The Lens and Kit Buying Plan

Spend on camera gear by the photograph: log the shots your kit misses, count the stops of light and the sharp zone they need, price every lens or body per stop and per shoot, total the whole kit, and test it before the return window closes

CameRoll's Camera Gear Cost Calculator adds up a kit list and checks it against a budget, but it never asks what any item on the list does to a photograph. Our Exposure Calculator counts light in stops and our Depth of Field Calculator measures the sharp zone in millimeters; until now they had never met the price list. This plan joins them. In its worked example, an evening living room metered at f/5.6, 1/30 s and ISO 3200 on an APS-C kit zoom is 2.74 stops short of the 1/200 s a moving child needs. A $220 50 mm f/1.8 prime reaches 1/290 s at $67 a stop; the f/1.4 version adds 0.73 stops for $260 more and thins the zone at 2 m from 107 mm to 83 mm; a $2,100 full-frame body with an f/4 zoom still stops at 1/132 s. With cards, a battery and a backup drive the f/1.8 kit comes to $367 of a $600 budget, and the lens works out at $1.38 a shoot (24 shoots a year for four years, 40% back on resale). Every figure is computed from our own calculators, and the scene and prices are dated examples, not quotes; circles of confusion are called conventions and shutter targets rules of thumb. It endorses no brand, and it says never to look at the sun through a viewfinder or lens and to ask before photographing people. Inside: 7 steps, 4 printable working pages (a shoot log, a light and blur worksheet, a candidate comparison sheet and a return-window test log), hyperfocal and stops tables and a quickstart, plus a personalised sheet worked from the numbers you enter in the exposure, depth-of-field, gear cost and storage tools.

Look inside

Two full pages from the plan, exactly as printed. Click either to read it at full size before you decide.

What is in it

• The Shoot Log Rule: twenty misses from your own files, sorted by what went wrong, and how often you shoot that scene
• The Light Budget Rule: EV and EV at ISO 100, the handheld and movement shutter limits, and the stops you are short
• The Blur Budget Rule: the sharp zone at your real distance by aperture, and the aperture that holds a group
• The Stops-per-Dollar Rule: lenses and bodies on one table, stops gained, dollars per stop, and the shutter each allows
• The Marginal Stop Rule: pricing the last stop on its own, against the zone it thins
• The Whole-Kit Rule: the kit with cards, battery and backup against a budget, cost per shoot, and decimal versus binary gigabytes
• The Return Window Rule: three test shoots before the last day, with sun safety and asking before photographing people
• Four working pages: a shoot log, a light and blur worksheet, a candidate comparison sheet and a return-window test log
• Hyperfocal tables for APS-C and full frame, a stops-between-apertures table, and a quickstart
• A personalised sheet worked from the figures you enter in the exposure, depth-of-field, gear cost and storage tools

The plan picks up where the free Camera Gear Cost Calculator leaves off. The calculator totals a kit against a budget; the plan asks what each item does to your photographs, counting the stops of light you are short with the Exposure Calculator, measuring the sharp zone at your real distance with the Depth of Field Calculator, and pricing every candidate per stop and per shoot, with the cards and backup from the Storage Space Calculator. The prices in it are dated examples, not quotes, and it endorses no brand. Never look at the sun through a viewfinder or lens; ask before photographing people.