob. I feel like I struggle more with the Paterson model. I've definitely used the Paterson a lot more than the Peak so far as I've only had it for a few months. They'll both do the job. I'm 61 and even with glasses, my eyes can always use a little help.

 

[pentaxuser]

It could be psychological but to my eyes, the image appears more clearly/brighter? before I start to adjust the focus knob. I feel like I struggle more with the Paterson model. I've definitely used the Paterson a lot more than the Peak so far as I've only had it for a few months. They'll both do the job. I'm 61 and even with glasses, my eyes can always use a little help.

My problem is that with my Paterson each grain seems to come into focus so clearly that I wonder how any other grain focuser can improve on this. In my case I focus on the grain at f2.8 using a 50mm lens so the projection is very bright. Yes it is less bright with my 80mm with a min f stop of 5.6 and grain is anyway less prominent in MF negs but the difference between in focus and slightly out of focus is still clear.

I need glasses to read comfortably but with the Paterson I find that I can focus as easily without glasses. I think the Paterson is designed to be equally usable with or without glasses - at least in my case using reading glasses makes no difference

pentaxuser

 

[Stephen Prunier]

My problem is that with my Paterson each grain seems to come into focus so clearly that I wonder how any other grain focuser can improve on this. In my case I focus on the grain at f2.8 using a 50mm lens so the projection is very bright. Yes it is less bright with my 80mm with a min f stop of 5.6 and grain is anyway less prominent in MF negs but the difference between in focus and slightly out of focus is still clear.

I need glasses to read comfortably but with the Paterson I find that I can focus as easily without glasses. I think the Paterson is designed to be equally usable with or without glasses - at least in my case using reading glasses makes no difference

pentaxuser

The more I read about them the more I believe they're all pretty much equal. I mostly use a 105mm f4.5 so not very bright either. That could be one of the reasons I felt I needed something better. I think if you are asking because you're thinking of purchasing something else. I would just stick with the Paterson if it's doing what you need one to do.

 

[reddesert]

A grain focuser works by focusing on an aerial image. It uses a simple magnifying lens and a target (like a crosshairs or circle). The mirror and target are arranged so the target plane is placed at the same distance as the printing paper from the enlarging lens. The target forces your eye to focus on that plane, so when the projected aerial image is in the same plane as the target, the image will appear to snap into focus. The magnifying lens of course magnifies the image enough that you can see the grain.

Typically, the image will appear as if it was some distance away (like about 1 meter or so) - this depends on the lens distance to the target. I need reading glasses to see close up, but I don't need them for objects at 1 meter, so I can use a grain focuser, a loupe, or an SLR viewfinder without glasses.

Grain focusers use this aerial image method because it is inexpensive and the aerial image is much brighter than a ground glass.

A cheap grain focuser can be very accurate. There are ways to make a fancy grain focuser that can make it easier to use (pivoting loupe, longer eye relief, etc), for the same reasons that an expensive achromatic loupe is somewhat nicer to use than a cheap magnifying glass.

 

[John51]

Now that I've made enough boards to use all my lenses on my Kodak Precision enlarger, my current project is hacking a webcam to use as a grain magnifier.

De-lensed webcam taped to piece of wood and the naked sensor should, in theory, give a sharp image when the enlarger is in focus.

In practice, the image isn't sharp. More like an out of focus picture of a pizza. The time lag is annoying. It takes a second or two for the image to stabilise after changing focus. Very easy to go too far. When it does comes in, it's all or nothing. Either blurry pizza or a nondescript blank. Final adjustment done by just putting a little pressure on the focus wheel, no noticeable turning at all. A 100:1 fine focusing wheel would be welcome.

I've used a grain magnifier in the past but the focusing wasn't so all or nothing super critical. I'm wondering if the lens on the grain magnifier adds to the depth of field.

If, with practice, I can reduce the time needed to focus, it's going to be a handy tool. The image is conveniently shown on a netbook placed on a shelf next to the enlarger head. No body contortions. I did notice some chromatic aberration on at least one lens. Another advantage is that the working aperture can be used for focusing.

 

[Pieter12]

In Barry Thornton's book, Edge of Darkness, he tests a half-dozen grain focusers. Only two agree. I think the issue is because they focus an aerial image and they might not be made precisely enough so that image will focus in the same place. However, if one focuses wide open and then closes down a couple of stops, the minor difference goes away--the image is equally sharp, not matter the grain focuser. Having said that, the Peak/Micromega is very nice in that you can use it over a wider area of the image.

