Photography versus Rendering

[BrianKitts]

One of our designers requested today that I be sure and render with a 50mm lens so that they get an accurate representation of the space. I know that's a standard for lenses, but I also know that the human eye can perceive approximately a 60 degree field of view, which a 35mm camera / 50mm lens does not.

 

So I gave him a lengthy reply about how I don't use a 50mm lens, but I'm confident that the representation of space is still accurate... with a detailed paragraph about how there's multiple settings in the camera paremeters that can be adjusted and still achieve a realistic field of view regardless of the specific focal length.

 

So it just got me to wondering, for those using physical cameras, specifically those with real world photography experience.... what are you typically use for a camera setup when rendering. I tend to leave the film gate set at 35mm, but drop the focal length to give me approximately a 60 degree FOV.

 

Anyone the wiser able to prove me wrong or prove me right?

[Peter M. Gruhn]

> One of our designers requested today that I be sure and render with a

> 50mm lens so that they get an accurate representation of the space.

> I know that's a standard for lenses, but > I also know that the human

> eye can perceive approximately a 60 degree field of view,

 

170 or so. Do the wiggle finger test. Once heard that Dr. J had over 180; helped his game.

 

which a 35mm camera / 50mm lens does not.

 

> So I gave him a lengthy reply about how I don't use a 50mm lens,

> but I'm confident that the representation of space is still accurate...

 

50mm is so hard to take in an interior space with. On my list of things to do is "really study some architectural photography". There is a fight between "50 mm looks normal" and "50 mm doesn't show anything".

 

But... as you go narrower than that you get telephoto compression; wider telephoto .. expansion as well as obvious linear perspective distortion. All of these things tend towards an inaccurate representation.

 

If you say "well, people can see 170 deg so I'm rendering 170 deg" you hit some glaring problems. The first is linear perspective distortion. That's not really how eyes see or people perceive. Second is that "yes, people can detect wiggling fingers out to 170 deg but don't really see much out there. AND... how close to the screen do their noses have to be for your rendering to take up 170 deg of their field of vision?

 

_But_ sometimes you want certain distortions in order to create not an accurate _perception_. What are you trying to show, how will people there feel about it? Yes, you can tell all sorts of lies with cameras and sometimes those lies are the lies that people tell themselves when they experience/remember a place.

 

> that can be adjusted and still achieve a realistic field of view regardless

> of the specific focal length.

 

There's more to it than "field of view" and I don't know what you are referring to or how you think it achieves what. Hard to "prove wrong" or "right" such an elusive assertion.

 

> I tend to leave the film gate set at 35mm, but drop the focal length to give

> me approximately a 60 degree FOV.

 

I taught 3d modeling to archie students back in the day and the head studio prof considered 60 deg the widest he would allow. A couple shots that didn't have quite the things distorting right here in your face we were able to let a kid squeak out 70. This exterior shot I'm about to press the "go" button on is 2 deg and it is starting to suffer.

 

> Anyone the wiser able to prove me wrong or prove me right

 

Look at it not as a chance to be right/wrong, to beat the other guy, but to get together and learn what works and what doesn't. Suspect you are both opperating on incomplete assumptions and possible jargon failures.

 

And hey, why is my roof looking so blue.... gotta go.

[Matt McDonald]

Its an interior? I would think that would give too narrow a view to be effective. Is the designer a photographer? A 50mm lens on a 35mm back would give you a FOV of 37mm which is pretty narrow.

 

A lot of pros shoot medium format cameras for interiors. As you go from small format to medium format to large format that 50mm lens is going to produce a wider and wider FOV. You can see this by changing the output size in max from 35mm (small) to 6cm x6cm (medium) to 4'x5' (large). Be sure to reset your lens focal length as max inherently preserves the FOV.

 

So my guess is that your designer is a photographer and is thinking about a lens with a different camera back or your designer did a little half hearted research and has made a silly request as a result.

 

Surely its the first right? The other could never happen could it?

[Crazy Homeless Guy]

Nothing better than telling him to grab his 50mm lens and bring it to work, and prove that interiors are best viewed this way. Tell him to grab a wider angle lens also, and shoot some photos around the space. Then tell him to leave you alone, and learn why there are different mm lenses for different situations.

 

All that said, most wide angle lenses barrel distort, something that is not a common practice when rendering architecture with wide angle lenses. If you add a little barrel distortion to your renderings, the space won't feel so enormous when rendered with a wide angle lens. But then you will have people complaining about the fact that all of the lines are not straight.

 

But basically, tell him to stop telling you, and start showing. Then if he is right, he has something tangible to back it up with.

