Genesis 200 vs. 400

Am currently weighing the pros and cons of Genesis (and some other manufacturer's) lighting kits. One of the real pro's of the Genesis 200 is its price point.

My question is, how do you know (without physically having the lights) how large a room the 200 (or any other size set of lights) can accommodate?

I am interested in the lights for portraits, but also for lighting wedding receptions.

Thanks,

George

It's not the room size, but flash to subject distance that matters. For individual portrait, we place the strobe with modifier 4-6 ft from the person, the 200 will provide about f8-f13 at iso100, which is more than good enough. For wedding group shots, where the strobe with umbrella need to to be 10-12' away from the group to get even coverage, the 400 will have more power to play with before raising the iso.

Lotto wrote in post #5750012
It's not the room size, but flash to subject distance that matters. For individual portrait, we place the strobe with modifier 4-6 ft from the person, the 200 will provide about f8-f13 at iso100, which is more than good enough. For wedding group shots, where the strobe with umbrella need to to be 10-12' away from the group to get even coverage, the 400 will have more power to play with before raising the iso.

I am deciding between the 200 or 400, too. Would a pair of 200s do a good job for a family indoor portrait of 5-8 people?

Thanks!

zmaker123 wrote in post #7160261
I am deciding between the 200 or 400, too. Would a pair of 200s do a good job for a family indoor portrait of 5-8 people?

Thanks!

In short, yes, long term, I'd get the 400. More power is never a bad thing. coincidentally, I have the 400s and love them.

I used a pair of 200's to shoot a group of 17. It clearly was not enough as the beautiful light on the near side became increasingly dim across the field. Nonetheless, for such inexpensive lights, it was striking how well they did given the distance. I do have plans to add one 400, though.

The web site says Guide Number 125. So you could shoot from 30' away at f/4 at ISO100 (standard reflector). Using 30mm FL on APS-C, from 30' you would capture a 15' x 22' area, plenty for even a crowd of 20 (two rows of 10)! Even allowing for -1EV due to umbrella or softbox usage, at 21' distance from light to subject you have f/4 across a 10 x 15' wide area seen by the lens.

Thanks for the responses everyone!

Wilt: I have read a number of your posts related to lighting and you seem to have the lighting down to a science. What is your thought processes and formulas for making these various calculations? Do you have any links that you'd recommend that I visit to learn how to make these calculations?

Thanks!

zmaker123 wrote in post #7163788
Thanks for the responses everyone!

Wilt: I have read a number of your posts related to lighting and you seem to have the lighting down to a science. What is your thought processes and formulas for making these various calculations? Do you have any links that you'd recommend that I visit to learn how to make these calculations?

Thanks!

The Guide Number is the most basic of flash calculations. Unfortunately the automation which is availalble in flash output has created generations of technical know-nothings among the user community, whereas everyone had to know it in the distant past. Hard to find kids who know how to drive cars with manual transmissions, too! I just learned in the days when you needed to know more

The Guide Number is often provided by the manufacturer, and it assumes the 'standard reflector' coverage angle and not other modifiers on it. (Speedlights with zoom heads now give the narrowest coverage angle, so the GN is more impressively high. which is how we have flash units with higher GN values which have LESS power than flash units with lower GN values (e.g. 580EX vs. Metz 45) If a Guide Number is not given, you can easily compute it if output results are reported:

Guide Number = Aperture * Light-to-subject distance

Wilt wrote in post #7162884
The web site says Guide Number 125. So you could shoot from 30' away at f/4 at ISO100 (standard reflector). Using 30mm FL on APS-C, from 30' you would capture a 15' x 22' area, plenty for even a crowd of 20 (two rows of 10)! Even allowing for -1EV due to umbrella or softbox usage, at 21' distance from light to subject you have f/4 across a 10 x 15' wide area seen by the lens.

1. Can you really take a picture of two rows of people at 4 apperture ?
2. I am afraid if you set the lights only 30' from the side with such a large group you might get uneven lighting.

Papa Carlo wrote in post #7165067
1. Can you really take a picture of two rows of people at 4 apperture ?
2. I am afraid if you set the lights only 30' from the side with such a large group you might get uneven lighting.

1. DOF is not an issue. And at 30' it is scarcely a difference in light intensity (at 33' vs. at 30')...about -1/3EV light at that distance.