 

[Mick Fagan]

Like a lot of others, I purchased the Paterson version when I was starting out. I now have the Peak 2030 model and there is a noticeable difference. I have a question for those using the Peak unit for B&W printing. Do any of you have and use the optional BG filter with it? What does it do?

Have a read of this thread, it was 13 years ago.

Read it right through.

I still use the BG filter when doing critical enlargements, razor sharp.

https://www.photrio.com/forum/threads/peak-bg-filter-for-b-w-enlarging.22866/

Mick.

 

[tezzasmall]

I have a question for those using the Peak unit for B&W printing. Do any of you have and use the optional BG filter with it? What does it do?

I still use the BG filter when doing critical enlargements, razor sharp.

Mick.

I too have the blue filter, and like the majority I could see no difference in focus and it actually made it harder to focus it in the first place!!!

I've read the link before and on there and on the web, you will get people with differing opinions, as you do with all subjects, but I think the majority agree that it doesn't do anything. If you have one, you just have to try it out for yourself.

Terry S

 

[Doremus Scudder]

The reason for using a blue filter with a grain magnifier is because graded photo papers are sensitive only to blue light. Many older enlarging lenses (especially before color photography was prevalent) were not well color-corrected and focused blue and red at different places.

Filtering out the red and green (where the eye is most sensitive) when using such lenses enables one to focus on the right spot, where the blue that the paper is sensitive to focuses, without any confusion introduced by other colors.

Nowadays, most (if not all) quality enlarging lenses are corrected to focus all three colors at the same spot, so a blue filter is not needed because of the lens. Plus, VC papers are sensitive to green as well as blue, not to mention color papers, which are sensitive to a full visible spectrum. With these lenses, a blue focusing filter is really no longer an aid and can actually hinder achieving accurate focus, since it dims the image being focuses significantly.

Bottom line, if you have a good color-corrected enlarging lens, forget the blue filter. If you're using 19th-century enlarging lenses, it probably wouldn't be a bad idea.

Best,

Doremus

 

[Sirius Glass]

I have a setting on the enlarger that allows me to have bright white unfiltered light plus I open the lens fully to use the grain focuser. Once focused the lens is stopped down so the image is even sharper. I never focus in any colored light, mainly because a do not believe in self-flagellation.

The human eye sees the poorest in blue light, so why paint oneself in a corner when focusing?

 

[markbau]

Like a lot of others, I purchased the Paterson version when I was starting out. I now have the Peak 2030 model and there is a noticeable difference. I have a question for those using the Peak unit for B&W printing. Do any of you have and use the optional BG filter with it? What does it do?

In Ctein's book, he devotes many pages to this subject. As to the question of does it make a difference, I think there are too many variables to arrive at a definitive answer. I don't use the blue filter and my prints are sharp to my eye but I'm sure there are people who swear by the blue filter. I always focus at the working aperture. Focusing at wide open the image is too bright for my eyes. (maybe I have very sensitive eyes) because I never understand why people say the image is too dim unless they focus wide open.

 

[Mick Fagan]

I too have the blue filter, and like the majority I could see no difference in focus and it actually made it harder to focus it in the first place!!!

I've read the link before and on there and on the web, you will get people with differing opinions, as you do with all subjects, but I think the majority agree that it doesn't do anything. If you have one, you just have to try it out for yourself.

Terry S

Terry, my question is this, was there a difference in the prints done with a BG filter, versus those done without the BG filter?

If so, what was the outcome?

Mick.

 

[Mick Fagan]

One issue I see, is the way most enlargers use friction to hold focus, instead of a locking mechanism.

Before acquiring my DeVere enlarger, my previous best enlargers were both LPL units, a 7700 followed by a 7450 which were capable of 6cm x 7cm negatives and 4" x 5" respectively. I really liked these and had them set up to give their best.

Meanwhile, I was using DeVere enlargers at work and knew just how good they were at locking focus in, and, when I say lock, I mean lock.

My LPL enlargers were both fitted with the critical focusing knob, which enhances one's ability to get super accurate focus; which is fine. That said, the focus was held in place by the amount of tension applied to the mechanism so that once you took your hand away, it stayed in place; it isn't a locking mechanism.

The DeVere units have a locking mechanism for the head/negative stage and another locking mechanism for the lens stage. These locks are unbelievably well thought out and make it virtually impossible for focus to move even a fraction of a millimetre from where you place it. These locks, combined with the front mounted focusing wheels, allow one to achieve perfect focus then lock it in exactly where you wish it to be locked, with the knowledge that absolutely nothing will move, are the ultimate in focusing mechanisms I have ever seen on enlargers. Even a slight bump to the enlarger baseboard may move super critical focus, but this is almost impossible with the DeVere enlargers.

