interesting fact about the Sony UWA/fisheye converters

Started Jul 27, 2011 | Discussions
willang77 Regular Member • Posts: 148
interesting fact about the Sony UWA/fisheye converters

I remember reading some discussions/concerns about whether the Sony ultrawide/fisheye (ECU1 and ECF1) converters that is mated to the 16mm sel16f28 results in changes to the f-stop and seems that no one was sure about this.

Yesterday night, I stumbled on Sony's marketing information on these converters that states that the f-stop is unchanged!

Sony's statement:

Both converters attach securely with bayonet mounts, ensuring optimum optical alignment and image quality. Furthermore, these converters cause no light loss so f-stop values remain unchanged.

Link:
http://www.sonydigitalimaging.com/lenses/e-mount/VCL-ECU1.html

Karsten Meyer
Karsten Meyer Contributing Member • Posts: 811
Re: interesting fact about the Sony UWA/fisheye converters

willang77 wrote:

Sony's statement:

Both converters attach securely with bayonet mounts, ensuring optimum optical alignment and image quality. Furthermore, these converters cause no light loss so f-stop values remain unchanged.

That's nothing new and it applys to all converters which fit on top(!) of a lens. There's only a minimal light loss because of the glass, but no change in optical meaning.

Regards,
Karsten

OP willang77 Regular Member • Posts: 148
Re: interesting fact about the Sony UWA/fisheye converters

I was under the impression that usually, converters that fits on top of a lens will change the f-stop by at least 1 stop or more.

So I was pleasantly surprised that these don't change the f-stop.

GodSpeaks
GodSpeaks Forum Pro • Posts: 14,250
Re: interesting fact about the Sony UWA/fisheye converters

willang77 wrote:

I was under the impression that usually, converters that fits on top of a lens will change the f-stop by at least 1 stop or more.

You have it confused with tele-converters, which fit between the lens and the body.

-- hide signature --

The greatest of mankind's criminals are those who delude themselves into thinking they have done 'the right thing.'

  • Rayna Butler

 GodSpeaks's gear list:GodSpeaks's gear list
Panasonic Lumix DMC-TS5 Panasonic FZ1000 Sony Alpha DSLR-A850 Nikon D800E Panasonic Lumix DMC-GX7 +49 more
mynakedsoda Contributing Member • Posts: 701
Question For Any Owners of the Fisheye Converter

Does anyone who owns this know if it turns the lens into a true horizontal fisheye? I know it states 180 degrees but the images look odd to me that I can find. My basis for comparison is the Nikon 10.5mm horizontal fisheye I own. I tend to use it for people shots mainly for effect or inside or on park equipment. I know I could simply use it on the Nex with an adapter but the Sony converter would take up much less space in a camera bag and seems pretty cheap.

blue_skies
blue_skies Forum Pro • Posts: 11,945
Re: Horizontal Fisheye?

I think that you mean that the fish eye lens reaches a 180 degree in the long direction (horizontal typically) of the sensor?

It doesn't do that, and I doubt that the Nikon does it either. Maybe on FF, but this is an APS-C sensors.

I forgot the angle of view - it is on the Sony website. The adapter converts the 16mm to a 10mm fish eye, it sounds very close to your Nikon.

mynakedsoda wrote:

Does anyone who owns this know if it turns the lens into a true horizontal fisheye? I know it states 180 degrees but the images look odd to me that I can find. My basis for comparison is the Nikon 10.5mm horizontal fisheye I own. I tend to use it for people shots mainly for effect or inside or on park equipment. I know I could simply use it on the Nex with an adapter but the Sony converter would take up much less space in a camera bag and seems pretty cheap.

 blue_skies's gear list:blue_skies's gear list
Sony a6000 Sony a5100 Sony a7R II Sony DT 18-55mm F3.5-5.6 SAM Sony 75-300mm F4.5-5.6 +35 more
edwardaneal
edwardaneal Veteran Member • Posts: 9,101
Re: Horizontal Fisheye?

When they talk about a full frame fisheye like the Nikon 10.5 having a 180 degree field of view they are talking about the diagonal field of view, not horizontal

I would assume the Sony converter is measured the same way.

look here:

http://imaging.nikon.com/lineup/lens/specoalpurpose/fisheye/af_dx_fisheye105mmf_28g_ed/index.htm

"Full-frame fisheye images with a picture angle of 180° (diagonal)"

-- hide signature --

My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
NEX-5 18-55 OSS

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

 edwardaneal's gear list:edwardaneal's gear list
Sony Alpha NEX-7 Sigma 60mm F2.8 DN Art Carl Zeiss Touit 1.8/32
mynakedsoda Contributing Member • Posts: 701
Re: Horizontal Fisheye?

edwardaneal wrote:

When they talk about a full frame fisheye like the Nikon 10.5 having a 180 degree field of view they are talking about the diagonal field of view, not horizontal

I would assume the Sony converter is measured the same way.

look here:

http://imaging.nikon.com/lineup/lens/specoalpurpose/fisheye/af_dx_fisheye105mmf_28g_ed/index.htm

"Full-frame fisheye images with a picture angle of 180° (diagonal)"

I own the 10.5 and it is a true horizontal fisheye on my D100 or D200 cameras. As you know they both use 1.5 crop sensors. Meaning you can move your finger to the edge of the lens on the horizontal side and it will appear in your image. The pictures I'm seeing with the Sony Converter don't have the same look I'm used to seeing with my 10.5 thus the reason I'm asking.

