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Mike O'Pray
30th April 2009, 10:50 PM
I have recently obtained a Paterson Major for the very few large prints I do. Just out of curiosity I checked the focus with both the major and minor and found that:

1. The grain seems slightly less clear with the major than the minor
2. Each requires a slight alteration to the bellows knob to bring the grain into focus. So in focus with the major requires a slight alteration to the bellows knob to be in focus with the minor and vice versa.

Anyone else who has both noticed this? I suspect that the difference on the print with the naked eye is probably negligible and may even be undetectable but I'll have to do two identical prints using each finder and compare.

I had expected both to be the same and it's a bit disconcerting to find otherwise.

Mike

Bob
30th April 2009, 11:54 PM
Yes, I can see that might be a little disconcerting... :eek:

I also have both and use them interchangeably. The focus is the same on mine: no detectable difference.

I just popped up to the darkroom and had a check because I recognised your mention of the grain being less clear. My Major is perhaps half a stop darker than the Minor but, as I say, the focus on both is identical as far as I can tell.

I wonder is the mirror on your Major is in the right location? See if it will push upwards at all along the "legs".

Mike O'Pray
1st May 2009, 12:37 AM
Bob. Thanks Where else might you get an answer this late at night on photography? Nowhere is the answer. FADU is fantastic. The wife's asleep. Just as well. If she knew I was still messing around, she'd be telling me to get a life and some sleep!

Anyway I have just re-checked and the mirror is fixed and hasn't moved so no adjustment possible there. You're right about the minor being a little brighter. Is that to do with the major's mirror just being further away from the baseboard? The major doesn't seem to be able to cover such a large centre area either which may be related to the position of the mirror as well. maybe the bigger the focus finder the smaller the centre area it can cover.

Anyway the only adjustment on both finders is the top viewer which ensures that the line is sharp and I think there was maybe a marginal difference in the sharpness of the lines. I have adjusted these moveable parts and the difference in focus is now very marginal

I'll do 2 identical prints tomorrow and compare. The minor does seem to pop into focus more and this, I think, is a function of what appears to be its extra light gathering ability.

It might just also be a case of getting use to the slightly darker major as this is the first time I have tried to use it.

Regards

Mike

Daud
1st May 2009, 05:29 AM
Mike,
I have the same problem and after tests; have always used the 'minor', even if it means a stretch to reach the focus knob.
Cannot figure out why as there does not seen as if the major is damaged in any way, I just gave up using it.

David.

Dave miller
1st May 2009, 05:59 AM
I too have both and have never noticed any difference between them, but I would be unlikely to use both on the same print, so probably would not have noticed minor differences between the two.

Mike O'Pray
1st May 2009, 01:52 PM
Thanks both. Daud I am not sure but I think you are saying that the major didn't focus as accurately so you stopped using it or hopefully, it was simply that sticking with one i.e. the minor was better as you know where you are with just one finder? Which of these two interpretations of mine is correct?

Dave I think you are saying that while a direct comparison might reveal a very slight difference, in practice those prints focused with the major are just as sharp as those with the minor.

It would be re-assuring if this is the case. The minor is a bit of a bind with large prints as your hand is way above your head and fine adjustments in this position are difficult.

Thanks

Mike

Daud
1st May 2009, 02:46 PM
Mike,
I was not happy with the 'major' point of focus - if was off!
Just put it down to sample variation as they are not what one would call expensive.
One day I will buy a 'Peak' but I must have been saying that for years.

David.

Dave miller
1st May 2009, 02:48 PM
Thanks both. SNIP

Dave I think you are saying that while a direct comparison might reveal a very slight difference, in practice those prints focused with the major are just as sharp as those with the minor.

It would be re-assuring if this is the case. The minor is a bit of a bind with large prints as your hand is way above your head and fine adjustments in this position are difficult.

Thanks

Mike

That's what I meant Mike, now you have mentioned it I will have to make a comparison between the two. :)

B&W Neil
1st May 2009, 04:39 PM
I used both the Patterson Major and Minor focus finders for years and never noticed any difference between them at all, although I must say I never checked them as there was no visual need to do so. They each need setting up to your preferred focusing eye so maybe that was not done correctly ? Or if you are not using the same eye for each focus finder that may be the problem ;-)

Neil.

Rob Archer
1st May 2009, 05:25 PM
I got a major at a junk sale a few years ago and found the same thing - it appeared very slightly 'out' compared to the minor. A little tweak to get the line as sharp as possible and it was fine. There's no discernable difference on a 12x16 print from a 35mm neg, so I guess it's fine - I can't afford a Peak anyway!

Rob

Mike O'Pray
1st May 2009, 06:12 PM
I know there's just a danger that this thread could go on forever but I have been back to the darkroom "experimenting" and have confirmed by some more messing about that the position of the adjustable part( for want of a better word I'll call it the telescopic part) is quite critical in getting the both finders to perform the same but perhaps more interesting than that is the fact that moving the telescope part actually got me to a point where the grain was clearer but then I noticed that at that point the focusing wire wasn't as sharp.

Then I decided to see if I could find my Paterson instructions on the micro( not minor - myfault) focus finder. My major didn't come with instructions but given its construction they must be the same. Eureka! I found them.

