Why is my A7Sii cropping??

[RGLmotion]

Hi guys,

 

Need some tech info here....

 

Based in the UK and looking to film with my a7sii in some high frame rates to take advantage of slow motion in editing. Set to PAL as it seems to get rid of light flicker with the UK stuff over here.

 

 

So.....MP4 gives a max of 60fps which is cool but I want even slower so I've had to set to XAVC HD instead to use the 100+fps which is great.

However......I usually switch between 24mm 35mm 50mm Samyang full frame primes when filming but (on XAVC format) after i hit record it crops itself automatically, it didn't do this on MP4, so now everything looks like an 85mm lens?!

 

Basically I want to use the best codec that will give me HUGE fps for slow motion, full frame use of all my lenses and in an NTSC or PAL format that combats the UK frequency of lights etc.

 

Any helpers??

 

Appreciate it as always 

[RGLmotion]

Another thing I should add, the Samyang lenses I'm using are its range of UMC lenses that are advertised for sony Emount as full frame lenses, the new de-clicked ones.

 

Ive also tried all the shooting modes on the selection wheel, some of them don't crop and give me full view with all my lenses but these modes are the ones that give me ZERO control over settings. I always need to shoot in movie mode or manual so the fact that it doesn't crop in other modes tells me that its possible to use all my lenses un-cropped....I just need the right settings in  XAVC S HD and manual to get it.

[cws]

Hi guys,

 

Need some tech info here....

 

Based in the UK and looking to film with my a7sii in some high frame rates to take advantage of slow motion in editing. Set to PAL as it seems to get rid of light flicker with the UK stuff over here.

 

Basically I want to use the best codec that will give me HUGE fps for slow motion, full frame use of all my lenses and in an NTSC or PAL format that combats the UK frequency of lights etc.

 

Any helpers??

 

Appreciate it as always 

 

PAL is correct for the UK (same as Australia, 50Hz electricity system) so normal shooting at 25fps (1/50th sec) will eliminate most light-flicker issues (not always though... but you are limited what you can do with a non-cinematographic camera).  You could try shooting NTSC for higher frame-rate and adjust your shutter speed to try to compensate for flicker (say 1/60th)... may or may not work...  there's math involved in that and my brain doesn't like trying to figure it out anymore.

 

There's a little bit of info here (quick Dr Google search) that's relevant, but not super-techy..

http://mitchmartinez.com/a-few-notes-about-high-frame-rate-slow-motion/

 

Camera specs for the A7Sii in PAL format are:

^{IMAGE SIZE (PIXELS), PAL}

AVCHD: 1920 x 1080 (50p/28 Mbps/PS, 50i/24 Mbps/FX, 50i/17 Mbps/FH, 25p/24 Mbps/FX, 25p/17 Mbps/FH),

MP4: 1920 x 1080 (50p/28 Mbps, 25p/16 Mbps), 1280 x 720 (25p/6 Mbps),

XAVC S 4K: 3840 x 2160 (25p/100 Mbps, 25p/60 Mbps), XAVC S HD: 1920 x 1080 (50p/50 Mbps, 25p/50 Mbps, 100p/100 Mbps, 100p/60 Mbps)

Looks like the best you are going to get in high frame rate is XAVC HD 1920x1080 100p (100 progressive frames /sec) @ 100 Mbps.

 

In NTSC mode, high frame rates

^{XAVC S HD: 1920 x 1080 (60p/50 Mbps, 30p/50 Mbps, 24p/50 Mbps, 120p/100 Mbps, 120p/60 Mbps)}

so 1920x1080 @ 120p/100Mbps  is top rate.

 

In other words, at 4k the best you can expect is 30fps (in NTSC) or 25fps in PAL, drop to full HD and you get 100 or 120fps.

 

Whether the FULL HD is subsample of the entire 4K sensor, or is a crop... I can't seem to find stated on their web page.

It''ll be in a review somewhere on the interwebs.

Hope this helps.

 

 

Note:  a few more seconds searching found this... full explanation for you:

https://suggestionofmotion.com/blog/sony-a7s2-recording-modes-overview/

[Golem]

`

[cws]

If that question is to me (?).... and I have no idea why you'd be shouting...
the camera can't unload the data from the sensor fast enough to record 4k video at high frame rates, so your choice becomes limited to your shooting speed vs resolution.
Reduce the resolution (crop the sensor) and you can get higher fps.  That's a pretty common choice you deal with even in professional digital cinema cameras.
 

[RGLmotion]

Really appreciate the detailed reply!!

