Reducing Lens Contrast

Discussion in 'Camera Building, Repairs & Modification' started by cbphoto, Mar 28, 2010.

  1. cbphoto

    cbphoto Member

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    I would like to try to "de-modernize" some modern lenses to give them a more gentle contrast without really sacrificing on detail. I've read threads about using toothpaste or cigarette ash to grind away the coatings, and I tried it it once with no success. Are there other options to remove modern coatings? I don't mind taking some risks, as I'm only doing this to junk cameras for now (ex: original Olympus Stylus). Thanks.
     
  2. unclemack

    unclemack Member

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    Cerium oxide is used to polish glass & will remove coating - aluminium oxide is used by some to make GG's if you want even softer.
    You could of course do the same to a filter.
     
  3. cbphoto

    cbphoto Member

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    Thanks. Is the cerium oxide common in hardware stores, or will I likely have to order it?

    I don't see how altering a filter would do what I want. I'm not going for a soft focus effect, but rather a less modern look.
     
  4. keithwms

    keithwms Member

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    Why not just use an older lens.
     
  5. cbphoto

    cbphoto Member

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    Oh I do! I need pocket af cameras for certain purposes (beach, drunken nights out, clandestine shots, etc...)
     
  6. Rick A

    Rick A Subscriber

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    Why not soften a filter, and save the lens. That way, if you make a mistake, its easy(and cheaper)to remedy.

    Rick
     
  7. cbphoto

    cbphoto Member

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    Again, not going for soft focus.
     
  8. Mainecoonmaniac

    Mainecoonmaniac Subscriber

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  9. keithwms

    keithwms Member

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    Okay. Are you printing optically? If so then perhaps you can produce the desired effects by using a not-so-optimal lens or printing through plastic or such.

    The other thing that comes to mind is that if you only want lower contrast, you might just adjust your exposure and/or dev times.
     
  10. cbphoto

    cbphoto Member

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    I am printing optically. Lens contrast and printing contrast are not the same. If so, nobody would shoot old Leica lenses (like I do). There a special look that you get when shooting old lenses that has to do with the way light is channeled to the film and cannot really be recreated with filters or printing. Now I know I can't turn a Stylus lens into a Summarit, but I don't want to be on the far opposite end (modern cold look).
     
  11. keithwms

    keithwms Member

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    I realize they aren't the same thing, but.... shooting with old lenses and shooting with intentionally degraded modern lenses are also not the same thing :wink: Anyway, go ahead with your plans and let us see how it works out!
     
  12. cbphoto

    cbphoto Member

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    Yeah, unfortunately. I bought a lot of old Styli on ebay, so I'll experiment a little.
     
  13. Rick A

    Rick A Subscriber

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    To get the "uncoated" look with a modern lens, are you going to disassemble a lens to polish all the elements? I dont think you can just clear the coating from the front element only to attain the look you are after. How about choice of film combined with printing method and paper selection to get there. I've been using enlarging lenses from the 50's as an aid to my style of printing, along with cameras and lenses from the era. IMO, to get the look you want, you will have to do the same thing. Pick a film, lens, paper combo, and experiment until you hit the set-up that works for you.

    Rick
     
  14. cbphoto

    cbphoto Member

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    I was planning on front and back, and see what happens then. Film, paper, and developer have nothing to do with this.
     
  15. darkosaric

    darkosaric Subscriber

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    Adox/efke films together with adox APH 09 will help you also, imho.
     
  16. Yeeski

    Yeeski Member

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    With uncoated lenses, increasing the number of glass-to-air surfaces increases the amount of flare, resulting in a decrease in contrast. Before taking the extreme step of polishing away the coatings, you could try inducing more flare. Maybe you could attach some plain optical glass filters to increase the number of glass-to-air surfaces. You may need to use larger filters and a step-up ring to minimize vignetting. Perhaps a polished metal or aluminum foil lined lens hood would also increase the level of flare.
     
  17. paulie

    paulie Member

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    look for an old lens, i recently found boyer lenses, low contrast is great.

    buy old buddy
     
  18. Ian Grant

    Ian Grant Subscriber

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    That special Channel is called flare :D

    You might just try adding some (2-3) older uncoated filters UV etc

    Ian
     
  19. 2F/2F

    2F/2F Member

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    Try working on lighting first. Then see what noticeable difference, if any, a lens makes in comparison.
     
  20. Yeeski

    Yeeski Member

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    The internal surfaces of the lens barrel and the edges of the lens elements are darkened to reduce reflections and improve contrast. Surfaces may be painted or lined with black flocking material. If you decide to experiment on a sacrificial SLR lens, try repainting the internal surfaces of the lens barrel white and/or removing the darkening from the edges of the lens elements. You could do this in stages to see the effect on contrast until you reach the desired effect. If this doesn't give you what you want, you could then try removing the coating from the lens.
     
  21. unclemack

    unclemack Member

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    "Lapidary supplies" is the search term I used but check ebay too. It's not expensive at all and different grades are available in kits with a felt buffing wheel for drill or angle grinder (you have to choose which - drill is slower but safer). I wouldn't want to polish six elements by hand.
    I bought aluminium oxide in 5,9,15 & 25 micron and cerium oxide in fine & extra fine - enough to last me until the next millennium was about £15 I think.
     
  22. cbphoto

    cbphoto Member

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    Thanks, unclemack!
     
  23. michaelbsc

    michaelbsc Member

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    Over expose and reduce development time. I know it's not the same thing, but I find it effective in my stuff.
     
  24. lxdude

    lxdude Member

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    Maybe using a couple of uncoated filters on the lens would help. They could reduce contrast in at least some situations without much effect on clarity. I think it would do as much as removing the accessible coatings on a lens, which would be difficult to do while maintaining a high degree of polish anyway.

    Other than that, just using older lenses would the most logical. As you're saying it's the way light is channeled to the film, I don't know that modifying any modern lens will give what you want. Reducing contrast by removing the outer coatings on a modern lens won't do as much, in my opinion, as having a couple of uncoated filters on the front of it. If you're trying to remove all or most coatings from the elements, that just seems like an awful lot of work, and it will still not "channel" light differently, except for increased flare.

    Some say part of the old lens look is due in part to the designs, which had less complete aberration correction due having older designs and the need for fewer elements to avoid excessive transmission loss and contrast loss.