The role of hoods on a lens.

[newton]

An "expert" at a local camera store, which is quite large and and all over the country, once told me that hoods make no difference in IQ.

I have actually wondered what the role played by hoods really is for longer vs. shorter to 'no' hoods on a short vs. longer vs. 'any' lens.

I have noticed that hoods do have an effect on the images captured, but what that effect or how small or large it is, I have no idea.

Also, why do so many older lenses come with pre-built-in hoods while the newer lenses do not. I could buy a few lenses for the price charged for one name brand hood. Why bother or should I? I am not talking about protecting the glass because that is obvious, if at all, or is this some marketing gimmick?

[Cistron]

Stray light might cause flare and reduce the image contrast. A hood will block off some of this stray light. It's a bit like using your hand to shield your eyes from the sun.

Some lenses have superb coatings and are blackened on the inside of the lens barrel, making them almost immune to stray light causing flare. So depending on the lens, the hood will have a more or less significant influence on picture contrast.

[poilu]

hood make a difference against the sun, this is true even for the best lenses
a good lens without hood is better than a standard lens with hood
if you don't have a hood, you can do the job with your hand
when I use hood, it is to protect the glass
if I don't have a hood, I envelop the front glass with my hand in crowed place
one of the main reason I don't use hood is that my bag is too small
when I take the bigger bag, I always carry some hood
China metal hood are cheap and it is clever to use them

p.s. : I see an improvement in your style

[scsambrook]

Hi Newton!

Lens hoods work. They make more of a difference with uncoated or indifferently-well coated lenses than with high efficiency multi-layer coated ones. They work better with long lenses than wide angles, and they work best of all when they're actually designed to use the maximum length and minimum diameter for the lens they're going to be used on.

What do they do? They keep the rain off so you don't get droplets on the front element. They reduce flare under most circumstances and, to some extent, internal reflections. But that can only apply to light sources outside the field of view - if you include the sun in the picture, for example, a lens hood can't do anything to mitigate the problems that causes. The result is largely the benefit of higher contrast which adds punch to our pictures.

But, a hood on a super-wide angle lens can't exclude much extraneous light. Even the petal shaped ones can't do a lot to help. And a short hood on a long lens will only do a fraction of the job a longer one will. On a zoom lens, the hood is usually optimised for the shortest focal length, so it's unavoidably compromised in its efficiency at longer ones.

Modern multi coatings might justify the designers of lens mountings leaving hoods off, but leaving them off also reduces costs which helps to increase profits . . . and if you can sell a separate hood (Hello! Messrs Leica and Zeiss) that adds further to profitability.

Your "expert" is - strictly speaking - talking rubbish. But, in some cases there's a smattering of truth is what he says. It's an easy job to put his assertion to the test, isn't it?

[Nesster]

The two usually overlooked benefits of the hood: 1) keeps off rain etc as scsambrook says and 2) reduces veiling flare - this isn't the type of thing we usually think of with the term 'flare'. It is caused by off-axis light glancing the surface of the front element, which reduces contrast. What you ideally want, even with the best coated lens, is to keep the front element itself in shade. To the degree even a short hood does this, one is ahead.

[newton]

Okay thanks. I have a few questions that come out of this.

1. What is better? multi-coated + lens hood or multi-coated alone or lens hood alone? I am sure each have its unique properties and advantages and each detracts in some ways from IQ.

2. Why do the newer lens hoods come in a tulip or flower pattern while the older lens hoods were almost always complete cones or cylinders?
a. Should I use a tulip hood on an older lens? (silly question)
b. Should I use a cylindrical or conical lens hood on a newer style lens?

If tulip hoods allow for more field of view and compensate for vignetting, stray light, flare, ... then that would mean that cylindrical hood designs on older lenses were a mistake, which I hardly believe is true, especially for the longer zooms. What is up with this design change?

