Profile pictures in low light

gossamer

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My first attempt at this post failed to get posted properly for some reason (despite "draft saved").

I have a D500 with a 14-24mm f/2.8 and an SB-700 in TTL mode and trying to figure out the best way to navigate environments with very low light.

This picture was taken in manual at f/4 ISO 1250 1/160th and was still slightly underexposed. The main problem is the boy in front is somewhat soft, presumably because of the DoF at f/4. I'm already starting to see some noise at ISO 1250, so really don't want to go beyond that.

Ideally I'd like to take the shot at f/2.8, of course, but it also means a much more shallow DoF and would result in an increase in softness.

You can really see the focus point in the picture is the man. Perhaps if I had set the focus point on the woman it would been less soft both in the area in front of and behind her?

Hypothetically speaking, if I took this shot with the family standing as they are, except with a wall directly behind them, would it have made any difference? Is this a matter of better understanding how this lens works, or perhaps increasing the flash exposure compensation?

I have the original NEF if anyone is interested.


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tirediron

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A wall would have made virtually no appreciable difference. It may be provided a very slight amount of reflected fill, but that's about it. In this situation, my recommended approach would have been to get them more on the same plane, and given that you've got a relatively low, white ceiling, fire the flash behind you, aimed at the ceiling (aimed up 45 degrees, facing to your back). If moving the people wasn't an option, than choice #2 would have been to use a single AF point and focus on the middle of the group (Women's chest area) as this will middle the DoF and give you the best average.
 
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gossamer

gossamer

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Yes, thank you. I just simultaneously updated the post to ask that question about focusing on the woman to give me the middle DoF.

I think I need to use a DoF calculator for this lens and study and memorize these values.

Would increasing the flash exposure have given me the ability to keep the ISO the same and choose an f/5 or so aperture to increase the DoF?

Thanks for your help, as always.
 

tirediron

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...Would increasing the flash exposure have given me the ability to keep the ISO the same and choose an f/5 or so aperture to increase the DoF?
Assuming the flash had more light to give, then yes. I've not used the SB700, in that scenario, with an SB600, I think I would have been shooting more like f5.6 @ ISO 800 at most, so I don't think you were any near maxing out the flash.
 

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I have a D500 with a 14-24mm f/2.8 and an SB-700 in TTL mode and trying to figure out the best way to navigate environments with very low light.

This picture was taken in manual at f/4 ISO 1250 1/160th and was still slightly underexposed. The main problem is the boy in front is somewhat soft, presumably because of the DoF at f/4. I'm already starting to see some noise at ISO 1250, so really don't want to go beyond that.

Ideally I'd like to take the shot at f/2.8, of course, but it also means a much more shallow DoF and would result in an increase in softness.
Your speedlight should be able to do iTTL, which takes the guesswork out of it. A small pre-flash is reflected back to the camera, which then measures the exposure, and sends a corrected signal back to the flash which then flashes at the power setting that is needed to produce a good exposure. This feature will work even when you bounce the flash off a nearby surface, such as the ceiling or wall.

My next recommendation is to set your aperture to give you the depth of field (DOF) that you need to get your subject(s) in reasonable focus. I have downloaded a DOF app on my phone so I always have that available. You should carry a tape measure so if you ever need to measure distances, you will have that, too.

Next; the shutter speed will be practically irrelevant, unless you are using ambient to capture the background, for instance. The exposure illumination will be the flash, which is pretty fast.

Next; stop fiddling with your ISO setting. I usually leave mine set to "auto". It will be what it will be.

So when you've got a small family group, have a look at the side of the group to see how "deep" it is. You can measure them, or measure out a place on the floor and put a strip of tape, or chalk line, or whatever they will need to line up within your pre-established DOF.

If one person steps too far forward, just ask him to step back half a step and get the group to "get close".

Select one fairly central "edge" to focus on, such as the lady's sleeve in the group above.

Should be good to go.
 
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Hypothetically speaking, if I took this shot with the family standing as they are, except with a wall directly behind them, would it have made any difference? Is this a matter of better understanding how this lens works, or perhaps increasing the flash exposure compensation?
A wall behind them would have no bearing on the exposure (unless you meter ambient light on the wall surface, which you wouldn't do anyway).

On the other hand, a wall behind YOU would make all the difference in the would, photographically speaking. That is what you use for the modifier, or perhaps a wall to the side of your subjects would be even better. Sometimes the ceiling is better, but then the light is really too high for modeling your subjects.

Yes, you can apply exposure compensation, but you really have to have a good handle on regular flash before you start making adjustments like that.
 

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F/5.6 and a slightly different focus point might have helped.
 

