[mcgregni]

I keep things simpler now, and have switched all flashes and camera defaults to 1/2 stop steps. I just don't find the extra clicks and finer tuning worth it, especially since most images will have levels type adjustments as routine .... Let's face it, even half stop variations to key, fill and hair light intensities fall within standard RAW converter default opening adjustments.

[stevebrot]

Oh, that's great thinking, West Penn. The numbers express the Inverse Square law!

The strange thing is that I knew that, but never thought to apply them that way.


Steve

[pschlute]

I keep things simpler now, and have switched all flashes and camera defaults to 1/2 stop steps. I just don't find the extra clicks and finer tuning worth it, especially since most images will have levels type adjustments as routine .... Let's face it, even half stop variations to key, fill and hair light intensities fall within standard RAW converter default opening adjustments.

Me too Nigel.

[BruceBanner]

Right, pay attention young Bruce at the back of the class

One "stop" of light is a halving or a doubling of light.

Shutter speeds : 1/8 to 1/15 is one stop. 1/15 to 1/30 is one stop ...so 1/8 to 1/30 is two stops

Aperture : fstops are ratios. f8 to f5.6 is one stop. f5.6 to f4 is one stop. So f8 to f4 is two stops

Light output from a flash is in fractions of full manual power. So 32 means 1/32 power. To get a two stop reduction in flash output you need to use 1/128 (or 128 as the flash displays). The +7 represents 2/3 of an increment to the next power level. So 32+7 is one third of a stop away from 1/16.

The number of aperture clicks between stops on your lens allows you to fine tune the graduation between "stops". Same with shutter speed which is usually 1/2 or 1/3 stop customisable increments.

ps. Actually my maths was a bit awry on my first reply to you. to change your flash power by two stops from 32+7 you should use 128 or 128+3

hehe, thanks

Obviously with shutter speeds and ISO, these are linear quantities and it's easy to do halving/doubling in the head.

Aperture's logarithmic, though, but I think if by rote you remember f1.4, 2, 2.8, 4, 5.6, 8, 11 and 16 it will become second nature.

So the lensbaby V56 is a bit odd in that it starts at f1.6 but then has all the other stops on the aperture ring.

Yep...and try not to think too much about it; just learn the series by rote. I actually have a chart that I use, if needed, that includes 1/2 and 1/3 stops for both aperture and shutter speeds. That way I can easily remind myself that f/3.5 and f/4.5 are not a full-stop difference from each other.


Steve

So a true stop from f1.6 would be 2.2?, then 3.2 from 2.2? And so on so forth?

The aperture series of stops also can be used for the placement of speed lights or strobes. If you place your lights at 5.6 feet, meters, cubits, or whatever measurement from your subject and you need a full stop more of light for proper exposure, you can simply move the lights to 4 feet, meters, etc. Or if you want a full stop less of light, you simply move the lights to 8 feet, meters, etc. The half and third aperture stops work for finer adjustments of your lights as well. Here's a chart listing full, half and third aperture settings -- F-Stop Chart Infographic - Aperture Cheat Sheet for Photographers

That chart is helpful, definitely laminating and keeping that.

I keep things simpler now, and have switched all flashes and camera defaults to 1/2 stop steps. I just don't find the extra clicks and finer tuning worth it, especially since most images will have levels type adjustments as routine .... Let's face it, even half stop variations to key, fill and hair light intensities fall within standard RAW converter default opening adjustments.

I think I will do that also.


So... to take the V56 example;

Shot 1
Aperture: F8
Shutter Speed: 1/8
ISO: 100
Flash Power: 1/64

Shot 2
Aperture: F4
Shutter Speed: 1/15
ISO: 100
Flash Power: 1/128

Shot 3
Aperture: F2
Shutter Speed: 1/30
ISO: 100
Plash Power 1/256


Doing those 3 shots I should have differing apertures with same exposure roughly in terms of flash power output and varying apertures to work with in post? I'll have to try it and report back...

[clackers]

So the lensbaby V56 is a bit odd in that it starts at f1.6 but then has all the other stops on the aperture ring.

f1.8 lenses (lots of those across many brands) are the same.

[Class A]

So a true stop from f1.6 would be 2.2?, then 3.2 from 2.2? And so on so forth?

Yes.

You get from one stop to another by multiplying by the square root of two (~1.414).
That's why f-ratios that differ by a factor of two (such as f/2.8 and f/5.6) are two stops apart from each other (you need two steps of square root of two multiplications to get a factor of two).

[pschlute]

So a true stop from f1.6 would be 2.2?, then 3.2 from 2.2? And so on so forth?

But a better way of remembering it is to use the stops in the sequence 1.4 ; 2; 2.8; 4.0; 5.6; 8.0; 11; 16; 22; 32.

These are the conventional whole-stops that you will see on the old lenses with aperture rings for example. Anything else in between is a subdivision of these.

Use Class A's method of doubling or halving the number to get a two stop jump, thats how I started off memorising them. Of course it was easier in film days to just look at the aperture ring !