Lightstream wrote in post #2131325
Telephoto hoods can be quite useable. However, the narrow angle of view of tele lenses tends to keep the sun out of the frame anyway. They are deep enough to provide physical impact protection.
It's not a matter of the sun being in the frame - it's a matter of the sun's direct light striking the front element of the lens. No hood blocks the sun if you choose to have it in the image frame. Otherwise, it would vignette. But if the sun is outside the frame and still shines on the front element, it will generate internal reflections in the lens. It may result in visible flare, it may weaken contrast, or it may not have any visible effect at all.
Standard zoom hoods are questionable. I leave them off indoors, but outdoors with VERY strong sunlight, I put them on anyway for what little benefit they may offer. Note that things like the 24-105L hood only works well at 24mm. 24-70 hood is better, it works at all focal lengths due to the unique design.
Yes, the hood, by design, has to accomodate the widest focal length of the lens. The 24-70 hood is unique in that it's effect varies according to the focal length.
The ultrawideangle hoods are *HOPELESS* IMO. They neither provide adequate shielding area against flare, nor physical impact. They make it incredibly difficult to pack a lens in a bag, and they are UGLY. You can probably guess which one I am referring to, the 17-40/16-35/10-22 hood. Useless. I skip this one. Flared out an entire shoot even with the hood on. Stuff it. If it is so small, it isn't even going to help with the usual 'it improves contrast' argument. If I don't notice a contrast improvement, I don't care. I have chased percentage points of incremental improvement before in another interest, and it is a totally pointless exercise, looking back.
I have to agree somewhat - these hoods are very shallow, as they need to be for the angle-of-view presented by the lens. More effective would be to keep the sun away from the front of the lens. You gain a few degrees of angle before the shade of the hood no longer protects the front of the lens.
300 f/4L IS and 400/5.6 have the nicest hood designs I've seen. I love the integral pull-out-and-twist hoods, those are genuinely easy to live with and work with, and hardly add anything to the size of the lens.
Yes, great hoods on those two lenses.
Bottom line however, is that all of them make your lens at least 2-3X more intimidating and impressive looking. However, none of that has any effect on the chicks, who do not seem to show any increased interest in either my gear or myself. YMMV. You and I seem to have made up our minds already though

Chicks dig nice hoods. 