photo tips

Understanding exposure is crucial in photography as it determines the amount of light that reaches the camera sensor. It is influenced by three key factors: aperture, shutter speed, and ISO. Balancing these variables is essential to achieve the desired exposure in your photos.

Exposure - the amount of light per. unit area reaching the camera sensor

• Digital - exposure dependent on Aperture & Shutter Speed only. ISO adjusts the amplification of the sensor's output

• The exposure triangle is a common way of associating the three variables that determine the exposure of a photograph: aperture, shutter speed, and ISO. One must balance all three of these to achieve a desired result, an adjustment of one requiring adjustments of at least one of the others.

Aperture

Aperture refers to the diameter of the lens diaphragm, which controls the amount of light entering the camera. 

• Wide Aperture: Lower f-number, more light, lower (shallow) Depth of Field (increased Bokeh) - better for potrait photography

• Small Aperture: Higher f-number, less light, greater (deeper) Depth of Field - better for landscapes

Focus ratio (f-number) - The f-number is a measure of the aperture size and is calculated by dividing the focal length of the lens by the diameter of the aperture.

Focal length - the distance from the point at which all light rays converge inside a lens (the lens’ nodal point) to the camera’s sensor, and it’s usually measured in millimeters(mm)

Depth of field is the distance from the nearest and furthest objects that are determined to be in-focus by your camera

Bokeh - the aesthetic quality of the out-of-focus areas (blurred background)  produced by a lens

o    F-Number: (Lens FL / Lens D)

o    ex: 

Focal Length, FL = 100mm & Lens diameter, D = 6.25mm , F-Number = FL/D = 16

• Doubling the diameter of the opening is equal to 2 stops

FL = 100mm & D = 6.25mm * 2 =12.5mm , f/ = FL/D = 100/12.5 = 8

• Increasing the diameter of the opening by (√2) is equal to 1 stop

FL = 100mm & D = 6.25 mm * (√2) =  8.83, f/= FL/D = 100/8.83 = 11.3

o    f/ (f-stop): Geometric progression of 1/(√2)^n,  where n = 0, 1,2,3…

• • • • • √2 is 1.41421; 1.41^0 = 1, 1.41^1 = 1.41, 1.41^2 = 2, 1.41^3 = 2.8, 1.41^4 = 4, …

        • f/ = 1, 1.4, 2.0, 2.8, 4, 5,6, 8, 11, 16, 22, 32,

        • Each stop doubles or halves the amount of light

o    Area of a circle:  A = pi*r2. If the radius doubles, the area quadruples.                        

o    For D = 6.25 mm &, r = 3.125 mm : A = pi*3.1252 = 30.7 mm2;

o    If r doubled, (r --> 6.25 mm), D = 12.5 & A = pi*6.252  = 122.7 mm2; 

o    A(2r) / A(r) = 122.7 mm2 /30.7 mm2 = 4      [2*r  => 4*Area]

          each doubling of f-number is 2 stops of light

• Find aperture that takes sharpest image for each lens ~f5.6 (typ f4-f8) 

Shutter Speed

Shutter speed (exposure time) - Shutter speed, also known as the exposure time, refers to the length of time the camera's shutter remains open, allowing light to reach the sensor

• Fast shutter speed - freeze motion, faster shutter (1/Tv), less light

• Slow shutter speed - blur motion, slower shutter, more light. 

• Rule Of Thumb: use tripod for shots < 1/60th of a sec

ISO: 

• Film - denoted the amount of light-sensitive silverhalide crystals present in the film strip

• Digital - ISO is the amplification of sensor data after an image has been captured

• Lower ISO: less signal amplification, lower noise, less light sensitivity

• Higher ISO: more signal amplification, higher noise, more light sensitivity 

• Changing ISO independently of any other camera settings will not change exposure, but it will change the BRIGHTNESS.

• Increasing ISO decreases dynamic range.

• Dynamic range refers to the range of light intensities that a camera can capture, from the darkest shadows to the brightest highlights. Higher ISO settings can decrease the dynamic range, resulting in loss of detail in shadows and highlights. Understanding the trade-off between ISO and dynamic range can help in making informed decisions when shooting in challenging lighting conditions.

The Rule of Thirds is a compositional rule that involves mentally dividing up your image using 2 horizontal lines and 2 vertical lines. You then position the important elements in your scene along those lines, or at the points where they meet. A rule of thirds grid.

The Golden Ratio is a slightly more complex rule of composition than The Rule of Thirds. The rule involves mentally overlaying your image using spiral. Place your focal point to the center of the spiral and move around your image in a more circular movement.

Negative space is the area surrounding the main subject in a photograph which is left unoccupied. It is a compositional style, where a subject is without a lot of distractions and can draw attention.

