Help for angle of view conversion

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 !

This is the starting pointnof your confusion. 😄

..

First.

Laowa is the fixed focal length (FL) lens. It has only 15mm focal length.

Pana is the variable FL lens, aka zoom lens. Its FL can be changed (zoom-ed) from 14mm to 45mm.

Second, FL numberical value is the represent of thr Angle of View (AoV)number, which is very, very easy to understand too. (Trust me, i'm not the engineer!).

On any specific sensor size, the smaller the FL value, the wider AoV. That's the confirmed truth. (Trust me ... 😁)

Thus, your Pana 14-45, when being zoomed to 14mm FL position, will have wider AoV than the Laowa 15mm.

QED.

..,

No need to convert the FL to other sensor size. It only confuses you more.

BTW, ff you want to compare the AoV, please remember that the sensor's light recieving area must in the same format and be equal.

First, Pana is known to have one sensor in the body but varied light receiving area and format!

Second, the 4/3 system does not enforce the area size, just the sensor format! Thus using Pana lens on Oly body may give you a bit narrower AoV than using the same lens on Pana body.

Third, nowadays lens's error can be corrected by the body. The correction will change the AoV. Oftenly, it narrows the AoV.

This procedure requires body-lens communication. Laowa is the manual lens and has no such comm, thus no correction. ALL automatic m4/3 lenses have, thus the AoV may not be 100% conformed to the FL as the manual lens.