The need for a lens hood.


Horst

Link Posted 04/08/2014 - 04:59
The following pictures show the difference between using a:

1.) With UV filter (high quality Hoya HMC) and no lens hood.
2.) Without filter and no lens hood. Note the slight improvement.
3.) With lens hood and no filter. Much improved.

The sun came from the front left direction.

With filter, but no lens hood.




Without filter and without lens hood.




With lens hood and without filter.




The above images clearly show the advantage of using a lens hood.
This really applies to any lens. It can never do any harm.

the lens hoods of lenses with build in lens hoods never seem to be fully effective. For example the 77mm f1.8 Ltd and 31mm f1,8 Ltd.

Also of course with the APS-C sensors a 1.5 times longer lens hood can be used.

I can never understand the when a lens is reviewed, the comment:
The lens is more or less prone to flair, but a lens hood will improve it.

How obvious. Also all new lenses this days come with a lens hood supplied. I wonder why?

Regards, Horst

johnriley

Link Posted 04/08/2014 - 07:46
The dedicated lens hoods are tailored to each lens and offer the best protection, and yes, always use a hood. Your pictures also show why I ditched routinely using filters a long time ago.

Modern coatings are superb, but lenses have many more elements, so there's still potentially a fair bit of scattered light around.
Best regards, John

walkeja

Link Posted 04/08/2014 - 10:23
Or set the metering correctly?
Pentax K1-ii and MZ6
Pentax Lenses 28-80 F, 300 DA*, 80-200 F, 35 F2.4 AL, M50 F1.7, 28-105 DFA, 20 F4 SMC
ONE UNITED Member

Horst

Link Posted 04/08/2014 - 10:33
Flare has nothing to do with the metering.

It has to do with the Sun shining in to your objective especcially on certain angles.

regards, Horst

MrB

Link Posted 05/08/2014 - 10:17
Horst wrote:
Flare has nothing to do with the metering.

It has to do with the Sun shining in to your objective especially on certain angles.

regards, Horst

The photos shown above are not the results of a fair test - if they had been, they might show smaller differences. The exposure changes by -1 EV from #1 to #2, and by -1 EV again from #2 to #3 - this is not responsible for the flare but it does exaggerate its appearance in the first two. Also the camera position changes for each shot - it is tilted downwards more in #2 and #3, and it is closer to the fruit tree in #3; these changes alter the angle of the incident light, and that can have a significant effect on the amount and appearance of any flare that might occur.

The principle is OK - it is sensible to use a lens hood to reduce the risk of flare. However, the advances in lens coating technology have already reduced that risk to very low in most cases so, for me, always using a lens hood is more important for the protection it gives the lens from the odd accidental knocks against a wall, fence, door, etc. Also for the latter reason, I usually use the rubber types.

Cheers.
Philip
Last Edited by MrB on 05/08/2014 - 10:20

wvbarnes

Link Posted 05/08/2014 - 10:32
Hi, Interesting exercise. I found UV filters detrimental too so stopped using them. I always use lens hoods including a nice cheap folding Kood silicone rubber one for the 35mm DA2.4 AL which lacks one in the box.

cbrog

Link Posted 05/08/2014 - 13:25
Quote:
Also of course with the APS-C sensors a 1.5 times longer lens hood can be used.

Why? Surely the focal length of a lens remains unchanged regardless of sensor size.

Roger
Last Edited by cbrog on 05/08/2014 - 13:26

johnriley

Link Posted 05/08/2014 - 13:28
cbrog wrote:
Quote:
Also of course with the APS-C sensors a 1.5 times longer lens hood can be used.

Why?


Roger

Because the field of view is narrower as only the centre of an imaginary film frame is used. So the Pentax 50mm snap on lens hood can be used quite happily on the 35mm DA lens. They both have the same field of view, therefore need the same amount of shading.
Best regards, John

Horst

Link Posted 05/08/2014 - 14:11
MrB wrote:

Quote:
the advances in lens coating technology have already reduced that risk to very low in most cases

You are quite right of course.
however no matter how and what sort of coating you use, there is still glass in an lens-objective with plenty of surfaces.
Compared to a nothing, this is still a murky state of affairs.

so flair is still possible, especially when light strikes it at certain angles.
As you said the test was not completely fair, because I changed the angle a bit.

