Modern Classic SLRs Series :
Additional info on Nikon Ringlight Macro Flash SR2/SM-2

Nikon Ringlight for Macro photography

Nikon recently introduced a new macro ringlight called SB-29 Macro Flash which they claim is more efficient, feature-rich and cheaper than their TTL flash capable SB-21A/B which was a replacement model for the non-TTL SR2/SM2 Ring flash that has been around for quite a while, since the seventies. If you are an owner of any TTL flash capable SLR body, you should look at one of those units mentioned earlier (Nikon F3 with its special accessory shoe should select the dedicated SB-21A (Or with AS-17 coupler, the F3 can use the SB-21B in TTL flash mode but not the other way round, because there is still not a flash coupler that would allow TTL flash mode to be retained when a SB-21B is used on a Nikon F3 body - it would work only at best - in AUTO mode) while those camera bodies that have the standard ISO type hot shoe should go for the SB-21B). Neither of the first generation macro ring lights SR-1/SM-1 or the later SR-2/SM-2 are TTL capable, and would provide any significant differences with the SB-21 A or SB-21B.

What is a Ring flash or ringlight as Nikon called theirs ? Ring Light is basically a flash designed for close-up photography. Situations where you want to photograph very close to the subject or in copying work and you may not wish shadows or the harshness of a direct or indirect flash. When you get right down to being ultra-close, the smallest variation of light intensity falling on the subject is magnified many folds. The properties of the flash light emitted is even and diffuse. There are many possible photographic applications that a ringlight can do other than copy work, you can use them for macro photography outdoor. A Medical Nikkor lens is actually a modified ringlight which has an electronic flash tube in the shape of a ring which is fastened to the front of the lens.

Nikon Original SR-1/SM-1 Ring lights
SM-1.jpg SR-1.jpg
Just came across these two rarely seen images of the original SM-1 and SR-1 macro ringlight by Nikon in a late sixties brochure. Managed to scan and restore close to its original form in photoshop program.

SM-1 Ringlight

"... As with all ringlights, this unit is designed to provide shadow less lighting for close-up subjects". 
It attaches to the rear of the lens via the bayonet mount (it has a bayonet release lever similar to that on the M2-tube as well as a semi-automatic diaphragm plunger). It is designed for photography at mag. ratios greater than 1:1 with 24mm to 135mm lenses, reversed on bellows (via the BR-2). The permanently attached cord has two plugs, a PC-type sync and a 4-pin power plug, which attaches to the SB-1. There is a switch on the SM-1 to cut output from full to 1/4 power, but overall power is controlled from the SB-1. It has a small modelling light built-in for ease of focusing when up close to the subject.

Different lenses have different exposure effects with the SM-1. If I had some skill with cgi, I'd write a script to automatically look up the f/ stop based on your subject-to-film-plane distance. Unfortunately, you have to settle for the following tables:

24mm f/2.8
35mm f/2.8, f/2, f/1.4
28mm f/3.5, f/2
55mm f/3.5
50mm f/2, f/1.4
45mm f/2.8
105mm f/2.5
85mm f/1.8
subject focal point distance  f/stop  subject focal point distance  f/stop  subject focal point distance  f/stop  subject focal point distance  f/stop 
305 mm 5.6 360 mm 5.6 310 mm 11 420 mm 11
250 mm 8 305 mm 8 240 mm 16 300 mm 16
200 mm 11 250 mm 11 205 mm 22
195 mm 16
chart is linear with evenly spaced f/number progression
ASA 100 @ 1/4 power (close two stops for full power, one stop for each ASA doubling)
When you use the above tables, note that extension factor has already been taken into account, and the f/ stop indicated is as it should be set on the lens. The "chart is (non)linear" notation indicates whether if, the data, when scatter-plotted with distance on the y-axis and f/ stop progression (i.e. f/1.4, 2, 2.8, 4, 5.6, etc.) spaced evenly on the x-axis, are linear or not. The linear ones may be linearly interpolated, using the logarithm of the f/ stop.." - Michael Liu - .

SR-1 Ringlight " ..... As with all ringlights, this unit is designed to provide shadow less lighting for close-up subjects". 
It attaches to the front of the lens via a 52mm threaded ring, which may be turned via the knurled ring in the centre of the flash tube housing. A cord is permanently attached to this unit. The cord has two plugs on it; one is a standard PC-type sync plug and the other is the 4-pin power plug, which attaches to the SB-1 only. Thus for those of you who have scrounged up a spare, SD-3 can't use the SR-1 (or SM-1) with the SB-1 and SD-3. The SR-1's power is controlled via the SB-1's power switch, and the SR-1 has a light-output switch which cuts the output from full to 1/4 power.

The SR-1 is recommended for subject-to-film-plane distances greater than 200mm. The guide number appears to be 14m (45.5ft) at ASA 100 and full power. 1/4 power would require opening up two more stops. Since the SB-1/SR-1 is a fully manual flash, without exposure confirmation, your best bet is either to obtain and use a flash meter, or use the guide number calculated above. A chart is included below for your convenience:

subject focal point distance  f/stop 
 625 mm
500 mm
375 mm
250 mm
130 mm
chart is linear with evenly spaced f/number progression
ASA 25 @ 1/4 power (close two stops for full power, one stop for each ASA doubling)
".. There's not much else to say. If you're a fan of flat, featureless lighting, or have a burning need for a ringlight, you could probably do better than an SR-1. More modern units will provide TTL flash metering, which is a godsend for close-up photography. On the other hand, if you want to assemble the complete SB-1 system ...".   - Michael Liu -
Note: The Nikon Handle mount flash SB-1 featured earlier can also be used to power the SR-1 Ringlight or the SM-1 Ringlight.

