Lens Hood (Page 3): And metal saving , cutting cost to make...

Bram boy Loc: Vancouver Island B.C. Canada

Bram boy wrote:

It's strictly for looks and weight cutting , ask thom

And metal saving , cutting cost to make

Rufus Loc: Puget Sound area, WA

Note that the useful angle of view of any lens is larger in the corners than at the sides because the sensor is not round. Therefore, any lens hood should allow for this, and block the stray light that would reach the corners of the sensor, without affecting the desired light on the rest of the sensor.

dickwilber Loc: Indiana (currently)

RRS wrote:

The reason is the range (zoom) of the lens. A full even lens hood would cause vignetting at 28mm. Look at the lens hood and it's shape and you will see that it is designed to coincide with the shape of the sensor.

Half right! The vignetting is an issue at all focal lengths, whether the lens is a zoom or not. A hood designed for a particular lens, utilizing the most efficient shape, will always have a "tulip" shape. This includes telephoto as well as wide angle, though the effect will be more dramatic for wide angle lenses. Being a zoom lens only means the "tulip" shape will be made to accommodate the widest focal length of that lens.

Peterff Loc: O'er The Hills and Far Away, in Themyscira.

WmLeeGriffin wrote:

I'll throw out my thoughts. . . because you use a Canon. It doesn't have to make sense. Nikon is quality, it's like a tool that was made for the serious photographer. Canon, always trying to make the grade, does stuff like "tulip lens hood" to make it sound . . . special. Just my thought on it. ;)

While this thread is definitely photography related, it has a quality rating at the level of the attic from some, but certainly not all contributors ....

Apparently some people skipped the classes on physics, optics, or critical thinking...., or even the concept that humor is actually meant to be funny!

James R. Kyle Loc: Saint Louis, Missouri (A Suburb of Ferguson)

CLF wrote:

Just traded/up graded my lens set to include a 28-135 Canon lens, 72mm. When checking out lens hoods I see it is to use a tulip type hood. Simple question, why is this?

Greg

==========

I am a Canon user - But I have used Nikon and other cameras as well.

I do think that the lens hood (ANY lens hood) give a good protection to the objective element of the lens. And to shade ambient sunlight from somewhat entering the lens and "bouncing" around - thus causing lens-flare on the image that you are capturing.

I have them on all my lenses. However, I do remove them from time to time when not in direct sunlight (i.e.= indoors and doing portrait work).

Others here will, and should, have their own feelings on this. This is what I do.

RRS Loc: Not sure

dickwilber wrote:

Half right! The vignetting is an issue at all focal lengths, whether the lens is a zoom or not. A hood designed for a particular lens, utilizing the most efficient shape, will always have a "tulip" shape. This includes telephoto as well as wide angle, though the effect will be more dramatic for wide angle lenses. Being a zoom lens only means the "tulip" shape will be made to accommodate the widest focal length of that lens.

"A hood designed for a particular lens, utilizing the most effective shape, will always have a "tulip" shape" is not true. The 300mm/400mm/500mm/600mm and the 800mm lenses all have round lens shades. I think I said the same thing as your last sentence indicates in reference to the vignetting with the lens set to the widest zoom. The design in regard to the length of the lens shade is a direct relation to how wide the lens is in terms of the angle.

melismus Loc: Chesapeake Bay Country

It should either have tulip shape, or be rectangular.

RRS wrote:

"A hood designed for a particular lens, utilizing the most effective shape, will always have a "tulip" shape" is not true. The 300mm/400mm/500mm/600mm and the 800mm lenses all have round lens shades. I think I said the same thing as your last sentence indicates in reference to the vignetting with the lens set to the widest zoom. The design in regard to the length of the lens shade is a direct relation to how wide the lens is in terms of the angle.

CathyAnn Loc: Apache Junction, AZ

I notice that my primes (35mm and 50mm) and my 70-300mm have the even width hoods. My 10mm and 18-270mm, and the 18-55mm kit lens have tulip hoods. To me, that means the wide angle needs the tulip shape.

Being new to photography, the physics of it goes right over my head, but perhaps someday it will all sink in. Just trying to figure out what aperture, shutter speed and ISO to use are keeping my very occupied. :roll: :D

Murray Loc: New Westminster

RichardSM wrote:

Trouble maker 32 post and already snarky!!!

10-4

RRS Loc: Not sure

melismus wrote:

It should either have tulip shape, or be rectangular.

What you think it should be it isn't. Please reread what I said. 300/400/500/600/ and 800mm lenses all have round lens hoods. If you don' believe me just look up any of those lenses on the B&H site. It really doesn't make any difference as ALL lens hoods are designed to do a specific job regardless of their shape. You are right, tulip or rectangular, you just forgot round.

melismus Loc: Chesapeake Bay Country

Round lets in a little non-image-forming light. The stuff that gets marketed is not necessarily optimum.

anotherview Loc: California

Ditto.

This discussion may help to inform you:

http://www.naturephotographers.net/articles0507/rb0507-1.html

jethro779 wrote:

Because a round lens hood would vignette the sides.

dickwilber Loc: Indiana (currently)

RRS wrote:

"A hood designed for a particular lens, utilizing the most effective shape, will always have a "tulip" shape" is not true. The 300mm/400mm/500mm/600mm and the 800mm lenses all have round lens shades. I think I said the same thing as your last sentence indicates in reference to the vignetting with the lens set to the widest zoom. The design in regard to the length of the lens shade is a direct relation to how wide the lens is in terms of the angle.

The key words are "utilizing the most efficient shape"! No, not all lenses in the longer focal lengths have "tulip shaped" hoods. But the most efficient design is a tulip shape. Older lenses, of any focal length had circular hoods; the tulip shape is a relatively recent innovation. (Probably occurring after the manufacturers went to computer designing lenses when it became relatively easy to lay out the tulip shape.)

None-the-less, the tulip shape is more effective at all focal lengths. That said, the efficiency gain at longer focal lengths is pretty moderate.

ecar Loc: Oregon, USA

WmLeeGriffin wrote:

I'll throw out my thoughts. . . because you use a Canon. It doesn't have to make sense. Nikon is quality, it's like a tool that was made for the serious photographer. Canon, always trying to make the grade, does stuff like "tulip lens hood" to make it sound . . . special. Just my thought on it. ;)

That's True, Canon's require "light" in order to work, Nikons do not............

Jakebrake Loc: Broomfield, Colorado

RichardSM wrote:

Trouble maker 32 post and already snarky!!!

Agreed. We do seem to be getting newbies here on the forum with little to no class! :wink: