Accurate focus through enlarger

marciofs · Mar 22, 2013

I don't have that lope to find the focus so I use my eyes.

Is there a way to make sure the focus is right. any technique?

horacekenneth · Mar 22, 2013

I tried focusing by eye for a while. It was frustrating. Also my enlarger was frustrating. A loupe makes it a lot easier, I would highly recommend one.

But- at the same time of course - totally possible to focus by eye without the loupe. Don't have any recommendations except make sure the lens aperture is all the way open.

pentaxuser · Mar 22, 2013

Get a grain focuser such as a Paterson. In terms of focus still probably the best way and the Paterson one is the cheapest. Much more accurate than the eye

pentaxuser

marciofs · Mar 22, 2013

I will check the Paterson one. Thanks.

Rick A · Mar 22, 2013

(there was a url link here which no longer exists)
A couple of different grain focus scopes for sale here.

baachitraka · Mar 22, 2013

You may get the scoponet 20x...

cliveh · Mar 22, 2013

I focus the enlarger by eye and then check with a focus scope and often find it is as sharp as when just focusing by eye.

baachitraka · Mar 22, 2013

Tip: Focus the grain without paper.

cliveh · Mar 22, 2013

baachitraka said:
Tip: Focus the grain without paper.

Please explain.

Arvee · Mar 22, 2013

Or, use your 50mm lens reversed. Makes a great, super high quality, high magnification loupe.

jp498 · Mar 22, 2013

I've focused by eye for 20 years. The cheap grain focusers are annoying and I'd rather do it by eye. A Nice grain focuser is indeed nice, but expensive. I got a Peak brand one from someone unloading darkroom stuff on clist. It's the one to aspire to if you want an actual good grain focuser. I don't get sharper photos with it since I can focus fine without it. It just makes things a little quicker.

Focusing by eye, you just rack the focus through the focus zone and iteratively back and forth like you would with an image on a ground glass. You watch what's happening and settle on a spot and it's good.

winger · Mar 22, 2013

I've focused by eye most of my printing life and only found the grain focusers to be helpful when I went to 4x5. But I don't need glasses, my safelights are red (and therefore slightly dim), and I open the lens all the way up to focus. I've also spent a great deal of time looking through microscopes and am used to focusing through something to find the focus.
I agree that it's worth getting a really good one if you do it. Check the prints you've made to see if you can see the grain. If you can, then you're focusing the enlarger just fine.

Newt_on_Swings · Mar 22, 2013

A good pair of glasses will work wonders or even a handled magnifying glass should work to enlarge what you are looking at without blocking the stream of light from the lens. At home I use a Peak 1 grain finder, and it was well worth the investment, it performs fantastically, if you ever come across one at a reasonable price get it!

As for tips, use a bright lens of smallest focal length you can for the format. eg 45mm or 50mm 2.8 lenses for 35mm. Focusing wide opening will give you a bright image to work with. The rest is practice focusing forward and back until the image snaps into focus. Try looking for spots on your image that have text, or detailed edged, which will make it a bit easier to judge how sharp it is.

AgX · Mar 22, 2013

As a cheaper alternative to a focusing loupe one could use a groundglass viewer. A simple device made out of a frame, a mirror and groundglas.
It yields the same image as seen on the baseboard, but is brighter and and more comfortable to view due to ist angled groundglass.

marciofs · Mar 23, 2013

Fred Aspen said:
Or, use your 50mm lens reversed. Makes a great, super high quality, high magnification loupe.

Cool. i will try this one.

Newt_on_Swings · Mar 23, 2013

AgX said:
As a cheaper alternative to a focusing loupe one could use a groundglass viewer. A simple device made out of a frame, a mirror and groundglas.
It yields the same image as seen on the baseboard, but is brighter and and more comfortable to view due to ist angled groundglass.

This is the same effect a tool marketed as the hocus focus used to great effect. It is basically a question marked shaped piece of plastic with a frosted top and within the bottom portion rested a mirror, and the bottom tip allowed you to rest and tilt it any way you'd want on the baseboard. Easy and a quick way to get focus, but I still preferred the magnified view through a grain finder.

megzdad81 · Mar 23, 2013

Why focus the grain without paper?

AgX · Mar 23, 2013

Because the height difference due the paper should be negligable.

Steve Smith · Mar 23, 2013

megzdad81 said:
Why focus the grain without paper?

We had a long thread on this a while ago. Basically, it makes no difference.

There was quite a discussion and in the end, I contacted three manufacturers of focusing aids. The two who answered said not to bother with paper under them as it makes no difference.

Ralph Lambrecht also stated this as did Gene Nocon in his book, Darkroom Printing.

There is a fairly wide depth of focus at the paper stage - much more than the depth of field at the negative. In order to make a difference in the focus position equal to the thickness of paper, the negative to lens distance would have to change a tiny amount. A much smaller amount than you could hope to achieve using the enlarger's focusing control and probably no more than the thickness of the emulsion.

Another interesting test is one carried out by Barry Thornton in his book, Edge of Darkness. He set up his easel on a piece of 1/2" thick board, focused and made a print. He then made two more prints - one without the board and one with a second board. So 1/2" below and above the focused position.

He claimed that he could see no difference in sharpness - and he was obsessed with sharpness!

The conclusion was to use paper if you want to or don't if you don't want to as it makes no difference.

Steve.

baachitraka · Mar 23, 2013

I cannot say anything about other grain focusers except scoponet 20x. I normally place it on easel and focus without paper.

Focusing with paper has resulted in not so sharp print. :-( At-first I thought focus errors during shooting but I tried one more print by focusing without paper.

I do not know, scoponet might have built-in compensation for paper thickness(I know they may lead lots of questions...).

Negative: 135
Enlarger: Durst 600 @f/8
Paper: Adox Vario Classic.
Print Size: 8x10 inch.

Steve Smith · Mar 23, 2013

baachitraka said:
I do not know, scoponet might have built-in compensation for paper thickness.

That's what I used to think and it's what I would do if I was making them but according to the manufacturers I contacted, this was not done.

I think you might be fooling yourself into thinking that you get sharper prints without the paper just as others will swear that they get sharper prints with it. I think if you did a more scientific test with a decent batch of prints both with and without, the results would be inconclusive.

Steve.

baachitraka · Mar 23, 2013

True, there was nothing scientific about those test. But right now, I am comfortable to focus without paper atleast with the scoponet I have.

megzdad81 · Mar 23, 2013

OK, I re-read Way Beyond Mono, and based on the sizes I normally enlarge/print 4x5 and 8x10 negatives, I guess the way bigger concern is flatness of the negative. With these size negs and not having gone beyond 16x20 prints, I still can't see the print or neg grain with or without my glasses, but it's something I won't worry about anymore. I actually found the Paterson easier to use. Now I'll test output with my Scoponet. I don't trust my glasses other than to get it close.

jp498 · Mar 23, 2013

I think total enlarger alignment is a bigger factor in focus than with/without paper or method of focusing. If you're out of alignment, it's possible for the center to be in focus, but somewhere else on the image will be thrown way out.

M Carter · Mar 26, 2013

Cheapest darkroom accessory: a pair of $15 reading glasses from the drug store. They're basically a magnifying glass that's hands free.

Great for view camera work too, for checking negs and prints, spotting, for maintaining delicate gear, etc. I keep them all over the place. They come in a range of strengths - try a few on at the store and look at the fine print on a package and see if they work for you.

Accurate focus through enlarger

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