SHEER frustration... anybody know any focusing tricks...???

Discussion in 'Enlarging' started by Sparky, Oct 4, 2008.

  1. Sparky

    Sparky Member

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    Hey all...
    So - I've been printing on my devere 504 for the last year or so... to make a long story short I can't use the focus knobs because it's set up for murals... that being said - I have to unlock the neg or light source track and then guide it gently up and down from the position it needs to be in for best focus, and then lock it down again. At any rate- when I'm doing bigger prints - it requires a lot of back and forth between the floor with my focuser and the head. This can be a multi-hour affair - JUST TO GET THE FOCUS. The pay off is totally worth it - ultra crisp grain, etc... but getting there is a BIG pain in the pitootie...!! Has anyone dealt with this kind of thing before?? Maybe Bob Carnie....?? Others?? I'm at the 1.5 hr. mark right now - and short of rigging up a special mechanical assembly... I was hoping one could set up some sort of trick, using mirrors - or god knows what to achieve rapid, accurate focus...

    any takers??
     
  2. snallan

    snallan Member

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    Hi Sparky, is this a wall mounted, bench, or floor standing enlarger.

    When you say you cannot use the focussing knobs, do they have no effect whatsoever. If so, it sounds as if the control cables in the column have either broken, lost tension, or been partially disconnected. As the locking knobs are working, the control cables from each to the head/lens stages are OK (so probably not broken).

    If it is a floor standing enlarger, the drive chains in the pedestal may have been disconnected.

    There is a service panel on the back of the column which you can remove to check the state of the drive cables, and if it is floor standing, there are two service panels on each leg of the pedestal, which can be removed to check the state of the drive chains.

    For the drive cables, there is a retaining block on each onto which the two ends of the drive cable are attached. The lower section of the cable goes into an adjuster bolt, so if the tension has been lost, and there is not enough friction for the drive pulleys to drive the cables, undo the lock nuts on the bolt, and tighten the cables with the adjuster bolt.

    For the locking knobs to work, the upper section of the cable will be OK, but the lower section may be broken, or disconnected. If it has been disconnected, it will probably still be attached to the adjusting bolt, so will be easy enough to reattach. If it is broken, then spares can be obtained from Odyssey Sales in the UK, they have a contact form so hopefully would be able to refer you to a local distributor.

    If it is floor standing, removing the top panel on each of the legs allows you to check the tension in the drive chain. If it is a floor standing enlarger, let me know and I will sort out the details for adjusting the chain tension. I seriously doubt these would ever break, even if the drop bed had been used as a jack for a car! :D
     
  3. sun of sand

    sun of sand Member

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    I have no idea what the situation is but I can focus well without a grain magnifier
    I rack to focus and then beyond focus and then do it once again counting in my head the time it takes from out of focus to out of focus
    Split that time or distance and you're pretty good.

    why wont this work?
     
  4. dancqu

    dancqu Member

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    I know! I call it Focus Once. May be of some help. Next time
    you go through the chore of focusing make note of the head
    height AND A exact dimension of the projected image.

    No need to focus other than to that exact dimension for same
    repeats. I add a new column mark now and then as I change
    negative size and have a short table of projected sizes. Dan
     
  5. ic-racer

    ic-racer Member

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    **Motor focusing. Though probably not an option for the 504.
    **WA enlarging lens.
    **There used to be a 'long' grain focuser, perhaps 2 feet long, don't recall the vendor. (This would be a 'trick' using a mirror :smile: )
     
    Last edited by a moderator: Oct 6, 2008
  6. Maris

    Maris Member

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    When the enlarger head is too high and no amount of "ape hanger" position will reach the focus knob I get a friend in. One person watches through the focussing magnifier and calls "up", "down", "ok" while the other tweaks the focus knob.

    Doing mural size enlargements is usually a two person job (in my darkroom at least) so the "focussing assistant" job already has a volunteer.
     
  7. srs5694

    srs5694 Member

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    I recall reading a suggestion to use a small telescope to aid in focusing mural-sized enlargements. I've never tried this myself, though; I'm just passing on something I recall reading (I believe in another thread here on APUG).
     
  8. Mick Fagan

    Mick Fagan Subscriber

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    Having done mural enlargements with horizontal 10x10" DeVere enlargers on rails, I can verify that getting quite reasonably correct focus is not that easy.

