4K 100Mbps vs 60Mbps

MH7 wrote on 12/28/2021, 1:48 AM

Hi guys,

I have a question that I hope some can answer. I film with a Sony FDR AX700 4K video camera. I mainly film family events, so no professional usage, although I do try to film using the usual pro filming techniques (i.e. framing, amongst other things). I have had this camera for a decent amount of time and have filmed a fair amount of family videos.

By default the camera films in 4K @ 100Mbps. However, I filmed two videos, each about a 1:00 minute each. They were exactly the same, one filmed at 4K 100Mbps and one filmed @ 4K 60Mbps. Upon observation, I found no real difference in quality. You might think that an extra 40Mbps would make quite a visual difference. But, to my eyes, I saw no real difference. Nevertheless, the videos were about 292MB in difference.

The first 1 minute video filmed in 4K @ 100Mbps had a file size of 716MB, whereas the second video filmed in 4K @ 60Mbps had a file size of 424MB. Given the results, should I continue to film in 4K @ 100Mbps or get more video per SDXC card and film @ 4K 60Mbps.

On that note, has anyone else notice any visual quality difference, regardless of your camera model, filming in 4K @ 100Mbps vs 60Mbps?

Finally, I want to say, that I have absolutely no buyers remorse at all in buying my Sony FDR AX700. It’s been a great camera and definitely films much better video quality @ 1080p than even my previous 1080p camera, the Canon Legria HF G10 (but I mostly film in 4K on my Sony for better quality video when looking back in years to come, what you might call archiving).

Thanks in advance for any help!

MH7

Comments

Dexcon wrote on 12/28/2021, 2:29 AM

I've got the FDR-AX100, the predecessor to the AX700. The AX100 originally had a max Mbps of 60 but a firmware update brought 100Mbps to the camera. Ever since, I've recorded in 4K @ 100Mbps and, yes, the file size is larger than 60Mbps and therefore the length of footage per SDXC card is less than with 60Mbps. OTOH, the cost of SDXC cards (SanDisk Extreme PRO 64GB in my case) is now significantly less than was the case when I first got the camera in 2016.

My understanding is that bigger file size of 100Mbps means that there is more 'information' per frame than would occur with the same shot using 60Mbps. The advantage is supposed to mean that images with lots of movement will fare better with 100 than 60 but there may be no appreciable difference with static shots with little of no movement.

I found on the internet a short YT demonstration between 100 and 60 shot at the seaside including a flock of seagulls flying by -

Watching this at both 1440p and 2160p on a Dell 4K color-calibrated monitor, the sharpness of the seagulls is so much better in 100Mbps. Freezing the YT playback, the birds' wings are somewhat blurred in 60Mbps but much, much better defined in 100Mbps. At 1080p, there's little difference IMO.

MH7 wrote on 12/28/2021, 2:45 AM

Hi @Dexcon,

Thanks for your help. I had a look at that video and can kind of see what you mean. I guess, in the end, I’m not going to be disappointed that I filmed in 4K @ 100Mbps, but I might be @ 60Mbps. I guess, I might use the 60Mbps option if I were in a desperate situation and cannot get to a third SDXC card (I currently have two 128GB SDXC cards in the Sony along with two other 64GB SDXC cards. I don’t usually have any lack of storage issues. So, I’ll probably stick with 100Mbps.

Dexcon wrote on 12/28/2021, 5:19 AM

I currently have two 128GB SDXC cards in the Sony

@MH7 ... I wish that the AX100 had dual memory card slots like the AX700. But I'd really like to know what happens when shooting and the first SDXC card fills up. Does the shot continue on seamlessly swapping over to the No 2 card, or does recording stop (like the AX100) with an out of space warning, and pressing record must occur again to access the No 2 card?

And what happens with the AX700's shot naming convention? In the AX100, swapping SDXC cards results in shot naming on the new card resetting to '0', so the shot names on the 2nd SDXC card have exactly the same name sequence as on the 1st SDXC card (not so with photos - the numbering sequence is sequential until reset back to zero in the camera's settings). Has the AX700 been upgraded to permit sequential video naming when changing cards?

Your advice will be most appreciated.

MH7 wrote on 12/28/2021, 6:35 AM

I currently have two 128GB SDXC cards in the Sony

@MH7 ... I wish that the AX100 had dual memory card slots like the AX700. But I'd really like to know what happens when shooting and the first SDXC card fills up. Does the shot continue on seamlessly swapping over to the No 2 card, or does recording stop (like the AX100) with an out of space warning, and pressing record must occur again to access the No 2 card?

