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-   -   Fish eye v Wide angle (https://e-group.uk.net/forum/showthread.php?t=47301)

MJ224 27th February 2018 09:19 AM

Fish eye v Wide angle
 
I thought I knew what a fisheye lens was.

Do they distort always? And if so presumably are different from a very wide angle lens.

I see on Ebay there are quite a few 7.5mm fish-eye lens for around the 100 mark, but few "proper" wide angles around the 8mm mark............:(

pdk42 27th February 2018 10:04 AM

Re: Fish eye v Wide angle
 
Fisheye lenses will curve anything away from the centre of the field of view. The curvature gets greater as you move away from the x/y axis. So yes, they distort always (if rectilinear is your view of "undistorted" :)).

They can be defished easily but lose resolution towards the edges as a result. I've found that the Samyang 7.5mm FE (an excellent lens BTW) can be defished to about an equiv rectilinear view of 7mm without too much loss of resolution.

This post I did some time ago might be of interest to you:

https://www.mu-43.com/threads/iq-of-...-images.60658/

MJ224 27th February 2018 10:27 AM

Re: Fish eye v Wide angle
 
Sounds good. What does de-fishing entail? (without googling) .

I would assume the removal of that dome lens somehow!!

Thanks for that link........

EDIT..........See that the defishing is in software manipulation.

Could it be done in the camera via Keystone?

Graham_of_Rainham 27th February 2018 10:53 AM

Re: Fish eye v Wide angle
 
Have a look at DxO Viewpoint. The early versions can be available for free. :cool:

So many cameras offer sweep panorama that the Ultra Wide image can often be "created"

Fisheye is something that can be used very effectively but is best used sparingly. :eek:

MikeOxon 27th February 2018 11:50 AM

Re: Fish eye v Wide angle
 
I use the free Panotools plug in, for GIMP or Photoshop Elements, to 'de-fish' my shots. Be careful when downloading any free software from the web since there are many unscrupulous sites that will 'bundle' software that you definitely do not want on your computer.

My fisheye lens is the Meike 6.5mm f/2, which is a well-made, small and light lens. The circular image is slightly cut-off at top and bottom, on an M4/3 sensor, but, in most of my photos, it's easy to fill in a bit of sky or ground.

The fast aperture makes it an excellent indoor lens and the images de-fish quite well, if that's what you want.

pdk42 27th February 2018 12:06 PM

Re: Fish eye v Wide angle
 
The Samyang 7.5mm FE is a superb lens. It's razor sharp corner to corner even wide open. It also delivers excellent sun-stars! For its price, it's sort of a no-brainer.

Ross the fiddler 27th February 2018 12:44 PM

Re: Fish eye v Wide angle
 
Quote:

Originally Posted by pdk42 (Post 441160)
The Samyang 7.5mm FE is a superb lens. It's razor sharp corner to corner even wide open. It also delivers excellent sun-stars! For its price, it's sort of a no-brainer.

Maybe it's an affordable lens for me to dabble with too. I'll fix a few more violins & buy it. ;)

Graham_of_Rainham 27th February 2018 04:24 PM

Re: Fish eye v Wide angle
 
When a Fish eye lens comes up against a concave mirror, "interesting" things happen...

I found one at the top of the Orbit in the QE2 Park

http://e-group.uk.net/gallery/data/5..._DxO_DxOVP.jpg

Phill D 27th February 2018 09:32 PM

Re: Fish eye v Wide angle
 
Interesting way to de-fish Graham :)
I've never bothered to de-fish mine, I just enjoy the shots the way they turn out. It's a fun lens and as Paul says nicely sharp and great value.

MikeOxon 28th February 2018 01:15 PM

Re: Fish eye v Wide angle
 
I should mention that there are different types of fish-eye lens. Only the shortest focal lengths will provide a circular image within the sensor frame.

Many, such as the Olympus 8mm, fill the frame, so that the circular effect is lost. Check reviews of lenses to make sure you will get whatever effect you want. The full-frame versions are more suitable for 'de-fishing', while the circular images provide a character that is all their own.

My Meike 6.5mm, which is an excellent lens, provides a result as shown below:

http://www.e-group.uk.net/gallery/da...ernery2017.jpg

Graham_of_Rainham 28th February 2018 03:49 PM

Re: Fish eye v Wide angle
 
I sold my Samyang 7.5mm :confused:

I'm thinking of getting the 7.5mm f/2.8 from 7Artizans.

Anyone tried one ?

MikeOxon 28th February 2018 04:16 PM

Re: Fish eye v Wide angle
 
If you just want to play with the circular effect, then one of the cheap add-on converters (~ 25) will do the job and can provide a good image, if you stop the main lens down to f/11 - f/16.

I have an ancient Panagor Semi Fisheye converter, which I've attached to various lenses with filter-ring adapters. On an MFT 14mm lens, it provides the full circular 'look'.

MikeOxon 1st March 2018 11:56 AM

Re: Fish eye v Wide angle
 
Just to show what can be done with an add-on converter, this is a holiday record shot taken using my Panagor semi-fisheye attachment mounted onto an Olympus 14-42 kit lens (set to 14mm) The exposure was 1/3s@f/11 (ISO 500) on my E-M5. The angle of view is about 150.

It's provided me with a memory of an extraordinary place (Borneo Rainforest Lodge, Sabah) that would have been difficult to achieve otherwise.

I used the same attachment, on a compact camera, to record whole sky images during a solar eclipse in China (pics on my website)

http://www.e-group.uk.net/gallery/da...alleyLodge.jpg

MJ224 1st March 2018 12:21 PM

Re: Fish eye v Wide angle
 
Quote:

Originally Posted by MikeOxon (Post 441389)
If you just want to play with the circular effect, then one of the cheap add-on converters (~ 25) will do the job and can provide a good image, if you stop the main lens down to f/11 - f/16.

I have an ancient Panagor Semi Fisheye converter, which I've attached to various lenses with filter-ring adapters. On an MFT 14mm lens, it provides the full circular 'look'.

I was after as wide an angle as I could get, without the fisheye distortion...I guess the 8mm Wide angle is gonna be the biz.........*chr

Thanks all for gems........:)

Petrochemist 2nd March 2018 09:59 PM

Re: Fish eye v Wide angle
 
Quote:

Originally Posted by MikeOxon (Post 441389)
If you just want to play with the circular effect, then one of the cheap add-on converters (~ 25) will do the job and can provide a good image, if you stop the main lens down to f/11 - f/16.

I have an ancient Panagor Semi Fisheye converter, which I've attached to various lenses with filter-ring adapters. On an MFT 14mm lens, it provides the full circular 'look'.

If you're just after the circular look many short focal length c-mount lens can give you that - without the ultra wide FOV. IQ is probably about as good as I've got from most of my collection of wide angle adapters :)

Fish eye lenses always distort significantly, some types much more than others. However they also give much wider views than a rectilinear lens. Two of my fish-eye lenses give a 180 diagonal FOV (something no rectilinear lens can do) Nikon even made one with a 220 FOV.


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