DOF
Dec 16, 2019 07:26:07 #
Larz wrote:
A question begats a question. Doesn't using multiple focal points cause the autofocus to search and acquire constantly thus making acceptable focus in a group shot less likely?
AF generally focuses on the subject closes to the camera. When the shutter button is pressed, focus is set. For multiple-row groups, a smaller aperture will result in a sharper focus.
Dec 16, 2019 07:54:10 #
In my opinion, you are correct to go for sharpness first and worry about noise second. If you have a big group and you need to shoot at F7 to get everyone in focus, you will find that the noise usually "looks" better on a final product than blurry faces.
There are still two things that you can do to help, though.
1. Add Light.
If you are shooting a group, take the time to go ahead and set up a big flash and a cheap umbrella. If you don't have an umbrella then you can aim your flash at the ceiling. If you don't have a big enough flash, then just set up a bunch of light bulbs. (Be careful using different color bulbs, or you will end up with oddly colored shadows.)
2. Shoot slower.
A lot of cameras these days have pretty good image stabilization, if you have steady hands you will find that you can shoot as low as 1/80 without a tripod. If you use a tripod and turn the IS off, you can usually shoot group photos as low as 1/40 assuming everyone knows how to sit still. (If there are kids, all bets are off.)
There are still two things that you can do to help, though.
1. Add Light.
If you are shooting a group, take the time to go ahead and set up a big flash and a cheap umbrella. If you don't have an umbrella then you can aim your flash at the ceiling. If you don't have a big enough flash, then just set up a bunch of light bulbs. (Be careful using different color bulbs, or you will end up with oddly colored shadows.)
2. Shoot slower.
A lot of cameras these days have pretty good image stabilization, if you have steady hands you will find that you can shoot as low as 1/80 without a tripod. If you use a tripod and turn the IS off, you can usually shoot group photos as low as 1/40 assuming everyone knows how to sit still. (If there are kids, all bets are off.)
Dec 16, 2019 07:57:18 #
jerryc41 wrote:
AF generally focuses on the subject closes to the camera. When the shutter button is pressed, focus is set. For multiple-row groups, a smaller aperture will result in a sharper focus.
Thanks Jerry.
Dec 16, 2019 08:35:58 #
Larz wrote:
A question begats a question. Doesn't using multiple focal points cause the autofocus to search and acquire constantly thus making acceptable focus in a group shot less likely?
Depends on the mode. For this shot you wouldn't use continuous. You'd pick a face that was somewhere between the closest person and the farthest and select the focus point on them.
Dec 16, 2019 08:40:24 #
That's what I thought. As I shoot manual, that would be my choice and then use the other variables to obtain my desired depth of field and exposure.
Thanks.
Thanks.
Dec 16, 2019 08:49:12 #
billnikon wrote:
NO, lenses are curved, so even at 2.8 (which is wide open on many lenses) things on the edges of your frame may not be in focus because lenses are not flat, they are curved, so if the middle is in focus, the edges may or may not be, it depends on a lot of variables.
Optics is nutty sometimes. Not claiming expertise but I think in an ideal scenario it is the curved lens that forces the light to focus on a flat plane. Imagine the pupil of an eye in a group shot. Light from that point bounces everywhere and strikes everywhere on the surface of the curved lens, center, edges, everywhere. The curved lens system bends all those rays back no matter where they strike the lens to meet at one tiny point on the sensor. So it ends up that unless you have tilt lenses the sensor plane and the plane of focus in the world are parallel.
I get what you say about the edges though, I think those distortions are from real world lenses being imperfect. Thank you lens correction profiles.
Dec 16, 2019 09:19:52 #
A. T. wrote:
Hedgehog family,
My question is this......if you are on f/2.8, everyone on that same focus plane should be in focus, correct?
My question is this......if you are on f/2.8, everyone on that same focus plane should be in focus, correct?
The answer to your specific question is YES!
Now, unless you are talking about a f/2.8 lens that is a rather wide angle lens that would not be a wise choice for a stop (aperture). There would be very little depth of field.
For a lot of uses these days with digital I tend to stay between f/4 and f/11 even though some of my lenses cover f/1.4 to f/22. Often choosing f/5.6 or f/8. But that is all just generalities, for specific subjects or projects i'll choose the stop that gives me the depth of field I need and often little more as to get a blurred background on purpose.
Dec 16, 2019 10:00:57 #
tcthome wrote:
D500 is one of the best cameras out for ISO. What was the ISO set at ?
No it isn't. The D3S, D4 and D5 and the Canon 5DMkIII are WAY better for high ISO than the D500. Though for a crop camera, the D500 is pretty good with noise.
Dec 16, 2019 10:02:33 #
Larz wrote:
A question begats a question. Doesn't using multiple focal points cause the autofocus to search and acquire constantly thus making acceptable focus in a group shot less likely?
No.
Dec 16, 2019 10:05:09 #
Dec 16, 2019 10:07:52 #
mmcgavin wrote:
Don't forget to focus one third of the way into the depth of the subject so you use the DOF in front of the plane of focus.
This is a tired old myth that doesn't reflect reality. Using a full frame camera, the depth of field of a 50mm lens at F2.8 at 10 ft is 2.06 ft, with 45% (.92 ft) in front and 55% (1.13 ft) to the rear.
However, at 6 ft, the distribution of depth of field is 47% front and 53% rear. At 20ft, its 40% front and 60% rear. Only when you get to 33 ft, does the 1/3 - 2/3 rule apply. Change the aperture, and everything changes.
Dec 16, 2019 10:17:39 #
A. T. wrote:
Hedgehog family,
My question is this......if you are on f/2.8, everyone on that same focus plane should be in focus, correct?
My question is this......if you are on f/2.8, everyone on that same focus plane should be in focus, correct?
I suppose so, yes. But why would you choose f/2.8 for a group shot? If it's a large group there's virtually no way they will all be situated in the narrow plane of focus you get at f/2.8. You might get a nicely blurred background but some of the people will probably be out of focus too.
Dec 16, 2019 10:31:20 #
Larz wrote:
I don't understand why not. Could you explain please?
I turn on many focus sensors, sometimes as many as 51 on my D800/D810, or all 315 on my Sony RX10M4, but generally only using one active sensor to acquire focus. This allows me to designate any one focus point to acquire focus. Sometimes with really active subjects - little kids, dogs, birds in flight, etc - I may use Group Autofocus or it's equivalent in Sony-speak - to acquire a moving subject and keep it in focus. But this can fail, especially if there foreground stuff - the camera will almost always focus on the nearest object in the focus group. I tend to get better results with single point or Dynamic 9 point.
Dynamic AF is can be helpful sometimes, but I get better results not using Dynamic AF at all. If I focus on the head of a flying bird, I will not be happy if it refocuses on it's belly.
It's important to keep the number of focus points and the number of active focus sensors separate in your mind.
Dec 16, 2019 10:34:09 #
Kozan
Loc: Trenton Tennessee
A. T. wrote:
I thought so but wanted to get confirmation. I'm ... (show quote)
If you are taking groups, you probably want to be at F/7.1 to F/11. Those F stops will give a wider depth-of-field, and chance of someone being out of focus is smaller. Of course, that depends on how much light is available and how high you want to go with ISO. I tend to always use a flash, both indoors and out. The flash will give catchlights in the eyes. And you won't have to use such a high ISO.
Dec 16, 2019 10:34:22 #
Thanks Gene. I got a bit confused because in my head I was thinking of a posed group shot, not anything moving. Your explanation is very helpful.
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