Real World Camera Compared to DAZ Studio Camera
ArtXtreme101
Posts: 68
Hi all!
I have been playing around with the camera in DAZ Studio because I am currently working on creating a digital clone with Genesis 8.1. I wanted to use photos I took of my model as a reference, but an issue I found is that the focal length (mm) for the DAZ Studio camera doesn't seem to match the focal length of my camera. I tested this theory on a human head scan I had. I compared it to one of the references used to create the scan and sure enough, I could not get the DAZ camera to match up. After playing around, I discovered that to match the DAZ Studio Camera to the real-world camera, you have to multiply the DAZ Studio focal length by (2). Is this common knowledge? I just learned this today (after around 9 years of using DAZ Studio) so I wasn't sure if others knew this too! Just thought I'd share!
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Comments
Now that is a useful tip - thanks! I wondered if there was some way to interconvert.
I find my Carrara camera 50mm = DAZ studio 65 for example and the Carrara render will match an iClone and I think Blender 50mm
Unreal needs to be 20mm
I don't know what that quite means but just throwing it out there
I did want to make an update for those curious on details:
Tested on a Canon EOS 100D from ranges 50MM-85MM. Still a working theory!
I was going to ask if it was a full frame camera or one with a more limited frame, but I think that answers the question. Still, could the factor be 1.6 - that would suggest that the DS camera might be acting like a cropped-frame, more consumer-level, camera.
For more real world camera behaviour my go to is IG Photographer's Toolbox: 35mm Cameras
Especially when it comes to F/Stop settings and focal length settings I think they match the settings I know from real world cameras pretty good.
Also, the aperture (f-stop) seems to have very little to do with real-world cameras. I frequently find myself setting it to 64 or 128 to get the depth-of-field effect I'm looking for, which is usually a sharp foreground figure and a blurred background. Out in the real world, I've never seen a lens that went to more than 32. A 65mm lens (the default setting) set to f/32 would give you sharp focus over a very large range, which is definitely not what you get in DAZ Studio.
This setting does behave consistently -- smaller numbers give you a smaller depth of field, larger numbers give you a larger one -- but despite it being called "F/Stop", the numbers themselves definitely don't match up with real-world f-stop values.
My take on it:
I had the link and everything ready to post but you beat me to it!
I use pretty much nothing but these cameras.
They are not EXACT, but closer than the main Daz camera and when it comes to f/stop...well...an amazing tool.
I'm going to have to try the times two thing and also look into this IG Photographer's Toolbox item as the camera is always so frustrating to me having come from the film world and knowing what lenses should look like and do.
Too bad this isn't on sale https://www.daz3d.com/ig-photographers-toolbox-35mm-cameras
I also wonder what's up with the f-stop settings. Is this something that only affects Iray? I have no experience in 3Delight, so how is it there?
My guess would be that it could be a unit mismatch between DAZ and Iray - The depth of field you get in iray for a given f-stop would make more sense if iray treats meters as centimeters or decimeters or something like that.
I just discovered this 2x focal length factor on Daz3D as well. I come from the world of filmmaking and still photography; I've started using Daz3d to storyboard. For an upcoming project, I built a set to scale on Daz because I wanted to see if this specific location would work. I'm planning to shoot this on a s16mm film camera, so I did a bunch of experiments to make sure what I was seeing on Daz would equate to the real world. My tests were the following:
Using a field of view calculator app (called "f8 lens toolkit"), I calculated that a s16mm sensor size (11.75mm wide), at 2 meters from the subject, would give a 1.68 meter wide field of view with a 14mm lens. So in Daz, I entered the 11.75mm frame width, with a 14mm focal length, and set the camera 2 meters away from a 1.68m horizontal cylinder primitive I created. But the field of view was much wider than the 1.68m I had calculated. I then tried changing the focal length to 28mm and... it matched PERFECTLY. At first I thought that maybe the Daz lenses were calibrated to 35mm, and had a normal 2x crop factor, and that I had to input the 35mm lens (even though I had already changed the sensor size). So then I tried:
A second camera, in exactly the same place. This time, I calculated using a s35mm 3-perf camera sensor in my app; and calculated that to get the same 1.68m width field of view from the same 2m distance, I'd have to use a 28mm lens. However, again, it was too wide. To correct this, I multiplied by 2, and used a 56mm focal lenth lens. And yes, it matched perfectly!
For the sake of the experiment, I did a third camera, this time with the default 35mm (full frame) sensor size. Doing the same calculations, a 43mm focal length (using 16:9 aspect ratio) would do the trick. But, to no surprise now, it was too wide. I douled it to 86mm, and it matched perfectly again.
Both s16mm and s35mm 3-perf sensor sizes are 16:9 native aspect rations; for the full frame sensor size, which is natively 3:2, I modified it to 16:9 on Daz so they would all have the same aspect ratio. However, even if left as 3:2, the full frame calculations in real life didn't match the Daz3d lenses.
I've been trying to find information on this online, but this thread is the only thing I've found so far.
Soooo... All of this to say that "yes, it appears that to match real-life sensor sizes and focal lengths to Daz3d settings... you just have to 2x your real-life focal length in Daz3D. Why? I don't know".
I hope this helps! And if anybody finds an answer as to why this happens, or to a solution that allows for the Daz3D lenses to actually match, please let me know!
That's briliant and when done with my current project I will look into this and double check you and try and post results. I have been just eyeballing it for years now. I do get the sensor size is really important but prefer to render only in 4:3 or 1:1. But for my current workflow of ai bumping, this makes a huge difference in the results when using img2img, because believe it or not, this has big results on ai model detection and emergence for generative ai. I'm guessing because the model trained on thousands of "real" photos. so it wants to bump to those, not somthing made from a daz camera.