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Tricks with macro photography

Discussion in 'Off-Topic Members Lounge' started by FuZZ1L0G1C, Apr 29, 2019.

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  1. FuZZ1L0G1C

    FuZZ1L0G1C

    368
    117
    Mar 25, 2014
    Electronic submissions often require a clear closeup (macro) photo of the subject.
    For those that own a DSLR (removable and interchangeable lens), here is a compilation of a few handy tips and tricks.

    Based on a Pentax K2000 SR automatic, the reader can modify where applicable to suit camera used.

    Shooting on auto:

    Auto (AF) works to a certain minimum distance, depending on which lens is used.
    Built-in-flash shots on auto can be tricky when shooting close, as flash circuitry may not be able to compensate enough, resulting in an overexposed, high-key subject.
    If shooting very close, the lens barrel itself may mask part of the flash beam, resulting in highly contrasted unevenly lit subject.
    For increased depth-of-field, set menu to "aperature priority" then use a low f-stop such as f11 or f22 with sufficient lighting to avoid pixel noise from underexposure.

    Shooting manually:

    No macro lens or diopters?:
    A macro lens is designed to focus at closer distance than a mid-range.
    Wide-angle lenses are sometimes dual-purpose, such as my Ricoh 28mm which is "Wide" and "Macro".
    Wide-angle lenses can generally get closer focus than a mid-range or zoom lens, and give a wider FOV, the disadvantage of wide being 'fisheye' distortion when close.
    A diopter is basically a "magnifying glass" lens that fits onto the front of a normal lens to shorten the focal distance, but may degrade sharpness, as the light rays have to pass through extra layers of glass.
    Reverse the lens to turn your mid-range (say 50-52mm) into a macro.
    Remove the lens, turn so that lens filter faces body / mirror, hold central, focus and shoot.
    Keep lens centered by monitoring the viewfinder / LCD screen.
    "Reverse-mount adapter rings" are available for this purpose.
    Beware that inner (rear) lens is now exposed to the elements and fingers, so only use for brief periods to avoid dust etc from fouling the pristine inner glass.

    Macro attachments:
    All lenses, whether magnifying glasses, projectors, or camera lenses follow the same basic principle of focal distance and focal length.
    A short focal length, or lens closer to the CCD* results in a longer focal distance (lens to subject), up to infinity.
    A long focal length, or lens away from the CCD* results in a shorter focal distance (lens to subject), down to zero distance or even inside lens (then unfocused).
    * CCD = (image-recording wafer of pixels) AKA "Charge-Coupled-Device". (= an eye's "retina").
    Macro attachments to increase focal length:
    Macro Tubes are rings, or short lens barrels without an internal lens.
    These are of fixed length, and can be combined to get summed fixed focal lengths.
    A Macro Bellow is length-adjustable, made of a black accordian-pleated hollow "tube" mounted on a base, driven back (compressed) and forward (extended) on a toothed gear-rail, via a knob which photographer turns to adjust focal length to any within range of bellows.
    The lens clips or screws onto the front of tube or bellows, the back end clipping into the body.

    Things to note with macro tubes and bellows:
    The LUX, or light intensity falls off drastically when primary lens is moved away from the CCD, so pictures taken in normal lighting may appear too dark in the photo.
    There are ring-lights available (or you can build one from multiple U/B white LED's).
    Bright outdoor light may cast shadows if lens is close, so artificial lighting fill-in improves this.
    A fairly wide, bright light source can help to illuminate subject while minimizing shadows.
    I use a 20W U/B LED halogen powered by AC mains for too-dim indoor shoots.
    An U/B LED torch / flashlight also works for small subjects, although very 'point-source' directive.

    Images double-ghosted or "shake-blur?":
    When an image is magnified, whether via macro-photography, zoom, vibration, or hand-held shakes, there are electronic and mechanical solutions available:

    Electronic:
    Many modern DSLR's have a built-in "anti-shake" function, using solenoids in the X and Y planes to physically move the CCD at high speed opposite to the movement detected, thus minimizing camera shake.
    This is limited to a small scale oscillation, so violent camera movement or subject movement will not be "shake-less".

    Mechanical:
    A tripod, or raised support such as books, loudspeaker cabinet, or edge of table can help to steady the camera.
    The tripod should be sturdy, so that the "clunk" of the mirror movement does not shake the camera.
    When using a tripod that has and extended arm, say for shooting vertically from above, the weight of the camera / lens and long unsupported extension may make the structure tend to wobble or vibrate when shooting.
    Try to support the free end with another tripod, or solid object of equal height.

    Focus, focus:
    If depth of field is shallow, decide what part it is that you want the reader to be drawn to.
    Where a component identification is required, then screen-printed markings are probably more important than the dust particles on the PCB.
    That being said, a smaller aperature will help to show both the component(s) and the PCB markings.
    Again, if using extensions, photo is darker, so further lowering light with low f-stop F11-F22 may create noise, so extremely bright light needed.
    Otherwise experiment and compromise until satisfied.

