How to compose your pics with a Rangefinder at wide aperature F2 or F1.4 ??

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alfcnka

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Hi,

If you were to position your subject at one corner yet shooting at F2 or F1.4 how would you do it?

As we know the center rangefinder patch merges and indicates focus sharp. But when you compose and position your subject at one corner, the subject in picture turns our blur due to wide F2 or F1,4 !

Whereas a SLR, you can focus and view and focus the subject at one corner sharp before you click the shutter. But for Rangefinder......??

So how should i move? Move the camera? move my whole body?
 
Don't turn the camera (or head) but shift the camera slightly. Works well with 50/1.0 at not to close distance (down to ~3m).
 
You mean i have to take a few step sideways and remain parallel to my subject ?

Anyone done it before ? Any pics to show if this Side-Step theory works ?

thanks mate.
 
I have actually seen an illustration on the web with a clear description why and how it works (but can't find the link anymore ...). Usually you just have to move your camera slightly.
 
if you're focused at or near minimum focus, you won't need to take any steps to get the subject in the corner or near the edge. farther than that and you'll have more leeway, so a couple steps probably wouldn't hurt (or just recomposing).
 
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i just focus and recompose, I've never given it much thought, and it seems to work just fine for me even at 1.4.
 
Focus, pan, compose, snap, hope. That's it. This element of rangefinder focusing is one of the weak points, but with enough practice you should be ok.

Here is an example at f/2. While not completely to the left side I still used the technique described above.

406368195_76d25d1178.jpg


Happy hunting!
 
tmfabian said:
i just focus and recompose, I've never given it much thought, and it seems to work just fine for me even at 1.4.
Click to expand...

Same here. At 1.4, I usually give up on absolute sharpness. It will be sharp enough in relation to the immense oof within the entire composition.
 
Is this not about curvature of field? You could try deliberately misfocussing if you know how much of that is needed.
 
alfcnka said:
As we know the center rangefinder patch merges and indicates focus sharp. But when you compose and position your subject at one corner, the subject in picture turns our blur due to wide F2 or F1,4 !
Click to expand...

Actually, when you do the math, there is no problem, DOF takes care of it, unless you have a very very fast wide angle. The longer the lens, the smaller the angle of error.

So just focus and recompose, the shift of the focus will be covered by DOF.

Also, use the old 1/3rd - 2/3rd DOF rule (don't focus in the middle of the desired DOF range).

Like Roger indicates, field curvature of some lenses is often more of a problem.

Roland.
 
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This is not a problem. I am used the SLR fast lenses for such situations, so switching to a RF does not make things more complicated.
 
JohnL said:
Isn't it actually lenses with a "good" flat field that give more of a problem in this respect?
Click to expand...

Depends which direction the curvature goes. If it is concave towards the camera (most lenses) you are right. But some lenses make it worse.

Roland.
 
Quite simple: you center subject, measure focus to the front of the nose, NOT the eyes! turn and shoot and the eyes will be in focus.

Why? Assuming your lens of a flat field lens (as good lenses are), then by turning and not refocusing you will keep a plane in focus that originally contained the nose, rather than the eyes (which you want in focus after the turn). This turned in-focus plane rotates to land a wee bit behind your original nose focus when the head is at the edge of the frame. And most likely it will now reach a bit further to make the corner subject eyes in focus.

Try and see, and if not convinced, draw yourself a diagram of that rotating plane of focus and find the distance between the 2 planes near the edge: just 1 inch or so.
 
OK. Let's take a practical example:

- the Noctilux 50mm/f1 wide open at 1m focus distance
- the FOV is around 46 degrees (across the diagonal)
- if you do a typical 1/3rd composition, you focus in the center and then rotate the camera by 46 degrees / 6 = 7.66 degrees.
- assuming that it's perfectly straight (which for the Noctilux, it's not ...) the focal plane will have moved to the back a little, and is now from the camera, at distance 1 m / cos(7.66 degrees) = 1.009 m.

Meaning, you have about 0.9 cm focus error. The DOF of the Noctilux at that distance is around 2cm and covers the error well.

Best,

Roland.
 
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This is an overkill. Photography is about having fun taking photos. It is not really a problem, as Roland's example shows.
 
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