2. The full scene width is 41 degrees, and single studio flash covers that very easily!

Wilt wrote in post #7165327
1. DOF is not an issue. And at 30' it is scarcely a difference in light intensity (at 33' vs. at 30')...about -1/3EV light at that distance.

2. The full scene width is 41 degrees, and single studio flash covers that very easily!

Well taking a group picture at F4 is something I never do. The facial features are very small already and you risk to get inrecognizable picture.

And are yo saying you are going to cramp 10 people in 3 feet line ?

Papa Carlo wrote in post #7165633
Well taking a group picture at F4 is something I never do. The facial features are very small already and you risk to get inrecognizable picture.

And are yo saying you are going to cramp 10 people in 3 feet line ?

30mm lens at 30' sees 15' high x 22' wide area in the APS-C frame....wide enough to fit 10 people across that space. If we use f/4, the DOF is 18'-82', so focus is not an issue. With the light at 30' and assuming a GN120, there is 0.3EV of light loss from 30' back to 33', where the second line of 10 people is standing. Because the AOV of the scene is 41 degrees across, a single light would span the entire group, but we can put two lights across instead, to provide more assurance of evenness of illumination across the front.
So I don't see a problem with that scenario, as you seem to be.
As for the facial detail concerns of yours, each face is 6" wide or 1/44th of the frame width, or about 72 pixels wide in that scenario (shot on a 50D), and that makes a head about 0.9" wide on a 16" wide 1280 x 1024 monitor. Lots of heads are quite smaller in examples posted on POTN yet no one complains about the size.

Where is the issue that I have missed?

Wilt wrote in post #7165776
30mm lens at 30' sees 15' high x 22' wide area in the APS-C frame....wide enough to fit 10 people across that space. If we use f/4, the DOF is 18'-82', so focus is not an issue. With the light at 30' and assuming a GN120, there is 0.3EV of light loss from 30' back to 33', where the second line of 10 people is standing. Because the AOV of the scene is 41 degrees across, a single light would span the entire group, but we can put two lights across instead, to provide more assurance of evenness of illumination across the front.
So I don't see a problem with that scenario, as you seem to be.
As for the facial detail concerns of yours, each face is 6" wide or 1/44th of the frame width, or about 72 pixels wide in that scenario (shot on a 50D), and that makes a head about 0.9" wide on a 16" wide 1280 x 1024 monitor. Lots of heads are quite smaller in examples posted on POTN yet no one complains about the size.

Where is the issue that I have missed?

Ok Let's start from the very beginning so we would not have to return and reread what was written above:

One normall sets the strobe at the side of the group. Of course you can set it directly in front and blast at the subject faces, but who would wants such a shot ? So let's say you set the strobe at 45 degress at 10 meter as you said.
and another strobe for a fill in front. Since the fill is much weaker let's just omit it.

You need to give at leas 2 feet ( 60 cm ) to each person in the group. That means for 10 people you have 6 m from side to side.
Take some simple calculations and you'll see that if the closest person is at 10 m then the farthest one is at 14.7 m So the last person will get 0.46 of the light the first person does. That is more than a stop and is going to show up on the photos.

About the aperture. Not sure what lens you use but at F4.0 at the very edge of the frame as you pushed it to the limit the IQ loss (CA, light falloff, loss of sharpness) is going to be very noticeable for many with exception of the most expensive lenses.

Papa Carlo wrote in post #7172449
Ok ... you set the strobe at 45 degress at 10 meter as you said....Take some simple calculations and you'll see that if the closest person is at 10 m then the farthest one is at 14.7 m So the last person will get 0.46 of the light the first person does. That is more than a stop and is going to show up on the photos.

About the aperture. Not sure what lens you use but at F4.0 at the very edge of the frame as you pushed it to the limit the IQ loss (CA, light falloff, loss of sharpness) is going to be very noticeable for many with exception of the most expensive lenses.

Ah! now I see your point. Yes, if you set it up as stated, that can be a problem because of falloff due to increasing distance across the group. Two mitigating methods to deal with that...

1. Set the main in a softbox and rely upon the edges of the light from the softbox and the lesser output to handle the part of the group closest to the light, 'feathering' as shown in this illustration that I put together a few years ago...