Target Distance changes FOV

[davision]

On physical camera changing the target distance -- at very short distances causes the FOV to shift ever so slightly. I don't know if this is supposed to happen or not. My concern came about because this happens even when the phys cam does NOT have "targeted" checked. I assumed the target distance would be irrelevant in this case.

So maybe it's not a bug -- but it seems counterintuitive at the very least.

[Da_elf]

target distance = focal length
in a real camera changing the focal length moves the lenses around. this will have an effect on your field of view

[davision]

I don't think target distance equals focal length.

I don't know of any cameras with a 16' or 500' focal length.

Target distance is just a value reflecting the distance to the "focal point". It's not equivalent to the camera's focal length. If you are taking a picture of something nearby or something far away, the focal length of your camera doesn't change (thinking of manual not auto focus). Only if you change the object you are "focusing" on does the focal length potentially change. Vray phys cam has a "focus distance" parameter which is different than target distance to control this. It seems like target distance and focus distance are being conflated and I don't think that makes sense.

[vlado]

Sometimes you may not want the camera to be focused at it's target (for example, if you have a targeted camera that is already animated by someone else, but you need it to focus on a different part of the scene, or if you want it to focus on a specific object that is not linked to the target), that's why you can control that separately with the "focus distance" parameter if needed.

Best regards,
Vlado

[simmsimaging]

Having the separate control is handy, but having the zoom factor change at the same time (like a real camera does when you change the focus point) is a problem for me too.

Is it possible to have that turned off, or maybe not affected when you use the target as the focus point?

b

[vlado]

It might be possible; I have to check.

Best regards,
Vlado

[davision]

Hi Vlado -- my point is different than Simm's I think. I was saying that if you turn OFF "Targeted" in Physcam then the target distance should no longer have an affect on the camera. The Focus distance control would still be relevant, yes -- but not Target distance.

[vlado]

Ah. It is logical of course... will think about it.

Best regards,
Vlado