DV Info Net - F3 vs Alexa

DV Info Net (https://www.dvinfo.net/forum/)

- Sony XDCAM PMW-F3 CineAlta (https://www.dvinfo.net/forum/sony-xdcam-pmw-f3-cinealta/)

- - F3 vs Alexa (https://www.dvinfo.net/forum/sony-xdcam-pmw-f3-cinealta/508182-f3-vs-alexa.html)

I can't lie...I think the underlying reason I do these things is to make myself feel better about my purchase. I like to think I have an eye for winning gear combos (I don't always). In the end, it's never the gear that gets you where you want to go anyway...

Nevertheless, I had access to an Alexa for a few hours yesterday and I brought the F3/S-Log/Samurai over to play.

F3: Samurai, S-Log, Red 18-50 lens, stop was about 4-5.6 split I think. 0db gain, of course. Alexa Log-C LUT applied in DaVinci. Then a slight reverse S-curve correction to match percieved contrast.

Alexa: ProRes 444, Log-C, Angenieux Optimo DP 16-42, monitored/exposed with 709 LUT over top of LogC. Alexa Log-C LUT applied in DaVinci.

The still below has the F3 *LIGHTLY* corrected to match the Alexa. Be default, the F3 had more contrast, and was clipping blacks and whites a touch more than the Alexa...likely because the F3 is known for holding 12-13 stops and the Alexa a good 14.

But, even in this frame of hard sun with no fill, both cameras handled the key/fill ratio without trouble, and essentially were identical. We did another backlit facing the sun shot, where the Alexa's latitude was a bit more apparent. I can't stress enough though how little correction was applied to the F3...and I did some to the Alexa as well, as there was a slight green cast, possibly from the heavy ND on the Arri.

I'm not going to tell you in the grab below which camera is which. I love guessing games :-)

That is interesting. I see some banding in the sky of the left side image that doesn't appear on the right. Is that obvious to anyone else?

I'm going to say the F3 is on the left and the Alexa is on the right.

Quote:

Originally Posted by Chris Medico (Post 1736042)

That is interesting. I see some banding in the sky of the left side image that doesn't appear on the right. Is that obvious to anyone else?

That would be your monitor, displaying in 8bit, likely with an ICC or Colorsync profile influencing things as well. The F3 was recorded 10bit, and the Alexa 12, can promise you there's no banding in either from the source.

I downloaded the image and viewed it outside the browser. There was no banding visible.

Thanks Nate, very interesting to see.

My guess is Alexa on the right. It looks slightly sharper to me and I slightly prefer the colour but it could easily be the other way round.

I thought I'd be clever and download the picture into Photoshop. I wanted to play with exposure, gamma and sharpening to see if I could make out each camera reflected in the glasses. It's close, but I can't really tell.

What was a surprise was how each shot reacted to my adjustments differently even though they were applied to the whole downloaded png. When you push the gamma you can make out some slight banding on the left picture, it's in the sky around the hat, and yet the right side looks clean. However, when you apply way too much sharpening, the right side breaks down into a really nasty coloured noise pattern very early. The left side stays cleaner much longer.

It looks like the left side has less colour information but is actually a cleaner picture. The right side has no banding but is surprisingly noisy when pushed. So on that basis I'd guess left is F3 (4:2:2) and right is Alexa (4:4:4)

But I'm usually wrong!

I think just the fact that it is hard to tell which one is which speaks volumes.

I think the F3 is the right image. My reasoning: It has that slightly yellow cast common with Sony cams and the highlight on the face is starting to overexpose.

Damn close though, that's why I love my F3's. Baby Alexa's. Would have been nice to have seen 444 from the F3, but I don't suppose the difference would have been significant.

Thanks for the fun test and thanks for the fun guessing game.

Alexa on the right. Softer, more organic looking or filmic as some Alexa users like to say.

I'd almost tell you which is which, but I won't quite yet. I will say this though, the picture was created as a screen grab inside Resolve, using the OS X screen grab function. So it is most certainly an 8bit image, and possibly even modified by Colorsync.

Alister, before I slightly corrected each camera, each could have said to have a slight warm/or green color cast. It wasn't alarming, but possibly enough to give things away, which is why I did a quick balance on each.

Likely a giveaway. No LUTS, no corrections:

I was handed some uncorrected Alexa POV footage of a coaster we were shooting in Hershey PA last week and it looked more like the one on the right.

To my surprise we were able to match the footage from our F3 pretty darn closely using only the color correction in Avid.

OK, I've changed my mind now, F3 on the left, my reason, right hand image has greater latitude, most noticeably more shadow detail. But boy is it close and demonstrates that an F3 could be used as a very effective B camera to a Alexa.

I'd guess Alexa on the right because it looks a little more filmlike and natural, but I'm basing that mainly off the fact that the image on the left seems to have more color in the sky & background that could be more artifical and videolike, also a bit more contrast. But could that be do to grading difference? Very close for sure.

The left image is more out of focus on the background also though which implies to me either different lenses or f stops. What's up with that?

More than anything its great to see image quality at this level available across such a range of price points.