new to video help please

[adwb1949]

A couple of questions her from me which I dont understand after looking and looking on google. I did find shutter speed vs shutter frame rate which made things clearer but:-

I have seen it written that if you have the camera set to auto for the aps-c / super 35 then movie mode uses super 35 but on myA7r2 that does not happen i need to select it manually am I misunderstanding something?

also for XAVCS there are the two choices of 25p 100M and 25p 60M

25 is the frame rate ? is that correct ?

and should be matched to double the shutter speed =1/100 is that correct?

100M and 60M is the bit rate and 100 M will give a smoother video is that correct?

if that is then correct then why is there a choice?

I note that on XAVC S HD there is the choice of 50p 25p and 100p all at 50M compared to the XAVCS which only offer 25p

So why is there a choice 3 frame rates avaialble for the XAVC S format?

[Jay]

Hello and yes you will need to set the Super 35mm mode manually as far as I know.

25p is the frame rate (how man frames per second), yes. 100M is the bit rate (how much data, potentially more dynamic range and color)

Shutter speed would be 2 x frame rate of 25 = 1/50sec or 1/60sec

The choice is for saving card space, lower bit rates still look really good and the files take up way less data on memory card...

Different frame rates serve as options. Slow motion can be created with 50p, and 100p. Also, 50p is better for high speed subjects if you don't want any blurring. My drone footage is filmed in 60p and it looks super smooth when panning. It's not as smooth at 25p for example.

I hope that helps??

Jay

[adwb1949]

I seem to get jerky or stuttery playback in every mode except MP4. if i use 4 k and dual record the mp4 is smooth but the 4k is very jerky no matter how slowly I pan or move.
even the auto zoom (digital zoom) is smooth on the MP4 but jerky on the 4K.
I have tried various shutter speeds from 1/50 to 1/200 but and lower as well but it seems the same. Any Ideas what I am doing wrong ?

[Jay]

Perhaps your computer can't play back the 4k video smoothly? That sounds like your trouble to me. It does not play smoothly on my computer due to the amount of data to process per second. It's to much and must be processed first in order to playback smoothly on the PC. Even on youtube it can buffer when in 4k mode depending on data rate. You basically need a super computer to playback 4k at full quality. It is really hard for me to work with and bogs my computer down so much it takes forever to process in FinalCut. I prefer shooting in the lower qualities for the most part, because the 4k is just not needed for my purposes yet, other than review footage of course...

MP4 is pre-processed video and a much smaller playable file. I don't think you are doing anything wrong!!

Jay