Olympus XA4 focusing

erickim228

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Just another question with XA4. If I set the focus scale to 3m, will it focus from 3m to infinity? If so, what happens if I set it to 1m or 1.5m? Will that focus from 1m,1.5m to infinity?

Eric
 
My XA4 shoots at F5.6 and above at normal distance (5m and above) and shoots wider when set at smaller distances.


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Just another question with XA4. If I set the focus scale to 3m, will it focus from 3m to infinity? If so, what happens if I set it to 1m or 1.5m? Will that focus from 1m,1.5m to infinity?

Eric

Hi,

At 3m it focuses on 3m and the DoF you get depends on the aperture but you don't know this as it's a program mode camera. On page 33 of the manual you'll find an exposure chart and looking at it should give you an idea of the aperture's used in normal circumstances, depending on the film speed of course.

Having typed that I thought about the worst case; it's a 28mm lens with a widest aperture of f/3.5 so at 3m you'd get roughly 7 ft to 16 ft as your DoF. I'll guess that the ∞ setting covers about 12ft to ∞ based on the hyperfocal distance at f/3.5. (Also guessed from reading page 11 of the manual.)

I'm guessing as the XA4 manual says the CoC is 0.01mm and that's not what DoF charts normally use...

I also guess/hope you've used the XA4 and suggest you look at old prints to see how it turns out in practice as you used it.

Regards, David
 
No, it means you've focused at 3m. From there it will depend upon the aperture selected by the camera just how much depth of field you have on either side of that. With a 28mm lens, there's going to be a lot, even at f/3.5. The XA4 has two program modes, with close-up shots being limited to f/5.6 to ensure adequate DOF (source: http://www.cameramanuals.org/olympus_pdf/olympus_xa4.pdf )

If you're really curious, use one of the online DOF calculators and you'll see how it works.
 
So if I want to make sure that the camera selects smaller aperture, I would need to increase the ISO to 800+ even in a broad daylight?
If I set the scale to infinity, will it focus from approx. 3m to infinity?
 
Shooting faster film (or pushing) will, on balance, offer smaller apertures.

Read the manual I linked to to understand the XA4 program parameters, and go here to fool around with DOF at different apertures: http://dofsimulator.net/en/ . All the information you want is easily available, so there's no need to guess.
 
So if I want to make sure that the camera selects smaller aperture, I would need to increase the ISO to 800+ even in a broad daylight?

It is a film camera, which means that changing the ISO setting on the camera DOES NOT change the sensitivity of the film. The ISO must be set to match the film loaded.

If I set the scale to infinity, will it focus from approx. 3m to infinity?

NO!!! That is not the way to do things.

If you set the scale to infinity, only things at great distances will be in focus. Some things closer might be adequately sharp depending on what f/stop the camera selects, what size print you make, how sharp the film used, and how demanding your opinion of what is sharp. Setting the focus to infinity will "waste" 2/3rd of the depth of field as DoF extends about 1/3 in front (closer) than the point of prime focus and 2/3rds behind.
 
the xa4 was meant to be a small p&s, when you open the front it defaults to the 3m and even at f/3.5 most thing will be relatively in focus.
only change the distance when you know you're shooting something reallt close or really far
 
the xa4 was meant to be a small p&s, when you open the front it defaults to the 3m and even at f/3.5 most thing will be relatively in focus.
only change the distance when you know you're shooting something reallt close or really far

Correct, you'll probably find that DoF, even at its widest aperture, is adequate for subjects from 1m to infinity if you only make the standard (for the XA4's day) 4x6" print. If you are printing "enlargements" or scanning and pixel-peeping then you'll find that more careful adjustment of the focus is desirable.
 
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