STOP using Focus & Recompose

[Adam Filipowicz]

This is what i am trying to do. just inform those that are not already aware.

 

[User4286416121]

Great!

Opening title came off a bit strong. Have great weekend

 

[scokill]

I am not a beginner. this is why I am posting this for beginners to learn from it. it is a technique for any photographer to use or not. Knowledge is power.

A beginner that hasn't asked the question would not even know the term focus and recompose. Second, not sure I would give universal advice...like never shoot wide open, don't go above ISO3200, always use AFC and back button focus, only shoot RAW, ISO is part of the exposure [sorry couldn't resist]). If there is sufficient depth of field or very little difference in distance after recomposing that not really an issue at all.

 

[mamallama]

When your subject is to the right of the frame and you acquire focus it is a certain distance from your lens. when you recompose the focus distance on your lens hasnt changed but the rotation shifts the plane of focus behind where it originally was.

in this diagram the blue line and black line are same length (focus distance)

when recomposed the focus plan shifts back (indicated by pink horizontal line)

this example shows 20 degree rotation

And whether it really matters or not depends on the camera-to-subject distance.

 

[FrancoD]

I am not saying never use it.. just consider what it does.

All photography tecniques need to be considered.

I have many great photos using Focus and recompose, I am just recommending people try another technique to increase keepers

It may sound odd to you, but : STOP USING Focus and Recompose

means exactly : don't do it , (that is : never do it....)

 

[tcg550]

I've been focusing and recomposing for all of my photography life which goes back to film, pretty sure I won't be stopping.

 

[GodSpeaks]

I have used it all my life. going all the way back to the 60's when the only focus aid in the camera was in the center of the viewfinder. Focus and recompose was all there was.

Funny thing is, for all those years I used focus and recompose, OOF images was never an issue.

Trying to tell people to not use a tried and true technique is kind of silly. If YOU don't want to use it, that is certainly your call. Me, I'm sticking with focus and recompose.

 

[Mark_A]

Why isn't the focal plane a curve?

Because if you think about it, if it is flat and square to the sensor there will be points to the extreme left and right which are actually a lot further away from the sensor than points in the middle of the frame.

Mark_A

 

[tko]

Because in the case you illustrated, the photographer and model are probably swaying enough so the focus point has changed by the time the photo is actually taken. Instead, use continuous focus by assigning it to another button.

Tongue-in-check of course. In most cases you CAN focus and recompose and you CAN use one-time focus. Then is no need to STOP, just think about what you're doing.

The math:

If you focus and recompose from 5 feet away and the rotation angle of the camera to recompose is 15 degrees, the focus distance has changed 2 inches.

If you hit the focus button, and the model moves her head one inch and you sway by one inch, all before you the shot is actually taken, the focus distance has also changed 2 inches.

Actually, I've been a victim of the latter more often than the former. Half press the focus model, wait for the model to smile, press it all the way = out of focus image. You or her has moved. No, mashing the shutter button doesn't help, that leads to other problems.

Of course, if you focus and recompose, odds are you moved in space slightly as well, so focus and recompose is bad for two reasons.

The solution is to use the back focus button and pick the correct focus point to start with--but only if you need critical focusing.

 

[tko]

Good question.

As I understand it, there are two types of lenses. Ones with a flat focal plane and one with a curved one. The flat one is typically more desirable. You wouldn't want to take a photo a painting or wall and have the more far away elements out of focus, right? So, optical designers tend to design lenses with flat focal surfaces, but with varying degrees of success.

https://www.dpreview.com/forums/thread/1483611

 

[rurikw]

Good question.

As I understand it, there are two types of lenses. Ones with a flat focal plane and one with a curved one.

That sounds like curved focal surface lenses are deliberately designed that way, I doubt that's the case except maybe for fisheye? At least it would be very rare.

The flat one is typically more desirable. You wouldn't want to take a photo a painting or wall and have the more far away elements out of focus, right? So, optical designers tend to design lenses with flat focal surfaces, but with varying degrees of success.