 

However, either I didn't ask correctly or you missed what I was asking. I know all the codecs, FPS, Mghz, NTSC, PAL options and I've also went through that article already.

 

My main issue is with the severe cropping during filming in XAVC or 4K, what I'm asking is WHY IS IT HAPPENING and is it just a simple fact of life that XAVC and 4K will be cropped? When I switch to any FPS in both XAVC or 4K it crops automatically.

 

My main goal is to film WIDE angle high FPS 1080 or 4K....main hope is wide angle....not cropped.

 

I also agree that when you do homework on the issue you can't actually find a straight answer

[cws]

Hi.

 

Can't answer with confidence specifically to the A7SII as I have an A7RII I'm getting used to, and I know there are differences between the cameras sensors.  Do you have APS-C "ON" all the time for video mode? that could account for 4K 25/30 fps apparent crop.
Most of my digital video/cinematography experience over the last 10-15 years is with RED or video cameras, so still finding my way around the vagueries and limitations of these hybrid stills jobs but a lot of the basics are the same, and I find trawling (not trolling) forums like this is invaluable for picking up hints... so I try to pay back where I think I can be helpful.
 

Seems to be some reasonable info on the actual crop mode v frame rates in this review https://www.cinema5d.com/sony-a7s-ii-vs-a7r-ii-test-which-one/

"In theory:
The cameras share a lot of similar specs in video mode, like the 100Mbps XAVC-S codec, 4K (UHD) internal recording, but the recording and crop modes differ as follows:
The Sony a7S II records:

• 4K Full Frame: up to 30 fps
• HD 1.6 crop: up to 60fps
• HD 2.2 crop: up to 120fps

The Sony a7R II records:

• 4K Full Frame & 1.6 crop: up to 30 fps
• HD Full Frame & 1.6 crop: up to 60 fps
• 720p: up to 120fps"

So, you need to take into consideration the crop factor when considering lens choice.  A 16mm FF wide angle lens will give you a field of view angle of 25.6mm as soon as you are in a 1.6 crop configuration (up to 60fps HD), or will be roughly equivalent to a 35mm at 2.2 crop factor up to 120fps HD mode.
If you already get this, then I will admit to not understanding what info you are looking for.

Best of luck either way finding a solution.

cheers

[RGLmotion]

I was literally about to type this before you even replied! Thanks again for the details.

 

By the looks of things I'll need to stock up with 10mm-18mm lenses if I'm going to get any kind of super slow and wide XAVC or 4K!!

 

I've tried it will every variable setting I can think of, APS-c settings included, A/P priority, M, MOVIE, auto etc. Admittedly it doesn't crop in several of the different modes but strangely it's the modes that completely lock out any control, I always need to shoot in M for adjusting.

 

However...maybe the fact it does it without cropping....but in some crap modes that film makers can't use....suggests the solution is out there?

[cws]

You can wish, but the limitations of the electronics within the camera set what can be offered by firmware upgrades.  If they've hit the wall with the amount of data they can safely get off the sensor for a given resolution/frame rate then that's it...  went through this 6-7 years ago with the early RED cameras.. it was always the "next sensor/camera upgrade" that gave what you needed at a particular time, and thats $$$$

[JustSolutions]

I know this answer is kind of late, but for everyone reading this conversation, I had the same question and found the answer.

The Sony a7sII crops your footage in case you film with XAVC HD and 120fps/HFR. Now as RGLmotion mentioned it seems like the camera doesn't crop with this settings if it is in auto or scene mode.

RGLmotion: "I've tried it will every variable setting I can think of, APS-c settings included, A/P priority, M, MOVIE, auto etc. Admittedly it doesn't crop in several of the different modes but strangely it's the modes that completely lock out any control, I always need to shoot in M for adjusting.

However...maybe the fact it does it without cropping....but in some crap modes that film makers can't use....suggests the solution is out there?"

But it only seems like that. One of the last references on this sony page (german version of sony user guide, you have to find your lown language if you need to https://helpguide.sony.net/ilc/1530/v1/de/contents/TP0001088623.html?search=XAVC%20S%20HD%20) says that the sony a7sII can not record 100p or 120p in auto or scene mode. And this is true. If you select 120fps and the switch to auto Mode it really doesnt crop anymore, but what you don't see on the first glance is that the camera also automatically reduced your framerate to 60fps (because in auto and scene mode you can't record 120fps). If you record  and check the framerate on your PC you will see.

So I don't have a solution for filming in 120fps without cropping, probably there is no solution for the sony a7sII at the time, but I have the solution why auto and scene mode "seem to not crop"

Hope this helps someone.

Greetings