So this will also proof that flair is possible.
I don't believe that the lens manufacturers include a lens hood just because it may look nice, but because they are aware of the problem of flare.

Regards, Horst

Mike-P

Link Posted 05/08/2014 - 14:31
Horst wrote:
Also all new lenses this days come with a lens hood supplied. I wonder why?

Only Canon L lenses come with a hood, for all other they are an optional extra.
. My Flickr

johnriley

Link Posted 05/08/2014 - 14:53
Yes, but we're talking Pentax here, not Canon. It is true to say that, apart from a few low cost lenses, Pentax lenses are generally supplied with a hood.
Best regards, John

Horst

Link Posted 05/08/2014 - 15:00
Mike-P wrote:


Quote:
Only Canon L lenses come with a hood, for all other they are an optional extra.

Wow, what a statement.

Let me give you a few examples of my Pentax lenses and lenses for Pentax by other makers.

1.)DA 40mm f2.8 with lens hood
2.)Fa 77mm f1.8 with lens hood
3.)FA 31mm f1.8 with lens hood
4.)DA 18-55mm Kit lens with lens hood
5.)FA 35mm f2 with lens hood
6.)Super Takumar 35mm f2 with lens hood
7.)Super Takumar 55mm f1.8 with lens hood
8.)Super Takumar 50mm f1.4 with lens hood
9.)Pentax SMC-A 28mm f2.8 with lens hood

10.) Sigma AF 70 - 210mm with lens hood
11.)Tamron SP AF 24-135mm with lens hood
12.)Tamfon AF28-200 with lens hood
13.)Promaster Spectrum AF 28 -200mm with lens hood

All this lenses came with lens hood supplied by the manufacturer.

My other lenses some I am not sure of, because I bought them secondhand and I don't know if they came originally with a lens hood.
Example Pentax-F 50mm f1.4. and Pentax-A 50mm f1.4

So your statement above may not be quite correct.
I agree, that some Pentax and other early brands where not supplied with lens hoods. but all the current lenses I believe are.

Ah, I forgot my Pentax FA 50mm f2.8, A 50mm f2.8 and 100mm f2.8 macro lenses dis not come with a lens hood, because the lens elements are so far back in the body, that the body acts as a lens hood.

Regards, Horst

McGregNi

Link Posted 05/08/2014 - 15:12
I always use hoods, just seems like common sense .. sure, it won't always make a difference , but it reduces one potential cause of contrast reduction. Lets not forget also the clear advantage of the physical protection offered to the front glass by hoods - on my Samyang the rather short petal hood has saved it from scratches a few times because the front element is bulbous and it is very easy to forget to protect it when moving around.

I've given up with 'protective' filters or UVs / skylight types - the extra flexiblity available in processing now seems to outweigh any IQ advantage they may offer, if indeed they offer any.
My Guides to the Pentax Digital Camera Flash Lighting System : Download here from the PentaxForums Homepage Article .... link
Pentax K7 with BG-4 Grip / Samyang 14mm f2.8 ED AS IF UMC / DA18-55mm f3.5-5.6 AL WR / SMC A28mm f2.8 / D FA 28-105mm / SMC F35-70 f3.5-4.5 / SMC A50mm f1.7 / Tamron AF70-300mm f4-5.6 Di LD macro / SMC M75-150mm f4.0 / Tamron Adaptall (CT-135) 135mm f2.8 / Asahi Takumar-A 2X tele-converter / Pentax AF-540FGZ (I & II) Flashes / Cactus RF60/X Flashes & V6/V6II Transceiver

Mike-P

Link Posted 05/08/2014 - 15:35
johnriley wrote:
Yes, but we're talking Pentax here, not Canon. It is true to say that, apart from a few low cost lenses, Pentax lenses are generally supplied with a hood.

The post was actually just to show that Pentax are quite good in that respect as they provide hoods with even their cheapest lenses. Canon on the other hand charge for anything they can get away with.

But never mind.
. My Flickr

johnriley

Link Posted 05/08/2014 - 15:37
I'm not the only one who interpreted your post in another way Mike!
Best regards, John
Add a Comment
You must be registered or logged-in to comment.