Friday, June 8, 2012

Some LX5 explorations on the billiards table

One of the great things about the LX5 optics is the f/2.0 lens.  I am curious how much background blur I could get with the aperture wide open, given that the LX5 has a small sensor compared to a dSLR.  I know I'll continue to explore that feature, but I did an initial look on our billiards table.  In the widest angle setting, I positioned the camera very close to the number 4 ball and selectively auto-focused on that.  Below is a side-by-side comparison of f/2.0 vs. f/4.0.  The background is certainly blurrier in the f/2.0 shot, but also interesting to compare is how the number 15 ball is blurry in the f/2.0 shot, but much sharper in the f/4.0 shot.  I should have taken an f/8.0 shot, but since reading that these compact cameras suffer from diffraction blur beyond about f/4.5 I thought I'd "focus" my efforts at about f/4.0.

And just a quick comparison of the zoom range effect on viewing angle.  Note that the zoom range of the LX5 is 24 to 90 mm (35mm camera equivalent).  Obviously I was closer to the ball at the widest angle, but this image is actually also a visual comparison of the closest focusing distance between the two zoom ranges.    I set the camera down onto the table at a distance where it would not focus (giving me red warning indicators), and kept sliding the camera further away until the camera could successfully focus.  I had the macro focus switch on (on the left side of the lens) and used autofocus to selectively focus on the number "12".  Note that when focusing at the closest range possible, the background balls end up blurred at f/4.0:

In macro mode (switch on left side of lens) the closest focusing distance at wide angle is extremely close (1 cm), but when zoomed in at the longest focal length it is much larger (30 cm is the spec I saw).  One way to reduce the minimum focusing distance at longer focal length is to use a close-up lens.  I just happened to have one, a cheap Rolev +2 diopter I bought back in the early 1980's for my Olympus OM-2 camera.  It just happened to have 52mm threads that screw right on to my LX5 adapter tube.  So below is a visual comparison of the minimum focusing distance at full zoom, with and without the close-up lens:

I was concerned that the Rolev diopter, given that it is an inexpensive single-element close-up lens, would cause a degradation in image quality, but in this case I do not see an adverse effect.  I think it's worth continued explorations...

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