This is a minor contribution from me and it is not complete.
There are still several unanswered questions in my mind. While I input whatever I know, experts in Clubsnap may contribute as well. Lastly, if my input is wrong or misleading, kindly correct me. I want to learn as much as possible.
There is a lot more in flash techniques.
Due to my limited skills, I will touch on the very basic idea of manual flash.
It will be greatly appreciated if there are experts to touch on more advanced knowledge such as multiple manual flash lighting ratio, how light modifier/diffuser affect the aperture etc.
Ok, before I start, you must know the basics of photography.
My primary objective to this thread is to:
1. Share our knowledge together
2. Make manual flash knowledge easier to digest
3. Provide a cheaper alternative to those who want to try using a flash
4. Know what guide no flash that you may require
5. Know what type of flash you want
Pros of using manual flash:
- Majority is cheaper than TTL flashes etc
- Consistent results. Even if your image is over/under-exposed, it will be consistently over/under-exposed
- Good knowledge to have
- Better control over lightings, know what aperture to use
Cons:
- Can be troublesome to calculate
- Not so good for fast type of events
Months ago, the BBB virus hit me hard. I was thinking of what lens and flash to buy so that I can cover most focal length and lighting conditions. In reality, factors such as “want vs need”, budget constraints and best value for money, spin around in my mind. Basically, my heart is arguing with my mind.
I took the route of trying out flash 1st. After some searching here and there, I got a China flash for $55. The reason: If I don’t like it, it’s only $55 that I wasted.
After a few tries, sometimes my pic is always extremely over/under-exposed on the 1st image. I need to adjust a lot more times to get what I want to achieve. All I did was…anyhow adjust…ISO/aperture/flash power/shutter speed…all anyhow one.
I realized that I need to have the basic knowledge to shorten the time to adjust for the exposure I want. This is where our learning journey starts…
Nowadays, technology is very good and it can calculate everything for you. Manual flash is different from TTL (Nikon/Canon etc) calculation. Please do not be mixed up.
Basically, there are 4 components in manual flash calculation to get the correct exposure for your subject:
- Aperture (f/stop)
- Guide number (GN)
- Distance of flash to subject
- ISO multiplier
F/stop = GN (feet) / Distance of flash to subject (feet) * ISO multiplier
GN: This tells us the furthest distance that the light of the flash can reach at a certain ISO level. Normally, it is stated in feet at ISO 100.
Distance of flash to subject: Of course we use visual estimation here. Alternatively, if your lens has a distance marker, half-press the shutter button and look at the reading.
If you want to use meters instead of feet, just convert 1feet = ~0.3m.
ISO multiplier: Every 1 stop of ISO increased will affect the aperture output.
The multiplier is as follows:
ISO 100: 1.0
ISO 200: 1.4
ISO 400: 2
ISO 800: 2.8
ISO 1600: 4
ISO 3200: 5.6
Assuming that GN(feet) of my flash at ISO 100 is 40, distance of flash to subject is 4feet and I am using ISO 100:
F/stop = 40 / 4 * 1 = f/stop 10
Assuming GN(feet) at ISO 100 is 40, distance of flash to subject is 4 feet and I want to use ISO 400.
F/stop = 40 / 4 * 2. = f/stop 20
* you may use this to achieve larger DOF.
If you are considering getting a flash, you may use this equation also.
Assuming that you normally shoot at f/5.6, distance between you to subject is normally 20 feet.
5.6 = GN (feet) / 20 * 1
GN (feet) = 112
you may require a flash of minimum GN 112. This is base on ISO 100. You may also increase ISO to increase light sensitivity and high ISO is very well controlled in most DSLR nowadays.
Some may argue that TTL flash is faster to deploy in the sense that you don't waste time calculating. Some say that using lightmeter is more accurate.
Well, it's up to you whatever method that you want to use or whatever you like.
Basically, it's making the best/most of what we have.
Experts, kindly correct me if my info is wrong.
Sorry that I did not post any image here cos my photography sucks.
