Tools for product photographers
Calculators and simulations for the set and for learning. Everything in real centimetres and millimetres.
Reflections
Place highlights on glossy products.
ReadyDOF and stacking
Depth of field and a focus stacking plan.
ReadyPerspective
Same framing, different focal lengths and distances.
ReadyModifiers
How different modifiers shape light and shadow.
SoonTutorials and mini-courses
Product photography lessons on Gumroad
How to install the app on your phone
- Open this page in Google Chrome.
- Tap the three-dot icon to the right of the address bar.
- Choose “Add to Home screen”, then “Install”.
- The app icon appears on your home screen.
In some Chrome versions the item is called “Install app”.
- Open this page in Google Chrome.
- Tap the Share icon to the right of the address bar.
- Choose “Add to Home Screen”.
- Check the name and tap “Add”.
On iPhone the same works in Safari: Share → Add to Home Screen.
Questions, bugs, ideas: steblovskiystudio@gmail.com
Reflections
A glossy product, softboxes, a reflector, a table and a backdrop in real centimetres.
Tips: what the numbers mean and why
The angle of incidence equals the angle of reflection
A highlight appears where the surface of the product faces exactly halfway between the camera and the light. So moving the softbox moves the highlight, and moving the camera changes which part of the product “sees” the light. The rays in the top view show exactly this.
Light size and distance set the highlight size
The bigger the softbox and the closer it is, the wider the highlight. On a cylinder (a bottle) the highlight always stretches into a vertical stripe, and its width depends on the width of the light and how close it is. A narrow strip gives a thin line, a big softbox gives a wide fill.
Power changes brightness, not shape
Power cannot make a highlight smaller or more even. Only position, light size and the modifier can. Power sets how much brighter the highlight is than the rest of the frame and how light the backdrop turns out.
Why dark gloss has bright edges
Glossy glass and plastic reflect about 4% of the light head-on and almost all of it at a grazing angle. So the edges of the silhouette reflect whatever stands behind and beside the product: a light backdrop gives a light outline, a black one merges the edges with the background. Chrome reflects 60–80% at any angle, so it shows the whole studio.
The backdrop darkens by the inverse square law
Move the light twice as far from the backdrop and the illumination drops four times, that is, by 2 stops. The “backdrop” value under the frame shows how much lighter or darker the backdrop is than middle gray. To get a black backdrop from white paper, keep the light off the paper and move the product away from it.
Table and flags
The table reflects in the lower part of the product and cuts the highlights off: on a small round table the cut is lower, on a large one it is higher. A black flag gives no light and only blocks what is behind it. Use it to remove bright edges where you do not want them.
Depth of field and focus stacking
Depth of field and a stacking plan for a product of a given depth.
Tips: what the numbers mean and why
What depth of field is
Depth of field is the zone in front of and behind the focus point that looks sharp. Sharpness falls off gradually, so the limits are conventional: the calculation uses a circle of confusion of 0.03 mm for full frame. Viewed at 100%, the limit is stricter.
What increases depth of field
A smaller aperture (a larger f-number) and a longer distance. Distance matters most: get twice as close and depth of field becomes about four times smaller. That is why in macro and close-up product work sharpness is measured in millimetres.
Focal length barely matters if the framing stays the same
A common myth says a long lens “eats” depth of field. If you step back so the product fills the same part of the frame, at the same aperture depth of field barely changes. What changes is the perspective and how much backdrop you see.
Where the distance is measured from
From the sensor to the focus point. The sensor plane is marked ⊖ on the camera body, and the distance scale on the lens and the minimum focus distance in lens specs are measured from it too. The calculation uses a thin-lens model, so at close range the result is approximate: lenses with internal focusing, macro lenses especially, have a shorter real focal length up close than the one on the barrel.
Distance based on framing
In this mode you do not set the distance: the calculator finds how far from the sensor the product has to be to fill the chosen part of the frame at the selected focal length. That part is set by the “Product in frame” slider, 80% by default: the product fills 80% of the frame height or width, whichever it reaches first. A tall product gets a vertical frame, a wide one a horizontal frame. The calculator estimates the product size from its depth by taking a typical object of that size (a ring, a lipstick, a bottle, a mug and so on), shown in “Camera view”. In “Manual distance” mode it works the other way round: you set the distance and the calculator shows how much of the frame the product fills.
In front of and behind focus
The “one third in front, two thirds behind” rule only works at long distances. At product distances depth of field splits almost evenly, so put focus in the middle of what has to be sharp.
Effective aperture: why f/11 turns into f/17
The closer you shoot, the further the lens moves away from the sensor to focus. Light through the same opening spreads over a longer distance, so less of it reaches the sensor, as if the aperture were closed down further. That is the effective aperture: the set f-number multiplied by (1 + magnification). For example, f/11 at 1:1.8 works like f/17, and at 1:1 like f/22. A magnification of 1:4 means 4 cm of the product lands on 1 cm of the sensor. Diffraction depends on the effective aperture, so up close it starts earlier than the number on the lens suggests.
Diffraction and stacking
Stopping down beyond f/11–f/16 on full frame gives more depth of field, but the whole image gets softer. So instead of f/22 it is better to shoot several frames at f/8 and merge them. The calculator plans the focus step with a 25% overlap so there are no soft gaps between frames.
Perspective and focal length
The product fills the same part of the frame while the camera moves back or forward to match the focal length. The grid on the backdrop and the table is 10 cm.
Tips: what the numbers mean and why
Perspective is set by distance, not focal length
How big the near and far parts of the product look relative to each other depends only on where you shoot from. Focal length only sets the angle of view, that is, what fits in the frame. Shoot from one spot at 24 mm, crop to the 135 mm frame, and the perspective is identical.
Why a wide angle “distorts”
To make the product fill the same frame with a wide lens, you have to get close. The near part is then noticeably closer to the camera than the far part and looks bigger: the label spreads and verticals converge. The distance is to blame, forced by the focal length.
A long lens “compresses” space
From far away, the front and back of the product are almost the same distance from the camera, so the proportions stay true. The backdrop looks closer and bigger, and little of it fits in the frame: a small sheet is enough, but a light spot on the backdrop also gets bigger.
What to use for product shots
85–135 mm on full frame gives true packaging proportions, the catalogue standard. A wide angle is for dynamics, deliberate distortion and shooting a product in an interior where the surroundings matter.
Crop sensor
On a crop sensor the same framing needs a shorter focal length from the same distance, so the perspective is the same. “Equivalent focal length” only describes the angle of view.
Light modifiers
One product, one light: switch the modifier and see the difference in shadow, contrast and highlight.
- Softbox, stripbox, octabox, umbrella, beauty dish, standard reflector
- Grids and barn doors: how they narrow the spot
- Light size and distance: shadow hardness