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philslizzy
Joined: 07 Aug 2012 Posts: 4744 Location: Cheshire, England
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Posted: Sun Apr 06, 2014 9:11 am Post subject: Which is better overall? |
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philslizzy wrote:
So which would produce better results?
1: A lens with a front focusing element
2: A lens who's optical block moves in and out
3: One in which an internal element focuses _________________ Hero in the 'messin-with-cameras-for-the-hell-of-it department'. Official. |
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Oldhand
Joined: 01 Apr 2013 Posts: 5999 Location: Mid North Coast NSW - Australia
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Posted: Sun Apr 06, 2014 9:22 am Post subject: |
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Oldhand wrote:
The biggest advantage to IF (internal focusing) is the lack of change to the dimensions of the lens.
This is an advantage in macro work where the lens in focusing gets too close to the subject.
If the front of the lens does not rotate, then this is an advantage in using filters like polarisers and graduated ND filters.
Other than that, I can't see that it makes much difference to the final result either way.
OH |
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bernhardas
Joined: 01 Jan 2013 Posts: 1432
Expire: 2017-05-23
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Posted: Sun Apr 06, 2014 9:26 am Post subject: |
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bernhardas wrote:
Edited
Last edited by bernhardas on Tue May 10, 2016 7:43 am; edited 1 time in total |
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calvin83
Joined: 12 Apr 2009 Posts: 7555 Location: Hong Kong
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Posted: Sun Apr 06, 2014 9:32 am Post subject: |
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calvin83 wrote:
A lens design and made for a certain application. _________________ https://lensfever.com/
https://www.instagram.com/_lens_fever/
The best lens is the one you have with you. |
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paulhofseth
Joined: 05 Mar 2011 Posts: 575 Location: Norway
Expire: 2018-06-28
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Posted: Sun Apr 06, 2014 8:00 pm Post subject: case 2 |
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paulhofseth wrote:
For a unit being moved, it cannot avoid being designed for a particular set of "conjugates": plane of object-plane of image.
You will find that some enlarging lenses are listed as !:10, others as 1:4. You will see that the Zeiss\CY 60macro is optimized for 1:10, while one Olympus 80mm bellows performs best at 1:1. This is also why one turns some lenses around in order to get up close.
Someone with deeper knowledge of optics will have to reply on moving elements. I have noticed that some zooms (such as the Leitz 35-70) move an internal element in order to get closer and still does maintain reasonable quality of image. One must assume that this is far better than just providing a longer helix. Some macros also have elements moving in relation to each other when they go closer. Whether they perform better than those designed for the distances involved, I do not know, but those I have used satisfy my medium strict demands.
p. |
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Gerald
Joined: 25 Mar 2014 Posts: 1196 Location: Brazil
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Posted: Sun Apr 06, 2014 8:02 pm Post subject: Re: Which is better overall? |
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Gerald wrote:
philslizzy wrote: |
So which would produce better results?
1: A lens with a front focusing element
2: A lens who's optical block moves in and out
3: One in which an internal element focuses |
There is no best focusing system. Each has advantages and disadvantages.
The technical names of those focusing systems are:
1. front-cell focusing
2. unit focusing
3. internal focusing
If you Google these names you'll find a lot of information about them. _________________ If raindrops were perfect lenses, the rainbow did not exist. |
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pdccameras
Joined: 23 Aug 2009 Posts: 825 Location: Putnam, CT
Expire: 2014-08-11
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Posted: Sun Apr 06, 2014 8:30 pm Post subject: |
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pdccameras wrote:
In the most general of cases, front cell focusing lenses will not usually be as good performers as the other two options you presented.
P. _________________ Canon 5D Mii, Canon 40D, Canon 350D IR, Sony A7 Mii, Sony Alpha-6000, a ton of lenses: AF & MF and too many cameras to count, all formats: 110 - 4x5. |
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Lightshow
Joined: 04 Nov 2011 Posts: 3666 Location: Calgary
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Posted: Sun Apr 06, 2014 8:57 pm Post subject: Re: Which is better overall? |
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Lightshow wrote:
philslizzy wrote: |
So which would produce better results?
1: A lens with a front focusing element
2: A lens who's optical block moves in and out
3: One in which an internal element focuses |
In general I prefer #2 + with close focus correction in WA lenses. _________________ 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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