Hyperfocal distance for 20mm F1.7 pancake?

[magicbuzz]

As the title says, can anyone tell me the hyperfocal distance for the 20mm pancake on the GH1?

 

[Pinko]

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

 

[ardez]

Just in case you don't know, to set the 20mm lens to hyperfocal position just set focus mode tu manual, then switch the camera off and on again. This will put the 20mm in its hyperfocal position. I'd set it to f/4 at least to have a depth of field that goes from infinity to say 2 meters from you.

Giacomo

 

[Fredrik Glckner]

Just in case you don't know, to set the 20mm lens to hyperfocal position just set focus mode tu manual, then switch the camera off and on again. This will put the 20mm in its hyperfocal position. I'd set it to f/4 at least to have a depth of field that goes from infinity to say 2 meters from you.

Respectfully, I don't believe that this is true. I believe the lens goes to "near infinity" when powering on.

As far as I know, there is no detailed information about the focus distance being communicated between the lens and camera in the 4/3 or m4/3 system. If this was communicated, there would be a requirement for expensive and complicated focus distance calibration of the lenses, which is outside of the scope for this price range.

Of course, "near infinity" is pretty close to the hyperfocal, for larger apertures. So keeping the lens in manual focus mode and not touching the focus ring will be a pretty good solution when stopping down a bit and not photographing close objects.

http://m43photo.blogspot.com/

 

[John Bean (UK)]

Of course, "near infinity" is pretty close to the hyperfocal, for larger apertures.

Did you mean to write "smaller apertures" (or perhaps "larger f-numbers")?

--
John Bean [GMT]

 

[Fredrik Glckner]

Of course, "near infinity" is pretty close to the hyperfocal, for larger apertures.

Did you mean to write "smaller apertures" (or perhaps "larger f-numbers")?

Not really. When the aperture is large (small f-number), the hyperfocal is close to "near infinity".

On the other hand, as you stop the aperture down (larger f-numbers), the hyperfocal creeps downwards, away from infinity, smaller focus distance numbers.

So approximating the hyperfocal with infinity only works for larger apertures (small f-number), as I tried to explain.

http://m43photo.blogspot.com/

 

[ardez]

Just in case you don't know, to set the 20mm lens to hyperfocal position just set focus mode tu manual, then switch the camera off and on again. This will put the 20mm in its hyperfocal position. I'd set it to f/4 at least to have a depth of field that goes from infinity to say 2 meters from you.

Respectfully, I don't believe that this is true. I believe the lens goes to "near infinity" when powering on.

As far as I know, there is no detailed information about the focus distance being communicated between the lens and camera in the 4/3 or m4/3 system. If this was communicated, there would be a requirement for expensive and complicated focus distance calibration of the lenses, which is outside of the scope for this price range.

Of course, "near infinity" is pretty close to the hyperfocal, for larger apertures. So keeping the lens in manual focus mode and not touching the focus ring will be a pretty good solution when stopping down a bit and not photographing close objects.

That's what I meant, being a little approximate. Thank you for the clarification Fredrik!

Giacomo

 

[WT21]

DOF master has it right there. Very easy. Interesting to note, though, the hyperfocal distance is also related to stops.

On the 20mm, HF distance is the following
f4: 22ft
f8: 11ft
f11: 7.8ft
f16: 5.5ft

I rounded off, but you can see the distance doubles (or halves) with two stops (f4 to f8 is two stops, and the distance halves from 22 to 11ft).

Even more interesting is that with the 17mm, the hf distance is roughly inverse to the stops (with f8 being the mid-point)!
f4: 16ft
f5.6: 11ft
f8: 8ft
f11: 5.6ft
f16: 4ft

If you have a 10mm lens its
f4: 5.5ft
f8: 2.77ft
f11: 1.97ft
f/16: 1.4ft

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

--

I refuse to wed myself to any of these vendors. I'm just having fun taking pictures,
and watching the technology develop.

 

[John Bean (UK)]

Of course, "near infinity" is pretty close to the hyperfocal, for larger apertures.

Did you mean to write "smaller apertures" (or perhaps "larger f-numbers")?

Not really. When the aperture is large (small f-number), the hyperfocal is close to "near infinity".

On the other hand, as you stop the aperture down (larger f-numbers), the hyperfocal creeps downwards, away from infinity, smaller focus distance numbers.

So approximating the hyperfocal with infinity only works for larger apertures (small f-number), as I tried to explain.

Ah, I had somehow misinterpreted what you wrote to mean that the close-to-infinity was just "near enough" if the lens is well stopped down, but of course that wasn't at all what you meant. Having re-read it (and your reply) I see you were exactly correct.

--
John Bean [GMT]