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mnewxcv

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Posts posted by mnewxcv


  1. 1 hour ago, KnightsFan said:

    @mnewxcv

    Sensors usually have a number of different readout modes with different resolutions, noise levels, and RS values. Samsung might be using a different readout method for HD on the NX1 and the NX500. 120fps  requires a readout under 8.333ms, and Samsung might have just made all HD framerates on the NX1 use that same 7.9ms mode, for whatever reason. The NX500 can't do 120, so there's no reason to use that readout mode at all.

    BUT...

    Tbh I am not sure whether the DVXuser test measured the NX1 HD in all frame rates. We'd have to dig through the thread to find out. It's possible that the NX1 has 7.9ms in 1080p120, and 20ms in 1080p30.

    Good point. Why is 8.33ms the magic number and not 16.66? Unless I'm doing my math wrong. 

     

    Edit: and wouldn't you know I did my math wrong. 8.33ms it is 😁


  2. 42 minutes ago, KnightsFan said:

    I haven't seen anything specifically about rolling shutter on the NX500. So take this with a grain of salt...

    The NX500 4K is a 1:1 crop, unlike the NX1's full pixel readout. Rolling shutter is likely proportional to the crop size, since it's the same sensor. That would estimate to be ~19.3ms for UHD. (NX1 reads 3650 vertical lines in 32.6ms, NX500 reads 2160 vertical lines. 2160/3650 * 32.6 = 19.3).

    user Otto K on another forum posted the following:

     

    Quote

    In light of recent popularity of talking about the rolling shutter, I did some measurements on my NX500 (crude measurements, FWIW)

    1080p30 20ms

    1080p60 20ms

    [email protected] 17ms

    [email protected] 20ms

    [email protected] - hacked to [email protected] 8ms

    Still capture 33ms

    Two interesting things are that next frame in [email protected] begins before the previous one ends and very fast 2.5k (suggests line skipping or similar).

    I'm heavily modifying my camera so I'm interested in what others can find out

    so it would seem you were pretty much on the money with your estimate. That is the only info I have been able to find on nx500 rolling shutter, though interesting that the 2.5k is so low, and also that the 1080p is significantly worse than the nx1 (7.9ms according to this thread: http://www.dvxuser.com/V6/showthread.php?303559-Measuring-rolling-shutter-put-a-number-on-this-issue! )


  3. I remember reading that the 4K of the NX500 had superior rolling shutter to the NX1, and I believe to other cameras as well. I cannot find a thread or the source of this information though. Can anyone cite a scientific source (controlled test on a camera site) that reveals this? I know the 1080p and 2.5k footage is marginally worse than the NX1 1080p. 


  4. 1 hour ago, Erik R.s.P said:

    Andrew, do you think this guide is pertinent to a nx500 user?

    the guide really focuses on GammaDR settings, including a lut to convert out of camera footage to something more gradeable. The NX500 does not shoot GammaDR. Still some valuable info, but it is catered to the NX1. Andrew can correct me if I'm wrong.

     

     

    OP, I want to say I have seen the green tint issue posted before, but I may be thinking of solid green frames in footage. I have definitely heard of the NX1 doing weird things occasionally. I've had about 4 NX1s and 4 NX500s in the past 5 years and have never come across it. 


  5. On 4/8/2019 at 3:33 PM, musaire said:

    Hi everyone! I am still using NX1 as well. :)

    Jitter and turning green?

    I have experienced both. When filming in nature I started noticing that when turning the camera towards greenery, the pic got more magenta-ish when WB was locked. Opposite happens too. This made me realize Samsung had all figured out correctly; if we lock the color on the Kelvin blue-yellow axis, it can still freely move on the tint axis. So it is not completely locked, obviously. The Kelvin is locked, tint is automatic. Very logical of Samsung 😄 😄 .  All color is locked when all axes are locked in custom color or presets.

    Jitter. I had always jitter when editing the H265 footage directly in Sony Vegas Pro, and the jitter even did remain on YouTube. With every camera setting and render settings I used.
    The jitter went away once I started to use RockyMountains Movie Converter and edited with anything but H265. I am still wondering what is the reason, but probably it has something to do with H265 and how players and NLEs handle it.

    you are the first person I heard mentioning setting tint/blue-yellow for color temp to avoid white balance shift. Very valuable post for those who have stated white balance shift occurs when set to a K value. Will surely be doing this.