Leading lines refers to a technique of composition where the viewer of your photos attention is drawn to lines that lead to the main subject of the image. A leading line paves an easy path for the eye to follow through different elements of a photo.

Perspective in photography can be defined as the sense of depth or spatial relationships between objects in the photo, along with their dimensions with respect to the viewpoint (camera lens or the viewer).

Portraits:  When shooting portraits, it's important to consider the focal length of your lens. Telephoto lenses are often preferred for portraits as they can create a more flattering perspective, avoiding distortion of facial features that can occur with wide-angle lenses. Additionally, using a smaller aperture (larger f-number) with a telephoto lens can create a greater depth of field, keeping more of the subject in focus.

General:

• White balance defines what the color white looks like in specific lighting conditions, which also affects the hue of all other colors.

• Kelvin is simply a unit of measurement for temperature - in photography is most often used to measure the color temperature of light sources.

  • • Candle: 1800 Kelvin

    • Tungsten: 3200 K

    • Fluorescent 4000 K

    • Daylight-Sun 5700 K

    • Cloudy 6500 K

• Landscape - focus on spot twice as far away as the subject to make sure DOF is maximized

  • Take landscape with zoom to focus on interesting subject & compress the distance between the background & subject

  • Sharper photos:

    • Use shutter priority

    • Find & set lens aperture that produces sharpest photo

    • Use USM for handheld, not when on Tripod

    • Prevent camera shock - lock-up mirror, use tripod & IR shutter release

  • Phone app to check out - Proshot

  • Compose shot using histogram  – use histogram as a guide to to set exposure

  • Portraits - shoot lens slightly below

  • Blue Hour - "hour" before & after sunrise/set

  • Use a tele converter to extend zoom range - experiment

• Use tripod

• Use self-timer or remote shutter release

• Bring flashlight

• Shoot in RAW

• Long Exposure Noise Reduction or High ISO Noise Reduction - Turn off, but experiment

• Turn LCD brightness down

• Set White balance to around 4,000 K to help you capture the colors of the night sky accurately.

• USM - Turn off 

• Shooting Mode - Manual

• Aperture 1 stop less than wide open to help you achieve better sharpness and depth of field in your photos

• ISO – try to limit to 1600 or less

• Tv: use shutter speed to adjust exposure

  • keep <15 sec to avoid star trails

• Focus - Manual

  • use live view, max ISO & aperture, 10x zoom , manually focus so stars are sharp

• Have something interesting in the foreground. Including a foreground element in your astrophotography can add depth and interest to your image. It can also help to provide a sense of scale to the night sky.

• Light painting - Light painting involves using a flashlight or other light source to illuminate a foreground element during a long exposure. This can add more interest and detail to the foreground and create a unique look to the overall image.

  • Take from same position as night sky photo

  • decrease ISO & aperture - experiment

  • illuminate from all angles

  • long exposure

• Moon - When photographing the moon, it's best to use a fast shutter speed to freeze any motion and ensure a sharp image. Adjusting your aperture and ISO can also help to achieve the desired exposure.

  • To start: 

    • Av: f8-f11

    • Tv: 1/125

    • ISO 100

  • Use shutter speed to adjust exposure

• Night Sky

  • Settings:              Night Sky    -|-    Evening

    • ISO         800                        100

    • f          2.8 – 4                   5.6

    • t              15 sec                    15

    • lens    11-16 mm        12

  • Recommended - A f/5.6, Tv 15sec, ISO 100

• Milky Way 

  • Av: aperture f/2.8 or the widest in your lens

  • Lens FL: 16/24 mm

  • ISO 1600-6400

  • Tv: shutter speed between 10-15 seconds up to 30 sec

  • Try Long Exposure Noise Reduction [Still-4]

• Ballpark "Rules" to eliminate star trails

  • "NPP Rule" NPF (No-Parallax-Point) rule can help to eliminate star trails in your astrophotography. This involves calculating the maximum time for no star trail based on your lens focal length, aperture, and pixel pitch
    [(35*Lens Aperture)*(35*Pixel Pitch)] / Focal Length

    • ex: Lens FL=25mm; A=7.1 PP=3.7um
      NPF=9.94 sec

    • Tokina: 16mm, Av-2.8 - 6 sec

    • Tokina: 11mm , Av-2.8 - 9 sec

  • NPF - Max Time for no star trail, max aperture

    • Tokina - 11mm --> 18mm = 20sec

    • Tokina - 16mm --> 26mm = 15 sec

    • Canon - 50mm --> 80mm = 4 sec

    • Tamron - 75mm --> 120mm = 5 sec

    • Tamron - 100mm --> 160mm = 4 sec

    • Tamron - 200mm --> 320mm = 2 sec

    • Tamron - 300mm --> 480mm = 1 sec

  •  Astro 220825 - good starts, min star trail

    • Tokina - 16mm --> t=15 sec, f/5.6, ISO 1600

    • Canon - 70mm -->

Canon version of technique

1. With the camera mounted on a tripod, enter Live View and establish critical focus on a high-contrast subject over the center point. Exit Live View.

