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timo832000
Joined: 09 Jun 2008 Posts: 544 Location: Germany / Cologne
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Posted: Fri Aug 17, 2012 7:49 pm Post subject: How to find a matching lens hood? |
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timo832000 wrote:
I still need hoods for two of my lenses.
1. SMC Pentax - M 2.0/28 (49mm filter thread)
2. SMC Pentax - M 1.7/50 (49mm filter thread)
Both lenses are used on Pentax K-r (Crop 1.5).
How can I calculate the dimensions of the perfect hood?
I would prefer to buy a simple metal hood for each lens, how long should they be?
Thanks for your advice.
Timo
[/list] _________________ I love Leica ! But I need Pentax |
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Attila
Joined: 24 Feb 2007 Posts: 57865 Location: Hungary
Expire: 2025-11-18
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Posted: Fri Aug 17, 2012 7:59 pm Post subject: |
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Attila wrote:
normal lens is easy any hood okay I think, wide is different , do you sure do you really need hood ?
I never use hoods , most lens works well without hood. _________________ -------------------------------
Items on sale on Ebay
Sony NEX-7 Carl Zeiss Planar 85mm f1.4, Minolta MD 35mm f1.8, Konica 135mm f2.5, Minolta MD 50mm f1.2, Minolta MD 250mm f5.6, Carl Zeiss Sonnar 180mm f2.8
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timo832000
Joined: 09 Jun 2008 Posts: 544 Location: Germany / Cologne
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Posted: Fri Aug 17, 2012 8:13 pm Post subject: |
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timo832000 wrote:
Yes I think so, I got some images with low contrast or lens flare caused by bright lateral light. On the other hand a hood will also protect the front elemet from unwanted touch.
I even got the feeling that a bright light source which shines into the lens but can`t be seen in the view finder because of the crop factor of my camera nevertheless can bother my image. _________________ I love Leica ! But I need Pentax |
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Attila
Joined: 24 Feb 2007 Posts: 57865 Location: Hungary
Expire: 2025-11-18
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Posted: Fri Aug 17, 2012 9:20 pm Post subject: |
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Attila wrote:
On 49mm filter thread my suggestion is take an East German rubber hood very practical, 20mm I have really no idea , I have factory hoods for some 20mm lenses they are usually nothing just a little ring. Try to make a DIY one from card board and look which size is okay . _________________ -------------------------------
Items on sale on Ebay
Sony NEX-7 Carl Zeiss Planar 85mm f1.4, Minolta MD 35mm f1.8, Konica 135mm f2.5, Minolta MD 50mm f1.2, Minolta MD 250mm f5.6, Carl Zeiss Sonnar 180mm f2.8
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TimHar
Joined: 24 Jul 2012 Posts: 8 Location: Amsterdam, The Netherlands
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Posted: Fri Aug 17, 2012 10:35 pm Post subject: |
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TimHar wrote:
A good read http://toothwalker.org/optics/lenshood.html |
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luisalegria
Joined: 07 Mar 2008 Posts: 6602 Location: San Francisco, USA
Expire: 2018-01-18
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Posted: Fri Aug 17, 2012 11:29 pm Post subject: |
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luisalegria wrote:
For 28mm on crop almost any "normal" metal hood will be fine. This is like a 42mm on crop, so there usually isn't a vignetting problem.
If you are concerned, get a plastic "flower" hood.
As Attila says, the ordinary rubber hoods are good also. I use one with my 24mm Pentax on crop (36mm equivalent).
Just be careful with filters, filter+hood could cause vignetting. On DSLR there is rarely a reason to use a filter, except sometimes a polarizer.
Another way, if you are concerned with vignetting, is to get a normal metal hood one or two sizes larger - say 52-55mm for 49mm, and use it with a step-up adapter. I would certainly do this with a polarizer.
Look in ebay, there are plenty of normal hoods from China for $3, plastic or metal.
Step up adapters are $2-3
The cheap 'wide angle' metal hoods they sell are usually too large and don't look good on a little lens, and I think they aren't such good protection.
I always use a hood, no matter what lens. Its better protection than a filter, and it improves results, often surprising by how much. _________________ I like Pentax DSLR's, Exaktas, M42 bodies of all kinds, strange and cheap Japanese lenses, and am dabbling in medium format/Speed Graphic work. |
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gmonkman1
Joined: 08 Jun 2011 Posts: 45 Location: se of Winnipeg Manitoba
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Posted: Sat Aug 18, 2012 2:35 am Post subject: |
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gmonkman1 wrote:
I always prefer to use a hood on all my lenses too. With 1.5 sensor it is easier
to find lens hoods because you are only using most of the centre part of the
lens. Since I no longer use alot of my old film filters , I remove the glass part
and just use the rings as hoods. My pentax 50mm 1.7 uses four rings
(thickness may vary) so use 3 or 5. Makes a perfect hood.
Once you have them on...turn lens to smallest aperture (highest f number)...
aim at bright wall or blue sky...press aperture stop down button to check in
view finder to see if vignetting and adjust accordingly.Works for any lens. |
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Lightshow
Joined: 04 Nov 2011 Posts: 3666 Location: Calgary
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Posted: Sat Aug 18, 2012 5:51 am Post subject: |
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Lightshow wrote:
On 1.5x, I typically just go to the next longer hood, so far so good, just look for vignetting in live view.
24->28
28->35
35->50
50->85 _________________ A Manual Focus Junky...
One photographers junk lens is an artists favorite tool.
My lens list
http://www.flickr.com/photos/lightshow-photography/ |
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tao
Joined: 26 Oct 2011 Posts: 241 Location: Bangkok
Expire: 2015-03-12
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Posted: Sat Aug 18, 2012 10:22 pm Post subject: |
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tao wrote:
When I was new to m4/3 I simple made a long paper hood for each lens and cut it down until I did not see any vignette before go on hunting on eBay. Now I have so many hoods I don't have to do that any more. |
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Orio
Joined: 24 Feb 2007 Posts: 29545 Location: West Emilia
Expire: 2012-12-04
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Posted: Sun Aug 19, 2012 8:10 am Post subject: Re: How to find a matching lens hood? |
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Orio wrote:
timo832000 wrote: |
How can I calculate the dimensions of the perfect hood? |
It's quite easy Timo:
- Cut a strip of black floppy cardboard, 20 cm long is more than enough, and make it 10 cm wide.
- Wrap it around your lens, with the edge of the cardboard matching the front edge of the lens.
- Stop the lens down to f/8 or smaller
- Point the camera to the sky.
- Shift forward the cardboard, until you notice it's presence appearing in the corners of the viewfinder.
- Then shift back just as much as it disappears again, and hold it there.
- Take the measurement, that is the longest hood lenght that your lens/camera combination does allow. _________________ Orio, Administrator
T*
NE CEDE MALIS AUDENTIOR ITO
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timo832000
Joined: 09 Jun 2008 Posts: 544 Location: Germany / Cologne
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Posted: Sun Aug 19, 2012 4:55 pm Post subject: |
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timo832000 wrote:
Thanks Orio, this is really simple. Very good Idea, I will do that.
Timo _________________ I love Leica ! But I need Pentax |
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