  6. 9 hours ago, Giuseppe Porciani said:

    Hi,

    I found this forum looking for some way to synchronize a set of 4 samsung nx500 to take panopictures.

    I am totally incompetent in electronics.

    I found a samsung NX500 mod here: https://github.com/ottokiksmaler/nx500_nx1_modding

    which enables the camera to use fully electronic shutter.

    I was wondering if someone has ever tried to synchronise these cameras to shoot simultaneously (1ms accuracy) with some sorts of cable and/or firmware/software mod, something like SDM does for Canon cameras  which unfortunately do not have electronic shutter.

    Such a mod would be useful not only for 360 degree pictures but also for stereophotography.

     

    Any help and hints would be much useful.

    Thank you.

    Regards,

    Giuseppe

    .

     

    I don't know for sure, but I would think you could get a remote shutter compatible with the nx500 and then use 3 of these, and plugging into the 4 cameras. 


  7. using a samsung nx1 with the 16-50s lens. As for shooting in public, I would be very cautious and mainly shoot on roads without much traffic. Mostly looking for cinematic shots of vehicle passing other vehicles, coming around sweeping turns, etc. Back road stuff. I know if plenty of roads that are safe for this. The main reason I want to go gimbal is to be able to add a little motion to the shot with pan and tilt. I've also considered shooting 15fps and converting to 24 to make things appear faster.


  8. 1 hour ago, Grimor said:

    I found a second hand Camtree G51 for 80 euros and really happy with it.

    Not professional, but good enought for a dslr

    I do like the camtree g51. I will keep an eye out on ebay for one.

    1 hour ago, BTM_Pix said:

    We had a thread about this that didn't get much action but I put a link in it to a UK company that does a large array of affordable mounts for car shoots.

     

    Not much action indeed. At least for me, I am looking to do something to track 'high speed' action, at least road speed. I am unsure as of now how my gimbal will keep up with the vibrations and shocks, but here is a basic design I came up with. It involves a simple bike carrier which holds the gimbal in place, and some off the shelf hardware to mount it to the front as well.

     

    2087575073_Rxwithgimbal.thumb.jpg.633f8e75dd6e54f84a367699509c6bab.jpg


  9. Has anyone ever made a rig for a car to film either in front of/behind the vehicle, or the occupants/interior? I am planning to build some sort of rig that attaches to my vehicle to work with a gimbal to film vehicles in motion. If anyone has ever done anything like this, please post of some photos!


  10. 9 minutes ago, CyclingBen said:

    I’m not using the shutter priority mode, sorry that was possibly confusing. The S or Samsung special mode on the dial, it has a whole bunch of speciality shot options like the light trace and the baseball swing detection.

     

    ah that mode, gotcha. Will give it a try sometime for night photography. 


  11. 23 minutes ago, KnightsFan said:

    Nice, so ISO is consistent so any improvements in DR are from the boost itself. I guessed aperture because I can see some difference in sharpness, especially in the light in the background.

    However, one thing I notice now is that there is a bright column in the background on the right that is only visible in one shot, and in the same way there is more pure white in the lamp. Since a Histogram totals a constant value, then adding white will necessarily change all the other bars as well. So I'm focusing more on the waveform.

    It certainly appears that the lamp's patch raises a little bit farther past 100, which is interesting. Also it's got those noisy tendrils shooting way up to 110 almost. I wonder if it's possible that since the lamp is in sharper focus, the NX1's sharpening kicks in and adds some more local contrast to the lamp, sending a few pixels higher into superwhite? I mean it's not like the camera is actually resolving detail brighter than the center of the lamp. Though of course that doesn't explain the patch overall being taller, just the noise up to 110. Out of curiosity, are you using 0-255 of 16-235 here?

