High speed flash (ad200) how to take readings based on the ambient light?

[geru]

Balance ambient and flash. Neil Van Neikerk.

Works the same with on camera or off camera flash and requires no meter.

I used to love his blog.

Problem comes when you don't have enough flash power like when shooting outdoors in bright light. AD200 is good but when using HSS mode, you need a lot more power. That's why I sometimes gang 2 AD600s with a 1200ws head.

I just use an ND filter.

Can you suggest me what filter size to get? Please see my other post here ( my answer to my main post for understanding)

The size is dependent on the lens size they come in many sizes. Look at the glass end of the lens somewhere on glass rim you'll see a size like 52mm different lenses are different sizes. What I did was buy a variable ND Filter for the largest lens 67mm in my case. Then bought a set of step up rings from 49mm to 67mm now I can use the single Variable Neutral Density filter on any of my lenses.

This is a 9 stop VND filter in different sizes

 

[A_SCY]

Balance ambient and flash. Neil Van Neikerk.

Works the same with on camera or off camera flash and requires no meter.

I used to love his blog.

Problem comes when you don't have enough flash power like when shooting outdoors in bright light. AD200 is good but when using HSS mode, you need a lot more power. That's why I sometimes gang 2 AD600s with a 1200ws head.

I just use an ND filter.

Can you suggest me what filter size to get? Please see my other post here ( my answer to my main post for understanding)

The size is dependent on the lens size they come in many sizes. Look at the glass end of the lens somewhere on glass rim you'll see a size like 52mm different lenses are different sizes. What I did was buy a variable ND Filter for the largest lens 67mm in my case. Then bought a set of step up rings from 49mm to 67mm now I can use the single Variable Neutral Density filter on any of my lenses.

This is a 9 stop VND filter in different sizes

Thank you very much)

 

[fotowbert]

Thank you for sharing your knowledge .

I read your posts carefully

My flash meter doent meter in percentage, so i moved to your next post.

my light meter is the Polaris SPD100.

So if i understand correctly the ideal amount of flash light is between 20 - 50/100 or somewhere between ( a bit less than half of a stop to a full stop)

I mentioned that range of % Flash values because it produces a reasonable mix of flash plus ambient light. IMO below 20% the flash content is too little to make much difference and above 50% the flash becomes the primary light source which now is so obvious that it requires careful control just like studio lighting. Somewhere within the range of 20 to 50% may be your "ideal" % Flash target. I personally like 30% Flash for portraits.

so there are 2 ways to do this, or to add 20/-50/100 flash in the existing ambient exposure, or to keep the flash in the same exposure with ambient and just underexposed the ambient light by 20-50/100.

The flash content in your image changes with distance from your light due to the ISL (Inverse Square Law ). A memory aid I find useful in understanding the ISL is to remember that the following sequence of distances from the light source are all 1 stop apart: 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16 and so forth. This sequence should look familiar. The ISL makes it inevitable that portions of your image will receive less flash and be darker. By keeping the ambient the majority source in the image makes the flash falloff less noticeable.

The flash meter's recommended exposure accounts for the sum of both light sources at the location where you held the meter in incident mode. At 50% Flash your subject will be 1 stop overexposed if you use only your ambient exposure reading.

About your Nd filters:

I know that ND filters are used so they can allow the photographers to lower the exposure of ambient light by lowering the shutter speed and the same time allow the photographer to use wider apertures.

But what about if i can control the ambient light by aperture shutter speed and just i want a fill flash to the subject. i know in very bright light i will not be able to shoot in wide apertures but still that ok. I want to try this First before buying some adjusttable Ndfilters.

I mentioned ND filter as a workaround to avoid using HSS mode flash. ND filter doesn't change the ratio of flash to ambient in the image. A ND filter also doesn't work well with optical viewfinders because the darkness makes it difficult to compose. This isn't a problem for the EVF on mirrorless cameras.

You are correct that shutter speed will independently control the ambient content of the image. This is often not very useful due to motion blur and your camera's X-sync limit constraints on shutter speed. This leaves flash power (and distance) as your main controls to achieve your desired flash content when mixing flash with existing light.

Happy New Year,

• John

--
"[If you don't sweat the details] the magic doesn't work." Brooks, F. P., The Mythical Man-Month, Addison-Wesley, 1975, page 8.