Author Topic: Video Clarity?  (Read 290 times)

donfarrall

  • Newbie
  • *
  • Posts: 2
    • View Profile
Video Clarity?
« on: September 27, 2017, 04:08:34 PM »
I am a commercial photographer that shoots a fair amount of high-speed stills.  I also shoot some footage both with a DSLR and with an older Panasonic video camera, an HPX300.  I have been looking at the Chronos 1.4 with interest.  I have looked at a lot of footage samples and without wishing to sound like a critic, it seems to me that almost all of the video samples are pretty soft.  Is this just the limit of the current state of technology?  I'm not sure that what I am seeing is commercially viable.  Clearly fun to watch, but as "stock footage" I don't think what I am seeing would "fly".  Again, not trying to be critical, just wanting to understand what is possible, I would appreciate any feedback.

jasonfish

  • Jr. Member
  • **
  • Posts: 52
    • View Profile
Re: Video Clarity?
« Reply #1 on: September 27, 2017, 05:47:25 PM »
It's tough to answer that question by looking at posted footage. One can't say if the focus was perfect, which is really tough to get in some scenarios (DOF can be a few mm at best), etc.

The faster frame rates do contribute to a softer look, as we're only using a section of the sensor (digital zoom bad).

In general, I'd say that yes, overall picture quality is softer than I'd like. But with perfect focus, full sensor resolution, sharp lens, and <=50% shutter, it's not terrible for the price.

ExaltedDuck

  • Newbie
  • *
  • Posts: 10
    • View Profile
Re: Video Clarity?
« Reply #2 on: September 27, 2017, 06:23:12 PM »
The biggest concern I would anticipate if you want to use the footage commercially is whether the limited resolution would be suitable.  The native max  res is 1280x1024... a 4:3 aspect ratio that will letterbox in 1080 if left pixel perfect (and scaling will decrease sharpness).  The max unscaled 16:9 res is 720p.  Played back in 720 it should look good but scaling it up to 1080 might not so much.  And there is unfortunately no 540 vertical resolution which might gracefully scale to 1080 (2x2 pixels)

Other than that, some of it may be equipment configuration.  Most of us will run the recommended 12.5-75mm lens and its at its fully open stop.  Many reviews I've seen for that lens suggest this can both wash out colors and soften edges in the images.  Stopping down can help but might require increased gain which could add noise.  If you shop around, there are some very interesting c-mount lenses that were designed for 16mm film that can suit this camera quite well.  The sensor is only about 11mm in diagonal so the captured frame will be slightly cropped/zoomed (whichever way you prefer to think of it) and you'll get about a third to a half less light than you might expect at a given stop (but with all the bokeh of the selected stop).  micro 4/3 and aps-c lenses might be options with speed boosters and mount adapters but getting those adapters costs as much as - if not more than - some of the very interesting c-mount lenses.  But if you already have good lenses for other systems, it can be a very economical way to go. 

I've heard some of the other kickstarters bought the camera to rent it out.  It might be worth getting your hands on one and seeing what you can get out of it.
« Last Edit: September 27, 2017, 11:36:23 PM by ExaltedDuck »

donfarrall

  • Newbie
  • *
  • Posts: 2
    • View Profile
Re: Video Clarity?
« Reply #3 on: September 27, 2017, 09:24:47 PM »
Thanks for the quick responses; very helpful.  Yes, it would be much better if it produced an uninterpolated 1080p.  For some things 720p might be okay.  We are at the point where there are some digital still cameras that will shoot 120 fps at 1080p.  This isn't fast (slow) enough for my needs, but just a few years ago you were lucky to be able to get 1080p at 60 fps.  I think there are a few 240 at 720p options out there as well.  light level and depth of field shouldn't be a problem for me I have a studio full of lighting equipment, but if the images aren't pretty sharp, at least in the non moving portions of the image, I don't think they will be accepted for commercial use.  I know that the Phantom cameras are sharp at high frame rates, and I know that they cost more than a premium sports car.  I could afford to pay more than the price of a Chronos, if I can sell the footage, but the price jump between the Chronos and a Phantom is so extreme.  I think there might be a market for a 1080p 1000fps camera with good sharpness and fidelity in the sub $10,000 price range, but I haven't found one yet.  Maybe the next Chronos version.

