Fisheye or ultra wide angle lens

[CliveG]

I've been looking at some architectural photographs and have noticed some standout images (interiors) using very wide angle shots. I know this is normally an arch viz no no but am interested in trying to replicate this.

 

Is there a way with Max or Vray Camera of representing a photographers ultra wide angle lens, say anything around 12-18mm on a 35mm SLR?

 

I've only done a limited amount of trial and error and a quick search here but it would seem that setting an ultra wide angle with Vrayphysical cam just produces predictably horrible distortion (though it does have a "distortion" spinner and quadratic / cubic option).

 

Obviously I could just drop an image into PS lens correction but again there is only so much that an unsharp mask can achieve after you've effectively distorted pixels to that extent.

 

Is this simply not practical in CG terms?

[Chris MacDonald]

It's not an arch vis no-no at all. Wide angle shots are pretty much the bread & butter work that I do; architects love to see the entire building in one shot, rather than lots of far nicer, more focused shots.

 

Anyhow, I don't see how you're struggling? Just type in the focal length you want in the VRay Physical Camera, and hit the "guess vert" button to straighten the verticals in the same way a tilt-shift lens would.

[CliveG]

Thanks Chris,

 

I guess if you look at the sort of lens angles I'm aiming for you'd see that Max / Vray doesn't deliver a similar result to an SLR. You get to a point where the Vray Camera behaviour diverges from a real camera.

 

I'm not a photographer and I'm sure there are folk who could correct me, but it seems that there is a more general barreling or distortion across the whole image whereas the CG camera provides a flatter representation of that FOV. As I say the result can be closer replicated with the Lens Correction filter in PS but at the cost of blurring, which is what I'd like to avoid.

 

Try one of your regular images in PS apply lens correct and pull the "remove distortion" down to -40 or something and then go into Max and pull your camera to 8 or 10mm and see the difference.

 

It may be just me in which case I'll shut up but I think they behave slightly differently at the extremes.

[Chris MacDonald]

If you want to add barrel or pin cushion distortion then use the distortion control on the vray camera. It acts exactly as you'd expect a real camera to.

 

It is worth keeping in mind that architectural photographers strive to reduce/remove lens distortion.

[CliveG]

Thanks Chris,

 

Yep I was being too hurried with evaluating the distortion spinner, for me it doesn't preview and has to be rendered out to see the results - but now I can see this does give me the control I'm after.

 

I do understands that architectural photographers strive to reduce remove this distortion but as I said there are some standout interior shots where this slight distortion enhances the geometry in a flattering way. I just want to have this tool in the toolbox to achieve a similar effect where it's appropriate.

 

Cheers

[Francisco Penaloza]

Chris is right, just play with the lens size in the physical VRay camera and you can adjust the distortion to create a more real view. Now things to consider are, CG cameras can have virtually any lens size and won't create the glass distortion by itself like a physical lens does from manufacturing limitations, so you need to add those imperfections in post or with VRay controls. Also when comparing with real photography you need to consider what camera was used, this will help you to find what type of lens distortion it is in that shoot and how to replicate, Lightroom or photoshop are pretty good at this. Also remember that if is a DSLR camera you have mainly 2 type, Full frame and crop sensor cameras, if it is an entry level camera, it is possible that is crop sensor so any lens size that you are using, you need to multiply by 1.6 that is the crop sensor factor.

Now if you want to get really technical about it, you can use this camera utility designed by Chaos group.

http://help.chaosgroup.com/vray/help/200R1/tools_lens.htm

 

Regards.

[Chris MacDonald]

Exactly this ^

 

Or instead of working out the crop factor equivalent you could change the sensor size on the VRay cam to match whatever camera you're trying to match. Point and shoots generally have tiny sensors, which massively affects focal length. It's also worth doing this when doing photomontages too, just so you know you're absolutely correct.