focal points canon
Sep 22, 2022 08:51:19 #
lmTrying wrote:
You just mentioned something that I have often wondered about, plane of focus, or arc of focus. Lenses are spherical. If you stretch a string from the lens out to the focal point, it will not define a flat plane. I have noticed that the people on the ends of a long line tend to get distorted. Distortion or focus?
Focus.
The plane of focus follows an arc, even if you don't move the camera.
Lets try this without a visual....
If you focus at 10 feet directly in front of you, then rotate the camera, the plane will still be ten feet in front of you,
People on the ends may actually be 15 feet from you, therefore behind the plane of focus.
It's more noticeable if the depth of field is small, as there are actually three planes: 1) the focus point plane (center), 2) the far depth of field limit (back) plane, 3) the near depth of field limit (front) plane.
If you can use a large depth of field, more will be in focus in the range of focus (depth of field) arc, which is a band.
Did that help?
Sep 22, 2022 09:02:10 #
Longshadow wrote:
For odd number of rows I figure who is in the center of the middle row and focus on them.
For two rows I lock focus on the 2nd or 3rd person to the left of the "center" person and recompose. That way the actual focus should be approximately between the two rows. If four rows I use the 2nd or 3rd person to the left of the center person in the second row. (The plane of focus always follows an arc.)
(I always use single spot focus, for everything, just picking my focus point.)
For two rows I lock focus on the 2nd or 3rd person to the left of the "center" person and recompose. That way the actual focus should be approximately between the two rows. If four rows I use the 2nd or 3rd person to the left of the center person in the second row. (The plane of focus always follows an arc.)
(I always use single spot focus, for everything, just picking my focus point.)
The focal plane is an arc for a simple lens. Most camera lenses are complex and part of that complexity is creating a fairly flat focus plane to focus on a flat sensor. If the focal plane was curved you wouldn’t be able to focus and recompose. Now generally the cheaper the lens then less successful it is at creating a flat focal plane. Even so they’re usually fairly flat except at the edges and corners where sharpness falls off. Macro lenses maintain a very flat focal plane across the entire image, one reason they’re usually more expensive.
Sep 22, 2022 09:15:22 #
SuperflyTNT wrote:
The focal plane is an arc for a simple lens. Most... (show quote)
Key operator: fairly flat
Focus in the middle of something tall, then rotate the camera upwards towards the top of that item. with a small depth of field, the top may be out of focus. eg. focus on someone's belt buckle then move (recompose) up to the face. The lenses can correct some, but not all.
Sep 22, 2022 09:44:15 #
Sep 22, 2022 09:45:11 #
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Sep 22, 2022 09:54:35 #
MS. DONNA wrote:
thank you
Hint: If you use "Quote Reply" people will know to whom you are referring.
Sep 22, 2022 10:43:17 #
Sep 22, 2022 11:09:56 #
Sep 22, 2022 11:12:31 #
thanks I will be on the beach near Destin,,, hopefully ,,,( watching the tropics ugh )
Sep 22, 2022 11:35:03 #
MS. DONNA wrote:
How many focal points do you choose when you photograph a family or groups of people ( 8 to 10 )
5d markiv canon
5d markiv canon
As a starting point, I pre-plan my approach. Where will they be? How many rows? Can I compose them as a pyramid on three levels in three rows (for example). How deep is that composition on site?
I'll plug my answers into DOFC, my iPhone/Mac depth of field calculator, and arrive at my answer.
Here's an example of one I did recently. I had to photograph 10 people. I had three of them sit in chairs. Four of them stood behind those chairs. I had three more stand behind them, ON CHAIRS. The depth of the scene was roughly nine feet. The width of the scene was about nine feet. The second row was about three feet back from the first, and the third row was about three feet behind the second. The first DOFC screen shot shows WHY I did what I did.
I only had my 30mm macro lens with me, which is 60mm in full frame equivalent terms. So I had to back up to 17 feet from the second row to get it all in. I chose an aperture that gave me enough depth of field to focus on the eyes of the people in row 2 and still have the front and back rows in focus.
I used a SINGLE focal point.
..😁 😁 😁 Far limit of DOF is 27.1 feet so back row is no farther than that.
😁 😁 😁 😁 I focused on row 2 at 17 feet
..😁 😁 😁 Near limit of DOF is 12.4 feet so front row is no closer than that.
17 feet from camera to second row
>>> 📷 <<<
I also plugged in a scenario for a Canon 5D IV using a 50mm lens to give you a sense of what I would do with that.
Sep 22, 2022 12:14:58 #
MS. DONNA wrote:
the one focal point is what i needed to know there are so many I normally shot birds in flight and use spot metering and would like to learn more on families and people
Consider Evaluative Metering as it is the most widely used metering for a vast majority of photography. Spot metering and the other metering modes are for special uses.
Sep 22, 2022 12:36:19 #
John O. wrote:
Consider Evaluative Metering as it is the most widely used metering for a vast majority of photography. Spot metering and the other metering modes are for special uses.
Yes, but it also depends on the background. A lot of bright sky may throw it off.
Sep 22, 2022 12:36:29 #
MS. DONNA wrote:
one? put one middle person? and everyone will be in focus ?
Its a matter of DoF. Adding more focus points does not increase your DoF. One focus point allows you to place it wisely. Multiple points is out of your control.
There are variables to arranging a small group. All standing or front row seated ? Camera elevated or eye level ? Rows curved or straight ?
Such variables do affect how much DoF youll need but, as a rule, youll need all you can get.
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Since this is a controlled situation, you can take an extra minute to bracket the focus. I would focus on the front row. Then, without adjusting focus, step forward about five inches. Then another five. That should be enough. Multi focus points would not accomplish this for you.
TAKE MANY PIX at each focus. Subjects blink, twitch, etc much more than you may realize.
Do a reeeeeeally good job, lest you be embarrassed by the cell phone snapper standing next to you !!!!!
Sep 22, 2022 12:44:35 #
Haydon wrote:
I'd recommend two rows and try to have every face on the same focal plane.
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