I cannot remember ever reading where people have made their best print, (focus wise) then made a second identical print, with the exception of using the BG filter for critical focusing; then compared the prints alongside each other. This was what I originally did, then I asked a much younger person with better eyesight to do the same thing in my darkroom using the same enlarger. We both produced prints that were superior using the BG filter. Since then there have been two other people who have done the same thing in my darkroom, one about 9 years ago the other about 4 years ago. They too were able to produce better prints, with the BG filter.

I do agree that using the BG filter is harder, time consuming and often not worth the effort. However for something that you have a good negative, a good subject and is dear to your heart, then a print with the BG filter is worth the extra effort. Your technique from start to finish, has to be impeccable.

Mick.

 

[MattKing]

Even if there is no difference in the prints that result, if something is quicker and easier and more comfortable to use effectively, I consider it "better".

 

[Sirius Glass]

One issue I see, is the way most enlargers use friction to hold focus, instead of a locking mechanism.

Before acquiring my DeVere enlarger, my previous best enlargers were both LPL units, a 7700 followed by a 7450 which were capable of 6cm x 7cm negatives and 4" x 5" respectively. I really liked these and had them set up to give their best.

Meanwhile, I was using DeVere enlargers at work and knew just how good they were at locking focus in, and, when I say lock, I mean lock.

My LPL enlargers were both fitted with the critical focusing knob, which enhances one's ability to get super accurate focus; which is fine. That said, the focus was held in place by the amount of tension applied to the mechanism so that once you took your hand away, it stayed in place; it isn't a locking mechanism.

The DeVere units have a locking mechanism for the head/negative stage and another locking mechanism for the lens stage. These locks are unbelievably well thought out and make it virtually impossible for focus to move even a fraction of a millimetre from where you place it. These locks, combined with the front mounted focusing wheels, allow one to achieve perfect focus then lock it in exactly where you wish it to be locked, with the knowledge that absolutely nothing will move, are the ultimate in focusing mechanisms I have ever seen on enlargers. Even a slight bump to the enlarger baseboard may move super critical focus, but this is almost impossible with the DeVere enlargers.

I cannot remember ever reading where people have made their best print, (focus wise) then made a second identical print, with the exception of using the BG filter for critical focusing; then compared the prints alongside each other. This was what I originally did, then I asked a much younger person with better eyesight to do the same thing in my darkroom using the same enlarger. We both produced prints that were superior using the BG filter. Since then there have been two other people who have done the same thing in my darkroom, one about 9 years ago the other about 4 years ago. They too were able to produce better prints, with the BG filter.

I do agree that using the BG filter is harder, time consuming and often not worth the effort. However for something that you have a good negative, a good subject and is dear to your heart, then a print with the BG filter is worth the extra effort. Your technique from start to finish, has to be impeccable.

Mick.

My Chromega Dichroic II D5-XL has a locking mechanism - a knob that tightens the thread until it binds against the metal frame, not a friction stop.

 

[Mick Fagan]

Even if there is no difference in the prints that result, if something is quicker and easier and more comfortable to use effectively, I consider it "better".

Agree 100% with you Matt, but for a special print, one pulls out all the stops.

Mick.

 

[Ian C]

I used the spotmeter of my Sekonic L508 meter and determined that the BG filter of the Peak Model I holds back about 4 stops of light. For big enlargements, the image seen through the filter might be dimmed enough to make it difficult to focus.

For prints that I’ve made with and without the filter, I couldn’t see a difference when I examined them with reading glasses. I use variable-contrast papers exclusively. I don’t know if fixed-grade papers would behave differently. My papers are Kodak (nearly gone), Ilford, and Oriental.

 

[Mal Paso]

Maybe it's because I've used one or two grain magnifiers that were off I haven't used them for years, like 50. LOL The thing that troubled me was not being able to check calibration. Maybe that has changed? I've always focused on a sheet of processed paper in the easel although now I wear 2x readers. I've been fortunate to have good enlarging lenses and never had any focus shift issues. Usually print 2-3 stops down.
Good thread! Thanks!

 

[DREW WILEY]

Get a top of the line Peak in your hands (the Peak Critical Focus model with the tilting head), and you'll turn your back on those cheap ones for good. It's a precision device. Also read my previous post. The accessory blue filter has limited current use, particularly if you use modern well-corrected enlarging lenses. But all of this discussion is a waste of time unless you use a precisely aligned glass negative carrier which keeps the film truly flat.