    16-235. I just tried 0-255 as well in some random tests as well as messing with master black. The rabbit hole is getting deeper. You know how we said if you go negative on the RGB values it starts to clip highlights? Well that's true and it isn't. For instance, if you shoot at .50RGB, highlights clip at about 92 IRE. But if you expose to have your highlights under 92IRE, they don't clip. So my idea of shooting <1.00RGB values and raising in post could possibly be done. It seems the lower you go the less DR you get at a certain point, but I think .50 is still roughly the same number of stops. Also I did a shot of the bulb at 0.05RGB and the bulb had nice exposure, though everything else in the shot was black at base ISO. As we know boosting ISO would be useless since at that low of a rgb value the IRE cap would be very low as well. Taking the same shot with RGB boost at base ISO, image is still under exposed, but it can come up somewhat (there are limits obviously, I was shooting 1/4000 and base ISO to expose bulb, the rest of the footage was uselss, but there was some info there). However, the difference between -15 and +15 master pedestal was obvious when doing this extreme test. Lifting the shadows on the -15 MP shot, colors on the color checker were distorted and wrong. While MP +15 lacked contrast and DR, the colors were present and much more accurate. 


  12. 19 minutes ago, KnightsFan said:

    Ah, I see what you mean now. But could that be from changing light? I think that spike at the top end of the histogram is the color patch, and everything above that is the reflective bits of the the color chart borders. Looking at the waveform, on the top image there is nothing above the rightmost color patch, whereas on the second image there is some vague noise much higher on the waveform than the rightmost patch.

    I would say that is evidence of more detail in the highlights. The white on the color checker is supposed to be the brightest thing in your shot, but when using 1.99 it seems to pick up possible reflections from the light on the plastic casing of the color checker which since they are more reflective than the white show up. I believe this information is normally lost in the curve, but consists of especially bright highlights. Here is another example (this time I got the exposure right on both). You can clearly see the histogram extends further into the highlights and with a more gradual curve (almost linear at the end) and on the waveform you can see on the first clip IRE reaches maybe 102/103, while on the second clip it is probably closer to 107-108 where the light bulb is.You can also see the opposite happening in the shadows, especially on the histogram. The middle of the shot is very similar, but the ends show the biggest difference. So it shows that that info up above 103 IRE just was not present in the other footage. It is new information in the video. 

    2019-02-26 (4).png

    2019-02-26 (5).png


  13. 2 minutes ago, KnightsFan said:

    Does one image have some motion blur? The word x-rite is much sharper in the bottom image. It looks to me as though the lighting changes a little bit, too. The balance of brightness on the bottom right frame of the color checker vs. the center hinge changes considerably between the images.

    But it seems clear from the waveform that patches of every brightness are reduced in value by what appears to be a common factor. The apparent bump in shadows on the histogram I think is due to the lower bound changing from -.081 to -.131 (at least, that's what I assume those numbers are)

    not really sure. No motion blur but perhaps something moved a little (I rest my grey card on the color checker between shots to set exposure). It may be 1/3 of a stop difference though looking at it. In terms of the histrogram though, I'm more referring to the fact that the top highlight roll off is basically a round curve, while the second one (1.99) starts dropping and halfway juts out and is more of a line than a curve.


  14. 18 minutes ago, KnightsFan said:

    How are you judging highlight and shadow info from the histogram?

     

    based on how much info there is (intensity on histogram) and the curve from mids to high or low with saturation turned to 0. Shown below is 1.00 vs 1.99. Look at the curve blending mids with highs and lows. A question in my mind right now is is there any benefit to shooting 0.85, exposed for highlights so theyre not blown out, and lifting in post to reveal hidden shadow info, or is there any benefit to shooting 1.99, exposing for shadows, and dropping in post to reveal highlight info. Perhaps it's just a wash. 

    2019-02-26 (2).png

    2019-02-26 (3).png


  15. Using the histogram in premiere shows more info in the highlights when boosting and more info in the shadows when going 0.85 (what I consider the lowest without going below 100IRE). I also looked at the different gammas and see gamma C carries a lot if information in the mid range. I've never shot anything in GammaC but  may have to try and see how it comes out. \

    I'm thinking when in a situation where you cannot avoid highlights being blown out, it may be worth going to 0.85 and getting more shadow detail since the highlights are lost anyway. This doesn't apply to gradual highlights like skies, but rather like an indoor shot with a blown out window where it wouldn't make sense to expose for highlights. 

     

    I think in this case the color checker is a limited resource. I will fill in as the subject for the next tests to see how real world situations are affected. Good stuff so far.

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