nik282000

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Video Clarity?
« Reply #4 on: September 28, 2017, 07:58:07 PM »
When ever possible I have been using full frame Minolta lenses on my Chronos and it is capable of taking very sharp footage with smaller apertures (f/4-ish) at the 1500fps/720p resolution. None of the c-mount lenses I have tested are very sharp, everything from brand new eBay to 1960s, are pretty soft at all apertures. The problem is getting one or more kW of light on to your subject without cooking it or blowing breakers.

Dan Kanes

  • Newbie
  • *
  • Posts: 3
    • View Profile
Re: Video Clarity?
« Reply #5 on: September 29, 2017, 03:02:07 PM »
To add to the above discussion - lighting plays a critical role in getting something that has perceived sharpness.

Furthermore, once CinemaDNG raw frame sequences are available we should have more end user control over color correction, noise reduction, and encode using software like Davinci Resolve - which is free in its most basic version.

When DNG sequences are available I'll do a tutorial on my approach to lighting and color correction with the camera. It's an amazing camera, but you have to "know the ropes" as it is certainly very different than shooting high speed stills, or normal motion for instance.

David could probably add to this discussion - but there are several "blocks" to a system like this camera:

1. Sensor
2. Capture buffer (raw image sequence in temporary ram)
3. Recording - output - Encoder or image file "saver" - encoding can have an effect on image quality, perceived detail, color detail etc. Currently using a good quality H.264 encoder.

Personally, I'd be excited for all intra frame h.264 encoding with very high bit rate in addition to Cinema DNG raw sequences if it's possible.

I think when we have HDMI out working there will be a lot more footage captured in focus too as it will be easier to see on a large, sharp 1080P monitor for critical focus adjustment. Peaking which already exists in camera can help nail focus too.


Martin

  • Newbie
  • *
  • Posts: 8
    • View Profile
Re: Video Clarity?
« Reply #6 on: September 30, 2017, 03:22:48 AM »
When ever possible I have been using full frame Minolta lenses on my Chronos and it is capable of taking very sharp footage with smaller apertures (f/4-ish) at the 1500fps/720p resolution. None of the c-mount lenses I have tested are very sharp, everything from brand new eBay to 1960s, are pretty soft at all apertures. The problem is getting one or more kW of light on to your subject without cooking it or blowing breakers.

^^ This!!

There "might" be very good c/cs mount lenses out there, but I'm afraid they are either pricy and/or rather bulky/long..

I have a selection of manual focus lenses here, to use on my a6000, mostly Nikon, but also bought a Fujinon-TV 1:1.4/9 with cs-mount.

Even with the dirt cheap Nikon-E 50mm 1:1.8 lens (which is quite compact) image quality, sharpness and colors, improved dramatically over the cs-mount lens...!

I use a simple mount conversion adapter like this: https://shashinki.com/shop/images/VELACNAF-01.jpg

All the best
Martin

John DeLonghi

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Video Clarity?
« Reply #7 on: September 30, 2017, 04:47:31 AM »
Lighting is definitely half the battle, which is why a histogram function would be very useful.

Back in the days of 16mm film, there were some remarkably good results to be had if you had the right combination of film stock, lens and lighting.
Top end C-mount lenses are hard to come by now and as has been said, if we're going to use what are essentially CCTV lenses wide open with not enough light, the results are not going to be great.

The #1 priority should be to get more light so at least you can stop down whatever lens you have.
If you have some SLR lenses then buy an adapter and try them, but they will also inevitably give you soft results if you don't have enough light to get them into the sweet zone.

There is quite a lot you can do to the video once you have it in an editor. Even basic editing software has color correction functionality these days.

Here'a a comparison of some original Chronos footage at 800x480 (top) which has then been color corrected and sharpened in Edius:

https://youtu.be/trwI64Uiwgs

There could also be more quality to be gained by playing around with the re-encoding and interpolation methods when converting the native resolution Chronos files to whatever final resolution you want to play it at.