A simple lighting question-

[ewick]

So I am going to test my question tomorrow eve. so don't think I am only looking for an easy answer. I just want to know what I should expect. So this is my question: I am going to be using my alien bee 1200 tomorrow (shooting female portraits)night with my 18-105 kit lens and I know that when using strobes the shutter controls ambient light, but if I shoot at 3.5 with a shutter speed of lets say 50 will I get camera shake? Also my ISO will be at about 1250 so as to not get a lot of noise. Also if I shoot with my 85 1.8 D at F8 will I be abler to get shallow DOF? Thanks for any info and like I said...Planning on putting my question to the test tomorrow night. Thanks every body.

 

[Derrel]

Ummmm...a few things seem very amiss: ISO 1,250 with flash???? At "normal" ranges with a powerful monolight, think shutter speed of 1/160 at f/11 at 15 FEET or so...that is a POTENT monolight...so, f/11 at 1/160 at 15 feet is gonna be with like, ISO 100...

The flash durations will be VERY fast...camera shake will not be a factor.

Be prepared to shoot at 1/2 to even as low as 1/8 power at ISO 100, at f/8 to f/11.

Shallow DOF??? Ummm, "maybe", a bit....with the ISO at maximum low, and the flash at its very lowest power level, and moved back a ways, you mighty be able to get the flash power low enough to shoot at say, f/4.

 

[MLeeK]

No. Flash stops motion.
With an AB1200 why would you need to be at ISO 1250? you have a lot of power in that strobe
DOF is dependent upon 2 things: Distance to the subject (either by foot or by zoom) and aperture. Not by the maximum aperture of the lens, by the aperture you have the lens set at. So, at f/8 you would need to be considerably closer to the subject than the subject is to the background. Simply reduce your ISO and use a wider aperture if you need a shallower DOF.

 

[Village Idiot]

The flash durations will be VERY fast...camera shake will not be a factor.

No. Flash stops motion.

Unless enough ambient is introduced into the exposure to affect the photo and the shutter speed is slower than the camera's focal length (generally). A photo taken uses flash is a photo with two exposures after all, ambient and flash.

 

[Derrel]

The flash durations will be VERY fast...camera shake will not be a factor.

No. Flash stops motion.

Unless enough ambient is introduced into the exposure to affect the photo and the shutter speed is slower than the camera's focal length (generally). A photo taken uses flash is a photo with two exposures after all, ambient and flash.

Well, his original premise is...designed to "test" his preconceived concepts, which are I must say, a bit odd, to put it mildly...AlienBee 1200. ISO 1250. Night-time portraiture. In search of shallow depth of field with an 85mm lens at f/8. Thinking about shooting at f/3.5 at 1/50 second at ISO 1,250, with an Alien Bee 1200.

Ummmm, there's just so,so,so much "askew" with the original post that the replies to it are going to be shall we say, off-the-wall, and also reflective of the original distorted "reality" the OP planned "to test". Know what I'm sayin????

 

[kathyt]

The flash durations will be VERY fast...camera shake will not be a factor.

No. Flash stops motion.

Unless enough ambient is introduced into the exposure to affect the photo and the shutter speed is slower than the camera's focal length (generally). A photo taken uses flash is a photo with two exposures after all, ambient and flash.

Well, his original premise is...designed to "test" his preconceived concepts, which are I must say, a bit odd, to put it mildly...AlienBee 1200. ISO 1250. Night-time portraiture. In search of shallow depth of field with an 85mm lens at f/8. Thinking about shooting at f/3.5 at 1/50 second at ISO 1,250, with an Alien Bee 1200.

Ummmm, there's just so,so,so much "askew" with the original post that the replies to it are going to be shall we say, off-the-wall, and also reflective of the original distorted "reality" the OP planned "to test". Know what I'm sayin????

Yeah, we need to just scratch the "test," and start with a clean slate here. A good starting point here would be iso 100, ss 1/150ish, f10ish and adjust from there. This is were I generally put my settings when I set up with strobes.

 

[Derrel]

>>SNIP>Yeah, we need to just scratch the "test," and start with a clean slate here. A good starting point here would be iso 100, ss 1/150ish, f10ish and adjust from there. This is were I generally put my settings when I set up with strobes.

Hmmm...your suggestion sounds awfully, suspiciously,weirdly,eerily, similar to my suggestion of "1/160 at f/11 at 15 FEET or so...that is a POTENT monolight...so, f/11 at 1/160 at 15 feet is gonna be with like, ISO 100..."

Hmmmm...you be copyin' me girl???? lol

 

[amolitor]

Has anyone ever seen Derrel and Kathy in the same place, at the same time?

No? No? Anyone?

I KNEW IT!

 

[Village Idiot]

The flash durations will be VERY fast...camera shake will not be a factor.

No. Flash stops motion.

Unless enough ambient is introduced into the exposure to affect the photo and the shutter speed is slower than the camera's focal length (generally). A photo taken uses flash is a photo with two exposures after all, ambient and flash.

Well, his original premise is...designed to "test" his preconceived concepts, which are I must say, a bit odd, to put it mildly...AlienBee 1200. ISO 1250. Night-time portraiture. In search of shallow depth of field with an 85mm lens at f/8. Thinking about shooting at f/3.5 at 1/50 second at ISO 1,250, with an Alien Bee 1200.

Ummmm, there's just so,so,so much "askew" with the original post that the replies to it are going to be shall we say, off-the-wall, and also reflective of the original distorted "reality" the OP planned "to test". Know what I'm sayin????

I just sounds that at 1,200 ISO, a slowish shutter speed and a slightly wide aperture, it's a recipe for ambient bleed unless the OP is shooting in some place that's completely dark.

With a 640 w/s strobe and aiming for a shallow DOF, he should be shooting at the lowest native ISO and using an ND filter and a bright ass flash light so he can focus. A Bee that powerful is not going to be very dim at the lowest setting and he's going to be fighting with the magenta colorshift at those power levels.

 

[Derrel]

^^^^^^^^^Diz-actly!^^^^^^^^^^^ The original premise was so,so fraught with...well..."issues"....

 

[gsgary]

I say leave him to it he will soon have the answer

 

[Village Idiot]

I say leave him to it he will soon have the answer

Probably the best idea. It sucks if you're shooting someone with a purpose other than learning and you make them stand there while you're figuring out what you're doing, but actually trying it is probably the best thing to do. Also, I find unless I need the big guns, speedlights work better for single person photography in the dark because you can turn them down so low and you don't need all that much power in the first place.

 

[unpopular]

I think a good starting point would be f:11 at about 12' and 1/160s ™

 

[Mike_E]

Take a pure white terrycloth towel, bunch it up and shoot that until you don't get any blinkies and your shadows look OK.

You Do remember that your shutter speed is useless unless you want some ambient light in the shot, right? Set the aperture and ISO you want and adjust the strobe until get it.

 

[unpopular]

^^ Only I'd say pull the shadows in post.