DOF (master) question

[posiview]

OK, so there's no such thing as a stoopid question, right

I bought DOF Master and have a quesiton.

I set my aperture to f16 @ 14mm, for example, and it shows a a hyperfocal distance of 0.39 meters.

Now I know what that means.

What I can't figure out is how to focus at 0.39 meters

Do I switch to manual focus and turn it to 0.39 meters?

And, if I do this and look through the eye piece it won't show as all acceptably in focus, but when viewed it will be acceptably focused from half way before the HD to infinity..?

Thanks.

 

[Alastair]

Focus on something about 40 cm into the scene. Manual or autofocus, and then lock/isolate the focus (by switching from auto to manual, for example).

But look at the DOF table and the scene in front of you, do you need f/16 or would f/11 give you a workable hyperfocal as well? - you can use the DOF table to keep the aperture in the sweet spot of the lens.

Looking through the eyepiece won't show the full scene in focus, using the DOF preview button will - but the view might be so dark you can't tell. Take it on trust from you DOF table and take the shot. Experiment.

 

[HoppyUK]

HFD on a D300S with 14mm lens at f/16, is 63cm.

Easiest way is to just estimate that distance visually, and use the centre AF point to focus on it. Hold that focus position, or lock it, recompose and shoot.

Everything will be sharp from 31cm to infinity. You can see it in the viewfinder, very approximately, if the camera has a lens stop-down button (sometimes called a depth of field preveiw button) but the image will be very dark. Pretty useless frankly, but if you do the same thing in live view you can see better. Easier to just take a snap and check that though.

BTW, all DoF calcs are measured from the front of the lens. The lens' focusing scale reads distance from the sensor. Just bear that in mind when you're very close like that.

Edit: crossed post with Alastair.

 

[vizzair]

I was trying this this weekend, 18mm at f11, (hyper approx 2m ) using a Tamron zoom on manual, which has the distance marks on the lens, I simply set the focus to 1 metre and took the pictures. The only problem was of course my shaky hands , next time i will lug the tripod around, and have somewhere more interesting than Blackpool prom in winter with the tide out.

 

[weardalered]

I was trying this this weekend, 18mm at f11, (hyper approx 2m ) using a Tamron zoom on manual, which has the distance marks on the lens, I simply set the focus to 1 metre and took the pictures. The only problem was of course my shaky hands , next time i will lug the tripod around, and have somewhere more interesting than Blackpool prom in winter with the tide out.

I am a little confused now. I thought the aim of the game was to focus at the hyperfocal distance.

This would then give a distance of 1/2 the hyperfocal distance to infinity being regarded as "in focus". In this case, focus at 2m and everything from 1m to infinity will be in focus.

Have i got it wrong?

 

[gad-westy]

I am a little confused now. I thought the aim of the game was to focus at the hyperfocal distance.

This would then give a distance of 1/2 the hyperfocal distance to infinity being regarded as "in focus". In this case, focus at 2m and everything from 1m to infinity will be in focus.

Have i got it wrong?

Yes, I'm with you here.

 

[puggie]

BTW, all DoF calcs are measured from the front of the lens. The lens' focusing scale reads distance from the sensor. Just bear that in mind when you're very close like that.

We tried checking the lens scales on a bunch of lenses after failing at using them for hyperfocal focussing and came to the conclusion that they are so approximate they are pretty much useless. from memory it was a canon 17-40L, siggy 24-70 and the 50mm f1.4. you are far better using AF on a subject at the correct distance and using back button AF IMHO.

 

[vizzair]

I am a little confused now. I thought the aim of the game was to focus at the hyperfocal distance.


Have i got it wrong?

Nope , its me, i meant to say i focused at hyperfocal, communication problem between brain and fingers -- sorry to confuse:thumbsdown:

 

[HoppyUK]

We tried checking the lens scales on a bunch of lenses after failing at using them for hyperfocal focussing and came to the conclusion that they are so approximate they are pretty much useless. from memory it was a canon 17-40L, siggy 24-70 and the 50mm f1.4. you are far better using AF on a subject at the correct distance and using back button AF IMHO.

Quite.

Nope , its me, i meant to say i focused at hyperfocal, communication problem between brain and fingers -- sorry to confuse:thumbsdown:

Also, HFD with 18mm lens at f/11 on a D5000 is 1.45m. If you focus on 2m, you will lose 6in inches of sharpness at near range.

 

[woof woof]

When using hyperfocal technique I think it's a good idea not to use extremely small apertures or indeed apertures which are smaller than necessary. Apertures which would theoretically provide a DoF greater than the scene requires or can fit in either in the near or far distance could be pretty much pointless unless you're making a conscious decision to use them for other than DoF reasons such as shutter speed.

An alternative to hyperfocal is to do a little mental calculation based on aperture, focal length and resolution...

http://www.trenholm.org/hmmerk/DOFR.html