    What we used to do was don a pair opera glasses that had been fitted to a pair of spectacles without any glass. These are usually between 2x or 3x magnification only, plus they are quite light gathering and allow you to see grain remarkably well. These units are quite good for getting very close focus.

    Then we used to stand up at the wall with a Peak grain focuser with the remote unit in our hand. You would be surprised at how difficult it is to get dead accurate grain focus with a motorised set-up. The motor always has a slight over run, basically you end up guestimating and it usually takes about 5 minutes at the minimum to get correct focus, especially after you stop down and check the grain over the entire 6' high by 18' wide paper area.

    Reading your description it appears that you are using a free standing DeVere with the table dropped to the floor but no standard forward controls fitted. Either that or you are using a table top model wall mounted and no forward controls.

    We had one vertical 507 DeVere that we did enlargements onto 24x30" paper. That enlarger was bog standard and when the drop table was on the floor, with the head almost touching the ceiling, you needed an assistant to focus correctly.

    The reason was that you would be on your hands and knees and the lock controls are halfway up the wall, not being an Ape with extended arms, we used Maris's technique of lock, unlock, lock again, etcetera.

    I don't think there is an easy solution to getting super critical focusing single handed.

    Mick.
     
  9. haris

    haris Guest

    Can you focus by just looking a projected image, and when get reasonable sharpness, stop lens for small aperture, f11 or f16 or f22?

    It seems to me it would be only way without help of another person or some tool.

    Next, some enlargers have focusing aids in their heads. For example Meoptas enlargers have hairline focusing aid, that is when you pull negative carrier slightly out of head, you project two shorter white lines on image plan, and when those lines are combined into one longer line and that line is sharp and thin looking on image plane, enlarger is focused.

    Do your enlarger have something like that, or can you put something into negative carrier which will simulate hairline focusing aid? You can find images of Meopta enargers negative carriers, and make something simillar for your enlarger.

    And you allways can ask someone as for Maris's procedure.
     
  10. nworth

    nworth Subscriber

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    The DeVere has the advantage of a remote control. For the rest of us, you can usually rig something. There are long flexible shafts you can buy that fit in place of the focusing knobs and will give you two to four feet of extension. The problem with these is backlash - turning the knob at the end of the shaft does not always result in a corresponding smooth change in focus; rather, the changes may be jumpy and difficult. If you are electronically inclined, you might be able to rig up a big stepping motor and a remote switch. A small telescope or optical gunsight is a possibility, although poor illumination through one of these may be a factor.

    Another problem with focusing for murals is poor illumination. The easel may just be too dim. I don't know of a solution for this, except maybe a bigger enlarging lamp. With good lenses, you can open up to get more illumination. But with many lenses, the focus will change noticeably between wide open and a couple of stops down. Fortunately, exact focus is less critical for murals. You are at a degree of enlargement where the resolution of the taking lens and the film limit the sharpness. Poor enlarger focusing will make that situation worse, but getting fairly close will work.
     
  11. Bob Carnie

    Bob Carnie Subscriber

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    This is exactly how I do it, two man job for sure,,

    Bob
     
  12. Sparky

    Sparky Member

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    Sorry for the delay fellas... I got sick for a few days and totally forgot I'd posted this...!!! (great when you're posting in an emergency call for help, huh???). At any rate- yes, I think Mick and Maris/Bob pretty much have the idea. The whole problem is that it's a freestanding devere converted to wall mount. And I had to remove the fabulous focus shafts - since I didn't really want to make knob photograms everytime I made a print! I'm printing on a floor vacuum easel. So yeah - mick - it's on the floor on my knees. Then I have to stand halfway up to reach the locks and unlock... move the head a MICRON with my hands, lock... and check again - to discover it's even MORE out of focus. Great. It seems to take me in the neighbourhood of 30-100 of these iterations to nail the focus. I used to be able to do this by eye... (sigh).

    So anyway- I was just looking for some sort of trick (I guess the opera glass thing doesn't sound all that bad) to 'cheat' the process somehow. I think I may try to cut off the old focus shafts and fix a flex shaft to them or something (like a long spring, etc) so that I can use them from the floor. It's not a quick fix - but probably the most time/effort effective...
     
  13. Mick Fagan

    Mick Fagan Subscriber

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    Right, this is how you may be able to achieve a workable solution. I figured it was either a wall mounted free standing or tabletop unit. Yes a vacuum easel is almost mandatory but it must be in perfect alignment, I assume it is.

