How to understand video

[Rachael Padman]

(Similar question posted on DPR)

I have tried making a few videos of birds of prey with both the A7Riv and A9. They were good enough to persuade me that it's worth carrying on, but ""not of marketable quality"
I think I have a good grasp of stills technique (although I still have a lot still to learn), but almost no understanding of video. What is 4:4:2? Gamut? Slog2 vs Slog3?? Even more basically, how should one choose the shutter speed? What are the factors to consider. I am not looking for direct answers to these questions here, so much as pointing out the limitations to my knowledge.

So... where should one start learning? Are there recommended books (which is how old people like me like to learn), or particularly recommended web resources? Not necessarily specificially for Alpha, but if they are, so much the better. There are infinite books on digital stills photography, but most of those relating to video are (a) old, and (b) as much about financing and distributing a movie, as much as about the technical aspects.

Thanks for any guidance.

 

[garuda]

Be careful not to be intimidated by all the tech jargon. Start slow and face the unknown challenges of breaking into a new area like the rest of us looking for the light at the end of the tunnel, or so it seems sometimes.

Perhaps first pick an area of interest you would like to film. It's not necessary to master the volumes of knowledge before starting. Maybe like learning to ride a bike - while researching, get out and skin up few knees. Reading voraciously about balancing, inertia, etc. might be better learned from just riding vs reading, at least in the beginning. Then while your knees and elbows are healing, get on the internet and learn the tech stuff.

You'll likely learn more from making mistakes, so just go out filming and learn from correcting mistakes. Same road as still photography. Many of same rules in still shoots apply to video -- Thirds, composition, chopping heads/feet, leading space, etc.

Then research YouTube, articles, forums, etc. Google tech terms you don't know, but keep filming. Pretty much the same drill you did with still photography.

In video expertise, I'm still at the level of village idiot myself, so don't be embarrassed to ask questions on any forum. Good luck.

 

[tcoquelin]

One thing at a time:
4:4:2, this is a per color depth ratio.
First number is green, second is blue and red on even lines, third is blue and red on odd lines. Green is always full depth.
For a 8bits RGB image, 4:2:0 means 8 bits for green, 4 bits for red and blue on even lines, 0 bits for red and blue on odd lines. You have 12b per pixel average instead of 24b with full color encoding (4:4:4)
10bit 4:4:2 gives 10bit green, 10bit red/blue even, 5bit red/blue odd => 25 bits per pixel average (30 bits with 4:4:4)
The missing bits are computed for proper display.
This saves a lots of image/video size but can produce artifacts in some edge cases.
Don't use 4:2:0 when working with a blue or green screen for example

 

[Rachael Padman]

One thing at a time:
4:4:2, this is a per color depth ratio.
First number is green, second is blue and red on even lines, third is blue and red on odd lines. Green is always full depth.
For a 8bits RGB image, 4:2:0 means 8 bits for green, 4 bits for red and blue on even lines, 0 bits for red and blue on odd lines. You have 12b per pixel average instead of 24b with full color encoding (4:4:4)
10bit 4:4:2 gives 10bit green, 10bit red/blue even, 5bit red/blue odd => 25 bits per pixel average (30 bits with 4:4:4)
The missing bits are computed for proper display.
This saves a lots of image/video size but can produce artifacts in some edge cases.
Don't use 4:2:0 when working with a blue or green screen for example

Thanks for that. I think what I had not realised until I started searching was how hard it is to record video at the same detail as stills, and also how little it matters. So a lot of things start to make sense now...
One thing I am trying to understand is which video specifications matter - for example when comparing the A7S iii with my A7R iv. I will get there, but it's slow!

 

[Rachael Padman]

Be careful not to be intimidated by all the tech jargon. Start slow and face the unknown challenges of breaking into a new area like the rest of us looking for the light at the end of the tunnel, or so it seems sometimes.

Perhaps first pick an area of interest you would like to film. It's not necessary to master the volumes of knowledge before starting. Maybe like learning to ride a bike - while researching, get out and skin up few knees. Reading voraciously about balancing, inertia, etc. might be better learned from just riding vs reading, at least in the beginning. Then while your knees and elbows are healing, get on the internet and learn the tech stuff.

You'll likely learn more from making mistakes, so just go out filming and learn from correcting mistakes. Same road as still photography. Many of same rules in still shoots apply to video -- Thirds, composition, chopping heads/feet, leading space, etc.

Then research YouTube, articles, forums, etc. Google tech terms you don't know, but keep filming. Pretty much the same drill you did with still photography.

In video expertise, I'm still at the level of village idiot myself, so don't be embarrassed to ask questions on any forum. Good luck.