edwardaneal
edwardaneal Veteran Member • Posts: 9,101
the same but different

From what I can find in the specifications both the Nikon 10.5 fisheye and the NEX fisheye conversion attachment are full frame fisheyes and as such both are roughly equal to a 15mm fisheye lens on a full frame camera. They also both cover approximately the same diagonal field of view of 180 degrees

Where they could be very different is in how the image is mapped on the sensor

there are many different ways to do this mapping and if it is not done the same way in both lenses the images they produce would not look the same and the way things away from the center of the frame curved would be different. Perhaps this is the difference you are seeing.

look here
http://en.wikipedia.org/wiki/Fisheye_lens#Mapping_function

you can also learn about fisheye lenses field of view and mapping here
http://www.bobatkins.com/photography/technical/field_of_view.html

I do not have the NEX conversion lens so I can not directly compare it to my 10.5, but I hope you find this information helpful

-- hide signature --

My kit - D200, 10.5mm f/2.8D, 35mm f/1.8G, 50mm f/1.4G & 70-300VR
NEX-5 18-55 OSS

Lenses worth mentioning owned and sold– 12-24 f/4, 17-55 f/2.8, 35-70 f/2.8, 80-200 f/2.8, 20mm f/2.8, 35mm f/2, 50mm f/1.8, 50mm f/1.4D, 60mm f/2.8D, 85mm f/1.8, 105mm f/2D-DC, 180mm f/2.8, 300mm f/4D-ED

 edwardaneal's gear list:edwardaneal's gear list
Sony Alpha NEX-7 Sigma 60mm F2.8 DN Art Carl Zeiss Touit 1.8/32
blue_skies
blue_skies Forum Pro • Posts: 11,945
Re: Horizontal Fisheye?

mynakedsoda wrote:

edwardaneal wrote:

When they talk about a full frame fisheye like the Nikon 10.5 having a 180 degree field of view they are talking about the diagonal field of view, not horizontal

I would assume the Sony converter is measured the same way.

look here:

http://imaging.nikon.com/lineup/lens/specoalpurpose/fisheye/af_dx_fisheye105mmf_28g_ed/index.htm

"Full-frame fisheye images with a picture angle of 180° (diagonal)"

I own the 10.5 and it is a true horizontal fisheye on my D100 or D200 cameras. As you know they both use 1.5 crop sensors. Meaning you can move your finger to the edge of the lens on the horizontal side and it will appear in your image. The pictures I'm seeing with the Sony Converter don't have the same look I'm used to seeing with my 10.5 thus the reason I'm asking.

Then it is probably the same - see pic below

You can see my finger at the right hand side. This was 'beside' the lens, not in front.

Also - if you follow the pink concrete inlay (bottom) you can follow the curvature. You can see that both sides (180degree) are in the view.

As I understand it now - the fisheye forms a full circle on FF.

On DX (or APS-C) this is cropped to the size of the sensor, hence the different view.

The lenses can follow different mapping curves - you have to view them side by side, but at a first glance I'd say that they are very similar.

You can see that the scene forms a straight line in the second pic (taken from further away).

 blue_skies's gear list:blue_skies's gear list
Sony a6000 Sony a5100 Sony a7R II Sony DT 18-55mm F3.5-5.6 SAM Sony 75-300mm F4.5-5.6 +35 more
andrewD2 Veteran Member • Posts: 9,378
Re: Horizontal Fisheye?

Would you do me a big favour and email me a full size image of the stadium shot (or any shot showing corners really). I'm a big fisheye fan and really tempted by a nex C3. Have the minolta A mount 16mm FE and the canon 15mm FE.

Andrew

blue_skies
blue_skies Forum Pro • Posts: 11,945
Re: Horizontal Fisheye?

andrewD2 wrote:

Would you do me a big favour and email me a full size image of the stadium shot (or any shot showing corners really). I'm a big fisheye fan and really tempted by a nex C3. Have the minolta A mount 16mm FE and the canon 15mm FE.

Andrew

Try clicking on "Original"?

The file should be 6.6MB and measure 4592x3056 pixels (straight OOC).

If not, let me know -send me a PM - I will mail you original.

 blue_skies's gear list:blue_skies's gear list
Sony a6000 Sony a5100 Sony a7R II Sony DT 18-55mm F3.5-5.6 SAM Sony 75-300mm F4.5-5.6 +35 more
mynakedsoda Contributing Member • Posts: 701
Re: Horizontal Fisheye?

Thanks! That answers my question! Seems it is a true horizontal fisheye then like the Nikon 10.5mm. The 10.5 by the way was designed for the 1.5 crop sensor (Nikon didn't have any full frame digital sensor camera when they came out with that digital lens). I've had a circular fisheye before and found it a neat effect but not as useful as a horizontal fisheye like the 10.5 or the Sony converter would be. I've actually used it for months at a time as one of my three primary lenses in a three lens kit I found it so useful.

andrewD2 Veteran Member • Posts: 9,378
Re: Horizontal Fisheye?

"original" didn't show them full on an ipad but it does on the PC.
You're a star, thanks.
Andrew

Keyboard shortcuts:
FForum MMy threads