Matching Canon EF Lenses/VrayCam

[lichtmaschine]

Hello,

we got problems matching images photographed with Canon EF wide angle Lenses in Max. Even with various horiz./vertical shift settings, it does not match perfectly. Does anybody know where I can get the right distorsion settings for e.g. the EF 2,8/24-70mm ?

Kind regards
Ingo

[plastic_]

probably because the real focal length isn't really 24mm, as stored with the EXIF tags, but slightly different.
i remember from working with boujou that it was more accurate to calculate the focal length/FOV with boujou, than using the exif values.
i also read something on the web, but right now i can't remember where.

it's also a good idea to correct distorted images before using them for CG.

i'm not an expert on this topic, but last week i was talking with a very professional photographer who does really huge prints on buildings and stuff like that, with stitching, tilt-shift lenses, etc.
he said that DxO is the best software to correct distortion from canon lenses, before stitching panoramas.

[lichtmaschine]

Hi Marc,

thanks for answering, the weird thing is : The rendered image looks distorted, not the photographed one. It seems to be impossible to render a car like the photographed, which is the thing wa want to achive. In fact we need to manipulate the VrayCam to match the original camera, not vice versa.

Ingo

[flino2004]

You could find some info about the camera here www.DRPeview.com

[werticus]

Dxo probably has distortion information for that lens.

[jujubee]

I use PT Lens to correct lens distortion and and vignetting in PS. Maybe that can be used as reference?

[werticus]

Yeah id be correcting your photograph rather than trying to distort the vray camera to match.

[lichtmaschine]

Thanks for the answers, I know that it`s easier to correct the photograph rather the VrayCam, but there is no discussion with the client: in the image, the car looks good, in the rendering it looks not like it should be. We tried nearly any distortion setting possible. Am I the only one who has this problem, matching images 100% ?

[muoto]

get a better lens that has (almost) no distortion, like ef-s 10-22

[suurland]

What camera are you using? if it has a smaller sensor size you need to take the crop factor into consideration.

also you say "It seems to be impossible to render a car like the photographed" so it sounds like you have a photo with a car in it.. and if you have the same car in 3d you can easily match that using max's own camera matching tool.

/Thomas

[GLASS-CANVAS]

get a better lens that has (almost) no distortion, life ef-s 10-22

If the OP is talking about this particular lens http://www.canon.co.uk/For_Home/Prod..._USM/index.asp then there is no better lens available. A quick google of this lens for reviews reveal it to be one of the best wide zoom Canon lenses ever made, and whilst I know little about your 10-22 I would guess that the fact that the 24-70 is f2.8 throughout implies it has superior optics, let alone that it costs 50% more.

To the OP, get this: http://www.dxo.com/uk/photo there is no better tool for correcting distortion, plus it's cheap.

[dejaVu]

I'm with Suurland on this one. You don't mention the camera you are using.
It maybe that your camera isn't a 1:1 SLR equivalent, and therefore needs a scale factor. for example, the 400D needs to be multiplied by 1.6 to give you the 35mm slr equivalent.
Some more info on the camera itself might help clarify this.