Next part: Balancing ambient light with manual flash
There are still several unanswered questions in my mind. While I input whatever I know, experts in Clubsnap may contribute as well. Lastly, if my input is wrong or misleading, kindly correct me. I want to learn as much as possible.
There is a lot more in flash techniques.
Due to my limited skills, I will touch on the very basic idea of manual flash.
It will be greatly appreciated if there are experts to touch on more advanced knowledge such as multiple manual flash lighting ratio, how light modifier/diffuser affect the aperture etc.
Ok, before I start, you must know the basics of photography.
My primary objective to this thread is to:
1. Share our knowledge together
2. Make manual flash knowledge easier to digest
3. Provide a cheaper alternative to those who want to try using a flash
4. Know what guide no flash that you may require
5. Know what type of flash you want
Pros of using manual flash:
- Majority is cheaper than TTL flashes etc
- Consistent results. Even if your image is over/under-exposed, it will be consistently over/under-exposed
- Good knowledge to have
- Better control over lightings, know what aperture to use
Cons:
- Can be troublesome to calculate
- Not so good for fast type of events
Months ago, the BBB virus hit me hard. I was thinking of what lens and flash to buy so that I can cover most focal length and lighting conditions. In reality, factors such as “want vs need”, budget constraints and best value for money, spin around in my mind. Basically, my heart is arguing with my mind.
I took the route of trying out flash 1st. After some searching here and there, I got a China flash for $55. The reason: If I don’t like it, it’s only $55 that I wasted.
After a few tries, sometimes my pic is always extremely over/under-exposed on the 1st image. I need to adjust a lot more times to get what I want to achieve. All I did was…anyhow adjust…ISO/aperture/flash power/shutter speed…all anyhow one.
I realized that I need to have the basic knowledge to shorten the time to adjust for the exposure I want. This is where our learning journey starts…
Nowadays, technology is very good and it can calculate everything for you. Manual flash is different from TTL (Nikon/Canon etc) calculation. Please do not be mixed up.
Basically, there are 4 components in manual flash calculation to get the correct exposure for your subject:
- Aperture (f/stop)
- Guide number (GN)
- Distance of flash to subject
- ISO multiplier
F/stop = GN (feet) / Distance of flash to subject (feet) * ISO multiplier
GN: This tells us the furthest distance that the light of the flash can reach at a certain ISO level. Normally, it is stated in feet at ISO 100.
Distance of flash to subject: Of course we use visual estimation here. Alternatively, if your lens has a distance marker, half-press the shutter button and look at the reading.
If you want to use meters instead of feet, just convert 1feet = ~0.3m.
ISO multiplier: Every 1 stop of ISO increased will affect the aperture output.
The multiplier is as follows:
ISO 100: 1.0
ISO 200: 1.4
ISO 400: 2
ISO 800: 2.8
ISO 1600: 4
ISO 3200: 5.6
Assuming that GN(feet) of my flash at ISO 100 is 40, distance of flash to subject is 4feet and I am using ISO 100:
F/stop = 40 / 4 * 1 = f/stop 10
Assuming GN(feet) at ISO 100 is 40, distance of flash to subject is 4 feet and I want to use ISO 400.
F/stop = 40 / 4 * 2. = f/stop 20
* you may use this to achieve larger DOF.
If you are considering getting a flash, you may use this equation also.
Assuming that you normally shoot at f/5.6, distance between you to subject is normally 20 feet.
5.6 = GN (feet) / 20 * 1
GN (feet) = 112
you may require a flash of minimum GN 112. This is base on ISO 100. You may also increase ISO to increase light sensitivity and high ISO is very well controlled in most DSLR nowadays.
Some may argue that TTL flash is faster to deploy in the sense that you don't waste time calculating. Some say that using lightmeter is more accurate.
Well, it's up to you whatever method that you want to use or whatever you like.
Basically, it's making the best/most of what we have.
Experts, kindly correct me if my info is wrong.
Sorry that I did not post any image here cos my photography sucks.
Next part: Balancing ambient light with manual flash
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