exposure values (shutter, aperture, iso)

[Dave Buckley]

hi guys

 

just been doing a bit of research into the above as i use max but don't have much knowledge of photography

 

i am aware of standard values on a camera for each of the shutter speed, aperture and iso, but i was just wondering if everyone out there uses the standard values in max, or if you tweak the values to amounts that you wouldn't find on a camera to suit what looks good for you.

 

the reason i ask is that i see you can type values other than that which appear standard on a camera, but with Max being based on camera controls would it be best to stick to standards??

 

sorry if thats confusing

[Crazy Homeless Guy]

i vaguely adjust them to a standard, but if i am doing a mathematical calculation to match a color, then i go off of the standards. meaning i may have a 158 iso or something like that.

 

i tend to stick with f-stops that are available on real cameras, and to a lesser degree, shutter speeds that are on real cameras.

 

one thing i have noticed, or i think i have noticed, i am not really sure yet, ....i think Mental Ray's camera settings may be quite a bit off of what they would be in real life. again, i need to do more research on that.

[Dave Buckley]

thats the exact reason i asked

 

you answered my question in 1 so thank you

 

i also believe the settings in max are quite off, i think the default daytime, sunny day preset is quite a way off, almost to the point where it appears under exposed???

 

but that might be because i was hoping for it to create a look that isn't true of real cameras??? you know, the typical photorealistic arch viz render???

[Scott Erstad]

one thing i have noticed, or i think i have noticed, i am not really sure yet, ....i think Mental Ray's camera settings may be quite a bit off of what they would be in real life. again, i need to do more research on that.

 

I would agree. I too need to do more research, and I am thinking a good experiment would be to take a digi photo of an existing building, note my vantage point, be sure to keep a level camera position and recreate in max. Maybe try to get a broad bracket at that time and match up each in max.

 

If any of the Mental Ray gurus have any thoughts, I would sure like to hear them.

 

Scott

[mattclinch]

tend to just use a sunny-16 default (iso 100 and shutter 1/100th) and then tweak the f-stop to suit. though all those values really do is get fed into a formula which determines one eV value. pointless other than they refer to real world values on a camera, (or i think if you use mR DoF?).

 

and you are right, i think there is a slight difference to real world units. for example..

 

iso:100

f/ 5.6

shutter: 1/100

 

should be exactly the same exposure as

 

iso: 800

f/5.6

shutter: 1/800

 

but the eV value is totally different.

[Dave Buckley]

i also read a rule that the shutter value should be higher than the value of your focal length??? why is this??? or is this not true???

[Nic H]

if you arent doing dof mb, etc you can effectively 'lock' the iso and shutter on the same value and like matt said, then only use the f-stop to expose your image, its very easy to set up thsi way.

[Dave Buckley]

would this technique also apply for interiors day and night??? and exteriors at night??? or do different techniques need to be studied for these shots??? also does anybody have an good reference material for composing architectural renders both interior and exterior???

[Crazy Homeless Guy]

if you arent doing dof mb, etc you can effectively 'lock' the iso and shutter on the same value and like matt said, then only use the f-stop to expose your image, its very easy to set up thsi way.

 

i typically use shutter speed on f-stop to adjust my images. the main time i adjust the ISO is when i use Vlado's mathmetical calculation for matching a color in an image, or mathematically calculating the white balance. i have only used this process on Vray, and not Mental Ray, but.... with the MR physical camera shader/script that was posted on the German Mental Ray forums, i think the same calculations might be possible.