My understanding was that the telescope is adjusted so this wire is as sharp as possible( yes according to the instructions) and then and only then do you use the bellows knob to get the grain into focus. So I had presumed that getting the grain into better focus via the telescope first is wrong( see below). Presumably it actually throws off the true focus no matter how much better the grain looks( not so, if I have understood the instructions properly).

So here are the actual instructions: " Adjust focus finder to your individual sight by releasing screw B then look through the eyepiece and slide it up or down until the graticule cross wire appears sharp and clear( my comment -no definition of what constitutes sharp and clear but see my comments below). This gves the most comfortable setting in use. Keep both eyes open while doing this so they are relaxed and focused on infinity( sounds as if it would be a bad idea to have a neg on the baseboard while doing this as it would be a distraction). Lock eyepiece screw taking care not to overtighten. Now here's the really interesting bit: "Note this adjustment is for individual comfort and does not affect working of Focus Finder which is permanently set for accurate focusing

After roughly focusing the picture place Focus Finder on the baseboard directly below lens. Look through eyepiece at graticule and adjust enlarger focus until image grain and cross wire are seen sharp and clear. The enlarger is now focused with critical accuracy. End of instructions.

My definition of getting the wire to its sharpest point is to get it to a point where the wire is delineated by the appearance of sharpness on both sides of the wire and the middle of the wire appears to have a thin light colour in the middle. It's almost as if the wire is composed of three lines. Two black ones on the outside and one thinner light coloured one in the middle but this isn't defined in the instructions. Anyone else notice this 3 lines phenomenon with the graticule cross wire?

So it appears as if getting the cross wire sharp is for eye comfort and it plays no part in the grain focusing. Still leaves me puzzling about my observation that the grain seemed to be better focussed when the cross wire wasn't as sharp.

I must admit that to get the grain focused sharply I had always closed one eye a la using a telespope but maybe it's better to look down the finder with both eyes open and move the bellows knob when at some point the graticule cross wire and grain all come into focus.

Anyway I'll follow these instructions to the letter tonight with both finders and see what that brings.

Mike

Bob
1st May 2009, 06:48 PM
Lock eyepiece screw taking care not to overtighten. Now here's the really interesting bit: "Note this adjustment is for individual comfort and does not affect working of Focus Finder which is permanently set for accurate focusingHmmm... I know Paterson make the thing but this is clearly not the case! I just tried it and moving the eyepiece up and down clearly shifts the focus, requiring the lens to be moved to bring it back to focus in the finder (and hence out of focus on the baseboard). I'm therefore somewhat confused by this statement they make...

I think the lighter centre is just light reflecting off the wire - I tend to focus on the inevitable specks of dust on the edges of the wire...

B&W Neil
2nd May 2009, 07:42 AM
Some folks advise having a sheet of scrap paper under your focusing device so that the distance between paper surface and lens is precisely the same with the real paper in your easel. I have on occasions done this myself but I am blowed if I can spot any difference.

Neil.

Mike O'Pray
2nd May 2009, 06:21 PM
Neil, thanks. This point and the one about using a "blue light" filter to improve focusing occupied another site for days/ weeks :D:

People are divided on both issues to say the least. It had always seemed to me that focusing on a sheet of the same thickness in theory had to make a slight difference until the topic arose again very recently on another site and one member gave "a scientific proof" that it didn't. His proof centres around, I think, how much leeway you get with focussing and it I recall your actual paper would have had to have been more than 2-2.5mm thick to have made a difference and photographic paper isn't that thick. It sounded like a well made argument but I put scientific in inverted commas because my knowledge of the theory used is too poor to comment on its validity

On the blue filter argument, Gene Nocon is a believer and Tim Rudman is a sceptic. Gene gives an example in his book on printing but I couldn't see any difference in the before and after prints he used to illustrate the validity of his contention.

That could of course have just been me. Anyway I am digressing from the subject matter.

Mike

Dave miller
2nd May 2009, 07:42 PM
To take up the paper issue, I place a sheet backside up because it's easier to see the image. As for focusing, if you don't put your focusing aid on a piece of paper, then you must rely of the depth of field to correct focusing errors; which it will generally do. However there is but one plane of focus, and it has no thickness, so the purists can argue their case on a firm scientific basis that any error will introduce diffusion. Others may care to experiment and find out for themselves the leeway that is available to them.

Argentum
2nd May 2009, 07:58 PM
I have an idea. Why don't you put your focus finder on the easel and focus. Then put a piece of paper under it and see if the focus has changed.

Of course you'll also have to double triple guess whether the designer of the focus finder has allowed for the thickness of the paper in the finder design instead of assuming he didn't. Mind you, that might be a conspiracy theory to confuse you, so you'll have to double triple guess that as well.

I have another idea. Graded paper is only sensitive to blue light. There would be no point using other colours to focus on graded paper. I wonder if the genius who originally suggested using only blue was using graded paper and all those who have regurgitated the advice haven't considered that things would be different for VC paper. But since VC paper is sensitive to green light as well, then the actual focus point would be somewhere between blue and green. Of course that would mean that VC paper would never be as sharp as graded paper. Now you've really got something to worry about but that could be a conspiracy theory too so you'll have to double triple guess that one as well.

Let me know when you've worked it out.

RH Designs
3rd May 2009, 07:41 AM
I'm tempted to say "just print at f/8 and stop worrying" ...