Well, from my memory, you can do relay recording which would just seamlessly switches over to the other card, I assume, and probably sees both cards as one mass storage thingamabob (I know, very technical name, you like it? Haha). I never have actually tried it because I currently just switch over to the other card if I see the card that I’m using is getting full (i.e. low in recording time). All you do is press the button that’s above the card slots and it just quickly switches from one card to the next.

And what happens with the AX700's shot naming convention? In the AX100, swapping SDXC cards results in shot naming on the new card resetting to '0', so the shot names on the 2nd SDXC card have exactly the same name sequence as on the 1st SDXC card (not so with photos - the numbering sequence is sequential until reset back to zero in the camera's settings). Has the AX700 been upgraded to permit sequential video naming when changing cards?

To be quite honest, I haven’t noticed that. But I’ll have to take a look at get back to you.

Your advice will be most appreciated.

I have given the best info with what I know. I hope it’s helpful. One question that I have, as I’m not sure if the AX100 does this or not, but you can display a timecode (at least I think that’s what it’s called) so you can see how long your recording session is or has been. Whilst that is handy, do you know if it’s possible to setup this cameras to display the total recording time for each individual video you record (i.e. start and stop recording). Because I like to see how long my videos are recording for.

For example, on my iPhone it displays the recording time for each individual video and not the recording session (i.e. if I record a video for 10-15 minutes I am able to see that recording time. Then when I record a new video, the timecode resets on the phone and will show me how long the time is for the next video. However, unless I’m missing something, my Sony AX700 only shows the recording time in total and not the recording time for each individual video. Do you know if there is a way to see that on your camera?

The AX700 seems to use the menu of the more professional Sony video cameras vs that of the AX100. I do like it, but the timecode thing is just a bit of a nuisance. I’m sure there must be a way to fix it. I hope I have explained what I mean well enough.

FayFen wrote on 12/28/2021, 9:40 AM

If it just "family home movies" why to shoot even at 60mb and not lower. How much petabyte you have to keep them all? and 2 backups? Do you keep tagging and archive everything in a dedicated app?

I believe in keep it lean and simple.

my 2c.

Dexcon wrote on 12/29/2021, 12:39 AM

... but you can display a timecode (at least I think that’s what it’s called) so you can see how long your recording session is or has been. Whilst that is handy, do you know if it’s possible to setup this cameras to display the total recording time for each individual video you record (i.e. start and stop recording).

All I get with the AX100 is a couple of seconds display in the top RH corner of the viewfinder/monitor of the estimated amount of recording time left on the SDXC card. This display returns for a ccouple of seconds after stopping a recording. Unfortunately, there is no 'seconds elapsed' timer as occurs with your iPhone or my Samsung Galaxy.

The only way to see how much of the card has been used/not used in the AX100 is to go to Menu/Setup/Media Info where a progress bar is display along with a xx% display for 'used'.

Via the View Images button which is broken down into recording dates, an overall time is displayed for the total recording time that day - it doesn't show each shot's length. Selecting one shot has a time display, but its a progress time - I'd have to get to playback the entire shot to see the total length of that shot.

HOWEVER, I've trawled through AX100's menu settings and under Menu/Setup, scroll down to General Settings and then select Display Setting, there is an option to improve the display. Changing that setting from Auto to On resulted in the 'remaining time' for the card appearing permanently in the viewfinder/monitor as well as a 'seconds elapsed' timer appearing during recording. Yay!

Thank you @MH7 for asking the question - that's solved a problem for me. I hope that your AX700 has the same display setting option and resulting behaviour. Edit: I see that the AX700 has a much different menu to the AX100, so it might be Camera Data Display or Display Output under Display Set.

MH7 wrote on 12/31/2021, 6:18 AM

@Dexcon | I will reply to your above post ASAP, but I’m just wondering if you happen to know what are the max capacity SDXC cards that our cameras can take. Is there a limit?

Dexcon wrote on 12/31/2021, 6:53 AM

@MH7 ... the AX100's manual doesn't make it clear but Sony's Expected Recording Times pdf for the AX100 only lists cards up to a max of 64GB, so that's what I've only bought. Unfortunately, I've not got a card bigger than 64GB to test.

MH7 wrote on 12/31/2021, 7:27 AM

@MH7 ... the AX100's manual doesn't make it clear but Sony's Expected Recording Times pdf for the AX100 only lists cards up to a max of 64GB, so that's what I've only bought. Unfortunately, I've not got a card bigger than 64GB to test.

Thanks for your swift reply. When I bought my two 128GB SDXC cards I was kind of taking a risk, but that risk paid off because the AX700 does actually take 128GB SDXC cards. Phew! So, that’s why I asked. It makes me wonder, could it take even higher capacity cards, like 256GB. Who knows.