Hello. I'm finding my self more inclined to shoot video than stills lately, and I've been thinking about if I could get a camera with decent video capabilities, even If I have to compromise on the photography side. Underwater photography/ videography is a hobby, I don't do pay work. I live in Toronto and  I have to travel to get to the nice destinations, so size it is one of the factors that, as for many of you, will influence any future decision.

 Seems like a camera capable of record 4k 120 fps will be ideal, there are few out there that can do this, with some limitations, some will overheat, some will have a significant crop, others are very expensive, but life is a compromise.  

 I was looking at the Sony a6700, seems like a great aps-c choice, the body is small and as I understand smaller domes can be used with this sensor size and still achieve decent corner results. The Sony a-6700 has a limited flash synch speed that goes only up to 1/160s, this could be an issue while taking photos, but as per the specs, this camera seems to be a great camera. Then there is the Sony FX30, cropped sensor also, but people complain about overheating while shooting at 120fps. FX3 seems to be good, but then is the A7Siii. The more I read about these cameras the harder it gets for me to favour one of them.

 If any of you, experience video shooters, feels like sharing your thoughts on this topic I will appreciate your time and knowledge very much.

 Happy day everyone!

Edited March 25, 20241 yr by Aquatic Ape

13 minutes ago, Aquatic Ape said:

The Sony a-6700 has a limited flash synch speed that goes only up to 1/60, this could be an issue while taking photos

It's 1/160s, not 1/60s. As a long time A6300 user (same sync speed) who just upgraded to a6700, I don't find it particularly limiting. 

30 minutes ago, Barmaglot said:

It's 1/160s, not 1/60s. As a long time A6300 user (same sync speed) who just upgraded to a6700, I don't find it particularly limiting. 

 Thank you for the correction, that was a typing mistake.

FWIW, if you're worried about FX30 overheating, the a6700 is at least as susceptible to that when shooting 4k over prolonged periods, but honestly I can't imagine scenarios where you'd be shooting video for over 20 minutes straight while underwater. FX3 and A7SIII are full-frame cameras, so an entirely different price bracket. FX30 is definitely a more capable video camera than a6700, so if you're looking for a pure video device, it holds the advantage, but a6700 is an excellent hybrid choice, great at both video and stills.

 

Regarding corner quality, some years ago I did a comparative test with my a6300, 16-50mm and 10-18mm lenses, using SeaFrogs 6-inch and 8-inch ports, although the 8-inch port is more like 180mm in actual dimensions. You can see the results here: https://1drv.ms/f/s!AupWSggdlFYKjtRFu-IIxyopM8fvAA?e=oq7ekL - a6700 shouldn't be much different. As I understand it, a6700 and FX30 use the same sensor, but FX30 is purely a video camera, lacking the ability to fire strobes entirely as it has no mechanical shutter.

 

The 1/160s flash sync speed on A6xxx bodies (as well as A7C series) is not nearly as big a deal as some make it out to be. It's about half a stop worth of difference - shooting wide-angle, I'm at considerably slower shutter speed almost all the time anyway to keep background bright enough, and if I want dark background, 1/160s and f/16 at ISO 100 is plenty to make the background comfortably black. The only scenario where it really comes into play is sunballs, and even then, f/22 and full strobe power is generally quite enough.

 

Another point of note: if you want a fisheye for wide-angle, Sony has very limited native choices, and most users adapt Canon lenses (8-15mm on full-frame, 10-17mm on crop), but autofocus options with adapted Canon lenses are limited - at least with my Metabones IV adapter, its green mode works very well in stills, but does not autofocus at all in video, while advanced mode autofocuses in video, but has degraded performance in stills (tested with Canon 60mm macro and Tokina 10-17mm fisheye),

Edited March 25, 20241 yr by Barmaglot

1 hour ago, Aquatic Ape said:

Seems like a camera capable of record 4k 120 fps will be ideal, there are few out there that can do this, with some limitations, some will overheat, some will have a significant crop, others are very expensive, but life is a compromise.  

 

Out of curiosity, why do you need 120p?

 

3 hours ago, Davide DB said:

 

Out of curiosity, why do you need 120p?

 

 To slow down the footage for smother results..

4 hours ago, Barmaglot said:

FWIW, if you're worried about FX30 overheating, the a6700 is at least as susceptible to that when shooting 4k over prolonged periods, but honestly I can't imagine scenarios where you'd be shooting video for over 20 minutes straight while underwater. FX3 and A7SIII are full-frame cameras, so an entirely different price bracket. FX30 is definitely a more capable video camera than a6700, so if you're looking for a pure video device, it holds the advantage, but a6700 is an excellent hybrid choice, great at both video and stills.

 

Regarding corner quality, some years ago I did a comparative test with my a6300, 16-50mm and 10-18mm lenses, using SeaFrogs 6-inch and 8-inch ports, although the 8-inch port is more like 180mm in actual dimensions. You can see the results here: https://1drv.ms/f/s!AupWSggdlFYKjtRFu-IIxyopM8fvAA?e=oq7ekL - a6700 shouldn't be much different. As I understand it, a6700 and FX30 use the same sensor, but FX30 is purely a video camera, lacking the ability to fire strobes entirely as it has no mechanical shutter.

