Modern Classic SLRs Series :
Nikon FM - Its Metering

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The logical extension of TTL viewing is TTL metering. Virtually all modern cameras are now adopted with this principle in their respective metering system, which only differs by complexity and methods used, this applies to the rangefinder cameras as well (Asahi Pentax pioneered this technique, but Topcon was the first to launch a model commercially). Not only does it free the photographer from the burden of having to make complicated exposure calculations with external handheld meters in some complex lighting conditions. With the exposure indicators readily visible inside the viewfinder, you can readily get basic key exposure information relates while you are taking the picture. The Nikon FM's built-in meter, powered by a pair of Gallium Photo Diodes, located near the eyepiece in the viewfinder, operates on the principle of Nikon 60/40 center-weighted exposure measurement to provide quite accurate and responsive exposure measurement.

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The meter reads the intensity of the light coming through the lens over the entire viewfinder screen, with its sensitivity (60%) is concentrated on the central area (12mm) outlined on the screen (Balance 40% shared across the whole picture frame, that is how the term 60/40 metering composition came from - the standard metering pattern adopted by virtually all manual focus metered Nikon bodies (there are few models used average meter in early days and variations in either 75/25 or 80/20 combinations) until the arrival of a revolutionary metering method in the Nikon FA's Multi Segments Metering in 1983).

This method of exposure measurements has shown itself to be the most effective for achieving correct exposures in everyday picture-taking situations. The metering system, has very similar way with the electronic EL series cameras, which over the years tested and polished up a a lot during early days of computer circuitry for SLR automation. The adoption of some Nikon developed solid-state devices such as GPD photo sensors, Nikon's Functional Resistance Element (FRE) and a monolithic IC, all of which contribute to the FM's compactness and reduced weight, as well as tackling over a fairly wide range of light levels from EV 1 to EV18.

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Also, regardless of whether metering is at full aperture or stopped down, you can have all the basic exposure information right there inside the viewfinder. The exposure indicators are in the form of a five combination LED display which lights up to indicate the precise degree of overexposure or underexposure, or correct exposure.

The selected shutter speed is also indicated, as is the set aperture (in the case of Nikkor lenses with the Al facility). The meter can be switched on by moving the film advance lever, an action that will uncover a red dot; it can be switched off by pressing the lever all the way flush it back with the body.

LED display and ADR facility

The main advantage of the FM's exposure readout facility - the five-combination LED display - is that it enables clear and easy readings even in extra-dim or extra-bright light,something the more conventional needle-centering or matching-needles will find hard put to equal.

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Inside the viewfinder are three exposure indicators : '+' for overexposure, '0' for correct exposure and '-' for underexposure. With corresponding LED's, at least one of which lights up when the meter is switched on. Without taking his eye off the viewfinder, you can just simply adjusts shutter speed or lens aperture until the desired LED combination lights up.

The shutter speed set is indicated to the left of the viewing screen. With Nikkor lenses that have the AI facility, the selected aperture is also indicated through the FM's aperture-direct-readout or ADR window; it appears just above the screen.

| Next | Part 4/7

Index Page | Page 1 | Page 2 | Page 3 | Page 4 | Page 5 | Page 6 | Page 7 | Specification | Main Reference Map

First Section covers : Basic camera setup
2nd Section covers:
Optical Path | Viewfinder Screen
Earlier Section covers: Viewing Mechanism
Depth of Field Preview | Reflex Mirror Mechanism
Next section covers: Metering
Method | The Metering Cells | related info on ASA Film Speed Settings

| Back to Nikon FM's Index Page |
Back to Nikon FM Series Main Index Page |

Detailing its Basic Camera Operations (Instruction Manual)
Detailing its Technical Application of its features (6 parts)

| Message Board | for your favourite Nikon FM Series SLR models
| Message Board | for your Nikon Optics in a shared environment
| Message Board | Specifically for Dispose or Looking for Nikon/Nikkor Photographic Equipment

Standard production Nikon FM Series models:- Nikon FM | Nikon FM2 | Nikon FM2n | Nikon FM10 | Nikon FM3a |
Known variants:- Nikon FM Gold | Nikon FM2/T | Nikon FM2N Tropical Set | Nikon FM2/T Limited Edition | Nikon FM2N LAPITA | Nion FM2n Millennium 2000

Shared Resources: MD-11 | MD-12 | Focusing Screens | Titanium Shutter | Flash Units -SB-16 | SB-15 | SB-10 or other Options | Databack | Nikkor lens mount (related info)

Others:- Nikon AF-TTL Speedlights | SB-20 (1986) | SB-22 (1987) | SB-23 | SB-24 (1988) | SB-25 (1991/2) | SB-26 (1994) | SB-27(1997) | SB-28 (1997) | Nikon SB-29(s) (2000) | Nikon SB-30 (2003) | Nikon SB-600 (2004) | Nikon SB-800 (2003) Nikon AF-TTL Speedlight DX-Series: Nikon SB-28DX (1999) | SB-50DX (2001) | SB-80DX (2002)

