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Articles Table of Contents   Page 1: Answers about Asking Questions Page 2: Ultra-wide Zeiss 21mm or 24mm Tilt/Shift lens? Page 3: What is a “fast” lens? Page 4: Focus calibration for “fast” lenses Page 5: All about lens adapters for Canon, Nikon, Sony, etc Page 6: Lens hoods, Grazing flare and Contrast Page 7: Focusing Screens for Canon or Nikon Page 8: Wide angle lens quality with Canon and Nikon Page 9: Zeiss 21/2.8 Distagon vs Leica 19/2.8 Elmarit-R Page 10: What’s the best browser to view this site (and others)? Page 11: Fastest way to get image files into my computer? Page 12: Mac Pro memory requirements for photo editing? Page 13: Choosing a Windows PC for photographers.

What is a “fast” lens?

What is a "fast" lens anyway?

Applied to a lens, the term "fast" refers to faster shutter speeds made possible by the superior light gathering power of a lens.

A fast lens is always larger heavier and more expensive than a slower one. For example, a 50mm f/1.2 lens might cost $1600 compared to $300 for a 50mm f/1.4 lens and $100 for a 50/1.8.

Each f-stop represents a full shutter speed. So an f/1.4 lens allow one faster shutter speed than an f/2 lens, and two faster shutter speeds than an f/2.8 lens. That's a very big deal at dusk, or indoors.

Most consumer zooms are in the f/3.5 - f/5.6 range, meaning that they lose 2-3 shutter speeds, a huge difference leading to blurred images when the light levels drop (which requires a lower shutter speed).

Examples

An aperture which is 1.4 times the previous one is half as bright eg f/2 is half as bright as f/1.4. Faster apertures (e.g. f/1.4 or f/1.2 or even f/0.95) are far more challenging to design and build to achieve high quality.

Focal length range (for 35mm format)	Max Aperture
12mm - 21mm	f/1.4, f/2
22mm - 35mm	f/1.4, f/2
50m	f/0.95, f/1, f/1.2, f/1.4
85mm	f/1.2, f/1.4
90mm	f/2
100mm, 135mm	f/1.8, f/2
180mm, 200mm	f/2, f/2.8
300mm	f/2, f/2.8
400mm	f/2.8, f/4
500mm	f/4
800mm	f/5.6

Top recommendations for fast lenses

Lenses I've used and/or own, and can heartily recommend.

Click on links to each lens for reviews.

Zeiss for Nikon or Canon

View prices for Nikon or for Canon

• 21mm f/2.8 Distagon (not so fast, but oustanding at f/2.8)
• 28mm f/2 Distagon
• 35mm f/2 Distagon
• 50mm f/1.4 Planar
• 50mm f/2 Makro-Planar
• 85mm f/1.4 Planar
• 100mm f/2 Makro-Planar

Canon

View prices.

Canon's f/1.2 lenses are unique. Nikon does not offer f/1.2 lenses as of 2010.

• 24mm f/1.4L II
• 35mm f/1.4L
• 50mm f/1.2L
• 85mm f/1.2L II,
• 135mm f/2L,
• 200mm f/2L IS.

Nikon

View prices.

• 24mm f/1.4G
• 50mm f/1.4G
• 58mm f/1.2 NOCT (used market)
• 105mm f/2 DC
• 200mm f/2G VR

Leica

View prices.

• 21mm f/1.4 Summilux-M ASPH
• 24mm f/1.4 Summilux-M ASPH
• 28mm f/2 Summicron-M ASPH
• 35mm f/1.4 Summilux-M ASPH
• 50mm f/0.95 Noctilux-M ASPH
• 75mm f/2 APO-Summicron-M ASPH

 

See also

• Brand-new Blur
• diglloyd's Advanced Photography — in particular, focus shift with fast lenses, reviews of various fast lenses.