SharpShooter Loc: NorCal

I see countless references to using re-composing(r-c) here on UHH and something on it almost every day!
So, does it actually work? Lets have a discussion about it's pros and cons. I believe that there are many here that use it to mixed results but write it off as the camera focus being inconstant or miss-ficus. Of course with a WA lens at 10 feet distance the lens is probably at infinity.
What about with say a 50mm at 1.4, indoors in low light where many of us use that technique.
I personally have given up using r-c because of very poor and disappointing focus results and now use cameras with lots of Focus Points(fp) and use a corresponding fp with almost 100% reliability in sharp focus.
Let me explain my very unscientific test. The results were pretty obvious and predictable based on my personal experiences with r-c.
I shot 3 frames. I had repeated each shot about 5x for consistency.
I have frame 1,2 and 3 with 2 targets in each.
The left target is L. The right target is R.
The poles are 24" apart. I was about 6 feet away using an 85mm f1.8 prime shot wide open at 1.8 using a FF. I also used the same left side focus point for each of the tests.
Frame 1 is a control. I manually focused on L using Live View.
In 2 I did the same using AF.
In 3 I did the same using AF on L but with focus locked, I then r-c and put the fp over target R.
In frame 3 neither target is in focus, do to the shift in the plane of the sensor even though the same FP is actually dead focused on L. And in frame 1 and 2, target R is OOF.
This represents the way many use a fast lens indoors especially to shot a portrait of two people.

If it makes any difference these shots are SOOC except for a very minor brightness adjustment to even out the light in all the frames. All exif data is intact.
I did resize them down about 50% to make them more loading friendly but less sharp!!

Feel free to shoot some examples of your own and post them, especially if you are getting different results than my own. Maybe we can all learn a little about r-c since we recommend it so often!! ;-)
SS

Frame 1, Manual focus using LV on L

(Download)

Frame 2, AF on target L

(Download)

Frame 3, AF on target L, then r-c over R

(Download)

mcveed Loc: Kelowna, British Columbia (between trips)

I have no idea what you are trying to prove. In frame 1 and 2 the dollar bill on the silver pole is out of focus and the one on the black pole is sharp. This is understandable since you were focused on the one on the black pole and the one on the silver pole is further from the camera. It is very simple to measure the size of the image of the dollar bill on both poles and find that the one on the silver pole is smaller. In frame 3 neither of the dollar bills are sharp but the one on the silver pole is sharper. And the clamp on the silver pole is definitely sharper. So, I'm curious as to what you were trying to prove.

Rongnongno Loc: FL

No need to re-experiment on my side I was aware of the (r-c) problem long ago and mentioned it several time... To a deaf audience.

Maybe they will not be blind too.

I will likely refer folks this to this thread when it comes up again... (book-marked it)

SharpShooter Loc: NorCal

Hey..., at least we're talking!!! :lol:
That's what I want!!! ;-)
SS

Kmgw9v Loc: Miami, Florida

You are so far ahead of everyone.

SharpShooter Loc: NorCal

Wrongy, I won't call it a "problem".
But we do need to understand if there could BE a potential focus problem and understand it.
It's understanding that makes us better photographers! ;-)
SS

rpavich Loc: West Virginia

My camera only has a center focus patch so I HAVE to focus and recompose :)

RWR Loc: La Mesa, CA

I'd never given the subject a thought til now, but I only compose once, to take the picture - after I've set my focus and f/stop for the desired depth of field. Or am I missing something here?

rpavich Loc: West Virginia

I think so.

Focus-and-recompose just refers to focusing using the center point, and then reframing to make the composition more pleasing.

Example: you take a head and shoulders portrait of someone, and of course you want the closest eye to be most sharply in focus. You put the dot on his/her eye, focus, and then you recompose to frame them in a pleasing way. Because of that reframe, the focus point has shifted some. It's unavoidable. I've trigged it out before using 10 feet from the subject and 18" from the eye to the center of the chest on a reframe and it's amazing how much that focus point shifts. it can turn a tack sharp focus into mush.

BebuLamar

That is why I like to manual focus using the plain ground glass and not the center split image or using a range finder camera. I now use multipoint AF and if it doesn't work I focus manually. I hate the focus and recompose thing.

Howard5252 Loc: New York / Florida (now)

If by "Re-compose" you mean focus on what you want to be sharp (let's say an eye), have the camera keep that focus as you move the subject within the frame (w/o changing the distance to the subject). If that's it ... what is the purpose of the discussion? THAT I missed.

rpavich Loc: West Virginia

You have the general idea. What you MIGHT have not realized is that when you recompose, the focus point shifts forward or backward putting that eye out of focus now.

The purpose of the discussion is to make folks aware of this issue, if they haven't before.

Some folks say "how come my portrait is out of focus?" and nobody can pinpoint it because the person may not mention that he/she used focus and recompose or may not even realize that they SHOULD mention it. If now that they know this, they'll take steps to avoid that issue in the future.

Rongnongno Loc: FL

Unless you pre-focus on a tripod with the lens nodal point set you change the distance. In other words, you introduce a parallax error, simple as that.

The op purpose is to illustrate the problem (not a problem for SS, just an inconvenience) and make us aware of it.

RWR Loc: La Mesa, CA

I do point my camera at different parts of the scene to check focus, but considering that as "composing" is a new one to me.

oldtigger Loc: Roanoke Virginia-USA

looking closely at your results, the technique works exactly as anticipated and is effective so what is the problem you seem to be suggesting?