Hyperfocal distance

[David Bottel]

Hello, when using a hyperfocal distance calculator with a cropped senser do you use the actual focal length of the lens or it's 35mm equivelent

Regards David

[Donald]

David

You've got to factor in the crop factor.

Have a look at this. It explains the formula very well (scroll down to Step 7)

[DanK]

You also might find this posting helpful. It explains in practical terms the impact of sensor size on DOF.

[Black Pearl]

I have one of these:

http://www.nikonians.org/html/shop/h..._t-shirts.html

The chart is specific to DX or FX and I got to chose between metric or imperial - I particularly love that its printed upside down so I can read it when I look down. Explaining why its printed that way and what it is to passers by can be tricky though :-)

[David Bottel]

Donald and Dan, thank you for the info, very helpful.

Regards David

[David Bottel]

I am confused. I have just reread the article posted by Dan and towards the end, just before the "addendum" there is a sentence that says on a small senser the hyperfocal distance is 1.6x less than a full size senser, should this not say that the hyperfocal distance on a small sensor is 1.6x more than a full size senser

[dje]

Hello, when using a hyperfocal distance calculator with a cropped senser do you use the actual focal length of the lens or it's 35mm equivelent

Regards David

David it probably depends how the calculator is set up but for the one in the CiC tutorial here, you use the actual focal length.

Dave

[William W]

I am confused. I have just reread the article posted by Dan and towards the end, just before the "addendum" there is a sentence that says on a small senser the hyperfocal distance is 1.6x less than a full size senser, should this not say that the hyperfocal distance on a small sensor is 1.6x more than a full size senser

Is this the sentence to which you refer (my underline for emphasis)?

“So I'll just summarize the results
[. . . ]
5. Close to the hyperfocal distance, the small-sensor camera has a much more than 1.6x the DOF of a full-frame camera. The hyperfocal distance of the small-sensor camera is 1.6x less than that of a full-frame camera.” (*1)

That sentence is correct in fact.

The sentence assumes that the two lenses being compared have the same ANGLE OF VIEW and are being used at the same APERTURE. (These assumptions were spelled out previously in the Commentary)

*

For example (using ‘f-calc’ which I have loaded on the computer that I am presently using)

A32mm Lens on a (Canon) APS-C Format (‘crop factor 1.6’):
AoV(h) ≈ 39°, (39.058°)
Lens is used at F/8,
HD = 8122mm

A 50mm Lens used on a Canon 5D Series Format:
AoV(h) ≈ 40°, (39.598°)
Lens used at F/8
HD = 12495mm

To compute the relationship of “1.6x less than that of the full frame camera” - we must divide the HD of the Full Frame Camera by 1.6

12495/1.6 = 7809

7809 ≈ 8122

The discrepancy (313mm) is mainly because the AoV of the two lenses was not EXACTLY the same and there is a rounding factor and limit of the degree of accuracy for each entry when using the ‘f-calc’.

WW

*1 op. cit.

[lukaswerth]

David,

I am certain you learned now all you ever wanted to know about hyperfocal distance, perhaps more so.
Let me add another note: the concept was useful when you had large negatives which you wanted to moderately enlarge, say, to an 8x10" print which should appear sharp at arm's length. With enlargements possible with modern cameras, and particularly with APS sensors (but this is true for full sensor as well) the idea is outdated, there are far better, and easier methods to get the sharpness you want, and which is possible in a given situation.
One example: in a print for which HF was applied, the background tends to look slightly blurred, unsatisfactory. This is because the eye expects more details in the distance where items are rendered smaller.

Lukas

[William W]

Addendum –

You might have been confusing Depth of Field and Hyperfocal Distance.

Maybe think of it this way
(In the conditions assumed above)

An APS-C camera will provide MORE (a bigger distance of) Depth of Field.

But the Hyperfocal Distance when using an APS-C Camera is simply CLOSER to the camera.

That is to say “ there is 1.6 times LESS distance from the Camera to the Hyperfocal Distance for an APS-C Camera, than when using a Full Frame Camera”

WW

[russellsnr]

To make life easier I use
http://www.georgedouvos.com/douvos/O...s_Stacker.html
Russ

[David Bottel]

Thank you all for your helpful comments. William following your last post I am no longer confused.

Regards David

[BrianA61]

Here is a handy program that I use. I downloaded it, set up two of my lenses and then printed the charts. I laminated them and stuffed them in my camera bag.

http://www.dofmaster.com/charts.html

I believe that by changing the CoC to match what your sensor type is will automatically adjust the charts.

[rpcrowe]

Is the DOF less or more on a full frame camera than on a crop sensor...

The answer to that question is perhaps... depending on how you are determining the DOF....

If you are using a 50mm lens on a 1.6x crop camera at a distance of 10 feet and an f/stop of f/2.8; the total DOF would be 1.29 feet.

If you are using a 50mm lens on a full frame camera at a distance of 10 feet and an f/stop of f/2.8; the total DOF would be 2.06. That is wider than the crop camera DOF!

HOW CAN THIS BE? We always hear that a full frame camera has a shorter DOF than a crop sensor camera.

In reality it will because if you are shooting a 1.6x crop camera with a 50mm lens at 10 feet and want to switch to a full frame camera and attain the same subject framing, you would need to either switch to an 80mm lens or get closer to your subject. Both of which would result in a shorter DOF...

As an example the 80mm lens on the full frame camera at 10 feet would result in a DOF of .79 feet which is significantly less than the 50mm on a 1.6x crop camerq at 10 feet.

[William W]

. . . if you are shooting a 1.6x crop camera . . . and want to switch to a full frame camera and attain the same subject framing . . .

135mm lens on 5D and 85mm lens on 20D as an example:



WW