2. Set the lens to MF (Manual Focusing). Be careful not to jostle the focus ring when you move the switch - you don't want to alter the focus you established in step #1.

3. Set AF mode to Manual.

4. Look through the viewfinder to see if the camera thinks the subject is in focus by checking if the green focus confirmation dot is lit. You'll need to half-press the shutter (or AF-ON) while doing this to keep the metering/rangefinder from going to sleep. Assuming you get confirmation, increase the AF tune value and recheck the viewfinder, leaving the lens set to the original focus you established in step #1 - do not refocus the lens. You want to keep increasing the AF tune value until you no longer get a green confirmation dot. As you reach the edge of the range the green dot will either fail to light up or it may flicker...you may need to cycle the half-press of the shutter several times to confirm that the confirmation you get is consistent. You're done when you find the highest positive AF tune value that gives you a consistent green-dot confirmation - that value represents the positive end of the AF tune range.

5. Return AF tune to 0 and repeat the procedure in step 4, but this time decreasing the value of AF tune (going negative). When done you've established the negative end of the AF tune range

6. Calculate your final AF tune value, which is the midpoint of the range you established in steps 4 and 5. For example if your range was -2 to +8 then the midpoint is +3. If your range was 0 to +12 then the midpoint is +6. Set your AF tune value to your calculated midpoint. You're done.

Notes

* If you don't get a green confirmation dot at an AF tune of 0 then increase or decrease the AF tune value until you do. Your goal is to find the range of AF tune values that show focus confirmation - that range may be all positive or all negative, instead of the -/+ range described in the steps above.

* If either end of the AF tune range (-20 or +20) still gives you focus confirmation, this means the range of AF tune values is wider than the camera's supported +/-20 AF tune range. Marianne Oelund came up with a clever workaround for this here.

Edit 2/10/13: Decided to call this technique "DotTune", to have a quick and searchable moniker when referring to it. It's a bit more identifiable than just "new AF tune technique" 

Edit 2/17/13: I've created a simple midpoint calculator on my website. DotTune Midpoint Calculator

Edit 2/18/13: I've published a DotTune tutorial on YouTube.

" target="_blank">DotTune Youtube Video

Time-lapse photography is a technique that involves capturing images at regular intervals over a period of time and then combining them into a video sequence. 

Time-lapse (Canon - enable with dial in Movie Mode)

• Star Trails & Time-lapse with same photos

• StarTrax

• Photopills - calculates NPP Rule

 Time-lapse Intervals:

• # shots total = # sec of finished video x 20 or 30 fps --> 10 sec @20fps = 200 shots

• Shutter Speed depends on what you want to capture.

  • 1 sec

    • fast moving clouds

    • traffic

    • animals

  • 2-3 sec

    • sunset / sunrise

    • moonset / moonrise

    • slower moving clouds

    • people

    • using telephoto lens

  • >15 sec

    • flowers

    • stars

    • construction

  • ~3 min

    • astrophotography with star trails

• Twilight --> Night Time Lapse: 

  • Light to Dark Transition:

    • Set everything manual, but choose aperture priority 

      • Initial Aperture at f4.0, ISO about 800 

    • Camera will adjust shutter speed to keep exposure correct

    • OR manually operate aperture as scene darkens

  • Add at least 3 seconds buffer between frames

    • 24mm: 21 sec (max) - 3 sec = 18 sec

  • Keep time shutter is open to about 10 sec max (depends on aperture)

• R6 has In-camera Image Stacking

• Nodal slide to minimize parallax

• Use manual mode to get same exposure for all shots

  • shutter speed

  • aperture

  • ISO

  • white balance

  • focus

• Use editor to adjust, then copy/paste settings

• Use MS ICE to stitch together - try spherical; ofr stereographic projections

Wildlife - increase image sharpness

• High shutter speed 1/2000, 1/3200

• Use right aperture - 1 or 2 stops above max f5.6 - f8

• ISO - Auto

• Use right DOF

• Have enough negative space

• Use tripod / monopod

• Use best AF area you can keep on subject - focus on eye

  • Stationary - single AF

  • Increase for active subjects, like birds in flight

• Use AF Servo, keep AF engaged

• Use burst mode

• Engage mirror lock-up & use live view

• Micro Focus Adjust MFA

• use USM even on tripod if tripod head is kept loose