That sounds more plausible. Optical limits mentions field curvature in their reviews and treat it as a potential issue.

 

[mamallama]

Good question.

As I understand it, there are two types of lenses. Ones with a flat focal plane and one with a curved one. The flat one is typically more desirable.

How would a flat focus plane work? If you focus on the center of a flat wall 30 feet high and 100 feet wide would the whole wall be in focus? After all, it is on a the flat focal plane, is it not?

You wouldn't want to take a photo a painting or wall and have the more far away elements out of focus, right? So, optical designers tend to design lenses with flat focal surfaces, but with varying degrees of success.

https://www.dpreview.com/forums/thread/1483611

--
no, I won't return to read your witty reply!
professional cynic and contrarian: don't take it personally
http://500px.com/omearak

 

[tamaraw35]

There are a lot of strong comments here explaining the merits of focus & recompose and how using it, or prefocus can be very helpful.

Instead of duplicating what has already been said, I would like to point out that no focus plane is perfectly flat. Depending upon the lens, it can often be quite curved, either in concave or convex shapes. This is called field curvature.

Finally, if you are experiencing issues where focus and recompose puts your subject out of focus, then either you are using too wide of an aperture for the technique, or you have recomposed too far away from your original focus point and should just start over.

 

[a_c_skinner]

Thank you, I'll need to think about that.

 

[rurikw]

Good question.

As I understand it, there are two types of lenses. Ones with a flat focal plane and one with a curved one. The flat one is typically more desirable.

How would a flat focus plane work? If you focus on the center of a flat wall 30 feet high and 100 feet wide would the whole wall be in focus? After all, it is on a the flat focal plane, is it not?

As an avid wall photographer I can testify that it most certainly would.

 

[a_c_skinner]

I think the diagram is not correct. It shows two subjects which are a different distance from the camera, not a single subject recomposed. The distance from the camera to a single subject does not change as the camera is turned. To illustrate this correctly the right hand subject needs to be removed and the blue line should go from the blue camera to the single remaining subject and will be the same distance as the black line. I fear this thread is therefore based on an incorrect line of reasoning, but I am as ever open to correction.

 

[rurikw]

I think the diagram is not correct. It shows two subjects which are a different distance from the camera, not a single subject recomposed. The distance from the camera to a single subject does not change as the camera is turned. To illustrate this correctly the right hand subject needs to be removed and the blue line should go from the blue camera to the single remaining subject and will be the same distance as the black line. I fear this thread is therefore based on an incorrect line of reasoning, but I am as ever open to correction.

The point is the right hand subject which is focused on but then the photographer turns because he doesn't want it centered thus moving the focal plane away from the eyes. It's rather the left hand subject that needs to be removed as it has no necessary function and obscures more than it clarifies. Otherwise it's just a simpler and clearer representation of the same thing illustrated in the OP.

 

[AnthonyL]

Good question.

As I understand it, there are two types of lenses. Ones with a flat focal plane and one with a curved one. The flat one is typically more desirable.

How would a flat focus plane work? If you focus on the center of a flat wall 30 feet high and 100 feet wide would the whole wall be in focus? After all, it is on a the flat focal plane, is it not?

Yes, exactly, you've got it. That is why all these clever lens engineers end up with expensive lenses so you get exactly as you describe. Some do it better than others and macro lens design in particular aims to get a very flat field and that is reflected in the cost.

How else do you think it would work? Arrange everyone in a circle so they are all in focus.? Try it.

 

[a_c_skinner]

I believed it to be incorrect and I still don't follow the logic but I've just spent less time doing the experiment than I've spent arguing about it and it seems to be a real phenomenon. So apologies and thanks in equal measure.

--
Andrew Skinner

 

[stephang]

Pending the OP's explanation to the contrary we can only assume that this is what shall be known as Trumpian agreement to future generations.