 

The 1/160s flash sync speed on A6xxx bodies (as well as A7C series) is not nearly as big a deal as some make it out to be. It's about half a stop worth of difference - shooting wide-angle, I'm at considerably slower shutter speed almost all the time anyway to keep background bright enough, and if I want dark background, 1/160s and f/16 at ISO 100 is plenty to make the background comfortably black. The only scenario where it really comes into play is sunballs, and even then, f/22 and full strobe power is generally quite enough.

 

Another point of note: if you want a fisheye for wide-angle, Sony has very limited native choices, and most users adapt Canon lenses (8-15mm on full-frame, 10-17mm on crop), but autofocus options with adapted Canon lenses are limited - at least with my Metabones IV adapter, its green mode works very well in stills, but does not autofocus at all in video, while advanced mode autofocuses in video, but has degraded performance in stills (tested with Canon 60mm macro and Tokina 10-17mm fisheye),

 Thank you for sharing all these info, highly appreciated. Seems like the Sony a-6700 is a good compromise for  hybrid shooting.

1 hour ago, Aquatic Ape said:

 To slow down the footage for smother results..

 

Not to discourage your intentions but 60p is more than adequate, and in the long run the slow motion gets pretty boring. At 120 fps a normal reef scene is practically frozen. 120 fps is mainly used for very fast sports shots or to create special effects in very short moments.

The smoothest movements are achieved with properly balanced, lightweight kit and the right posture in the water.

2 hours ago, Davide DB said:

 

Not to discourage your intentions but 60p is more than adequate, and in the long run the slow motion gets pretty boring. At 120 fps a normal reef scene is practically frozen. 120 fps is mainly used for very fast sports shots or to create special effects in very short moments.

The smoothest movements are achieved with properly balanced, lightweight kit and the right posture in the water.

 Thank you for sharing your knowledge Davide, I appreciate it!

Edited March 26, 20241 yr by Aquatic Ape

I'm no video specialist, but I do know it pays to read the fine print on the video specs for gotchas.  For example the A6700 will do 120p but it does this as a 1.58x crop from the sensor.  the active stabilisation mode applies a 1.13x crop when activated as it is partially a digital correction.  Also pays to check the available codecs and profiles and any limitations they may impose upon you - possibly things like processing overhead.  You normally need to dig into the specs a little more deeply to find these limitations.

 

Also if stabilisation is important to you, the in-body stabilisation of the smaller m43 sensors is generally better as the smaller sensor has less mass and is easier to stabilise as a result.  For example the GH-5 II has 6.5 stops of stabilisation.

I use an A6400 mainly for videos and I'm absolutely happy with it. It can deliver high quality results and A6700 has some considerable improvements. The 3 most important specs of the A6700 for video are i) 10-bit video, ii) sensor-based image stabilisation, iii) larger battery.

I also agree that 120 fps is overrated ( I tested few times with my GoPro12), it is useful for slowing down some fast action (predation) but for stabilising standard footage it is overkill. 60 fps is enough most of the time (I miss this in my A6400, it can only shoot 4K 30 fps)

9 hours ago, Nikolausz said:

I use an A6400 mainly for videos and I'm absolutely happy with it. It can deliver high quality results and A6700 has some considerable improvements. The 3 most important specs of the A6700 for video are i) 10-bit video, ii) sensor-based image stabilisation, iii) larger battery.

I also agree that 120 fps is overrated ( I tested few times with my GoPro12), it is useful for slowing down some fast action (predation) but for stabilising standard footage it is overkill. 60 fps is enough most of the time (I miss this in my A6400, it can only shoot 4K 30 fps)

 Thank you for your input, you guys are bringing forward very valid points, highly appreciated it.

I think the A6700 is a sweet spot for video and agree with what everyone said about 60p instead of 120.  I also would say the A7c ii has very similar video spec to the A6700 if you view it as a crop camera for video, but with the ability to shoot FF @ 30p.  This would be useful if shooting in dark environments or you just need 30p, plus gives the opportunity to shoot FF stills if you so desire.  Sony is all about the heavy crop when shooting 60p in everything but the A7IIIs or A1.  I'm not sure I would go with the A7c ii over the A6700 but something else to think about.  

THE most important factor for an underwater video camera can white balance at depth. Without this capability, you will struggle to no end with color, and even if you are able to grade footage that wasn't correctly white balanced in the camera, you will lose alot of image quality in the process. And also, the camera's ability to produce quiet results at high ISOs. I can't speak for the 6000-series APS-C Sonys, but I can confirm that the A1, A7SIII and A7IV will white balance underwater just fine. The A7IV represents huge value as a hybrid video/stills underwater camera, but the one small downside is that it crops to APS-C in 4k60p. Also, I assume the FX3 will white balance at depth, as its core capabilities are the same as the A7SIII.

Side Notes:

• The A7SIII and A7IV will fit into the Nauticam A1 housing.
• When the A7IV is in the A1 housing, you cannot change from video to photo mode, but other than that, everything works.
• The A7SIII works beautifully in the A1 housing.
   

IMHO,

If going to Sony route I would suggest an A7SIII. Still the best video centric camera from Sony and there's a huge used market so you could find a good bargain.

 

For crop sensor I would choose a Pana GH5. Still solid performer. One of the best all round video centric camera out there. If you find a GH5MKII body you get a 4K@60p 10 bit while on the original GH5 is only 8 bit.

As the A7SIII, the GH5 was a best selling camera so full of bargains on the used market.