 

edit:

 

There is also a big difference between how we experience space in real life and how it is captured through a lens or rendering. Even though we can see 170, we don't focus on 170. We focus towards the center 60 or so, and are simply aware that the other 110 exists around us, and is three dimensional space. You can't really do this as easily in photography or rendering. Or at least it is very difficult to pull off successfully, and I doubt it can be pulled off easily with a 50mm lens.

Edited January 7, 2009 by Crazy Homeless Guy

[AJLynn]

50mm is the traditional "standard" prime lens on an SLR before everybody used zoom lenses. It's long been believed that the perspective on a 50mm most closely mimics the optics of a human eye. (I don't know if that's true, but it's what everybody thinks so it might as well be.)

 

I've been hunting for a 35mm prime for my D60 (35mm on a DX format camera has the same field of view as 50mm in full frame) but it turns out they're expensive so I'm leaning toward getting a fast 50. Anybody have any opinions on that one? It's going to have 50mm perspective but be cropped to a 75mm equivalent.

[TheAllusionisst]

50mm is the traditional "standard" prime lens on an SLR before everybody used zoom lenses. It's long been believed that the perspective on a 50mm most closely mimics the optics of a human eye.....................

 

Spot on Andrew, this is/was the standard for ages and if a condo buyer for instance bought a space based on an image rendered to make the interior look more spacious than it actually was, they could probably sue if it was proven that fudging was used. But, we all of course want to show off the space in the best fashion as possible and this really handicaps you in showing off your interior space.

 

You might want to contact a photographer that specializes in architectural photography and see what they use, I would love to know myself. I just wanted to pipe in and say that 50mm has long been considered the equivalent to the human perspective, right or wrong.

[Tim Nelson]

I am no photo expert, but who would actually use a 50mm lens for an interior? Seems like such a waste & constraint.

[Peter M. Gruhn]

So my guess is that your designer is a photographer and is

 

My guess was that the designer wasn't a photographer but had a little experience or was told or had read that "50mm lenses produce realistic views" and added it to his list of necessary magic.

[Jim Mann]

This thread stirred many memories so I went and dug out my dads old Olympus OM10 c1981 and sure enough, it has a 50mm lens. Its a brilliant lens which i used at college. Looking through it now, I would say that it matches what i see for real in terms of scale but you'd look like an amateur if you relied on it for interiors.

 

Best way forward would be for you to show your designer a draft with a "standard" wide setting, say 28mm and see what he thinks, then show him the same viewpoint with a 50mm. That should end the conversation.

 

This all sounded a bit like the conversations I sometimes have with clients about print size. i.e.

 

"How big do you need to print it?"

 

Client reply: "300 dpi"

 

Its a direction based on regurgitation rather than understanding.

 

Jim

[Koper]

I just recently acquired a fixed 50mm lens for my 5D and I must say it’s just brilliant. Haven't shot an interior with it yet.

 

I'd say a request from the client to use a 50mm lens is acceptable. Interior photographers (or any other pro-photographer) don't just plonk down their camera and shoot. there is a technical and aesthetic art form to it, they work for the shot, study the space (even re-arrange it). It is hard work.

 

 

With a wide angle you get distortion(s), and with a 50mm you get less in the view but much more focus(attention) on the subject matter and it becomes easier to create a still life.

 

 

just my 2cents

 

and in 3D anything is possible

[BrianKitts]

Thanks to everyone who's chimed in so far. I'll admit I'm quite a novice in the photography world, and starting to dive into it more as a hobby now, and enjoying it. So this thread really was more about pulling out knowledge for the future.

 

Overall everyone's assumptions are correct that the designer had read something somewhere and put that out there thinking it was correct.

 

Look at it not as a chance to be right/wrong, to beat the other guy, but to get together and learn what works and what doesn't. Suspect you are both opperating on incomplete assumptions and possible jargon failures.

 

Good point, I guess I could have said that differently, that was more or less my way of saying I think I'm on the right track, and that I'm curious as to if my assumptions are justified or headed in the wrong direction.

 

So my guess is that your designer is a photographer and is thinking about a lens with a different camera back or your designer did a little half hearted research and has made a silly request as a result.

 

Surely its the first right? The other could never happen could it?

 

After talking a bit more, I'm thinking he doesn't have any photography experience, so it's more likely the later.

 

Nothing better than telling him to grab his 50mm lens and bring it to work, and prove that interiors are best viewed this way. Tell him to grab a wider angle lens also, and shoot some photos around the space. Then tell him to leave you alone, and learn why there are different mm lenses for different situations.

 

That was pretty much what I said to him in my initial email, I left it out of my original post as it's something that I would assume most people on here would know.

 

I am no photo expert, but who would actually use a 50mm lens for an interior? Seems like such a waste & constraint.

 

So this gets back to my initial question, of what is typical for shooting interiors? For me I normally leave the camera at the defualt (vray) settings and when needed drop the focal length a bit, but I'd like to hear if anyone here does something different, or if you shoot in the real world, how does a realworld setup compare to something that you do for a rendering situation.

