When do you need a hood?

rincewind wrote:
How do you decide when you need to put a hood on a lens? I've read that
a hood is supposed to prevent flare, but what are likely conditions for
flare to appear? What does it depend on - the focal length, the angle
between you subject and the light, filters used, anything else?
I even made a dozen or so test shots, and a hood seems to make no
difference. Considering that it's bulky and very inconvenient, I'd
rather not use it unless it makes my pictures better.

Practically always; my hoods live on my lenses.

As others have mentioned;
1) Protection.
2) Preventing major flare.
3) Raising contrast (visible to different degrees in most conditions).

With the few lenses I have that don't have shades (super-wides), they
are sorely missed and I am considering building my own.

How do you decide when you need to put a hood on a lens? I've read that
a hood is supposed to prevent flare, but what are likely conditions for
flare to appear? What does it depend on - the focal length, the angle
between you subject and the light, filters used, anything else?
I even made a dozen or so test shots, and a hood seems to make no
difference. Considering that it's bulky and very inconvenient, I'd
rather not use it unless it makes my pictures better.

In article , rincewind
writes
How do you decide when you need to put a hood on a lens? I've read that
a hood is supposed to prevent flare, but what are likely conditions for
flare to appear? What does it depend on - the focal length, the angle
between you subject and the light, filters used, anything else?
I even made a dozen or so test shots, and a hood seems to make no
difference. Considering that it's bulky and very inconvenient, I'd
rather not use it unless it makes my pictures better.

Three things a well-engineered lens hood will do for you:

(1) If the sun (or another very bright point source) would shine
directly on the front element of the lens, but is outside the picture,
then a hood should intercept it and prevent some (usually very bad)
flare spots - typically, orange blobs, often in a repeated string,
across the image. Of course, hoods are a compromise, and may not shield
the lens if the sun is only just outside the image area; a hand or other
opaque object may be needed to "assist".

(2) In a more general case, all off-image lights or bright objects will
cause a more subtle degradation of contrast through internal
reflections. A good hood will minimise this degradation.

(3) A good rigid plastic hood will protect the lens against impact if
you should inadvertently bash the camera against a wall or some other
hard object. I always use a hood on all my lenses*, and I have lost
count on the number of minor collisions they have saved my lenses from -
and I don't consider myself particularly careless.

Yes, a good hood takes up room in the bag - though it doesn't add much
weight - and since all my lenses use different hoods it adds up to quite
a lot - but I've always found them well worth the effort. If you look at
professional movie makers at work, you will always see a hood on the
lens.

*Except the Canon 100mm macro, which has a very deeply recessed front
element and does not need one, nor is there one designed for it.

David
--
David Littlewood

rincewind wrote:
How do you decide when you need to put a hood on a lens? I've read that
a hood is supposed to prevent flare, but what are likely conditions for
flare to appear? What does it depend on - the focal length, the angle
between you subject and the light, filters used, anything else?
I even made a dozen or so test shots, and a hood seems to make no
difference. Considering that it's bulky and very inconvenient, I'd
rather not use it unless it makes my pictures better.

Whenever it can prevent a source of light from falling on the front
element or filter, a hood is doing its job. Flare is not always obvious
and nor is loss of contrast which is another consequence of light
falling on the lens.

For wide angle lenses, it is a bigger problem as the hoods are typically
shallower and wider and admit more light angle. You can add other
blockers like a grey card or umbrella to prevent direct light from
getting onto the glass.

If you're not sure just look at the front of the lens. If light is
directly on it, it will show in the exposure. You can then figure means
to block it (stand in the shaddow of a tree, building or friend;
umbrella, gobo, etc. or recompose from another angle.)

It is very manageable and a hood is just one of the means.

Cheers,
Alan

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"Alan Browne" wrote in message
...
rincewind wrote:
How do you decide when you need to put a hood on a lens? I've read that a
hood is supposed to prevent flare, but what are likely conditions for
flare to appear? What does it depend on - the focal length, the angle
between you subject and the light, filters used, anything else?
I even made a dozen or so test shots, and a hood seems to make no
difference. Considering that it's bulky and very inconvenient, I'd rather
not use it unless it makes my pictures better.

Whenever it can prevent a source of light from falling on the front
element or filter, a hood is doing its job. Flare is not always obvious
and nor is loss of contrast which is another consequence of light falling
on the lens.

For wide angle lenses, it is a bigger problem as the hoods are typically
shallower and wider and admit more light angle. You can add other
blockers like a grey card or umbrella to prevent direct light from getting
onto the glass.

If you're not sure just look at the front of the lens. If light is
directly on it, it will show in the exposure. You can then figure means
to block it (stand in the shaddow of a tree, building or friend; umbrella,
gobo, etc. or recompose from another angle.)

Isn't this why many photographers wear wide brimmed hats? - That's what my
dad used to use....

rincewind wrote:

How do you decide when you need to put a hood on a lens? I've read that
a hood is supposed to prevent flare, but what are likely conditions for
flare to appear?

Generally if the sun is not in the image, but sun shines on the front of
the lens:

\
\ sunlight from overhead
\
\ /\
\| |
| | lens = flare
\/


\
\ sunlight from overhead
_\____
/\
| |
| | lens with lens hood = no flare (mostly)
_____\/

William Graham wrote:

"Alan Browne" wrote in message

If you're not sure just look at the front of the lens. If light is
directly on it, it will show in the exposure. You can then figure
means to block it (stand in the shaddow of a tree, building or
friend; umbrella, gobo, etc. or recompose from another angle.)


Isn't this why many photographers wear wide brimmed hats? - That's
what my dad used to use....

I don't wear hats period. But it is a great use for them. Fireworks
and a baseball cap go a long way too.


--
-- r.p.e.35mm user resource: http://www.aliasimages.com/rpe35mmur.htm
-- r.p.d.slr-systems: http://www.aliasimages.com/rpdslrsysur.htm
-- [SI] gallery & rulz: http://www.pbase.com/shootin
-- e-meil: Remove FreeLunch.

no_name wrote:
rincewind wrote:

How do you decide when you need to put a hood on a lens? I've read
that a hood is supposed to prevent flare, but what are likely
conditions for flare to appear?

Generally if the sun is not in the image, but sun shines on the front of
the lens:

\
\ sunlight from overhead
\
\ /\
\| |
| | lens = flare
\/


\
\ sunlight from overhead
_\____
/\
| |
| | lens with lens hood = no flare (mostly)
_____\/


You can also substitute "bright sky" for "sun" and "some loss of
contrast" for "flare".

"David Littlewood" wrote in message
...
SNIP
*Except the Canon 100mm macro, which has a very deeply recessed
front element and does not need one, nor is there one designed for
it.

That would be the original model. The newer model requires an
additional hood. Because of the redesign of the lens, there is no
recessed front element anymore. A good thing about Canon lens hoods is
that they can be mounted in reverse on the lens, which usually saves
significant storage space.

Bart

In article , Bart van der Wolf
writes

"David Littlewood" wrote in message
...
SNIP
*Except the Canon 100mm macro, which has a very deeply recessed front
element and does not need one, nor is there one designed for it.

That would be the original model.

Yes; I should have pointed this out. It is such a good lens I have never
thought it worth upgrading.

The newer model requires an additional hood. Because of the redesign
of the lens, there is no recessed front element anymore. A good thing
about Canon lens hoods is that they can be mounted in reverse on the
lens, which usually saves significant storage space.

Indeed; although with some (especially the wides) this makes them
inconveniently wide for storage on a bag. I find it may be more
efficient to put them in a slot without the hood and store 2-3 hoods
nested together.

David
--
David Littlewood