This was my first legitimate test of the Sony A7sII's 120 frames per second slow motion capture. Unlike its predecessor, this camera can do this at full 1080p HD resolution, however, it does still crop in significantly (2.2x). I was curious to see not only the usual aspects of the footage (moiré, aliasing, noise) but also how integrating the crop and full frame footage would mix.
My previous camera was a Canon T3i, which has an APS-C sensor (1.6x crop). I found it difficult cutting my T3i's footage with full frame footage from other cameras (such as the 5D or 6D) because they almost always looked noticeably different (and I'm not talking different brands, I'm talking Canon with Canon). It's because of these challenges I've become so mindful of sensor size. Now to be fair, they differed in aesthetic for a number of reasons, not just the sensor size, but it was something that always bothered me. Cutting this footage together with the full frame 4k footage I think proved to be successful, at least in this instance. I only ended up using a couple of the 4k shots (simply because I didn't like many of the shots themselves), which I'm not sure if having one or two different shots would be more apparent than half and half. Either way I think it worked, mainly because the type of shots I chose to get in full frame were more Wide shots and everything else was Medium or Close-Ups (in crop mode, that is).
Another thing which helped make the footage look more cohesive was softening the 4k just slightly. I shot the full frame in 4k in case I wanted to crop in, but the couple of shots I did include looked better in full frame, scaled down. This of course meant it would look intensely sharp, and personally I'm not even a big fan of ultra-sharpness. I think many people are afraid to soften up an extremely sharp image in order to complement the the rest of the footage. I understand, it's pretty painful to see that sharpness go soft, but I think what you end up with is a much more professional looking piece, because of its consistency with itself.
Now to the more typical stuff. I definitely noticed much worse noise processing performance. It's not that there was more noise, it's that the noise blocks were bigger, which is a given since you are cropping in over double the sensor size. There's no way around this really, but the web compression even on Vimeo was quite forgiving, so if you know how to handle it and you're creating for web distribution, I wouldn't worry about it too much.
Given the practical approach to this test, I couldn't really test the moiré performance, but there was some very subtle aliasing. The amount was so minuscule though, any sort of web compression (and even the export) cleaned up a lot of it. Had I had a deeper depth of field, with more lines and edges in shot, it probably would've been more apparent and less salvageable, but that's the key to fixing these issues: knowing how to work around them. Even if something's slightly out of focus, moiré or aliasing will virtually disappear.
Finally, I want to talk about the use of the feature itself. It's nice to be able to slow down a piece of footage to 20% if necessary, but I do feel it's a bit overkill. Now you can argue that the extra frames give you a lot of leeway to manipulate the speed of the footage, which is only partially true. Slowing the footage to 20%, 40%, 60% looks great. As soon as you leave those three parameters, it starts skipping frames. It's sort of like conforming the footage to an obscure frame rate (like 32 frames per second) and dropping it into a 24fps timeline; the frames won't line up evenly and as a result some frames will be repeated and others will be dropped. It just doesn't work (if you don't believe me, try it yourself, and leave a comment so I can say, 'I told you so').
Here's a test (not mine and I feel I have to say I'm not featuring this video because I think it looks great, but simply to exemplify the difference in motion) done at 100fps instead of 120fps and I have to say, it looks much more natural. 120 frames is just too slow, it's almost anxiety inducing. Interestingly enough, I had realized this for quite a while before I shot this footage.
So why did I stick to 120fps? It's simple and really irritating actually. 100fps is only available in PAL mode. 24fps in any resolution is only available in NTSC mode. The problem is every time you want to switch between formats, you have to reformat the card (as in erase everything on it), which is completely impractical and in most cases just not an option. Really, I don't understand why we still have these different world formats. Why put this atrocious wall between the different frame rates? I actually enjoy the 25fps look when appropriate and wouldn't mind using it for some pieces if it didn't involve having to erase my card to do so.
And another thing I should note, the USA model (and the Japanese model, I believe as well) are locked in NTSC mode; you cannot switch to PAL whatsoever. I have the European version of the camera, which has its own format mode issue: when not in PAL mode (it's native mode, I suppose), every time I turn on the camera, I am greeted with this lovely alert that reads, "Running on NTSC." Every time. I know this seems pretty insignificant, which I will say it is compared to the inability to switch to PAL mode at all on the USA model, but this alert is surprisingly crippling and really bumped down my love for this camera (in fact it was only when finding out that the USA version doesn't allow PAL at all that I was a bit consoled).
I know this seems melodramatic but hear me out. The startup time of the camera is really quick, which is amazing (but necessary given this issue). However, that alert will sometimes take up to 8 seconds to come up and register and won't go away until you press a button. Still seems minuscule, I know, but here's the thing: when I'm trying to get a shot I see happening in the moment, by the end of that extra 8 seconds before I can take the photo, I've usually lost my window. And leaving the camera on really isn't wise either given the infamously mediocre battery life, thanks to the electronic viewfinder (but as a video/film guy, I'm not really complaining about that).
To bring all this to a close, it's a lovely camera and a lovely feature. I was really impressed upon hearing that they bumped up the resolution to 1080p for the 120fps. It looks much, much better than the previous iteration in 720p and even though that format issue is there, I really can't complain. It's still not a perfect camera, but it's really quite close. This is an incredible piece of equipment, packed with loads of practical features and really is a powerhouse for its price point and I can't stress that enough.