Yes, you are right, I have been intimidated. However, given the lack of a general introduction, I have done as you suggested, and gone looking for answers to specific questions. I do feel better informed. I still don'd understand why stills photographers don't worry about colour nearly as much as video photographers (as far as I can see), or why video photographers put up with such low quality picture quality compared to stills, but I guess looking at video is fundamentally different, and you don't have time to notice the defects.

 

[garuda]

... I still don't understand why stills photographers don't worry about colour nearly as much as video photographers ... or why video photographers put up with such low quality picture quality compared to stills ....

I'm not an expert so I offer only an opinion which may or may not be best answer for some tech questions, but I'll try.

Ref: photographers, often their cams are high qual and exposure can be controlled such that color needs no tweak. However in some cases highend guys or pros want max results and DO use software to perfect color, tones, FX, etc.

Ref: filmmakers, be careful telling them their footage is low-quality, especially if they're bigger than you or carry a Glock. Many hi-end guys/girls do "color grading" or play w colors to sim cinema effect, mood, or atmosphere.

Job requirements and personalities vary in both camps - still & vid. ie. some guys like are satisfied w stock models, while others prefer building fancy, exotic automobiles that average people think are too extravagant. Cam people are like that too. Some filmmakers actually intentionally soften or even blur footage for effect, and get applauded by some experts. Sometimes hard to know what's good or bad nowadays.

Keep on pedaling.

 

[garuda]

.....One thing I am trying to understand is which video specifications matter - for example when comparing the A7S iii with my A7R iv. I will get there, but it's slow!

a7Riv and a7Siii both shoot still & video, obviously. But R4 is a still camera, 7Siii is a video (movie) camera. I use my R4 for filming until Siii arrives.

 

[Rachael Padman]

a7Riv and a7Siii both shoot still & video, obviously. But R4 is a still camera, 7Siii is a video (movie) camera. I use my R4 for filming until Siii arrives.

I think I'm using my R4 for video until I know it's worthwhile worrying I can see that the S3 has better specs, but certainly don't know enough yet to know how much difference they would make to anything I might want to do.

 

[Rachael Padman]

I'm not an expert so I offer only an opinion which may or may not be best answer for some tech questions, but I'll try.

Ref: photographers, often their cams are high qual and exposure can be controlled such that color needs no tweak. However in some cases highend guys or pros want max results and DO use software to perfect color, tones, FX, etc.

Ref: filmmakers, be careful telling them their footage is low-quality, especially if they're bigger than you or carry a Glock. Many hi-end guys/girls do "color grading" or play w colors to sim cinema effect, mood, or atmosphere.

Job requirements and personalities vary in both camps - still & vid. ie. some guys like are satisfied w stock models, while others prefer building fancy, exotic automobiles that average people think are too extravagant. Cam people are like that too. Some filmmakers actually intentionally soften or even blur footage for effect, and get applauded by some experts. Sometimes hard to know what's good or bad nowadays.

Keep on pedaling.

I think my point about video quality is that stills photographers even argue about the difference between compressed and uncompressed *raw*. We would scream blue murder if you told us we could only use 2 pixels in 4, or settle for 8-bit, or mix up alternate rows of 2 pictures, or not worry about the blues. Or even settle for a sensor that was only 8MB. But I can see these have all been necessary tradeoffs to be able to save and store and edit anything at all for video. I suppose if my A9 can store 200+ frames of raw in buffer before slowing down, the day is coming when cameras will write fast enough they can shoot continuously, and then one could make video from endless stills. That *will* be interesting. But maybe I am missing the point about video raw as it stands already.

 

[garuda]

I think I'm using my R4 for video until I know it's worthwhile worrying I can see that the S3 has better specs, but certainly don't know enough yet to know how much difference they would make to anything I might want to do.

Your 9 & R4 are perfectly capable of video when starting out in video. Unless you're wealth, I'd be wary of dropping another 3.5K on an a7Siii as a beginner to video. I'd first get good at vid w 9 or r4, then consider Siii. Just my friendly opinion.

 

[Rachael Padman]

Your 9 & R4 are perfectly capable of video when starting out in video. Unless you're wealth, I'd be wary of dropping another 3.5K on an a7Siii as a beginner to video. I'd first get good at vid w 9 or r4, then consider Siii. Just my friendly opinion.

yes, exactly what I was trying to say I really can't imagine myself at this point doing that much video, but I did want to have the option, which requires at least a little understanding along with the equipment. Hopefully I'll get a chance tomorrow. Of course, part of me wants to own any wonderful bit of kit, but as you say, Sony FF bodies are not cheap.