    What you could do is this:- Go to an auto shop and purchase one of those ½" drive double jointed extensions, (actually a universal joint) mechanics use to screw and unscrew spark plugs and bolts in offset situations.

    These are usually about 50mm long. You cut either your existing set of focusing rods to a stub and weld one of these jointed adaptor to the stub, or make up a set of stubs.

    Then you buy (or manufacture) a long enough ½" rod with a T bar end which will allow you to kneel on the floor and move either your neg stage up and down, or your lens stage up and down. Locking the thing whilst you are on the floor, will depend upon just how long your arms are!

    Once you are finished focusing, simply pull the shaft out of the universal socket extender, then expose to your hearts content. :D

    I assume that you are already focusing in total darkness to aid your light gathering capacity?

    Mick.
     
  14. Claire Senft

    Claire Senft Member

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    This is just an alternative method. I will first state, for the record, my very impressive background in making murals...I have never even tried. You are using a vacuum easal on the floor. You have already found a means to provide alignment.

    While the movement of the negative stage is very critical to the focus of the image the movement of the easal is not nearly as critical.

    Why not start with half inch thick shims underneath the easel and focus as well as you can by eye while standing up. Then using a focus magnifier on the easal determine in the print becomes sharper by adding additional shims or becomes sharper by using thinner shims ?
     
  15. Sparky

    Sparky Member

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    I think i'll do something like that, Mick. I'll probably just get some springs - there's a rather good specialty spring company a few miles from here. I'll probably get a machine shop to cut off the shafts and weld the springs on... or something like that. Perhaps spray the spring with black rubber...

    Claire - well - a vacuum easel tends to be rather THICK and built-in... so there's no moving it. However - I've been getting excellent results simply taping the paper to the easel without vacuum power. So maybe I'll try a shim -- but the shim has to be at least as large as the print... but not a bad idea...
     
  16. Bob Carnie

    Bob Carnie Subscriber

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    I would stay away from shims under the easel.
    Once the vacumn easel is aligned with the neg/lens stage I would not play with that. Getting that perfect alignment is a job in itself , this is tempting disastor with edge focus problems.

    I like the idea of an extension arm and will persue this myself as I do a lot of odd hour printing where a second hand is not always availabe.
    For my horizontal Durst there is an unit for fine focus at the wall but not sure if Deveere makes them and also for Omega which I also use for murals. Extension hands would really be the cats ass.
     
  17. Sparky

    Sparky Member

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    Yeah- well the easel's not going anywhere - it's a 2x4 frame which is glued to the floor with about 10 tubes of liquid nails and covered with 3/4" baltic birch ply... amazingly (and i didn't even try) the alignment was perfect from the get-go. I can shoot a 40x50 print at f/8 and get near perfect grain across the board...!! Pretty cool, that.
     
  18. ic-racer

    ic-racer Member

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  19. ic-racer

    ic-racer Member

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    This photo from the web shows what looks like a telescope type focusing aid:
    [​IMG]
     
  20. johnnywalker

    johnnywalker Subscriber

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    Don't know where or when I read it, but I did see something about a fellow who rigged up a second wheel, attached to the main focusing knob with a bicycle inner tube. This seems to me to be prone to over and under runs, but maybe a loop made of heavy canvas instead?
     
  21. RJS

    RJS Member

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    I have never seen a DeVere enlarger but have had the same problem with my Beseler 4X5, especially as I have aged . I have managed this way which perhaps could be adapted tothe DeVere. The knob for focusing is made of plastic and held on to a shaft with a screw in the center. This knob is about 3" in diameter, and quite flat with knurling around the edge. I drilled four holes through the flat part and put in screws about 2" long with a nut hoding them in place. I then got some wooden pieces of a width such that they will go between the screws and act like a lever to turn the focusing knob. I've made up several of these of varying length (one could be 3 or 4 feet long) and drilled a hole or two to hold them on the focusing knob. They have worked really well for me after I wasted about $100 buying flex cables from Beseler which were absolutely, positively worthless. There is no spring - these could be mad of aluminium or just about anything.

    I would be very interested to hear if this works for you as I have never seen anything like it. If it sounds useful I could try and send pictures (At present I don't have a digital camera and have no idea how to send, but I can probably scare up someone.