DoF calculator apps on Android: an overview review

[kaihp]

I've used the same Depth of Field calculator app for some years, but recently noticed that it didn't calculate the correct DoF when adding a TC. At least, it didn't do what I expected it to do.

I'm only testing the apps for computing the correct DoF both with and without a TC (ie: also adjust for f-stop change when adding a TC).

I using a single datapoint to test (with and without TC=2x): FL=300mm, f/2.8, distance=180m.
The correct answer is a a dof=62.79m without a 2x TC, and dof=30,66m with the TC.

In hope that's useful to other forum members, here's my list of The Good, The Bad and The Ugly of DoF calculators for Android:

The Good
DOF Calculator	Correct computes the DoF. UI is a bit kludgy
The Bad
DOF and Hyperfocal Calculator	Doesn't include the TC factor in the f-stop (only FL is multiplied)
JDoF Calc	Doesn't include the TC factor in the f-stop (only FL is multiplied)
The Ugly
HyperFocal Pro	Doesn't support TCs
DoF	Doesn't support meters. No obvious way to set focus distance. Focal length and f-stop scale work opposite of each other
DOF Expert	Doesn't calculate DoF, but estimates background blur. Ancient release (2013)

Feel free to add comments about these or other DoF apps you are using.

 

[zim]

What camera are you using for your single point test? (CoC)

 

[gruhl28]

I was surprised that the depth of field is halved with the teleconverter. I figured that having an effective aperture two stops smaller would offset most of the loss of DoF from doubling the focal length, but apparently the effect from the FL change is much greater than the effect of closing down two stops. I'll admit I didn't quite believe it, so I compared 300 mm at f/2.8 with 600 mm at f/5.6 and the DoF is half as big.

I'm a bit confused by your conclusion, though. If you put a 300 mm f/2.8 lens with a 2x teleconvertor on your camera, doesn't the camera report that the f-stop is 5.6? So wouldn't you enter f/5.6 in the app, not f/2.8? I tried the DOF and Hyperfocal Calculator, and it's not that doesn't calculate the correct DoF, it just doesn't automatically change the f-stop when you select the 2x convertor. If you set 300 mm with 2x convertor and f/5.6 it does report DoF of 30.67 meters.

 

[3kramd5]

Doesn't it make more sense to do these comparisons with a constant framing rather than from a constant distance?

 

[chrysoberyl]

Is there an app that takes into consideration magnification? Specifically for macro?

Thanks

 

[kaihp]

What camera are you using for your single point test? (CoC)

I was assuming a Full-frame camera (so CoC = 0.03mm)

Is there an app that takes into consideration magnification? Specifically for macro?

The DoF Calc app allows you to set a custom CoC, but that's probably not very intuitive. Quite a few apps show up if you search for "depth of field" on Google play. My best recommendation is to look through the apps and see if one of them matches your need.

I'm a bit confused by your conclusion, though. If you put a 300 mm f/2.8 lens with a 2x teleconvertor on your camera, doesn't the camera report that the f-stop is 5.6? So wouldn't you enter f/5.6 in the app, not f/2.8?

I expected that the that if I tell the App that I'm using a 300mm f/2.8 lens with a 2x TC, that it would modify both the focal length and the aperture when calculating the DoF, not just the focal length.

The DOF Calculator does exactly that and informs you of the Effective values, which is what I had expected.

 

[zim]

What camera are you using for your single point test? (CoC)

I was assuming a Full-frame camera (so CoC = 0.03mm)

Cheers, I get 62.13 from dof droid, not as accurate but enough for me. I also like the graphs and it has a cat!!
And it's free

But it has a spelling mistake in it that really annoys me :-\

 

[eli452]

I recommend the hcpl "Photo Tools". Free, no adds, developed by a community (see http://pho.totools.net. Includes DOF & Hyperfocal, FOV, exposure, Flash exposure, and many other calculators.

 

[RGF]

hope that they make a IOS version soon

 

[kaihp]

I recommend the hcpl "Photo Tools". Free, no adds, developed by a community (see http://pho.totools.net. Includes DOF & Hyperfocal, FOV, exposure, Flash exposure, and many other calculators.

I took a look at it, and while it seems to have a lot of calculators, it has a rather steep learning/setup curve (you need to enter your camera and lenses). Since the DoF calculator doesn't support TC's, I've ruled it out for my own purposes.