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DOF for SX730

Started Apr 1, 2018 | Discussions
(unknown member) Senior Member • Posts: 2,265
DOF for SX730

As requested by saaber1. I wrote a new sheet as the long focal length DOF are crazy and doing it this morning has sent me crazy. To export the graphs from Excel I have to copy them in to Powerpoint and save thew slide as a JPEG and sometimes they sync in and change with the sheet and then not. The waterfall style is nice as it just runs flat when it sees the Infinity text.

The formulae are shown for people to tear apart from the single depth of field chart. They seem to agree reasonably when I have stop checked against an online calculator but take them at your own peril.

Correction of previous.

Plus all the different sensors with this lens and the 1/2.3" on the cusp of focusing to infinity. All the pixel size stuff needs checking so this is all work in progress.

Canon PowerShot SX730 HS
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saaber1 Senior Member • Posts: 2,164
Re: DOF for SX730

I didn't actually look at any of that data for now due to time constraints but I just wanted to pass along that the DOF equation is limited in it's applicability. For example macro shots of 2 cm distance to subject or whatever will give you whacko #s.

In regards to that equation, perhaps it's best to stick to distances like 10m from your graph on the other thread.

The cambridge in color calculator is a nice calculator in that it takes into account viewing distance, print size etc. They have some nice info. on DOF too. Also FYI there was some great discussion on DOF, sensor size, etc. on dpreview recently (I need to find that thread again).

Here is an example of the cambridge calculator for the sx730 at 10 m distance to subject, fully zoomed in (note that 6.6 is the max aperture of the sx730 at 172mm (960mm equivalent) but the calculator does not have "6.6" so I selected "5.6".). The numbers sound right to me, about 8.3 inches depth of field (actually it should be larger due to selecting 5.6 as aperture when it should be 6.6).

For reference, the bottom image is the same distance, focal length, aperture using a full frame camera. Note that "focal length" for this particular calculator is in actual focal length, not "full frame/35mm equivalent" focal length. Again the 1.6" ish DOF sounds about right to me.

sx730

Here is the cambridge in color link FYI:

https://www.cambridgeincolour.com/tutorials/dof-calculator.htm

OP (unknown member) Senior Member • Posts: 2,265
Re: DOF for SX730

Thanks for all that. The numbers on the previous posts are all right but the left axis of the waterfall charts is all is messed up so just look at the numbers. Sorry about that.

Here is a 0.5 to 10 metre which hopefully is a bit more useful. If I put in f5.6 I get 0.204 at 10 metres which is close enough.

Below a cross check at f5.6 to compare with your posted figures with the crop adjusted to match the 24-960 claimed equivalent focal length which makes little difference. Seems near enough and the circle of confusion is probably not an exact science. I just scale it off what I have found for full frame which seems to match other published figures for the particular sensors.

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