    Where battery power holds out long enough, I sometimes take 12 or more photos at different settings, of same subject, then scrap the rejects.

    Lighting:
    Bright and evenly lit, without being 'washed-out' overexposed.
    Incandescent (tungsten) lighting has a warm orange color cast, which can sometimes be corrected in a photo editor app, but for showing true colors such as resistor / cap color coding bands, rather go for bright, close-up U/B white LED lighting or sunny out door skies.
    If artificial, which is usually more directive and shadow-making than the diffuse outdoor sky, try more than one light source from different angles, ring light, or white reflector.
    A reflector also helps outdoors.
    Avoid using metal reflectors as these may create weird, confusing speckled patches of light.

    Framing / cropping / editing:
    Try to frame the topic of discussion squarely in the center of the photo.
    This also helps when AF camera auto-focuses on the center graticule of the viewfinder.
    The electronic subject is the topic, so surrounding table tops, non-applicable parts of device, etc can be cropped out.
    At editing stage, picture can be zoomed in / cropped, rotated, auto-enhanced, color-casts removed, color reduced, grayscaled (if suitable to subject), text labels / arrows added, resized and the file format changed to reduce final footprint.
    While not intentionally plugging one product over another, I use several graphic / photo editors to achieve this goal.
    MS paint is vector based, so lines, hollow squares, circles, arrows and text can easily be added.
    MSPaint also allows editing at pixel level.
    Corel's Photo Studio is a photo editor, with auto-enhance, sharpness, saturation, grayscale, etc.
    Photoscape is useful for removing indoor color casts from artificial lighting.
    Simply click the area that you think should be white and it performs its magic.
    Heavy casting can falsify or destroy colors in a photo, eg the orange of incandescent makes blue look black or dark gray, pinks or yellows blend into beige resistor body.

    Sizes does count:
    Forum websites differ in their maximum requirements of size in bytes and / or graphic dimensions.
    Typing this offline, I stand open to correction / editing, but think Electronics Point is maximum 100Kb and / or 800 Pixels largest side.
    JPG (or JPEG) is a lossy compress file format, it's algorithm searching pixels for repeated patterns of color.
    PNG uses a different algorithm, so one type of photo may be smaller in JPG, while another compresses better in PNG or GIF.
    Windows BitMaP or BMP is losses raw bytes after its header, so usually way too massive for web forums.
    GIF, also sometimes compressing smaller than others, dithers the pixels, so fine detail may be lost.
    Try all 3 to see which fits nearest to 100Kb.
    Cropping and reducing the graphic size (proportionally) can trim the fat of the byte count.
    In some pictures, eg a schematic or part where color is not valid, a file can be saved as 8-bit color or 8-bit grayscale (only 1 byte per pixel as compared to 3 bpp of 24-bit "true" color).
    Obviously, where color coding is required, then stick with 24 bits per pixel .

    If you usually shoot on one size setting (resolution), you could shortcut the file reduction process in MSPaint by choosing a percentage that you which to reduce to.
    Save it, then, keeping paint open, choose the same percentage for the next masterpiece.
    Example: Maximum 10Mp resolultion = 3872x2592 pixels as saved from camera.
    10% brings this to 387 x 259 pixels.
    Make picture smaller, but try to keep clarity of important fine details.
    Compromise, crop more if necessary.
    Of course, if your crop at high res is say, just one component, you may be lucky and get a high-resolution photo that fits within the forum's maximum requirement.
    Regards,
    FuZZ1
    bellows.JPG bellows allow intermediate magnification. macro tubes attenuate lux.JPG left image no lighting & used m/tube below/left. macrotubes.JPG marotubes-cropped no reduction.jpg NimH-chargerboard-top.JPG lit pcb (led floodlight) 011.jpg LM380N IC MACRO.jpg some extreme macros just because..
     
    davenn likes this.
  2. Abscissa5

    Abscissa5

    2
    0
    Sep 7, 2019
    Thanks for taking time and sharing this.
     
  3. davenn

    davenn Moderator

    13,669
    1,891
    Sep 5, 2009
    thaniks Fuzzy :)

    just some comments



    Never use AUTO mode, it's just too hap-hazard with the results

    Manual mode is a much better option where you can control the results
    DONT, NEVER ever use flash, apart from the lens barrel problem you stated, it causes too much glare of components/ PCB's
    Always use a good diffuse light source for even illumination


    and you can see how much of a problem using those setting are when you look at that pic of a light sensor/LED

    [​IMG]

    It's suffering from a serious lack of light .... you shouldn't need anything more than around F8 to F11 to get a reasonable DOF
    and it will give you much more light


    I find, often, that the modern phone cameras out perform a DSLR for closer up imaging.
     
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