Another flower

Discussion in 'Black And White' started by martin henson, Aug 14, 2017.

  1. martin henson

    martin henson Administrator Staff Member

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    Still experimenting using Pyrocay HD
    The negative was developed in Pyrocat HD using the minimal agitation method, to be more specific Pyrocat HD is a very sharp developer and when developed using low dilutions, long developing times with minimal agitation it gives very high acutance and excellent mid tone contrast.
    I am still experimenting with different films to find the best times and dilutions to give me a near correct highlight density for scanning, still working with Fuji Acros however I think I have got very near with this image in terms of shadow detail, highlight density and acutance, will be trying Ilford FP4 next.

    2017-08-11-0001-copy.jpg

    2017-08-11-0001-copy.jpg
    The Flower petal colour was yellow
    The outer center was dark brown
    The inner core was very dark brown


    Chamonix 4x5
    150mm lens
    Fuji Acros @100iso
    120 seconds @ f/64
    Developed in Pyrocat HD
    6mils A 4mils B to make up 1000mils
    Development time 32 mins 20c
    Minimal agitation, 2mins continues, then 30 seconds every ten mins
     
    Keith Haithwaite likes this.
  2. David M

    David M Active Member

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    On my screen, you seem to have got very close indeed to ideal exposure and development. You could easily tweak the contrast up or down for a final print, if you judged that you wanted to.
    How are you metering?
     
  3. martin henson

    martin henson Administrator Staff Member

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    Thank David,
    I metered the DR first which was well within the film developer range, I then spot metered the darkest part in the middle and placed that on zone 4, the petals were then on zone 8 ish,

    The DR was only 4 stops, i would have done a N plus 1 but needed a starting point to see how Pyrocat HD with minimal agitation would cope, from this I think I would leave as is and as you say alter the contrast slightly in post, but all in all not far off, great scanned file to work with.

    Thanks
    Martin
     
  4. David M

    David M Active Member

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    Yes, indeed. A clipped neg is a real problem. I think that a significant difference between wet and dry printing (although of course there are other differences and preferences) is that with patience, you can print through almost any negative density on an enlarger, but on a scanner, clipping is forever.
    It's just come into my head that we could call enlarging "post."
     
  5. martin henson

    martin henson Administrator Staff Member

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    Well post don't sound right maybe creation ;-)
     
  6. David M

    David M Active Member

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    It doesn't sound quite right, you are right. I was thinking of diehard wet printers who think that digital printing is easy. "You just have to press a button." they say.
    Now, I don't know about other people's enlargers, but on mine, you have to press a button too.
     
  7. KenS

    KenS Active Member

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    Martin....

    I am somewhat curious as to the necessity... or... the 'why' of your decision making for the choice of f.64. To 'my eye', there does not seem to be the amount of DOF that might have been required for that small an aperture.... at that 'subject to lens nodal point' distance. But then, I HAVE proven to having been 'wrong' in the past (probably much more often than I might 'like'.... or admit!)

    Ken
     
  8. martin henson

    martin henson Administrator Staff Member

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    Hi Ken
    I was very close to the flower, and stopping down the lens and looking at the GG it seemed the best f stop to get the maximum DOF
     
  9. David M

    David M Active Member

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    I found a website that calculates DoF for various factors.

    http://www.photopills.com/calculators/dof-macro

    It only works when the subject-to-film distance is at least four time the focal length, which gives 1:1 reproduction and an effective aperture of f128.
    It says that the DOF for a 1:1 image (which I'm guessing is slightly closer than Martin's sunflower) is 7.68mm, which doesn't clash with what we see in the image
    The site does assume a 35mm camera but I don't think this affects DoF.
    One way to increase apparent (NB: apparent!) depth of field is to be a bit less picky with sharpness in the sharpest parts. With no standard of maximum sharpness to view, the eye accommodates to the standard of acceptable.
    I don't think this is Martin's intention, but it's a factor in pinhole photography, where the circle of confusion is controlled by the pinhole size.
     
  10. martin henson

    martin henson Administrator Staff Member

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    I was not at life size, the fact that a smaller aperture will increase the DOF was the reason why i choose the smallest my lens will give.

    I feel that I might have done something wrong with movements , i tried different camera movements, however I could do nothing to get a better DOF with out something else going OOF in the frame, so opted for the small aperture, I was level and straight on to the flower, is there any other way I could have worked this image to get maximum detail without using such a small f stop ?

    Would I have been better putting the flower or the camera at an angle and slightly above and then trying front and rear tilts or at such a close distance with a field cameras is this not possible.
     
  11. Keith Haithwaite

    Keith Haithwaite Active Member

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    The depth of field so close in would be rather small Martin and if you were that square-on to the image then camera movements would probably do the exact opposite to what you were trying to achieve by tilting the plane of focus outside different areas of the plant. The laws of optical physics are what they are Martin and at f64 you are just past the generally accepted diffraction limit (f32) for 5x4 so I think you have got the best result you could under the circumstances. If you can remember the lens to subject distance I can calculate the depth of field if you are interested.
     
  12. David M

    David M Active Member

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    I'm sure that Keith is right. The subject is flat with no projecting feature that would need movements.
    Would the optimum (but not ideal) result be gained by having the near limit of DoF placed on the front surface of the flower, so that the actual plane of sharpest focus (when wide open) lies slightly behind it? A tricky thing to achieve on the GG.
    I'm aware that DoF doesn't really have a specific, defined boundary, as the diagrams in textbooks seem to suggest.
    Would a shorter focal length help?
    I presume we all know the Edward Weston story about DoF.
     
  13. martin henson

    martin henson Administrator Staff Member

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    Thanks for confirming my own thoughts on this. and yes i do think a shorter focal length would help with a different point of view however the negative been so big would crop quite nice with not much loss of quality, I don't print bigger than 18inch
     

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