Flash Options for FM2n

perkeleellinen said:

Thanks for all the comments, helpful in thinking this through.

Let me clarify - I'm not concerned with coverage, it's the close subject matter and not wanting to use f32. I'd like to have the edges and background 1-2 stops under.

Here's my thinking:
Ambient light = 1/1000 f2.8
or at sync: 1/250 f5.6

Suppose a flash with GN45, film ISO400, subject 1 meter.

Then: aperture = f90. Power reduction by 1/128 = f8.

Am I correct?

F8 for flash with the background one stop under at f5.6 would be ideal I think. So I need a GN45 flash with varipower down to 1/128.

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OK, suppose the ambient light is 1/250 at f/5.6. You want to have the background at 1 stop underexposure, thus you want to expose at 1/250 at f/8. To gain correct exposure with the flash, you need to have f/8 at 1 meter at ISO 400, which is nominally a GN of 8 meters at ISO 400, meaning it would have a GN of 4 meters at ISO 100. That is six stops less, or 1/64 power, from a GN of 32 meters (100 feet) at ISO 100, which is a pretty common flash power.

It's easy to find a flash that has settings of manual 1-1/16 power, but a little harder to find 1/64. I think the Nikon SB-26 and SB-28 can do manual 1/64 power. Another option is to find a flash that has an auto mode (not TTL, just A mode) that lets you do f/8 at ISO 400 as close as 1 meter. Also, you could set the flash to its widest setting or use a diffuser like a Sto-fen or mini softbox, which should be good for losing a stop or so. Anyway you do it, you'll want to run some tests.

(I'm ignoring that the subject's face will get full exposure from the flash plus 1/2 from the ambient. You could dial the flash down a fraction of a stop to compensate, but I don't think it's a huge problem, especially if the subject is facing down toward you and getting less light from the sky.)

Thanks, Reddesert. It looks like the SB-25 also does 1/64 power and is a little cheaper than the 26 & 27. It's probably a lot newer than the hammerhead Metz and Sunpaks I've been looking at.

Also I have an F80 and although I don't really use it for skateboard photography because of the 1/125 sync, a SB-25 would give me rear-curtain on that camera if I ever wanted it.

Any old flash that dials down plus a neutral density gel over the flash, such as a piece of developed black and white neg film, or a layer or two of tissue paper. The modern Nikon sb800 dials down to 1/128, and with its diffuser, covers 14mm equivalent field f view.

I think you're over thinking this. If you want the classic lit subject dark background what you do is you get any old flashgun, zoom the head (though if you're shooting with a 16mm that point is redundant!) and set your exposure to underexpose the background a couple of stops and the flash to lit the subject normally.

You can easily do that with something like an SB80DX. In that scenario you first work out your background exposure. Say it is 1/1000 at f/2.8 That makes it 1/250 at f/5.6 which is what you need as flash sync is at 1/250.

So, background is 1/250 at f/5.6. If you then close down to 1/250 f/11 that makes the background 2 stops down.

You can set the SB80 in auto mode at f/11 and your correct ISO/distance and that does the rest. You could zoom the head to 35mm ro whatever, just don't use the diffuser.

I think a simple Vivitar 2600 would work fine and probably cost you the princely sum of $10 clean used. You could go auto or manual. You're overthinking it. Especially if you're able to shoot at 1/1000 and f/2.8. 1/250 or 1/500 is fast enough, that buys you a stop or two. These are not fast-moving subjects, like helicopter rotors...

Thnaks all. I found a second hand SB-25 for a good price at a dealer so I'm going to experiment with that.

I think the over-thinking came from my experience with auto settings on flashes I had in the '90s where tiny apertures were needed with the subject at 1 meter.

The photo I posted on the previous page is a 'stall' manoeuvre but typically skateboarding is a fast action sport and motion blur is a risk at 1/500, especially when the board is flipped or when the skater's arms move fast for balance.

