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Very Large Array, New Mexico

Photo from fotoi's gallery.
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fotoi wrote in post #18848707
Very Large Array, New Mexico

Gallery photo (hosted):
posted by fotoi originally in forum: Astronomy & Celestial

...looking into an infinitely larger array

fotoi wrote in post #18848707
Very Large Array, New Mexico

Gallery photo (hosted):
posted by fotoi originally in forum: Astronomy & Celestial

Can someone help me with a problem?
This is a lovely photo and focussing seems good, but how is it possible to have so much in focus with the lens at f/2.8 ?
I would have expected a narrow d.o.f.
Thanks.

Cuttlefish wrote in post #18848795
Can someone help me with a problem?
This is a lovely photo and focussing seems good, but how is it possible to have so much in focus with the lens at f/2.8 ?
I would have expected a narrow d.o.f.
Thanks.

Hi Cuttlefish,

Depth of field is also affected by the distance to the subject as well as the aperture. The reason a wide-open aperture produces shallower depths of field has to do with how close the focal point is to the actual aperture itself. The closer to the aperture the focal point is, the steeper the converging lines are, resulting in a shallower depth of field. The further away the focal point is, the less steep the converging lines are, resulting in a deeper depth of field. This is how a lens open to 2.8 can still produce a fairly deep depth of field.

I'm sure someone can provide an easier-to-understand explanation than I just did, but I hope it helps.

kwp wrote in post #18849191
Hi Cuttlefish,

Depth of field is also affected by the distance to the subject as well as the aperture. The reason a wide-open aperture produces shallower depths of field has to do with how close the focal point is to the actual aperture itself. The closer to the aperture the focal point is, the steeper the converging lines are, resulting in a shallower depth of field. The further away the focal point is, the less steep the converging lines are, resulting in a deeper depth of field. This is how a lens open to 2.8 can still produce a fairly deep depth of field.

I'm sure someone can provide an easier-to-understand explanation than I just did, but I hope it helps.

Thanks very much for your reply, kwp.
I wonder if there is a diagram anywhere that makes this easier to understand?
It is a question that has baffled me for a while.

Barn at night

fotoi wrote in post #18848707
Very Large Array, New Mexico

Gallery photo (hosted):
posted by fotoi originally in forum: Astronomy & Celestial

Can you tell me what you focussed on in this shot?

Cuttlefish wrote in post #18849591
Can you tell me what you focussed on in this shot?

I had the lens set manually at infinity focus. It is interesting that the depth of field is so broad.

kwp wrote in post #18849191
Hi Cuttlefish,

Depth of field is also affected by the distance to the subject as well as the aperture. The reason a wide-open aperture produces shallower depths of field has to do with how close the focal point is to the actual aperture itself. The closer to the aperture the focal point is, the steeper the converging lines are, resulting in a shallower depth of field. The further away the focal point is, the less steep the converging lines are, resulting in a deeper depth of field. This is how a lens open to 2.8 can still produce a fairly deep depth of field.

I'm sure someone can provide an easier-to-understand explanation than I just did, but I hope it helps.

I suppose I am blown away by the f/2.8 in fotoi's photo.
I would never have attempted f/2.8 in such a setting and was expecting f/18 thru f/22

I still have a lot to learn.

Moonrise, Albuquerque, April 2014.

Photo from fotoi's gallery.
Image hosted by forum (755582)

fotoi wrote in post #18849594
I had the lens set manually at infinity focus. It is interesting that the depth of field is so broad.

Hi fotoi,
Thanks for replying.
f/2.8 blew me away

From archive - Prague 2010

Light painting in our backyard.

Photo from fotoi's gallery.
Image hosted by forum (791093)