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04-05-2013, 09:46 PM   #1
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Hood thingy ... er ... vent?

Just wondering if anyone can tell me what the clip out section on the hood of my DA 18-55 is for? The whole point of a hood is to stop extra light falling at an angle across the front element so would removing a little section defeat the purpose of the hood?

Someone enlighten me please (te he, light pun).

04-05-2013, 09:57 PM   #2
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Oh THANK YOU!

I am so glad you asked that question. Every time I take that hood on or off, I wonder the same thing. Hope someone answers!
04-05-2013, 10:00 PM   #3
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Its so that if you have a polarising filter fitted on the lens, you can still adjust it with your finger tips with the hood on.
04-05-2013, 10:34 PM   #4
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It is a finger port to allow adjustment of filters without the need to remove the hood and then put it back on afterward. It should have a cover for cases when you don't need to make adjustments or have finished.

04-05-2013, 11:06 PM   #5
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Yeah, if you use a polarizing filter with the hood on you will praise it as the greatest invention since the wheel! I don't know how many times I've tried using my Sigma 20/1.8 with both the hood and a filter and try to adjust the filter by trying to grip the outer rim of it, only to end up with two big greasy marks on the glass instead.
04-05-2013, 11:50 PM   #6
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It's so when you lose it and you feel compelled to replace it by buying a new one at hyper inflated prices , Pentax can make more money.
04-05-2013, 11:51 PM   #7
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Yup! The fingernail always slips off the knurling.

04-06-2013, 05:25 AM   #8
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Well, now that we've got that sorted out, I've got another: so what's so great about sliced bread?
04-06-2013, 05:30 AM   #9
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Agreed, I live in France and eat baguettes daily and rarely sliced bread ... oops, what was the question again ? ... oh yah, it's for the polarizing filter's adjustment access ... J
04-06-2013, 05:32 AM   #10
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Wow, when I use a polarising filter I just reach inside the hood to adjust it, or take the hood off (like a sucker apparently).

Thanks everyone. Curiosity now sated.
04-06-2013, 05:47 AM   #11
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It's just so you can poke your finger up it, to give it a wee twirl (polarizing filter) so to speak.
04-06-2013, 07:23 AM   #12
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You can also use it to get at the focus ring when the hood is reversed and shooting manual focus for close-up work. Yes, you can just take the hood off too, but the hatch fits better in my pockets than the entire hood. Extending the hood creates a shadow using the flash on close-ups.
04-06-2013, 07:28 AM - 1 Like   #13
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QuoteOriginally posted by dadipentak Quote
Well, now that we've got that sorted out, I've got another: so what's so great about sliced bread?
It's not that great.
The light transmission properties suck and if you are not careful you can get crumbs on the sensor when changing loaves.
04-06-2013, 03:36 PM   #14
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Actually, the side opening of the hood is for heat vent.

You know, when light hits the sensor, it generates heat. Heat causes noise. You can use Lightroom or Noise Ninja or Noiseware but it's best to avoid noise in the first place.

The opening is for heat vent, to prevent heat buildup.

You say that the heat can go through the big opening in the front of the hood? No. That big opening is for light to get in. If heat goes out that way, it'll interfere with the light, reducing contrast and even causing chromatic aberration, not good if you ask me.

This is why Pentax lenses are the best.....

Last edited by SOldBear; 04-06-2013 at 06:55 PM.
04-06-2013, 04:02 PM   #15
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Leica has vented hoods, always looked like a solution in search of a problem to me.

There is an unintended secondary use with WR or DA* lenses: drain.
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