3. How does one calculate exactly what the length and angle of view your new custom made / custom purchased lens hood should be so that everything is ideally kosher? Would a simple knowledge of angle of view and focal length be sufficient and if so how do all these come together in an equation, per se, or something like that?
a. If longer lenses typically benefit from lens hoods, then at what focal length can one stop using a lens hood, if at all. This seems like a strange conclusion, by the way.
b. Wouldn't most all lenses benefit from lens hoods?

4. For low light photography, wouldn't using a lens hood be detrimental as you would want as much light as possible, or would it actually be beneficial because you would be focusing more on the light that you need reflected back at hand, your subject.

[AhamB]

[AhamB]

[estudleon]

Leica masters have used the large lens shade that they could find.

Somebody can ask why? One of them (excuse, I don´t remember the name) said more, or less, in one note at the Leica magazine in 1994/5.

1- The large lens shade, the better pic.

2- Except: very clare walls un the sun light or clear cloudy days.

When the light font and/or strong reflexions are IN the image

3- Protection of the lens, better than a crap filter. Any filter can affect the IQ, the adecuate shade, never.

4- Normal and/or tele lenses. All of them will be benmeficiate with the use of the adecuate shade. Not matter MC or SC.

5- Wide angle lenses. Not much effective, but the minimal reflexion that the shade can avoid, will be fine.


Rino.

[RioRico]

What scsambrook said. Also, besides shielding from stray droplets and downpours, hoods provide physical protection against close encounters of the glass kind. I would have scraped numerous objectives if not for lens hoods. Even the cheap collapsible rubber hoods that I favor add a protective zone to the lens. THAT certainly maintains IQ, eh?

As for more short-term effects on IQ -- don't listen to sales droids. Watch pros. View some well-covered events and see what the press-corps fotogs have on their lenses. IMHO the tell-tale sign of a clueless newb is their big dSLR mounting a big kit.lens or upgrade, with no lens hood. Oh yeah, that's impressive...

[AhamB]

[Himself]

I use hoods most of the time. First move when I take the lens out of the bag is to put the hood on. Then I mount the lens and after that I remove the cap.
Even my Yashica ML 55/2.8 which has a recessed front element has a hood.

[estudleon]

Another question is which lens shade to use?

Circular or Rectangular frame, flower pattrern one?

Metal, plastic or rubber one?

My preference ( I dont' shot with wide angle lenses, generaly) metal and circular one.

Rino.

[Smull]

Very interesting topic. In fact, it brings another question : how long must hoods be and do that length change if shooting with APS-C?

[Nesster]

I use the 1.5x rule with aps-c.. in other words, a hood designed for a 50mm lens works well with a 35mm lens on an aps-c camera.

The tulip shaped hoods I think started off designed for zooms, where the wide end needed to be accommodated while not getting in the way at the long end.

The ventilated hoods started off for range finders where the hood gets into the viewfinder field.

[AhamB]

[estudleon]

In the lens shade world, there are some versions, another very good design, es that.

http://www.novacon.com.br/jupiter9_arquivos/image020.jpg

In the Novacon site, the sunshade is recomended for the J-9. But I saw that is similar design of the vented leica shade for the summicrons M series (that I used and it is very good)

A lot of options.

Rino.

[Scheimpflug]

[visualopsins]

All lenses flare and ghost, some more than others. Hoods reduce the flare and ghost by reducing light from outside cone of field of view, thus increasing contrast through less light pollution in darker portions.

Petal hoods are an attempt to even the shading over long and short dimensions and to let more light in the corners to reduce vignetting effects. Imho, these 'benefits' are 'gained' at the expense of less reduction of out-of-view lighting, less reduction of flare and ghost.

I try always to use a hood, for beneficial image effects and for lens front element protection.

[AhamB]

[visualopsins]

[Jeff Zen]

[aoleg]

[Rodinal]

[Attila]

Hood like tripod you can shoot without that , but in some situation it is essential.