Wide f/1.4 aperture outdoors question?

[burstintoflame81]

I am going to be shooting during the day outdoors, and want to use a shallow depth of field with my f1.4. However, I can only shoot at a max of 1/4000th of a second. If that is still overexposed, am I correct in thinking that I could use an ND filter? That way I can retain depth of field but cut down on the amount of light? Would a polarizer help as well ( how many stops do they typically cut? ).

 

[matt62485]

depends, i think u can get them up to 3 stops but i may be wrong. u could still get pretty shallow DOF even at 2.0. so if u need to compensate some do so. or, use AP and do some exposure compensation

 

[burstintoflame81]

Yeah, I figured I might open just slightly to around 2. but it will be portrait work so I really want to make sure I have a good range on my Depth of Field and am not limited due to the environment. I have a circular polarizer and a 3x ND filter I could employ. Do polarizers have an adverse reaction to skin tones and stuff like that? I know they are usually used to cut reflection and brighten colors, but didn't know if they could be used for portraits too.

 

[Josh66]

( how many stops do they typically cut? ).

1-2, or something along those lines. You could always just stop down a little too... Most lenses perform their best stopped down a little anyway.

 

[matt62485]

( how many stops do they typically cut? ).

1-2, or something along those lines. You could always just stop down a little too... Most lenses perform their best stopped down a little anyway.

cool, thanks for clarifying that. not sure why i thought i saw one -3 the other day

 

[Josh66]

not sure why i thought i saw one -3 the other day

Are you talking ND or CPL?

I meant CPL. ND, you can get anything from 1 stop to 10 stops, probably more than that even.

 

[Dwig]

...am I correct in thinking that I could use an ND filter? That way I can retain depth of field but cut down on the amount of light? Would a polarizer help as well ( how many stops do they typically cut? ).

Yes, you need a neutral density filter if your images will be in color. A polarizer is, in addition to its polarization effect, approximately a 1 to 1.5 stop ND. Common ND filters come in 1, 2, and 3 stop increments. Stronger filters are available.

A typical sunny day (summer, middle latitudes) requires f/16 at 1/100 sec with ISO 100. That means that at ISO 100, you T1i's lowest ISO, and 1/4000 sec the proper exposure on a sunny day will require f/2.8. It would require a 2 stop ND filter to allow you to use f/1.4 and with that there would be no "extra room" to allow for a overly light subject. You should probably look for an ND that is at least 3 stops (ND 8x using factor notation, ND 0.90 using density notation, see Neutral density filter - Wikipedia, the free encyclopedia).

 

[jubb]

Make sure your ISO is on the lowest setting. I love using the lowest iso possible on all my shots anyways.