Advertisements


Go Back   Four Thirds User discussion forum > Equipment > The Four Thirds User Knowledge Base Wiki

The Four Thirds User Knowledge Base Wiki The place to discuss the FTU Wiki, a knowledge base for Four Thirds and Micro Four Thirds photographers that is built and enhanced by you.

Reply
 
Thread Tools Display Modes
  #1  
Old 12th December 2015
Patrick Patrick is offline
Full member
 
Join Date: Jul 2012
Location: West Midlands
Posts: 339
Blog Entries: 1
Thanks: 15
Thanked 30 Times in 26 Posts
Likes: 1
Liked 4 Times in 4 Posts
Why?

Can anyone explain, why my my 7-14mm luminous lens is 114 degree field of view at the wide end when the Yamsang fisheye 7.5mm is 180 degree field of view. I would have thought being a similar focal length would give much the same field, obviously there is a technical reason.
I am considering buying one, reports say its a super sharp lens.
Patrick
Reply With Quote
  #2  
Old 12th December 2015
Ian's Avatar
Ian Ian is offline
admin
 
Join Date: Jan 2007
Location: Hemel Hempstead UK
Posts: 7,709
Blog Entries: 13
Thanks: 144
Thanked 760 Times in 466 Posts
Likes: 93
Liked 123 Times in 61 Posts
Re: Why?

Yes, fisheye lenses are not rectilinear so the way the field of view is calculated in relation to the focal length is different. Rectilinear lenses are where the optical design aim is to maintain straight sides and the same perspective as a pin hole camera.

Ian
__________________
Founder/editor
Four Thirds User (http://fourthirds-user.com)
Digital Photography Now (http://dpnow.com)
Olympus UK E-System User Group (http://e-group.uk.net)
Olympus camera, lens, and accessory hire (http://e-group.uk.net/hire)
Twitter: www.twitter.com/ian_burley
Flickr: www.flickr.com/photos/dpnow/
Pinterest: www.pinterest.com/ianburley/
Reply With Quote
  #3  
Old 12th December 2015
Patrick Patrick is offline
Full member
 
Join Date: Jul 2012
Location: West Midlands
Posts: 339
Blog Entries: 1
Thanks: 15
Thanked 30 Times in 26 Posts
Likes: 1
Liked 4 Times in 4 Posts
Re: Why?

Thank you Ian
Reply With Quote
  #4  
Old 15th December 2015
hschnee's Avatar
hschnee hschnee is offline
Animal Portraitist
 
Join Date: Aug 2007
Location: Chapel Hill, North Carolina
Posts: 2,516
Thanks: 414
Thanked 240 Times in 198 Posts
Likes: 155
Liked 99 Times in 71 Posts
Re: Why?

If you use software to "de-fish" an image from a fisheye lens, you'll see that as the curved lines get unbent, a significant part of the frame gets lost--it gets cropped out of the edge to create a rectangular image. A rectilinear lens like the 7-14 essentially does the same thing using optics.

- Hal -
__________________
A Still Mind - Photography, Music, Meditation, Ministry - www.astillmind.net
Olympus E-M5; Panasonic-Leica DG Summilux 25mm; Zuiko 12-60 SWD, 50-200 SWD; Sigma 105 Macro; Rokinon (Samyang) 7.5mm fisheye; Olympus 8/1.8 PRO fisheye; FL-50R; Giottos MT-8361 tripod with Gitzo GH2780QR ballhead.
Reply With Quote
The Following User Says to hschnee they like this post:
Ians Tata (16th December 2015)
  #5  
Old 16th December 2015
Patrick Patrick is offline
Full member
 
Join Date: Jul 2012
Location: West Midlands
Posts: 339
Blog Entries: 1
Thanks: 15
Thanked 30 Times in 26 Posts
Likes: 1
Liked 4 Times in 4 Posts
Re: Why?

I thanks for your response, before posting I had an idea about this, Ian's reply sort of confirmed it. Your reply confirms it most clearly.

Patrick
Reply With Quote
  #6  
Old 16th December 2015
Graham's Avatar
Graham Graham is offline
Full member
 
Join Date: Aug 2007
Location: Rainham
Posts: 1,007
Thanks: 52
Thanked 73 Times in 62 Posts
Likes: 30
Liked 29 Times in 20 Posts
Re: Why?

You can't use a 7.5mm if you have big feet, they will appear in every shot.

The 7-14 is really superb.

Have fun.
__________________
Graham

Keep smiling, it gets folk wondering what you've been up to
Reply With Quote
  #7  
Old 16th December 2015
Patrick Patrick is offline
Full member
 
Join Date: Jul 2012
Location: West Midlands
Posts: 339
Blog Entries: 1
Thanks: 15
Thanked 30 Times in 26 Posts
Likes: 1
Liked 4 Times in 4 Posts
Re: Why?

I,m size 101/2😉we shall see how I get on, I have just won a second hand example on eBay.
I first got interested in fisheye photography when I had a fisheye add on lens for my iPhone, gave impressive results.

I plan experimenting with panoramas with the lens, could be fun or great disappointment, we will see.

Patrick
Reply With Quote
  #8  
Old 16th December 2015
Graham's Avatar
Graham Graham is offline
Full member
 
Join Date: Aug 2007
Location: Rainham
Posts: 1,007
Thanks: 52
Thanked 73 Times in 62 Posts
Likes: 30
Liked 29 Times in 20 Posts
Re: Why?

They are a good "fun" lens that with the right subject can work really well.

Please show us your results.
__________________
Graham

Keep smiling, it gets folk wondering what you've been up to
Reply With Quote
The Following User Says to Graham they like this post:
Barr1e (17th December 2015)
  #9  
Old 17th December 2015
hschnee's Avatar
hschnee hschnee is offline
Animal Portraitist
 
Join Date: Aug 2007
Location: Chapel Hill, North Carolina
Posts: 2,516
Thanks: 414
Thanked 240 Times in 198 Posts
Likes: 155
Liked 99 Times in 71 Posts
Re: Why?

I have the Samyang 7.5mm fisheye and love it--it's quite sharp and a lot of fun. I do have to be careful about how I hold the camera because it's easy to get my fingers in the corners of the pictures. And if you point the camera down just a bit, your feet will appear, especially in vertical images. The challenges of composition are just part of the fun.

- Hal -
__________________
A Still Mind - Photography, Music, Meditation, Ministry - www.astillmind.net
Olympus E-M5; Panasonic-Leica DG Summilux 25mm; Zuiko 12-60 SWD, 50-200 SWD; Sigma 105 Macro; Rokinon (Samyang) 7.5mm fisheye; Olympus 8/1.8 PRO fisheye; FL-50R; Giottos MT-8361 tripod with Gitzo GH2780QR ballhead.
Reply With Quote
The Following User Says to hschnee they like this post:
Barr1e (17th December 2015)
  #10  
Old 19th December 2015
Patrick Patrick is offline
Full member
 
Join Date: Jul 2012
Location: West Midlands
Posts: 339
Blog Entries: 1
Thanks: 15
Thanked 30 Times in 26 Posts
Likes: 1
Liked 4 Times in 4 Posts
Re: Why?

Well the lens arrived yesterday, not been able to try it out yet but here is a shot taken in my room at home.
Not quite as sharp as I had hoped, the reviews say how sharp it is.

Hope to give it a proper tryout Sunday.

Patrick
Attached Images
File Type: jpg _1040027.jpg (29.3 KB, 12 views)
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT. The time now is 07:10 AM.


The Write Technology Ltd, 2007-2015, All rights reservedAd Management plugin by RedTyger