Nikon SR-2/SM-2 Macro Ringlight

Useful accessory:- Nikon original Flash couplers for various flash models foot incompatibility

Nikon SR-1.jpg Nikon SM-2.jpg
The Nikon SR-2 screws into the 52mm filter threads of 35mm to 200mm Nikkor lenses, and operates down to 20cm for close-up work. It also can be used for general photography. You can mount the flash on the forward end of the lens.

SM2map2.jpg (8k) Loading... SMm2map1.jpg (9k) loading..
The ringlights use either an AC power supply, LA-1, which can be switched to operate from 100VAC, 117VAC, 220VAC or 240VAC, or even with a battery pack (LD-1). These power supplies can also be shared and used with the Medical Nikkor lens.

Note: In extreme close up range, normal Guide Numbers are not applicable. You may use an accompanying chart to calculate proper exposures (Vertical scale is distance in "mm", horizontal values are in f-stop).

SR2/SM2 Full setup.jpg 923k) Loading..
Ringlight SR-2 : Designed for use with Nikkor lenses ranging from 35mm to 200mm, this unit screws into 52mm filter threads on the front of the lens. The ring light connects to its power source with one cable and to the camera-body sync terminal with a sync cord. It has a guide number of 48 feet with ASA 100 film when set for FULL power. A switch on the unit selects 1/4 power and a guide number of 24 feet.

Ringlight SM-2
: Used for macro and close-up photography, this unit provides shadow less illumination of subjects very close to the lens. Nikon SM-2 is designed for reproduction ratios of 1:1 (life-size) or greater, mounts directly to the bayonet mount of Nikkor lenses mounted in the reverse position on a bellows. Although the output light is similar in amount to the SR-2, no guide number is furnished for this unit because guide numbers do not accurately predict illumination at extremely short distances. Exposure is found by consulting charts and tables supplied with the unit.

SM-2 bayonets onto the rear of a reverse-mounted Nikkor lens for macro photography of subjects down to a 12:1 ratio (when the Nikkor 20mm f/4 or 20mm f3.5 is mounted in the reverse position on the Nikon bellows), plus it contains its own focusing lamp.

sm2sr2.jpg (12k) Loading...
The SM-2 contains a built-in incandescent focusing light. The push button switch that turns on the focusing light also opens lens aperture wide open, if stopped down. These ringlights provide a solution to optical-electronic flash combination close-up or macro photography. Both units can be powered by the Nikon LD-1 (DC power pack) or LA-1 (AC power pack) at full or in 1/4 light output.

However, these units are not TTL flash as with the SB-21A/B, if you want to take full advantage and happen to shoot a lot of flash pictures, you may want to consider getting an SLR that has TTL flash capabilities and invest into the SB-21 setup for more rewarding and less hassle photography.

DC Unit.jpg
" .... Visually, the SM-2 appears nearly identical to its predecessor, the SM-1. The main differences are that the SM-2 has sockets instead of the SM-1's permanently attached power and sync cords. The sockets on the SM-2 are similar to other Nikon speedlites.There is the three-prong sync socket and a half-moon three-pin power socket identical to the one on the later version of the Medical-Nikkor 200 (not wholly unexpected, as they share the same power supplies ...) Although I am not completely sure, the specs and usage for the SM-2 should be the same as those for the SM-1

AC Unit.jpg
The great advantage of using the SR-2/SM-2 (instead of the the corresponding SR-1/SM-1 products) is in not being tied to the SB-1 as a source of power, but rather being tied to largish, blocky power packs. Yes, there's always the SB-21A/B, which offers TTL closeup flash at a price...". -Michael Liu-

Specifications for SM-2

Flash exposure control: Automatic control is NOT Possible
Manual control
manual at full output and/or 1/4 power;
Guide number (ISO 100, m)
NOT ratable at macro distance;
Recycling time: manual Approx. 12 sec.
Number of flashes: Approx. 600 at full output and 1200 at 1/4 power (Alkaline batteries);
unlimited (LA-1)…
Angle of Coverage: sufficient for macro coverage

Power source: DC Unit LD-1, AC-Unit LA-1(Can be shared with 200mm f/5.6 Medical Nikkor lens);
LA-1 AC unit
Ready Light: Built-in
Open flash button: Built-in
Modelling Lamp: provided; button-activated
Synch Socket for Eyepiece Pilot Lamp: provided
Ready-light Contact for F2 Series Camera Finders: provided with accessory SC-4
Mounting: Bayonets onto rear of Nikkor Lens.
Dimensions: Approx. 70mm (W) x 100mm (H) x 35 mm (D)
Weight: Approx. 185g
(6.5 oz)
Accessories: DC Unit LD-1; AC Unit LA-1; ready-light adaptor SC-4; sync cord SC-5; coiled sync cord SC-6; sync cord SC-7; extension cord SE-2; eyepiece pilot lamp SF-1

More info and specification on SR-2 by clicking here or proceed to SB-18 and SB-19 by clicking "Next" button below.

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Modern Classic SLRs Series :
Additional info on Nikon Ringlight Macro Flash SR2/SM-2

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