Smaug01 said:

I think a simple Vivitar 2600 would work fine and probably cost you the princely sum of $10 clean used.

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Yes, for most of the flash issues discussed at Apug a generic flash out of the rummage box for few Euros would be sufficient.

perkeleellinen said:

Thnaks all. I found a second hand SB-25 for a good price at a dealer so I'm going to experiment with that. ...

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The thing to watch for in these old flashes is the capacitor. Capacitors are electronic components that store electrical charge but can be discharged near instantly. They go bad over time. If you find that it won't charge or takes a long time to charge even with good NiMH or Lithium batteries, it probably points to a tired capacitor. If you find a capacitor with at least the same voltage and capacity ratings in the same or smaller size, you may be able to replace it, but it probably wouldn't be worth the effort. Just find another one from the rummage bin.

The Nikon dedicated branded ones have the advantage of showing a ready light in or above the finder on your FM2.

Smaug01 said:

The thing to watch for in these old flashes is the capacitor. Capacitors are electronic components that store electrical charge but can be discharged near instantly. They go bad over time.

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My experience with countless flashes decades old is that those dead from the start are far below 5%. Some few make take some minutes to charge for the first time. What remains to check is the absolute output.

But capacitator issues would apply basically on flashes from camera manufactureres as well as from 3rd parties from same period.

I started a thread on using flash with fisheye a few years back. I was using a disposable plastic cup with a black circle on the bottom of the cup. It was not perfect, however, because the cup stuck out and came very close to the image frame (that is it sometimes showed in the pictures).

https://www.photrio.com/forum/threads/flash-with-fisheye.125854/

Reporting back. I set up a test using ISO 100 slide film to best gauge exposure. I sat my boy in the shade and photographed him using the 16mm fisheye holding pieces of paper with the details written with a Sharpie for each shot. Flash zoom was set to 20mm.The second half of the film I shot him jumping on our trampoline. I tried to position myself as close as I get when shooting skateboarding

Results:

I shot one frame in ambient light no flash: 1/250 f4 = exposure good
auto setting with exposure as for ambient ('0') = over exposed, cannot see the writing on the paper
auto setting with -1 exposure = over exposed, cannot see the writing on the paper
auto setting -2 exposure = over exposed, can just about see the writing on the paper
1/4 power 0 exposure = very over exposed, whites bleeding into the skin
1/4 power -1 = over exposed, cannot see the writing on the paper
1/4 power -2 = over exposed, cannot see the writing on the paper
1/8 power 0 exposure = over exposed, cannot see the writing on the paper
1/8 power -1 = over exposed, cannot see the writing on the paper
1/8 power -2 = well exposed on skin tones, can see the writing on the paper, a little bright
1/16 power 0 exposure = over exposed, cannot see the writing on the paper

2nd half of the roll - my boy bouncing with the flash set to auto and exposure -2 = unreliable; some frames very overexposed, others correctly exposed. I didn't move position for these photos.

Best of the test is 1/8 power 2 stops under. I'll test again now with 1/16 and 1/32 power to see what that does.

As I feared; auto setting is not good when using a fisheye very close to the subject and when the subject moves it becomes unreliable.

I should have continued the test to include 1/16 down to -2 and then also 1/32 and 1/64 but I was convinced this would lead to underexposure based upon the guide number in the manual when the zoom head is at 20mm

I've had a complete re-think over this. I realised that all these tests with slide film plus developing was becoming more expensive than a flash meter. So I sold the Nikon flash and bought an old Minolta flashmeter IV and a Sunpak flash with 1/64 setting - much simpler setup. Here's the rig I've been testing, I will use the FM2 for stills, that F5 is for sequences for another project.

Flash meter iv is still the king of flashmeters with more features than most people know what to do with. Sunpaks and old Nikon flashes tend to be reliable enough

The Sunpak 120J II has a bare tube head, manual power settings to 1/128 and GN177(ft) (ISO 100) with reflector in place.