Nikon BC-flash Series | Original Nikon Speedlight
SB-2 | SB-3 | SB-4 | SB-5 | SB-6 | SB-7E | SB-8E | SB-9 | SB-E | SB-10
| SB-12 | SB-14 | SB-140 UV-IR| SB-15 | SB16A | SB-17 | SB-18, SB-19 | SB-21A (SB-29) Macro flash | Flash Accesories | SF-1 Pilot Lamp

Instruction Manual: Nikon FM (HTML | PDF) | Nikon FM-10 (HTML) | Nikon FM2n's User's Manual available only in HTML format (6 parts) | Nikon FM3A (HTML)
Nikon FM, FM-10, FM2, FM2n and FM3A / Main Reference Map: (HTML) Nikon FM, FM2, FM-10, FM2n (Applicable to FM2T, FM2 "Year of the Dog"; Millennium 2000") and Nikon FM3A

weblibrary.gif   Nikon F | Nikon F2 | Nikon F3 | Nikon F4 | Nikon F5 | Nikon F6 | Nikkormat / Nikomat | Nikon FM | Nikon FE/ FA | Nikon EM/FG/FG20 | Nikon Digital SLRs | Nikon - Other models

Nikon Auto Focus Nikkor lenses:- Main Index Page
Nikon Manual Focus Nikkor lenses:- Fisheye-Nikkor Lenses - Circular | Full Frame | Ultrawides Lenses - 13mm15mm18mm20mm | Wideangle Lenses - 24mm28mm35mm | Standard Lenses - 45mm 50mm 58mm | Telephoto Lenses - 85mm105mm135mm180mm & 200mm | Super-Telephoto Lenses - 300mm 400mm 500mm 600mm 800mm 1200mm |

Nikkor Link.jpg

Index Page
  Special Application lenses:
Micro-Nikkor Lenses - 50mm~55mm -60mm 85mm -105mm 200mm Micro-Zoom 70-180mm
Perspective Control (PC) - 28mm 35mm PC-Micro 85mm
Dedicated Lenses for Nikon F3AF: AF 80mm f/2.8 | AF 200mm f/3.5 EDIF
Depth of Field Control (DC): 105mm 135mm
Medical Nikkor: 120mm 200mm
Reflex-Nikkor Lenses - 500mm 1000mm 2000mm
Others: Noct Nikkor | OP-Nikkor | UV Nikkor 55mm 105mm | Focusing Units | Bellows-Nikkor 105mm 135mm
Nikon Series E Lenses: 28mm35mm50mm100mm135mm | E-Series Zoom lenses: 36~72mm75~150mm70~210mm

MF Zoom-Nikkor Lenses: 25~50mm | 28~45mm | 28~50mm | 28~85mm | 35~70mm | 36~72mm E | 35~85mm | 35~105mm | 35~135mm | 35~200mm | 43~86mm | 50~135mm | 50~300mm | 70~210mm E | 75~150mm E | 80~200mm | 85~250mm | 100~300mm | 180~600mm | 200~400mm | 200~600mm | 360~1200mm | 1200~1700mm

Tele-Converters: TC-1 | TC-2 | TC-200 | TC-201 | TC-300 | TC-301 | TC-14 | TC-14A | TC-14B | TC-14C | TC-14E | TC-16 | TC-16A | TC-20E

Recommended links to understand more technical details related to the Nikkor F-mount and production Serial Number: by: my friend, Rick Oleson by: Hansen, Lars Holst

W A R N I N G: The New G-SERIES Nikkor lenses have no aperture ring on the lens, they CANNOT ADJUST APERTURES with any of these manual focus Nikon FE series SLR camera models; please ignore some portion of the content contained herein this site where it relates.

| Back | Main Index Page of Nikkor Resources
| Back | Main Index Page of Pictorial History of Nikon SLRs

| Message Board | for your Nikkor optics ("shared" because I do wish some of you to expose to other's perspective as well. Isn't it a sad sate to see photography has to be segmented into different camps from the use of various labels)

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Credit: To all the good people who has contributed their own experience, resources or those who are kind enough granting us permission to use their images appeared in this site. Mr. MCLau®, who has helped to rewrite some of the content appeared this site. Chuck Hester® who has been helping me all along with the development of all these Nikon websites;LarsHolst Hansen, 'Hawkeye' who shares the same passion I have; Ms Rissa, Sales manager from Nikon Corporation Malaysia for granting permission to use some of the official content; TedWengelaar,Holland who has helped to provide many useful input relating to older Nikkor lenses; Some of the references on production serial numbers used in this site were extracted from Roland Vink's website; HiuraShinsaku from Nikomat Club Japan. t is also a site to remember a long lost friend on the Net. Note:certain content and images appeared in this site were either scanned from official marketing leaflets, brochures, sales manuals or publications published by Nikon over the years and/or contribution from surfers who claimed originality of their work for educational purposes. The creator of the site will not be responsible for may discrepancies arise from such dispute except rectifying them after verification."Nikon", "Nikkormat", "Nippon Kokagu KK" & "Nikkor" are registered tradename of Nikon Corporation Inc., Japan. Site made with an Apple IMac.