Derrel

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Your f/stop and shutter speed and ISO value gave you a fairly good ambient light exposure, but perhaps you could have dropped the shutter speed significantly and lowered the ISO value and closed the lens diwn to 5.6 or 6.3 and you would have gained quite a bit of depth of field, while still maintaining the same ambient light exposure
 

JBPhotog

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FWIW, F2.8 is too shallow a DoF for this kind of event work. With a 14-24mm at 14mm on a DX body(21mm equiv.) @1 meter from the subject you have less than 2 feet(61 cm) of hyperlocal DoF. Take a look at your EXIF for the actual focus distance of this shot. You'll get 94 cm at F4 which may work but your focus point must be judiciously chosen as per your example, any closer than 1 meter and it only gets shallower. Picking a focus point on the females chin may have captured the young lad in the foreground, it depends on how tight they are as a group.

Be cognizant of reducing the shutter speed to capture ambient, too slow i.e. less than 1/60 and you may be subject blur depending on the ambient level. I wouldn't worry about noise for theses types of event shoots, you could employ in camera NR reduction but do some tests to see what is acceptable to you, of course shooting Raw you can turn this off/on in post. Working a higher ISO gets you the ambient so the backgrounds are not black.

An option for bounce flash in event work is use a 32" pop up reflector, point the flash up and back, hold the reflector with your left hand placing it behind your head so the flash skims your head and hits the white popup reflector. It'll bounce nice soft light onto your subjects in a butterfly fashion and being a known quantity, you get consistent results.
 

vintagesnaps

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And... flip the camera into vertical to eliminate the guy in the gray to the right and the woman's back in black to the left - they aren't part of the photo, they should be out of the frame.Then you wouldn't have had subjects' hands cropped off instead of in the frame. (Of course you can crop the photo but that won't put hands back in obviously.)

The people look fine, you got them all smiling, it's a matter of figuring out your flash and camera settings and framing shots. Next time go early and take some test shots, maybe of decorated tables, etc. before things get going.

Doing events takes practice to catch things as they happen. If you're going to keep doing events go to some in the community where attendees are allowed to bring in cameras and get in some practice. So you can figure out settings and timing and framing, etc.
 

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Does that camera+lens tend to have its depth-of-field basically straddling that focus-point with equal halves before and after the focus point, or does it tend to have say, the focus point leading the depth of field, with more of the focused area behind the focus point?

I ask because I assume if the camera+lens behaves a certain way, it might be necessary to bear that behavior in-mind.
 

JBPhotog

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Does that camera+lens tend to have its depth-of-field basically straddling that focus-point with equal halves before and after the focus point, or does it tend to have say, the focus point leading the depth of field, with more of the focused area behind the focus point?

I ask because I assume if the camera+lens behaves a certain way, it might be necessary to bear that behavior in-mind.

The focus points in the viewfinder indicate the “exact” place the lens is focussing. I have never heard of a cameras AF system focussing on the closest hyperfocal distance based on the f-stop.

Now some cameras front or back focus but that is not by design, that is due to errors in determining the correct focus distance. Many brands have ways to correct this using a focus target and making corrections which are then saved in the cameras memory for when that lens is attached.

Hyperfocal distance is 1/3 the distance in front of the focussed point and 2/3 behind it. This is an optical formula that applies to all lenses.
 

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Hyperfocal distance is 1/3 the distance in front of the focussed point and 2/3 behind it. This is an optical formula that applies to all lenses.

And that's why I ask these sorts of questions. That tells me that focusing on the woman might have resulted in the boy in front being sharper while still maintaining good focus on the man at the back of the group. Looking at how much background is sharp, both people and those ceiling ribbons, might even have focused on the boy to result in the whole group remaining sharp.
 
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gossamer

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Thank you all so much for your feedback. So much to learn.

I'm currently using matrix metering mode, which appears to work best in these environments where there is little light, and light that varies greatly from one area of the frame to another. Is that correct? Using matrix metering also enables the BL, or balanced fill-flash, on the SB-700. I'm currently also using iTTL mode.

The points I was trying to make about having a wall directly behind the subjects was regarding the depth-of-field focus area. Isn't the in-focus area of the center area of the picture dependent upon there being some area behind the center? I don't understand why sometimes I can produce a picture at f/2.8 that's in-focus throughout the entire picture, and not in focus when taken a certain focal lengths but not others.

There was a suggestion that I should have taken it at f/5.6 with ISO 800. I'm almost never able to get a nice blurred background in the picture when taken at anything beyond f/4 and I don't know why. Doesn't it really depend on the lens? Or was the comment made without the expectation of getting a blurred background, instead only that it be fully in focus?

My last question is about the comment that I should have lowered the shutter speed. This might deserve a separate post, but I'm confused here too. Every time I lower the shutter speed below 1/160th, there's motion blur. The flash is supposed to stop motion, but I don't know what I'm doing wrong that it doesn't do that. Even at 1/160th, if there's significant motion in the picture, it will show at least some motion blur.

I realize these are somewhat novice questions. I'd appreciate it if you had any input or could direct me to specific docs/videos/info that helped me to understand.
 

Braineack

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At that focal length, shooting at 2.8 still wouldn't help with the bg that much. you best best would be a longer lens.

upload_2020-2-2_13-59-49.png


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I knew from my distance/focal length that some people not perfectly on the same plane as the B&G would be slightly OOF using 2.8 here, but I was okay with that.
 

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