DoF calculator specific to the HVX

turing

turing

Active member
hi all,

wondering if anyone has come across either:

A DoF calculator for the HVX all packaged and ready to go... or..

A focal length range for the camera expressed in MM (we're ignoring adapters, etc here, I'm talking about the leica that comes on the thing), and the circle of confusion for the chip in the HVX so I can build my own freaking calculator.

:)

_a
 
i have that other DOF widget for OS X, but i have no clue what the hell any of it means on it . :(
 
Cynic821 said:
i have that other DOF widget for OS X, but i have no clue what the hell any of it means on it . :(
Click to expand...
If you're talking about the widget that was posted here a few days ago, go to this website for an explanation: http://www.fuerstentum.net/Widget/index.html

On the back of your widget, select the format (1/3" in the case of the HVX) then select meters or feet. LCF stands for "lens correction factor." Usually you will set this to 1.0, but (for example) if you are using a 0.6x wide angle adaptor you would set it to 0.6.

On the front, select your f-stop from the pull-down menu. The focal length (the box next to mm) corresponds to the numbers on your zoom ring. The "focus" box is the distance to your subject (in meters or feet, depending on your choice).

Now, the diagram on the left is a little confusing. "nf" stands for near focus; this area will appear slightly blurred, like an over-the-should shot of two people talking, where the back of one person's head is slightly out of focus. The first red number is the start of perceived focus (technically, only one exact distance is ever truly in focus in a shot, there is an explanation of this on the website). The little person is your subject. The second red number is "ff" or far focus; at this point the focus will become blurred again. Finally, "hf" stands for hyperfocal distance, which is the "closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp" (from wiki).

Hope this helps.
 
May I post a few warnings about the DOFC Widget? It's a neat and accurate enough calculator for the photographer, but its use for the videographer needs some caveats.

That is because the depth of field calculation is based on viewing a still picture at average viewing distances. Obviously, we start to diverge already, for we view moving images where we know our tolerance for unsharpness is greater.

Then DOFC is based on a circle of least confusion of 0.029mm i.e. that's the size of image dot which still appears to be a single dot with no diameter when enlarged for viewing at normal viewing distances: a bit bigger, and the dot appears to have a diameter. Normally, this dot ends up measuring about 0.25mm on a print. Well, that's way smaller than the typical pixel on a monitor, or about the pixel pitch of an Apple 23" Cinema Display running at full resolution.

In short, depth of field with moving images will appear to be much greater than that calculated by photography-based calculators. Furthermore, I don't think you can go just by the sensor size: depth of field with lower resolution is always larger because you can't tell the difference between sharp and unsharp so easily. The HVX offers a range of resolution that extends from 480 (or 576) to 1080. You'd need depth of field tables for each resolution. Working in HD reduces effective depth of field compared to the same zoom/f-stop/distance settings in SD.

In short, I would expect that the calculations tend to reduce dof compared to what you actually see on screen; so be prepared to be disappointed if you don't make allowance for that.
 
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