Help for angle of view conversion

Hi,

Could someone please help confirming my calculation ?

Is the following correct ?

>>> On a GH-4 M43 camera, the obtained angle of view on the sensor will be smaller with this Laowa 15mm ( https://www.venuslens.net/product/laowa-15mm-f/ ) than on this Lumix 14-45mm ( https://www.bhphotovideo.com/c/product/657970-REG/Panasonic_H_FS014045_Lumix_G_Vario_14.html ) ?

That is surprising to me as the Laowa is a wide angle lens, and the Lumix isn't, but if I understand correctly, because of the sensor crop factor, I would actually get a 30mm with the Laowa lens, and a 28mm with the Lumix, is that really how this works ?

Thank you !

More or less, but ...

Lens FLs are nominal values.

WA and UWA lenses vary a lot in the angle of view for a given type and nominal FL.

CapybaraFuture wrote:

Hi,

Could someone please help confirming my calculation ?

Is the following correct ?

>>> On a GH-4 M43 camera, the obtained angle of view on the sensor will be smaller with this Laowa 15mm ( https://www.venuslens.net/product/laowa-15mm-f/ ) than on this Lumix 14-45mm ( https://www.bhphotovideo.com/c/product/657970-REG/Panasonic_H_FS014045_Lumix_G_Vario_14.html ) ?

That is surprising to me as the Laowa is a wide angle lens, and the Lumix isn't, but if I understand correctly, because of the sensor crop factor, I would actually get a 30mm with the Laowa lens, and a 28mm with the Lumix, is that really how this works ?

Thank you !

The field of view from the M4/3s camera would look like a 35mm format camera with a 28mm (lumix) and a 30mm (laowa).

14mm is wider than 15mm if the specs are mostly correct (assuming no drastically fudging of numbers). However, there are caveats:

1) FL are typically obtained focused to infinity. If shooting macro, you tend to focus much closer which can change effective FL drastically.

2) It's possible to buy a lens with a smaller image circle, which will cause vignetting or a dark circle. Once you crop out those parts, the effective FOV can be much smaller. You see this with C-mount CCTV lenses that are sometimes available with bundled MFT adapter or with MFT mount.

Hi all,

First of all thank you very much for jumping in;

I am still trying to get my head around this.

From your feedback, I am understanding that if the values given by the manufacturers are accurate, I can conclude that I would have a slightly smaller angle of view with the wide angle Laowa 15mm than with the tiny vario 14-45mm Lumix kit lens. Can you please confirm super clearly that this is most likely true, just double checking to be sure I understand, sorry about that !

I have a follow up question then : it sounds a bit like a waste to buy such a nice lens like the Laowa 15mm macro WA , and not benefit from its full potential. So would using an adapter with optical parts in it, be a smart way to recover the full 15mm field of view (again, working on M43 GH-4 here) ? If yes, any model recommendations ?

Thanks a lot

CapybaraFuture wrote:

Hi all,

First of all thank you very much for jumping in;

I am still trying to get my head around this.

From your feedback, I am understanding that if the values given by the manufacturers are accurate, I can conclude that I would have a slightly smaller angle of view with the wide angle Laowa 15mm than with the tiny vario 14-45mm Lumix kit lens. Can you please confirm super clearly that this is most likely true, just double checking to be sure I understand, sorry about that !

Yep. While there’s always some fuzz in focal length measurements, this is almost definitely the case.

I have a follow up question then : it sounds a bit like a waste to buy such a nice lens like the Laowa 15mm macro WA , and not benefit from its full potential. So would using an adapter with optical parts in it, be a smart way to recover the full 15mm field of view (again, working on M43 GH-4 here) ? If yes, any model recommendations ?

Thanks a lot

What are you buying the lens for?

Right, I've been thinking that too, except that one doesn't have one of the key features I'm interested in, ability to focus at 1:1 macro as well as the 15mmdoes, resulting in a peculiar kind of perspective for macro. It's a very special lens, do you know it ?

What are you buying the lens for?

Partly landscape photography, partly for its capability to focus at 1:1 macro as well, resulting in a very peculiar kind of perspective, as you can have your tiny subject within a much wider field of view as with a regular macro lens. 

CapybaraFuture wrote:

Hi,

Could someone please help confirming my calculation ?

Is the following correct ?

>>> On a GH-4 M43 camera, the obtained angle of view on the sensor will be smaller with this Laowa 15mm ( https://www.venuslens.net/product/laowa-15mm-f/ ) than on this Lumix 14-45mm ( https://www.bhphotovideo.com/c/product/657970-REG/Panasonic_H_FS014045_Lumix_G_Vario_14.html ) ?

That is surprising to me as the Laowa is a wide angle lens, and the Lumix isn't, but if I understand correctly, because of the sensor crop factor, I would actually get a 30mm with the Laowa lens, and a 28mm with the Lumix, is that really how this works ?

Thank you !

When you compare lenses on the same camera, crop factor is irrelevant. Crop factor only becomes relevant across sensor sizes.

Indeed, I am just comparing the Laowa with a lens I already have, the Lumix I wouldn't want to get the Laowa if there is no way to exploit the real 15mm angle of view on my M43 camera and would get a similar angle of view

Right, but I would still be getting a pretty similar angle of view on the Laowa 15mm wide angle than on my Lumix 14-45 kit lens, which isn't even a specific wide angle lens, right ? 

I wonder if an extension ring might get you there.

Are you talking about something like this ?

Thanks for the clarification. Much appreciated 👍

Yeah ok I see. Yeah with tubes you still wouldn't be able to use that lens as a full wide angle 15mm lens then I can see how it would be useful for its use as macro lens though... Hmm... I'm not convinced about the tubes ! Have you seen the Metabones adapter link I sent (I picked the Canon version because I would be getting the Laowa with Canon EF mount) ? Why didn't that seem like a good solution to you ?