 

This all sounded a bit like the conversations I sometimes have with clients about print size. i.e.

 

"How big do you need to print it?"

 

Client reply: "300 dpi"

 

Its a direction based on regurgitation rather than understanding.

 

Agreed, that one's high on my list of pet peeves. I actually keep a copy of an email for my reply when I get that comment from someone, I got tired of explaining it all the time. It goes right up there with the request of TIFF files for all final renderings. I can give you a 4mb uncompressed jpg that will look and print just as good as your 60mb TIFF!

 

 

So my question now is this. Does the focal length make a difference when rendering? If you compensate using other parameters such as zoom or changing the film gate to get a proper FOV does different focal lengths impact the image in different ways..... Or does that only come in to play when you are rendering with the DOF turned on.

[Tim Nelson]

What we would often do at studioAMD, and I'm sure a lot of renderers do this, is to cut away walls, and/or use clipping planes so we don't have to use extreme wide angle fov's. Then we can back the camera up and use a more reasonable fov, which helps minimize the distortion and still allows us to see more of the picture,... something you could not easily do in the real world, unless you want to start knocking down walls just to get the shot.

[Nic H]

^ yep we always do this, pull back walls, add a few inches to make rooms a tad higher, stretch things, squash stuff. anything to make it look good.

 

clients dont want to hear 'the space is too small, this wont work' even if it is true. its very much an architectural mentality that models need to be perfectly accurate, when all you are doing is making a image of what a space 'may' be like. unless you are doing verified views anything goes.

[Neil Woodhouse]

I've had good results using 28mm with a slight 'tweak' with correction, so i stick with that, although i've seen work done using 180 FOV with loads of correction and also 8mm with the same but i wasn't impressed, very 'Arty Concept' stuff. Using clipping and holes in walls etc works too. I use 50mm or 35mm for exterior stuff.

 

I suppose in the end it's what the client perceives as looking good. I think sometimes us digital guys strive too much for the perfect image, then it becomes clinical and people go....CGI...Ughhhh. I know i have it said to me.

[ronll]

50mm as the so-called "standard" has many faults. One of which is it is highly dependant on the type of camera. The image on a physical camera has to do with not only the length of the lens, but the distance to the film plane which on digital cameras can be a lot different than on film cameras. Also, most professional architectural photographers use (or used to before digital) large format view cameras whose configuration made lens lengths very different than 35mm film cameras. So forget the lens length comparison. A much more accurate measure is FOV. BTW, another little thing to watch for is that sometimes camera or software specs will state FOV as from the centerline to one edge, resulting in a number only half the size as the more common edge to edge measurement.

 

There is also a lot of misconception about distortion. So-called telephoto compression can be exactly emulated by cropping. The image in the center of a wide angle photo is exactly the same as a narrow angle photo taken from the same place. And even the tilts and shifts of backplanes or lenses in a complex view camera can be exactly mimiced by cropping a wide angle photo off-center. The other uses for these complex view camera movements had to do with focus and depth of field, again things a computer rendering engine doesn't have to worry about unless artificially induced.

 

On several occasions I have provided expert testimony in court cases involving view corridor obstructions. The attorneys love to talk about how "real" or "accurate" a photo or rendering is. What it comes down to is there is no such thing as a "real" image. The geometry can be real, but any image or photo of that geometry is a representation of reality, not reality. No still image can accurately represent what can be seen by live vision, which among other factors, is constantly in motion.

 

Having said all this, I usually limit my renderings FOV (edge to edge) to about 60 degrees. I occasionally will fudge it a couple of degrees higher, but only if necessary. And as others have pointed out, removing the wall behind the camera so you can back up more is not really cheating, just one of the advantages we have over "real" photographers.

Edited January 7, 2009 by ronll

[innerdream]

No two spaces are the same. That said there is nothing wrong with using 24mm or 18mm for an interior if it looks good. I have done a lot of regular photography in Architecture and 3d just isn't apples to apples imo. I think you have much more ability to "get the shot" in 3D. As in normal photography we would sometimes spend hours and hours getting one view. In the 3D world you might even have to move a wall or two - what ever it takes I say.

[Iain Denby]

 

Having said all this, I usually limit my renderings FOV (edge to edge) to about 60 degrees. I occasionally will fudge it a couple of degrees higher, but only if necessary. And as others have pointed out, removing the wall behind the camera so you can back up more is not really cheating, just one of the advantages we have over "real" photographers.

 

Exactly what I do.

[Geoffc]

Exactly what I do.

That's what I was going to suggest.

 

Or, how about doing 3 (50mm) cameras, overlapped 1/3 and photostitching in PS?