T.Stops Blog

Sony F3 – Preliminary Tests

My DIT/Colorist friend Tom Wong, and DP’s Khalid Mohtaseb, Jon Bregel and I took the time to run the F3 through some simple preliminary tests.  This test was more or less for Tom to see the noise floor and clipping points of the Sony F3.

This is verbatim his thoughts.  Once he supplies me with some visuals i will post them up.

initial findings with the f3, not entirely scientific but gets the point across.

the camera is primed for these iso’s

280

400

800

1100

1600

3200

initial tests we had time for and attempts.

used my mac pro with decklink card to do uncompressed quicktime capture at 422 10 bit for the best quality the camera can output right now. 

f3 with panchro 75mm

subject was in front of a window, we shot 2 shots at each iso, one where we severely underexpose the subject by almost 8 stops to see how much detail stayed in. another by 4 stops where detail would definitely be there but we can assess what functional working iso’s would be chosen as the work horse iso’s. IE, how much we can crank the iso’s before we deem it unusable. 

under exposing by 8 stops at all iso’s had clipped the blacks and there was no detail to dig up. but the findings with noise were consistent with the 4 stops under exposed. 

280 iso

the truly clean iso. you can dig deep in the shadows, and can pull it up really hard and find little to no noise. on a normal working color grade, I probably wouldn’t bring up any noise at all doing several contrast expansions across the board. and i typically pull up and crush down blacks on various areas of the shot a minimum of 2-3 times on shots to really fine tune the image. 

of course there will be noise when you jam up the gain in post, but that just makes it unusable all together because it’s milked out and ugly. i would recommend this iso setting for interior lighting if you have the lights for it, studio work, green screen, vfx in general. basically when you have to or want it to be the best image possible. a lot of cameras hide their noise in the blacks even at low iso’s and fool the user thinking it’s a clean signal, but in this case that doesn’t happen.

400 iso

the “work horse” iso I would like to call it for interior and exterior work. This is probably the true sweet spot of the camera, I need to assess the dynamic range more, but I’ll need a step chart for that. but i find that though there is just a hair thin line of noise, it is unnoticeable to the naked eye, and you’d truly have to pixel peep and push the image in post hard to bring up the noise. in a typical grading session, this would be the iso that can give production a easier day, and post production plenty of room to work with to manipulate and fine tune the image. 

800 iso

this is where the noise starts to creep in, and again it’s is highly tolerable at this ISO, i wouldn’t say it’s clean at this iso. but it looks very good. i wouldn’t push the blacks up as hard as I would as 400 in his iso, but it is a workable iso for exterior lower lit situations where you need to gain the exposure. interior too when push comes to shove. but even if the image in post had to be pushed a little hard and the image got noised up a bit, a light denoise plugin like neat video will clean the whole thing up perfectly. 

1100 iso

i would deem this the emergency iso. noise is here, it’s not awful, it’s not a lot. but it’s there, you see the speckles, and it’s lightly layered in there. you don’t have to look hard for it, but it’s one of those things you can live with easily. this is if you are really in a jam, and production isn’t doing something right… 

1600 iso

again it’s not awful, but you see solid noise in this case. a simple crushing of blacks, maybe neat video will get rid of almost all of it. I personally wouldn’t shoot on this iso, but i can see a lot of people finding it absolutely usable according to your tolerance to noise. as a colorist and DIT, i wouldn’t recommend it just because it doesn’t meet my personal tolerance. 

3200 iso

yes, there is noise, and we are back to, it’s not awful. if this was a 5d at 3200 iso, there would be banding, tons of colored noise polluting the image, absolutely unusable. even straight out of camera 3200 iso on the f3 could easily pass broadcast standards in noise levels. I personally find this iso to be unusable, for most people’s standards, but the image doesn’t fall apart, it’s not completely polluted. it’s one of those, you want to avoid shooting at this, there’s probably no reason ever you should be shooting at 3200 unless you are in a dimly lit club or whatever, but still if you have to use it it’s not a unusable shot. denoise, clean up work in the grade, you can get something decent out of it. 

other findings

we also did a sxs record while doing the computer uncompressed capture. the comparison wielded obvious and expected results

the 10 bit 422 had much better color and skin tone rendition. gradation in color, and fidelity in the color with hair, skin, the whole nine yards was obviously better. the xdcam 35 mbps looks very good, but the compression adds noise to the image the color mushes together more (4:2:0) and you lose detail too in the finer details. fine hair, skin, etc. 

the sxs looks very good and will be aesthetically pleasing for a lot of people, but in the end with the capabilities of what this camera can do, i treat it only as the codec for editorial, and wouldn’t use it for the online when it comes to putting on the big screen or tv. that’s just my subjective opinion, lot of people might find it more than acceptable. 

in conclusion, some more obvious than others. 

consider your absolute work horse iso’s 

280, 400, 800. 

the higher iso’s is tolerable according to each person that uses it, but honestly in the biggest of emergencies it’s not a disaster if you have to use them. but if you are shooting a feature film, you should be able to light at a 280, and 400 most of to all of the time, and 800 when it’s a rushed night/day. and have little to no issues in post. 

xdcam codec is very good, we’ve all see now good it looks on ex1, it actually resolves more than i thought it would, but not enough to my standards for truly top grade work. 8 bit, long gop, mpeg compressed 4:2:0 is still just that. an off board recorder is completely recommended if you want the best the camera can give right now. which is a lot. and I can’t wait for s log 444 to come out already. “

I personally felt the F3 was acceptable up to ISO1600.  Tom is far less forgiving than i am.  Then again he is a DIT and Colorist.  He lives by the scopes.  I go by what looks good on the monitor.  

To give some reference, he feels the F3 @ ISO 1600 looks as clean as the Alexa @ ISO1600, which in his opinion, is too noisy.  To the rest of us, it looks amazing.  There will be images from the test posted in the next couple days.  our model did not give us permission to post what we shot today.  we will re shoot the test tomorrow with someone who is willing to be on the Interwebs.

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