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  1. #41
    clayne's Avatar
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    Versalab or not, how would just looking at the situations above one not notice that it's obviously misaligned for a standard enlargement? These are pathological examples, guys. The VLab and other similar laser alignment tools work fast and quite well for what 99.99999% printers will need them for.
    Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.

    http://www.flickr.com/kediwah

  2. #42

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    tAKE BLACK NEGATIVE USE SAND PAPER PROJECT ON BASEBOARD AT WIDE OPEN LENS ADJ FOR SHARP IMAGE AS NEEDED.

  3. #43

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    Which planes matter

    I am pretty certain that there are a couple of ideas which help here. I am concerning myself with this as I have just picked up a Philips PCS 2000 (LPL) which has no alignment options. The lens carrier is a plastic mount supported at the rear which looks flimsy. Philips are no slackers when it comes to technicalities, so I am thinking there must be rationale behind this decision to cut corners on the lens mount but not on the very rigid base plate, vertical arm and head connection.

    Obviously, it helps if the planes of image, object and lens are identical. However, due to Snells law regarding refraction of light rays being related to Sin(x) and Sin(x) being nearly equal to x for small x, I think I am right in saying that if the lens is slightly out it won't matter as much as if the object and image planes are out of kilter. [I say this because the increase of angle of incidence on one side of the lens will be equalled and opposed on the other side of the lens on a ray leaving the lens, as long as the angles involved are small, with this being particularly effective at the middle of the lens, thus cancelling out any deviation away from the correct plane]

    Regarding the negative and base plate (object and image planes), the effect of not having them parallel would be that the distance varies from the object to the image. Therefore, only one region on the base plate will be focussed perfectly. However, by stopping down the enlarger lens, the depth of field is increased, in the same way it is increased when taking photos in the first place. This should allow for some lee way in alignment. It also suggests that longer focal length enlarger lenses, with shallower depth of field, require better alignment, and would be a reason for going with shorter lenses.

    Just some ideas.
    Last edited by hoojammyflip; 12-04-2009 at 08:56 AM. Click to view previous post history.

  4. #44
    clayne's Avatar
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    jammy: Definitely some good ideas and observations thrown out there.

    I can tell you that having a lens mounted even slightly out of whack with everything else parallel seems to cause much frustration with sharpness and image quality. I once mounted my APO-N 50mm on my Kaiser using the lens mount adapter upside-down (one side is beveled, the other is flat). The adapter is pushed upwards by a spring pin system (which is also the lockout for lens removal/insertion from the enlarger). With the plate flipped it allowed the beveled portion to meet the top mounting plate rather than the normal flat portion. Obviously the lens was crooked at micro level - and as a result I could only achieve field sharpness at the grain level by stopping down to f/11 or more. Versalab also checked out fine with the enlarger itself being suitably aligned to the easel.

    Eventually I figured out what the issue was, but it was very annoying to track down and the difference was quite apparent once I rectified the situation.
    Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.

    http://www.flickr.com/kediwah

  5. #45

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    a SQUARE PROJECTION IS ONLY FOR NEG/BASE ALLIGNMENT. The lens needs to be aligned also. They vary all over the map except for Leica ones.

    I just put my long mirror Peak in the far edges and align with the lens full open. If you have sharp grain in all four corners and center, that is a good as it gets.

    The short mirror will not get into the corners.

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